COSMOLOGY

COSMOLOGY

AN INTRODUCTION TO THE PHILOSOPHY OF

MATTER

BY THE

REV. JOHN O'NEILL, D.Pn.

PROFESSOR OF SPECIAL METAPHYSICS, ST. PATRICK'S COLLEGE, MAYNOOTH

VOLUME I.
THE GREEKS AND THE ARISTOTELIAN SCHOOLMEN

\'

LONGMANS, GREEN AND CO.

39 PATERNOSTER ROW, LONDON, E.G. 4

NEW YORK, TORONTO

BOMBAY, CALCUTTA AND MADRAS

1923

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imprimatur :

WESTMONASTERII,

Die ii Oct , 192 v

C. SCHUT, S.T.D.,

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EDM. CAN. SURMONT,

Vicarius Generalis.

Made in Great Britain

He who believes Aristotle to be a god ou'*ht to believe that he never made a
mistake. But, whoever thinks him to have been a man must admit that he was
as liable to make mistakes as the rest of us. ALBERT THE GREAT.

Unless a man holds truth dearer than friends, he will be ready to pronounce
false judgments and to bear false witness for the >-ake of his friends. But that is
immoral. All men ought to hold truth dearer than friends because all men
have the use of reason. But this duty is particularly binding on philosophers
because they profess to teach wisdom, and wisdom is nothing else than the
knowledge of truth. . . . Truth is, indeed, divine for it is found fundamentally
and primarily in God. That is why Aristotle insists on the sacredness of the
duty of holding truth dearer than friends. . . . Plato is of the same mind. For,
once when setting aside a theory of his master, Socrates, he declares that truth
must be our supreme concern. And elsewhere, he declares : Socrates is, indeed,
a friend of mine, but truth is a greater friend. And in a third text, he de
clares that one may make little of Socrates, but one must make much of truth.

ST. THOMAS.

PEEFACE.

THE present volume is an attempt to prepare the ground for
a convincing exposition of the strong points of Scholastic
Cosmology. The main difference between it and most con
temporary treatises on the same topic is a more generous
usage of the historic method in the treatment of metaphysical
problems: a revival, as the Introduction points out, of the
precept and practice of Aristotle and St. Thomas.

The introductory chapter deals with four preliminary
topics : the origin in ancient Greece of Science and Philo
sophy — as synonyms; the emergence in late sixteenth
century Europe of Natural Science and Cosmology — as irre
concilable rivals; the subsequent rectification of frontiers,
and the resulting chasm nowadays between the ideals of the
natural scientist and the cosmologist ; the importance attri
buted by St. Thomas to Cosmology as a basis of Rational
Theism. This Introduction is followed by four chapters on
Greek Cosmology which explain the rise and the development
of Aristotle's Cosmology. The next five chapters are devoted
to an exposition of the complex speculative system reared on
that Cosmology by the medieval Schoolmen under the leader
ship of St. Thomas, Scotus, and Suarez. A final chapter
tells how this Cosmology was driven from the universities of
Europe by the gibes of the Humanists, by anti-Aristotelian
discoveries in Natural Science, and — above all — by the break
of decadent Schoolmen with the best traditions of their
forbears.

A second volume will be published to prove that the re
sumption, since the Leonine revival, of the older traditions
of Aristotelian Scholasticism has resulted in a Scholastic Cos
mology which is more in accordance with the assured results
of modern science and modern philosophy than any of its
contemporary rivals.

JOHN O'NEILL.

MAYNOOTH, October, 1923.

CONTENTS OF THE FIEST VOLUME.

INTRODUCTION.

The Creation of Rational Science, p. 2 ; The Originality of Greek Rationalism,

L7 ; The Religion of Rationalism, p. 10 ; Rationalism in Revealed
ligion, p. 11 ; Aristotle's Division of Speculative Philosophy or Science,
p. 15 ; The Physics of Aristotle, p. 16 ; The Revolt against Aristotelianism,
p. 18 ; Physical Science and Modern Philosophy, p. 20 ; The Evolution of
Modern Physics, p. 22 ; Theoretical Physics and Abstract Mechanics,
p. 24 ; The Practical Interest of Physical Science, p. 26 ; The Manufacture
and Diffusion of Irrational Science, p. 29; The Purpose of Modern
Cosmology, p. 35 ; The Utility of Cosmology, p. 39 ; Method in Cosmology,

p. 41 ... Pages 1-45

Notes „ 275-277

CHAPTER I.

PRE- ARISTOTELIAN THEOEIES OF MATTER.

The Milesians, p. 46 ; The Pythagoreans, p. 48 ; Heracleitus, p. 51 ; The
Eleatics, p. 56 ; Empedocles, p. 59 ; Anaxagoras, p. 61 ; The Atomists,

p. 63 ; Plato, p. 66 Pages 46-70

Notes . . ... . . . . . . „ 277-278

CHAPTER II.
ARISTOTLE'S CRITICISM OP THE COSMOLOGY OF HIS PREDECESSORS.

Aristotle on the Milesians, p. 71 ; Aristotle on the Pythagoreans, p. 72;

Aristotle on Heracleitus, p. 73 ; Aristotle on the Eleatics, p. 74 ; Aristotle

on Empedocles, p. 76 ; Aristotle on Anaxagoras, p. 77 ; Aristotle on the

Atomists, p. 77 ; Aristotle on Plato, p. 83 . . . . Pages 71-84

Notes . . . . . „ 278-279

CHAPTER III.
PERTINENT ARISTOTELIAN VIEWS IN NATURAL SCIENCE.

Aristotle's Theory of Scientific Proof, p. 85; The Terrestrial and Celestial

Universe, p. '89; The Structure of the Heavens, p. 91 ; Interaction of

Terrestrial and Celestial Bodies, p. 94 ; The Shape of the Universe, p. 95 ;

The Universe as a Whole, p. 95 . . . . . Pages 85-97

Notes 279-280

x CONTENTS

CHAPTER IV.

ARISTOTLE'S THEORY OF THE ULTIMATE CONSTITUENTS OF MATTER :
HYLEMORPHISM.

Proof of the Possibility of Change, p. 98 ; Facts and Factors of Accidental
Change, p. 103 ; Facts and Factors of Substantial Change, p. 104 ; Primor
dial Matter, p. 106 ; Substantial Form, p. 109 ; Substance and Attribute,
p. 115 ; Post- Aristotelian Greek Theories of Matter, p. 117 Pages 98-118
Notes ., 280-285

CHAPTER V.

THE ARISTOTELIAN SCHOOLMEN ON THE HYLEMORPHISM OF MATTER.

The Proofs of Hylemorphism, p. 121 ; Primordial Matter— What It is Not,
p. 123 ; Primordial Matter— What It Is, p. 124 ; Origin and Unity of
Primordial Matter, p. 127 ; A War of Words, p. 128 ; The Distinct Existence
of Primordial Matter, p. 129 ; The Possibility of Accidents in Primordial
Matter, p. 131 ; The Nature of Substantial Form, p. 141 ; The Unicity of
Substantial Form in Non-living Bodies, p. 142 ; The Simplicity of the
Substantial Forms of Non-living Bodies, p. 145 ; The Origin of Substantial
Form, p. 146 ......... Pages 119-154

Notes „ 285-2S&

CHAPTER VI.
A MEDIEVAL METAPHYSICAL AUDIT OF THE INANIMATE INDIVIDUAL.

Primordial Matter and the Essence, p. 155 ; The Problem of Union, p. 157 ;
The Problem of Totality, p. 158 ; Essence and Existence, p. 159 ; The
Principle of Individuation in Material Substances, p. 162 ; Essence and
Subsistence, p. 166 ; The Distinction between Substance and Material
Accidents, p. 168 ; The Origin of Accidents, p. 173 ; The Existence of the
Accident, p. 175 ; The Individuation of the Accident, p. 177 ; The Intro
duction of Physical Intrinsic Modes, p. 178 . . . Pages 155-182
Notes 289-292

CHAPTER VII.
THE ARISTOTELIAN SCHOOLMEN ON QUANTITY.

Medieval Presuppositions, p. 184 ; The Essence of Quantity, p. 18G ; The
Secondary Effects of Quantity, p. 191 ; The Endless Divisibility of Con-
tinua, p. 193 ; The Manner of Existence of Parts within a Continuum,
p. 196 ; Indivisibles as Links and Limits in a Continuum, p. 199

Pages 183-201
Notes • . 292-293*

CHAPTER VIII.

THE ARISTOTELIAN SCHOOLMEN ON THE QUALITIES OF MATTER.

Astronomy and Alchemy, p. 203 ; The Medieval Distinction between Primary
and Secondary Qualities, p. 205 ; The Medieval Theory of Sense-perception,
p. 206 ; The Democritean Theory of the Proper Sensibles, p. 211 ; Light
and Brightness, p. 217 ; Gravity and Levity, p. 220 ; Density and Rarity,
p. 220 ; Artificial Form and Figure, p. 223 ; Virtual or Occult Qualities,
p. 223 ; Impetus, p. 225 ; The Intensification and Remission of Material

CONTENTS xi

Qualities, p. 227 ; The Fact of Finite Activity, p. 229 ; The Active Qualities
of Matter, p. 229 ; Transeunt Causality a Making not a Migration of
Realities, p. 230 ; The History of a Phrase, p. 233 ; Contact as a Condition
of Action, p. 236 ; Unlikeness as a Condition of Action, p. 238

Pages 202-239
Notes 293-299

CHAPTER IX.

THE ARISTOTELIAN SCHOOLMEN ON THE MEANING AND CONDITIONS
OF MOTION IN MATTER.

The Ambiguity of the Medieval Term, Motion, p. 240 ; The Transcendental
Meaning of Potency and of Actuality, p. 241 ; The Medieval Definition of
Physical Motion, p. 243 ; The Motion of Generation or Corruption, p. 24-4 ;
The Motion of Augmentation or Diminution, p. 245 ; The Motion of
Alteration, p. 246 ; Local Motion, p. 246 ; The Distinction between the
Mover and the Moved, p. 249 ; Physical Terrestrial Motion and the
Heavenly Bodies, p. 256 ; Physical Motion and the Infinite, p. 262

Pages 240-262
Notes 299-301

CHAPTER X.
THE ECLIPSE OF ARISTOTELIAN COSMOLOOY.

'The Gibes of the Humanists, p. 264 ; The Retort of Vasquez, p. 266 ; Anti-
Aristotelian Discoveries in Empirical Science, p. 268 ; A Break with the
Tradition of Aristotelian Scholasticism, p. 269 ; The Leonine Revival of

Aristotelian Scholasticism, p. 273 Pages 263-273

Notes . ' . . .. . Page 302

INDEX Page 303

INTRODUCTION.

THE purpose of an Introduction is to put before the beginner a
correct preliminary notion of the scope and utility of the informa
tion to which his attention is invited. That task is exceptionally
difficult in Cosmology. Cosmology is denned as the philosophy
of matter. Philosophy is defined as a rationalistic search after
ultimate truth. But the beginner whose education has been
conducted in accordance with century-old traditions of English-
speaking peoples has been taught, in nine cases out of ten, to
believe that all the truth worth knowing about matter and its
properties is expounded in the various branches of physical
science. For him and for his teachers, there seems to be no room
in modern times for a philosophy of matter. He and they are
naturally slow to admit that there is anything they do not
understand in words and ideas which are constantly being used
about matter and its properties not only in the textbooks of
physical science but also in everyday thought and language.
Hence, when the cosmologist begins to ask troublesome questions
about the meaning and validity of these common and familiar
notions, ordinary practical men, and even many intelligent
English-speaking students of modern physics, are apt to complain
that he is wasting his own and everybody's time by raising idle
and uncalled-for difficulties about the self-evident. The full
vindication of Cosmology from this charge of futility can be
furnished only by such a critical examination of the actual
problems investigated by the cosmologist as can be attempted
in a complete treatise. However, I am publishing at the moment
only that part of Cosmology which deals with Greek and Medieval
speculation. Now, no one doubted the value of Cosmology
during the centuries covered by that period of human thought.
Moreover, these ancient cosmologists accepted in physical science
facts and theories which have been proven utterly misleading.
Indeed, these mistakes of the ancients in physical science is —
though our beginner may not be aware of the fact — the root of
his prejudice about the possibility of a philosophy of matter.
That is why I see no way of inclining this English-speaking
beginner to give an impartial hearing to the succeeding chapters
except by reminding him, at the start, of a few facts about the
origin and the historical development of science and philosophy.
This project has resulted in an Introduction that certainly runs
to an unusual length and apparently includes not a few irrele-
vancies. Starting from Greek superstition in the Stone Age for

1

2 COSMOLOGY

the purpose of arriving at contemporary ideals about the con
nexion between the science and the philosophy of matter, I have
wandered from topic to topic in a fashion that must seem
explicable only by sheer crookedness of mind. I am hopeful,
however, that the reader shall discover, long before he comes to
the end of the chapter, a thread of method running through the
maze. I am hopeful, also, that he shall appreciate the need of
copious quotations on certain topics. I could, of course, have
summarised these authorities. But the points at issue refer to
branches of knowledge distinct from philosophy. And on that
account, I thought it advisable to quote the actual arguments
employed by specialists in these sciences.

THE CREATION OF RATIONAL SCIENCE.

The Greeks of the sixth century before Christ were the product
of a long series of conquests and of colonisations.!1) Those in
the motherland were a blend of Northern or Centro-European
invaders with the aborigines of the Greek peninsula : in the third
millenium, the first Greeks descended from the Balkan peninsula
and conquered these aborigines, imposing on them the Greek
language but fusing with them in race and religion ; about the
sixteenth century, the Cretans settled on a few coastal spots in
Greece, bringing with them a civilisation as ancient and as
advanced as that of Babylonia or of Egypt ; about the thir
teenth century, the Achaeans came and conquered but adopted,
in the various parts of Greece, the civilisations of the conquered
peoples ; at the end of the twelfth century, the Dorians descended
on the peninsula and destroyed, wherever they penetrated, the
already existing civilisations. The coming of these Dorians
synchronised with the beginnings of Greek colonisation ; Aeolis
was founded in the twelfth century ; Ionia, Cyprus, and Doris
in the eleventh. And between the eighth and sixth centuries
Greek colonisation was completed elsewhere : colonies being
planted on the shores of Thrace and the Black Sea, in Italy and
Sicily, and even in Spain and Gaul. Thus, by the sixth century
B.C., the Greek race had acquired not only its definite instincts
and bias but also its widest expansion.

The practical and intellectual ideas of these pre-scientific
Greeks in art and literature as well as in life and religion were
based on a singularly manifold series of strange myths and
stranger rites. (2) There was, despite certain local and unim
portant differences, a common and uniform system of mythology
and ritual throughout the mother-land and 'its colonies. Even
the most civilised parts of Greece of that date tolerated and
welcomed all the myths and all the rites of the Greek pantheon.
That pantheon ruled princes and people, thinkers and poets,
city-states and tribal communities. It was the main factor in
the work and play, the hopes and fears, the affections and
antipathies, of all Greeks. At this stage of their civilisation, the

THE CREATION OF SCIENCE 3

Greeks had not realised the existence of the laws of nature :
unless, indeed, their worship of the Fates as sometimes controlling
facts independently of Zeus be construed as a faint adumbration
of some inevitable sequences in nature. At this stage, the
Greeks made no attempt to shape their conduct according to
fixed principles of right and wrong : their morality was not yet
rooted in the conscious exercise of reason, except in so far as rare
advances in the received ancestral code might be construed as a
sign of the trend of their ethics towards humanitarianism. Their
practice and their theory in every department were guided by
folk-legends, temple-legends, poet-legends. Their outlook on
nature and on man was governed by fanciful and trivial inter
pretations of natural events as brought about by preternatural
agents. And every day, they performed a number of rites for
the purpose of buying the favour or buying off the disfavour of
the gods and goddesses of Greek religion.

That religion was an inconsistent medley of nature- worship,
animal- worship, ancestor- worship, daimon- worship and Olymp
ian-worship. It was administered at every temple at home and
abroad ; each temple had its priests who claimed special know
ledge of the local god or goddess, and were ready to explain the
proper way of winning his or her favour and appeasing his or
her anger ; sometimes these temple-guardians advocated magic,
sometimes natural divination, sometimes inspired divination.
Those parts of the worship which dealt with the food-supply and
the tribe-supply were, in Greece as elsewhere, obscene and cruel :
phallic and orgiastic rites ; blood-magic, raw-flesh feasts, human
sacrifice, ritual cannibalism. Every part of the worship was
superstitious : here, charms and other magical arts were prac
tised in order to compel the divinity to fulfil the desire of his
worshippers ; there, the will of the divinity was supposed to be
made known by natural divination — the rumbling of thunder,
the flashing of lightning, the falling of meteors, the clanging of
cauldrons, the murmur of streams, the rustling of trees, the
cooing of doves, the cries and flights of birds, the swimming of
fish, the crawling of serpents, the inspection of entrails, the
drawing of lots, the casual utterances of men ; elsewhere, the
will of the divinity was supposed to be made known by inspired
divination — a divine ecstasy falling on a human intermediary who
was thought at such moments to be possessed by the deity, and
to be capable during this possession of displaying superhuman
wisdom. Such were the shrines at which for centuries all Greeks
worshipped, with absolute confidence both in the efficacy of the
local rite and in the power of the local deity : at those shrines,
the helot sought protection, the sick health, the maimed healing,
the suffering consolation, the farmer weather and crops and
herds, the artisan lucrative employment, the business man trade,
the wealthy security and pleasure, the adventurer and the poli
tician success, the artist and the man of letters inspiration and
skill. The replies that were given at these shrines varied from

i*

4 COSMOLOGY

the virtuous to the abominable, from the clear to the ambiguous.
The oracles had their good points : they emphasised the sanctity
of the oath, the sanctity of family duties, the sanctity of the life
of the kinsman : occasionally, they stressed the value of the
widow's mite, the need of making allowance for the strength of
excessive temptation, the guilt of the murderer. It is possible,
moreover, that there was at times a power at work in those
oracles greater than any dreamt of in the philosophy of crass
materialism or of cocksure rationalism. But, in most cases, the
replies were obviously dictated by nothing more than a shrewd
opportunism. Each oracle was in fact the mouthpiece in its
district of the dominant religious and political interest ; and,
in such circumstances, the lowest elements in human nature
were always tending to come to the top.

Each of these temples was dedicated to one or more of the
gods and goddesses sung for Greece by the Homeric and Hesiodic
poets. This national poetry was believed both by the loftiest
and the lowliest minds in pre-scientific Greece to be absolutely
true. The Homeric and Hesiodic Greek believed himself to be
constantly and universally surrounded by his racial deities and
to be dependent on their co-operation in all his enterprises ; and
he accepted literally and trustfully every line of the national
epics. Homer sings for the courts of princes : his Olympians are
the human-nature gods of those Northern invaders, the Achseans.
He throws a veil of decency over the orgies of phallicism and
blood-magic. He puts some kind of order in the pantheon :
Zeus is the father of gods and men. There are times, also, when his
poetry strikes a serious religious note : Zeus and the Olympians
are on the side of justice and mercy, their displeasure is aroused
by those who spurn the voice of prayer or those who injure the
suppliant, the guest, the beggar ; and there are powers in the
lower world who guard the sanctity of the oath and punish the
wicked after death. But at other times, Homer tells a different
tale : Zeus and his sons are a dissolute crowd of lecherous bullies,
Hera and her daughters a jealous crowd of wanton shrews ; Zeus
beats his wife and suggests her desire to eat Priam, he hurls his
son over the battlements of Olympus and pushes other gods from
their thrones ; his ill-assorted aggregate of sons and daughters
lead among themselves the lives of quarrelsome and deceitful
idlers ; and all the Olympians from Zeus downwards govern the
human race by methods of the frankest favouritism. When we
turn from the'Homerist, the poet of the heroes, to the Hesiodist,
the spokesman of the common people, we read a still more appal
ling account of the Greek pantheon. The coarse and savage
superstitions of the helots, which the Homerists disdained or
glossed over, are dragged into literature and flaunted as divine
truths. The gods and goddesses of Hesiod are for the most part
those of the Achasans, but the spirit in which their deeds are told
is that of the aborigines of the Greek peninsula. The Hesiodists,
also, introduced the era of literary cosmogonies : Hesiod sings

THE CREATION OF SCIENCE 5

how the world was made, the gods and the earth, the rivers and
the ocean, the stars and the heavens ; and some of these myths
have never been surpassed for coarseness and savagery.

A deliberate effort of attention is necessary for the modern
reader in order to realise definitely that this system of beliefs, so
intellectually puerile and so morally contemptible, constituted as
late as the sixth century B.C. the whole mental stock-in-trade of
the glory which then was Greece. If we analyse the intellectual
acquisitions of any Greek of that age we find that, over and above
the practical capacity and skill requisite for his daily wants, these
acquisitions consisted of various myths dealing with his state,
his kinsmen, his festivities, his mysteries as well as with the works
of art and the more striking natural objects in his environment —
all set off and glorified by some knowledge of the epic poets : an
aggregate of religious, patriotic, and social fancies blended into
one indivisible creed. Part of that creed was not a whit less
childish and barbarous than the religion of Tasmanians or of
Bushmen. None of it was any advance on the superstitions of
Babylonia or of Egypt. All of it was accepted as objective truth
by the rich and the poor, the learned and the unlearned, in every
place where the Greek language held sway. The wary student of
the psychology of human beliefs need not be told that the mass
of the Greek people never, in their pagan days, outgrew these
follies. It was so much easier to accept the ready-made world
of the oracles and the well-told world of the poets than to jog
one's brain about truth that the overwhelming majority of the
Greeks, and even of those in Athens, the most civilised city of
Greece, were not affected by the enlightenment begun in the
sixth century, and remained for centuries afterwards immersed in
the superstitions of their forefathers. The fact is that the Greeks
who really made a glory of Greece are a chosen few : most of them
lonians and Athenians.

What, then, was the momentous step which once for all lifted
Greek civilisation above the savage rites of Tasmanians or Bush
men and above the stifling superstitions of Babylonia or Egypt ?
It was the creation of rational science : the self-assertion of human
reason against man-made conventions. Thales and his philo
sophic peers, from about 585 B.C. onwards, gave up believing
blindly, either in literary fables about the origin of things or in
oracular fables about the activities of things, and originated the
method of finding out the origin and activities of things by
observation of, and experimentation on, facts and by hard reason
ing on these observations and these experiments. This Ionian
innovation was to lay an indelible impress on the future progress
of mankind. Within three centuries, it changed the course of
critical education not only for the Greeks but also for the whole
human race. By giving birth in Greece itself to philosophy and
science and history, it made that country the cradle-land of all
subsequent philosophy and science and history. It reacted also
on the art and literature of the Greeks and carried both forward

6 COSMOLOGY

in a surprisingly short time to that pitch of excellence which
fitted them to "be humanistic educators of Europe : the new
atmosphere of critical enquiry made possible for Greek artists and
Greek men of letters an unfettered treatment of the lite and
traditions of their race. But the most important fruit of this
Ionian championship of the absolute sovereignty of the intellect
in man-made truth was to teach the educated Greek the chasm
between God and God's handiwork : be that handiwork stock or
stone, bird or fish, animal or man. The tendency of the earlier
philosophers was towards some form of pantheism. By degrees,
however, philosophy progressed until it reached the heights of
rational theism with Plato and with Aristotle. This progress was
followed, as always happens in man-made progress, by a period
of decadence : a relapse with the Stoics into pantheism ; a
relapse with the Epicureans into atheism. But, ever since
philosophy had become a living power in educated Greece,
critical minds there or elsewhere never went back to the vulgar
polytheism of primitive paganism. Thus, Thales and those lonians
who created rational science had done an imperishable thing. A
thing, too, which is, in the natural order, the most wonderful
thing in the world. And a thing of which the world's history
shows no other example.

It is undoubtedly true that the Eastern peoples in the age of
Thales were considerably richer than the Greeks in accumulated
facts. But these facts had never been observed for any scientific
purpose, and had never suggested to the Egyptians or the Baby
lonians a revision of their superstitions. The Ionian mind had
that in its fibre which was to carry it farther : the gift of an
insatiable curiosity. " And it was just this great gift of curiosity,
and the desire to see all the wonderful things — pyramids, inunda
tions, and so forth — that were to be seen, which enabled the
lonians to pick up and turn to their own use such scraps of
knowledge as they could come by among the barbarians. No
sooner did an Ionian philosopher learn half-a-dozen geometrical
propositions, and hear that the phenomena of the heavens recur
in cycles than he set to work to look for law everywhere in nature,
and, with an audacity almost amounting to vftpLs, construct
a system of the universe. We may smile at the medley of
childish fancy and scientific insight which these efforts display,
and sometimes we feel disposed to sympathise with the sages of
the day who warned their more daring contemporaries to think
the thoughts befitting man's estate. . . . But we shall do well
to remember that even now it is just such hardy anticipations of
experience that make scientific progress possible, and that nearly
every one of these early inquirers made some permanent addition
to positive knowledge, besides opening up new views of the world
in every direction." (3)

" The Greeks achieved what they did, in the first place, because
they were born observers. The anatomical accuracy of their
sculpture in its best period proves that, though they never say

THE ORIGINALITY OF THE GREEKS 7

anything about it in their literature, apparently taking it for
granted. The Egyptians, we may remember, never learnt to
draw an eye in profile. But the Greeks did not rest content with
mere observation ; they went on to make experiments of a quite
modern character. That by which Empedokles illustrated the
flux and reflux of the blood between the heart and the surface
of the body is the best known ; for we have a description of it
in his own words. It also established the corporeal nature of
atmospheric air. We should certainly hear of many more such
experiments if our sources were less meagre, and more intelli
gently compiled. Further, the Greeks always tried to give a
rational explanation ... of the appearances they observed.
Their reasoning powers were exceptional, as we can see from the
mathematical work they have left us. On the other hand, they
were also quite conscious of the need for verification. This they
expressed by saying that every hypothesis must save the appear
ances . . . ; in other words, that it must do justice to all the
observed facts. That is the method of science, as we understand
it still. It should be added that the development of mathematical
and biological science at a given time to a large extent determines
the character of its philosophy. We shall see how the mathe
matical influence culminates in Plato, and the biological in
Aristotle." (*)

THE ORIGINALITY OF GREEK RATIONALISM.

The creation of rational science by a people so far from the
East and at a date so late in the history of civilisation seems
incredible. " We have, then, to face the question of the nature
and extent of the influence exercised by what we call Eastern
wisdom on the Greek mind. It is a common idea even now that
the Greeks in some way derived their philosophy from Egypt and
Babylon, and we must therefore try to understand as clearly as
possible what such a statement really means. To begin with, we
must observe that the question wears a very different aspect now
that we know the great antiquity of the ^Egean civilisation.
Much that has been regarded as Oriental may just as well be
native. As for later influences, we must insist that no writer of
the period during which Greek philosophy flourished knows any
thing of its having come from the East. Herodotus would not
have omitted to say so, had he heard of it ; for it would have
confirmed his own belief in the Egyptian origin of Greek religion
and civilisation. Plato, who had great respect for the Egyptians
on other grounds, classes them as a business-like rather than a
philosophical people. Aristotle speaks only of the origin of
mathematics in Egypt (a point to which we shall return), though
if he had known of an Egyptian philosophy, it would have suited
his argument better to mention that. It was not till later, when
Egyptian priests and Alexandrian Jews began to vie with one
another in discovering the sources of Greek philosophy in their

8 COSMOLOGY

own past, that we have definite statements to the effect that it
came from Phoenicia or Egypt. But the so-called Egyptian
philosophy was only arrived at by a process of turning primitive
myths into allegories. . . . But really it is not worth while to
ask whether the communication of philosophical ideas was possible
or not till some evidence has been produced that any of these
peoples had a philosophy to communicate. No such evidence has
yet been discovered, and, so far as we know, the Indians were the
only ancient people besides the Greeks who ever had anything
that deserves the name. No one now will suggest that Greek
philosophy came from India, and indeed everything points to the
conclusion that Indian philosophy arose under Greek influences.
The chronology of Sanskrit literature is an extremely difficult
subject ; but so far as we can see, the great Indian systems are
later in date than the Greek philosophies they most nearly re
semble. Of course the mysticism of the Upanishads and of
Buddhism was of native growth ; but though these influenced
philosophy in the strict sense profoundly, they were related to it
only as Hesiod and the Orphics were related to Greek scientific
thought.

" It would, however, be another thing to say that Greek
philosophy originated quite independently of Oriental influences.
The Greeks themselves believed their mathematical science to be
of Egyptian origin, and they must have known something of
Babylonian astronomy. ... It thus becomes important for us
to discover what the Egyptian mathematics meant. We shall
see that* even here, the Greeks were original. The Khind papyrus
in the British museum gives us a glimpse of arithmetic and geo
metry as they were understood on the banks of the Nile. It is
the work of one Aahmes and contains rules for calculations both
of an arithmetical and geometrical character. . . . [The arith
metic] corresponds exactly, in fact, to the description of Egyptian
arithmetic Plato gives us in the Laws, where he tells us that chil
dren learnt along with their letters to solve problems in the
distribution of apples and wreaths to greater or smaller numbers
of people, the pairing of boxers and wrestlers and so forth. This
is clearly the origin of the art which the Greeks called Aoyio-rtKr/,
and they probably borrowed that from Egypt where it was
highly developed ; but there is no trace of what the Greeks called
apiOfjirjTiK^ the scientific study of numbers. The geometry of
the Rhind papyrus is of a similar kind, and Herodotus, who tells
us that Egyptian geometry arose from the necessity of measuring
the land afresh after the inundations, is clearly far nearer the
mark than Aristotle who says it grew out of the leisure enjoyed
by the priestly caste. The rules given for calculating areas are
only exact when these are rectangular. ... It is even assumed
that a right-angled triangle can be equilateral. The rule for
finding what is called the seqt of a pyramid is, however, on a
rather higher level, as we should expect. ... It seems an
anachronism to speak of elementary trigonometry in connexion

THE ORIGINALITY OF THE GREEKS 9

with a rule like this, and there is nothing to suggest that the
Egyptians went any further. That the Greeks learnt as much
from them is highly probable, though we shall see also that, from
the very first they generalised it so as to make it of use in measur
ing the distances of inaccessible objects, such as ships at sea. It
was probably this generalisation that suggested the idea of a
science of geometry, which was really the creation of the Pytha
goreans, and we can see how far the Greeks soon surpassed
their teachers from a remark attributed to Demokritos. . . .
There is no real evidence that Thales had any mathematical
knowledge which went beyond the Rhind papyrus, and we must
conclude that mathematics in the strict sense arose in Greece
after his time. It is significant in this connexion that all mathe
matical terms are purely Greek in origin.

" The other source from which the lonians were supposed
to have derived their science is Babylonian astronomy. It is
certain, of course, that the Babylonians had observed the heavens
from an early date. They had planned out the fixed stars, and
especially those of the zodiac, in constellations. . . . They had
distinguished and named the planets and noted their apparent
movements. They were well aware of their stations and retro
grade movements and they were familiar with the solstices and
equinoxes. They had also noted the occurrence of eclipses with
a view to predicting their return for purposes of divination. But
we must not exaggerate the antiquity or accuracy of these
observations. It was long before the Babylonians had a satis
factory calendar and they kept the year right only by intercalating
a thirteenth month when it seemed desirable. That made a
trustworthy chronology impossible, and therefore there were not
and could not be any data available for astronomical purposes
before the so-called era of Nabonasser (747 B.C.). The oldest
astronomical document of a really scientific character which had
come to light up to 1907 is dated 523 B.C. . . . when Pythagoras
had already founded his school at Kroton. Moreover, the golden
age of Babylonian observational astronomy is now assigned to
the period after Alexander the Great, when Babylon was a
Hellenistic city. Even then . . . there is no evidence that
Babylonian astronomy had passed beyond the empirical stage.

"... Thales probably knew the cycle by means of which the
Babylonians tried to predict eclipses ; but it would be a mistake
to suppose that the pioneers of Greek science had any detailed
knowledge of Babylonian observations. The Babylonian names
of the planets do not occur earlier than the writings of Plato's
old age. . . . But even if the lonians had known them (i.e. the
Babylonian observations) their originality would remain. The
Babylonians recorded celestial phenomena for astrological pur
poses, not from any scientific interest. There is no evidence that
they attempted to account for what they saw in any but the
crudest way. The Greeks, on the other hand, made at least
three discoveries of capital importance in the course of two or

10 COSMOLOGY

three generations. In the first place, they discovered that the
earth is a sphere and does not rest on anything. In the second
place, they discovered the true theory of lunar and solar eclipses ;
and, in close connexion with that, they came to see, in the third
place, that the earth is not the centre of our system, but revolves
round the centre like the planets. Not much later, certain Greeks
took, at least tentatively, the final step of identifying the centre
round which the earth and planets revolve with the sun. These
discoveries . . . are only mentioned here to show the gulf be
tween Greek astronomy and everything that had preceded it.
On the other hand, the Greeks rejected astrology, and it was not
till the third century B.C. that it was introduced among them.

" We may sum up all this by saying that the Greeks did not
borrow either their philosophy or their science from the East.
They did, however, get from Egypt certain rules of mensuration
which, when generalised, gave birth to geometry ; while from
Babylon they learnt that the phenomena of the heavens recur in
cycles. This piece of knowledge doubtless had a great deal to do
with the rise of science ; for to the Greek it suggested further
questions such as no Babylonian ever dreamt of." (5)

THE KELIGION OF EATIONALISM.

" But while philosophy is thus intimately bound up with
positive science it is not to be identified with it. It is true that
in early times the distinction between the two is not realised.
The word o-o&a covered all we mean by science and a great deal
more besides, such as the arts of making pontoons and guessing
riddles. But the distinction was there all the same. If we look
at Greek philosophy as a whole, we shall see that it is dominated
from beginning to end by the problem of reality. ... In the last
resort the question is always, ' What is real ? ' Thales asked it
no less than Plato or Aristotle ; and, no matter what the answer
given may be, where that question is asked, there we have
philosophy. It is no part of a historian's task to decide whether
it is a question that can be answered, but there is one comment
he may fairly make. It is that the rise and progress of the special
sciences depended, so far as we can see, on its being asked. We
find that every serious attempt to grapple with the ultimate
problem of reality brings with it a great advance in positive
science, and that this has always ceased to flourish when interest
in that problem was weak. That happened more than once in
the history of Greek philosophy, when the subordinate problems
of knowledge and conduct came to occupy the first place, though
at the same time it was just the raising of these problems that did
most to transform the problem of reality itself.

" And this helps to explain why philosophy cannot be simply
identified with science. The problem of reality, in fact, involves
the problem of man's relation to it, which at once takes us beyond
pure science. We have to ask whether the mind of man can have

RATIONALISM AND RELIGION 11

any contact with reality at all, and if it can, what difference this
will make to his life. To any one who has tried to live in sympathy
with the Greek philosophers, the suggestion that they were
' intellectualists ' must seem ludicrous. On the contrary, Greek
philosophy is based on the faith that reality is divine, and that
the one thing needful is for the soul, which is akin to the divine,
to enter into communion with it. It was in truth an effort to
satisfy what we call the religious instinct. Ancient religion was
a somewhat external thing, and made little appeal to this except
in the ' mysteries,' and even the mysteries were apt to become
external and were peculiarly liable to corruption. . . . Again and
again (Greek) philosophy sought to do for men what the mysteries
could only do in part, and ... it includes most of what we should
now call religion.

" Nor was this religion a quietist or purely contemplative one,
at least in its best days. The mysteries had undertaken to regu
late men's lives, and philosophy had to do the same. Almost
from the beginning it was regarded as a life. It was no self-
centred pursuit of personal holiness either. The man who
believed he had seen the vision of reality felt bound to com
municate it, sometimes to a circle of disciples, sometimes to the
whole human race. The missionary spirit was strong from the
first. The philosophers believed that it was only through the
knowledge of reality that men could learn their own place in the
world, and so fit themselves to be fellow- workers with God, and
believing this he could not rest till he had spread the knowledge
of it to others. The death of Sokrates was that of a martyr,
and * intellectualism,' if there be such a thing, can have no
martyrs." (6)

RATIONALISM IN REVEALED RELIGION.

St. Augustine, St. Thomas, Scotus and Suarez would have
endorsed every line of this paean to the rationalists of Greece :
St. Augustine because of the theism of the divine Plato ; St.
Thomas, Scotus, Suarez because of the rational theism of the
Philosopher. These master-builders of Catholic Philosophy and
Catholic Theology held that there never were more wonderful
years in the history of pagan thought than these in which the
brains of Plato and of Aristotle were ceaselessly working. They
held, also, that it was no exaggeration to say there were no pagans
to whom Catholicism owed a greater debt for the soundness of its
philosophy of theism than to these two Greeks. And under the
guidance of one or other of these amazingly powerful and subtle
minds, the four master-minds of Catholic Apologetics insisted on
a twofold usage of rationalism in Revealed Religion : one for the
conversion of the unbeliever ; the other for the protection of the
believer.

The first and nobler usage of rationalism is to prepare the
adult unbeliever for faith by rational proof of the motives of
credibility. (7) It is only the rational study of philosophy which

12 COSMOLOGY

can convince atheist or agnostic or pantheist of the existence of
an infinite, knowable, personal God. It is only the rational study
of history which can convince infidel or heretic that the Gospels
and other writings of the New Testament are authentic documents
proving beyond all reasonable doubt that Christ was God ; that
He established a visible society, one and imperishable ; that He
appointed a perennial authority which is infallible in its religious
teaching and supreme in its religious control ; and that the
Catholic Church is that society. These are the ordinary processes
of enquiry that lead an unbeliever to the faith. Sometimes there
are conversions like those of Saul on the way to Damascus. But,
apart from these exceptional cases, conversion is a work of
reason, abetted by prayer, originated and sustained by super
natural grace. There are, of course, minds and minds. The
psychology of conviction concerning the motives of credibility is
as bewildering as the psychology of conviction concerning other
personal human opinions. The highways and byways of human
conviction are multifarious and tortuous. The way of objective
truth is straight and narrow. Now the strong point of the
attitude of the Catholic Church towards rationalism is her
insistence that the motives of credibility are objectively true
and will stand the most exigent rational tests in history and in
philosophy. St. Augustine and St. Thomas, Scotus and Suarez
taught that reason can demonstrate the existence of God and
that history can prove beyond doubt the divine institution of an
indefectible, infallible Church. And in later ages when Hume's
assault on miracles and Kant's assault on rational theology shook
the nerve of many famous apologists, the Church began by
disavowing this failure of nerve and ended by setting her seal on
the teaching of Fathers and Schoolmen about the necessity of
rationalism in religion. De Bonald, Lamennais, Bautain, Ventura,
Bonetty, Ubaghs appealed during the nineteenth century from
rational philosophy and rational history to Tradition ; each of
them in turn denying under one formula or another the possibility
of rational proof of the motives of credibility. But the Church
would have none of all this. Gregory XVI and Pius IX repu
diated all these attempts to rob theology of its philosophical and
historical bases. And at the Vatican Council, the Church made
that item in Traditionalism which appeals most to the unwary
the subject of her heaviest censure. " If any man says that
God, one and true, our Creator and Lord, cannot be known by
the natural light of human reason through the things that are
made, let him be anathema." (8)

" This, then, is one office of Reason, to help in leading men to
the faith who had it not before. But also for the faithful them
selves as such. Reason is of the highest value. It relieves the
pressure and strain upon faith, when it is attacked by argument
from without or by the mind's own questionings from within.
Faith, as we have shown,(9) is equal to the strain. The result of
adverse argument is not any doubt of matter of faith, but still

RATIONALISM AND RELIGION 13

it is a temptation, and temptation is always painful to those who
love good. It is painful as an accusation against a mother whom
one tenderly loves and has learned thoroughly to trust. The
accusation is not entertained in the mind for a moment as a thing
that could possibly be true, but perhaps it cannot be disproved,
and then it pains us. When a good friend rises up, and by argu
ment scatters the charge to the winds, we owe him gratitude for
a very sensible relief. So we are pleased when the orthodoxy, if
not the personal character, of certain Popes is vindicated by
historical argument. We knew and held firmly by faith that our
Lord would never permit His Vicar to teach heresy from the
chair of truth. . . . Still the confident assurance of this eminent
anti-Catholic historian loomed upon us as an ugly bogey, till one
day we read with relief how an historian of equal eminence and
learning had been able to write against all his allegations, non
proven. . . . The function of reason (in this second usage) is
rather negative, to show the inclusiveness of objections, than
positively to prove a dogma or a fact of faith. Much of the
matter of faith is beyond the reach of direct proof. But when a
disputant fresh from the Schools swoops down on us with an
argument, as he says, for the impossibility of transubstantiation,
and we find that he has got hold of the Lockian definition of
substance, as the sum of the sensible qualities of the object, we
congratulate him on the logical sequence of conclusion from
premises, but send him back to learn a better definition of
substance." (10)

Apart from all this theoretical evidence of the estimate set
on rationalism in religion by the Church, her methods of intellec
tual training gave a practical estimate of her belief in the import
ance and value of reason to Faith. " If a man of scant leisure
spends his time, and a man of limited means spends his money,
lavishly upon a certain pursuit, this is the clearest evidence that
he sets store by that pursuit. The Catholic Church generally is
not rich, and she wants ministers for service early in their lives.
Yet, under the name of Philosophy, Theology, or Divinity studies
she insists on putting men through a severe course of close reason
ing on things of faith, leading up to faith, or consequent upon
faith, and that for three, four or six years, ere she will ordain
them. And experience proves her right. One of the greatest
blows that the Church received in the French Revolution, as
great a blow almost as she ever could receive, was the closing of
her ecclesiastical Seminaries wherever the Revolution or the wars
of the Revolution spread. It was the policy of Julian the
Apostate reiterated ; for Julian would have cut off the Christians
from all culture and exercise of mind. That temporary paralysis
of philosophy and theology had its effect in enfeebling the teaching
ability of the Church's ministers far into the present (nineteenth)
century.

" Credo quia impossible was Tertullian's paradox, but the
Church has never endorsed it. Tertullian was a headstrong

14 COSMOLOGY

violent man, whose untamed impetuosity finally carried him out'
of the Church into the Montanist heresy. . . . The Church has
nothing to gain from prejudice, confusion of thought, ignorance,
mental darkness, surface habits of mind, and lazy reluctance to
investigate and face spiritual realities. No cause in the world
suffers so much as her cause from these human miseries. Though
faith is the very breath of her nostrils, yet she cries for reason'
also ; the cry of St. Augustine, Ama valde intellectum — Love
understanding exceedingly." I11)

" This train of thought brings us within sight of some hope
of removing from (the philosophy of) Scholasticism a reproach
which more than any other cause has prejudiced the modern
mind against it, and is the greatest obstacle to its propagation.
I mean the reproach of being pledged to foregone conclusions, of
being tethered to orthodoxy like a captive balloon to the earth.
This reproach grows greater with the lapse of time, as the attaching
ropes are multiplied and made stronger by new condemnations
of error and new definitions of faith. The reproach may be
removed by this reflection, that definitions of faith fall upon
judgments, not upon reasonings ; not upon speculations but
upon assents. It is a rule of the Higher Philosophy to speculate
freely, but to assent cautiously, to think much but believe little.
Faitn challenges our belief, not our logic : it does not say, this is
proved, but this is. You may call Scholasticism or any orthodox
philosophy a captive balloon ; but for tentative ascents, for
exploration and reconnoitring purposes, the ropes that hold it
stretch to infinity. You may see and meditate all that can be
said for any condemned doctrine, provided you do not hold the
doctrine itself. You may sound all the depths of Hegelianism
and see with your mind's eye all the gloomy visions of Schopen
hauer, provided you hold fast to the Nicene Creed and Vatican
Council, and do not deny, however little in some respects you may
be able to justify, the Providence of God. Nor is it quite exact
to say that the dogmas of faith are foregone conclusions. They
are foregone truths. They are not presented to our belief as
conclusions. We may never be able to reach them by way of
conclusions. Some are confessedly inaccessible to conclusive
argument, as the doctrine of the Triune God. Some may be
accessible, but I cannot find the way. There is a way up the
Matterhorri, others have gone to the top, I start and fail. I have
to take the feasibility of the ascent on the word of others. So
with such a doctrine as the immortality of the soul. I have not
the least doubt that the soul is immortal : my faith tells me so.
But I am as free as any other man in judging of the value of the
arguments for immortality. I may search them all and condemn
them all ; and, with Scotus, I may have to fall back upon my
faith as the one sure guarantee of my immortality. A truth of
faith can never be in question ; but my ability to vindicate a
given truth of faith is a very open question indeed. I am satisfied
with the word of God ; but my own philosophical or critical and

ARISTOTLE'S DIVISION OF PHILOSOPHY 15

historical speculations may fail to satisfy me, at least for the
present. Perhaps I may reason better to-morrow : meanwhile I
will believe, even to-day.

" A Catholic will say : this free philosophical speculation,
trying all conclusions, but holding aloof from assents, where the
word of the Church forbids them, is a dangerous game. It is
dangerous. Alpine climbing is dangerous, and fox-hunting. All
the stronger efforts of man's body and mind are fraught with
danger, not excluding the paths of higher sanctity. There is
danger of broken limbs, of lunacy, of intellectual pride and
apostasy. If Scholasticism is to revive — and Popes have bidden
it live again — the Neo-Scholastic who shall lead the movement of
revival will need to be a man of great faith, fearless speculation,
and absolute reliance on the word of God. . . . ' What makes
against the faith, either as a consideration in the mind of the
believer, or in the way of exterior persecution, augments the
merit of faith, so far forth as it reveals a will more prompt and
firm in the faith. Therefore also the martyrs had greater merit
in faith, not receding from the faith for persecution, and likewise
men of learning have greater merit of faith, not receding from the
faith for the reasons of philosophers or heretics alleged against
it.'— (St. Thomas, Summa Theologicz, 2»-2", q. 2, art. 10)." (12)

ARISTOTLE'S DIVISION OF SPECULATIVE PHILOSOPHY OR SCIENCE.

Aristotle (13) seems to distinguish all sciences into Speculative
and Practical : Speculative Philosophy comprises all the specula
tive sciences ; Practical Philosophy comprises all the practical
sciences. This distinction arises from differences in purpose, in
subject-matter and in exactness : the purpose of a speculative
science is to know, that of a practical science to do ; the subject-
matter of a speculative science is some form of reality which
" can by no possibility be otherwise," that of a practical science
is some form of reality which " can possiblv be otherwise " ; the
conclusions of a speculative science are rigidly universal truths,
those of a practical science are simply general rules which hold
good in the majority of cases.

There are three branches of Speculative Philosophy or Science :
First Philosophy, Mathematics and Physics. Each of these has
its own special topic for investigation "and its own special first
principles. First Philosophy (also called by Aristotle Wisdom or
Theology, and, later, called by his disciples Metaphysics) inves
tigates being as being and the connexions which arise between
various beings simply from the fact that all of them are in some
sense real : hence every kind of being as real and every funda
mental principle of being as real come under its scope. Thus
First Philosophy investigates what can be meant by saying that
anything is real : it distinguishes the various doses of reality that
are found in all these real beings ; it analyses being into substance
and accident, potency and actuality, and into its four causes ;

16 COSMOLOGY

and as the explanation of these four causes is impossible apart
from a motionless Prime Mover, the First Philosophy becomes
towards the close a rational theology of God. Mathematics and
Physics are distinguished from First Philosophy by the fact that
both of them deal with only certain classes of beings : they are,
then, " Second Philosophies." Mathematics deals with objects
that are motionless and immutable and yet are attributes of
material bodies : points, lines, surfaces, numbers — the ideal limits
or numerical properties of concrete things. Physics deals with
the motions or changes of sensible bodies. Thus First Philosophy
studies being as real, Mathematics studies being not as real but
as measurable «and numerable, Physics studies "being not as real
nor as measurable and numerable but as corporally changeable.
Finally, the special first principles of each speculative science
vary with its scope. First Philosophy has the least complicated
set of first principles because it has the widest range of objects.
Mathematics has a more complex set of axioms than First Philo
sophy : it needs not only the first principles that are valid for
being as being but also those first principles that are valid and
significant in the realms of numbers and figures. Physics requires
the most complex set of principles of all three : its subject of
investigation is change in bodies and bodies that are changeable
are also real, measurable, numerable.

THE PHYSICS OF AKISTOTLE.

The branch of Aristotelian science or philosophy of most
interest to the cosmologist is the Physics. That Physics is intel
ligible only from Aristotle's view of science and scientific proof.
The aim of demonstrative science or philosophy is, according to
the Stagyrite, truth. Truth is the undistorted mirroring by
consciousness of reality. Now Aristotle held that every existing
individual was what it was by reason of its essence or inner
ground. Hence we can have scientific knowledge of an existing
individual only when we are able to trace the connexion of the
contents of that individual with its essence. The scientist or
philosopher attains truth when he analyses and resynthesises an
individual in such a way as to make clear the inner necessity that
links the sensible accidents of that individual with its essence.
He is started on this quest by observing facts of experience.
These facts, inasmuch as they are merely known to happen,
belong to the world of opinion not to the world of science. But
their happening suggests to the scientist or philosopher a problem :
the problem of demonstrating a necessary connexion between the
observed fact and the essence. The solution of this kind of prob
lem involves both induction and deduction : induction for the
purpose of discovering essences and first principles ; deduction
for the purpose of converting a mere conjunction of fact into a
rational connexion. Should our scientist or philosopher succeed
in demonstrating this rational connexion, his conclusion is scien-

THE PHYSICS OF ARISTOTLE 17

tific or philosophic ; he knows not merely that the fact happens
but also why it must happen. An illustration from the science
or philosophy of Mathematics will make the meaning of all this
clearer. The man who convinces himself by measurement that
the sum of the angles of a plane triangle is equal to two right
angles has not a scientific or philosophical knowledge of that
proposition. Such a man attains scientific or philosophical know
ledge only when he sees that this proposition follows from the
definition of a plane triangle by repeated application of the prin
ciples of geometry. That is why Aristotle insists that it is the
aim of science or philosophy to find out the middle term — one or
more — which will convert facts of experience into demonstrated
conclusions. That is why he represents the scientist or philoso
pher as filling up the interval between a mere fact and the
definition of an essence by packing that interval with a middle
or middles as mediated necessary connexions. That is why
science or philosophy in reference to any class of individuals
presents itself, to Aristotle's mind, as a syllogism or series of
syllogisms in which the reason for all that is scientifically or philo
sophically known concerning this class of substances is shown to
be the specific essence of the class.

This view of science and of scientific method is the basis of
Aristotle's Physics.!14) The subject-matter of Physics is change
or motion in natural bodies : and a natural body is, for Aristotle,
any body that contains within itself an originative source of motion
and rest or an impulse to change. Hence his Physics is scattered
over several treatises : Physica, De Ccelo, De Generatione et
Conuptione, Meteorologica, De Anima, Parva Naturalia, Historia
Animalium, De Partibus Animalium, De Motu Animalium, De
Generatione Animalium. His Physics is, then, the science or
philosophy of all changes in bodies whether lifeless or living.
But these bodies exist only as singular individuals endowed with
an inexhaustible wealth of perceptible attributes. Science or
philosophy deals, however, only with an orderly sphere of neces
sary connexions between essences and properties. Therefore, the
duty of the Aristotelian Physicist is to select from the far richer
but only partly intelligible world of sensibly perceived bodies the
essences, the properties, and their reciprocal linkages. He starts
by reminding us that every science takes for granted certain
things on one or other of two grounds : some things are taken for
granted because they are so evident as to need no proof ; other
things are taken for granted because they are proved indepen
dently elsewhere. Physics takes for granted the existence and
meaning of natural bodies : it takes for granted the division of
natural bodies into various genera and into ultimate species ; it
takes for granted — as a second philosophy — the principles and
conclusions of First Philosophy. Then, it gets from observation
the clue to the existence of its own special problems. Next, it
discovers, by induction, the various definitions of essences and
the first principles that refer to natural bodies. Finally, it

2

18 COSMOLOGY

demonstrates, by deduction, that there are sensible accidents in
natural bodies which belong to these bodies as a necessary
consequence of their specific essence : accidents that are found
to qualify every member of a distinct species and that, strictly-
speaking, qualify no member of another species ; accidents that
are known, in Aristotle's technical terminology, as properties.

Had Aristotle in the Physics achieved the kind of knowledge
at which he was aiming and had he succeeded in expressing it in
what he would style the ideally appropriate way, that science
would appear in his text as an ordered system of apodeictic
syllogisms. " In these syllogisms every term will be universal ;
and in the basal syllogisms, on which the system depends, every
premiss will be an immediate commensurate judgment, reflecting
an immediate reciprocally-necessary nexus between substance
and proprium or substance and constitutive moment, or proximate
cause and proximate effect. The conclusion of every syllogism
will include the middle term and will be a mediate commensurate
judgment, reflecting a reciprocally-necessary nexus between sub
stance and proprium mediated through the proximate cause of
the inherence of the latter in the former. The three terms of
every such apodeictic syllogism can be rearranged and concen
trated so as to constitute the adequate scientific definition of the
proprium in question. . . . None of Aristotle's examples com
pletely fulfils the conditions of a perfect apodeictic syllogism,
adapted to form the basis of a system of scientific demonstra
tions." (15) What is worse, his view concerning what we may
call the empirical, as distinct from the metaphysical, science
of matter and its attributes turned out to be hopelessly fantastic.
Still, the student who does not realise Aristotle's aim in this
domain and also the methods by which he sought to achieve that
aim, can never hope to get a grip of the perennial value, despite
multitudinous errors and puerilities, of Aristotelian Physics.

THE KEVOLT AGAINST AKISTOTELIANISM.

From the middle of the sixteenth century onwards, the new
wine of modern science and modern philosophy burst these old
Aristotelian bottles — Physics, Mathematics, Metaphysics. Most
of the pioneers in modern physics and modern mechanics were
rigorous experimentalists : men who made the exact measure
ment of quantities and the careful testing of hypotheses the key
stone of science. Their immediate and astonishing success
destroyed the prestige of Aristotle's view of science and of scientific
proof ; the scrupulous observation of facts and the experi
mental verification of the laws of nature ousted everywhere the
Aristotelian preference for genera and species and for deductive
argument from essences to properties. One of the necessary con
sequences of this new outlook in science was a new classification
of those branches of learning which the Greeks had bundled
together under the synonyms, Science or Philosophy.

THE EEVOLT AGAINST ARISTOTLE 19

In every branch of knowledge, empirical science became
divorced from metaphysical science : each was cultivated' by
different men and along different lines. Thus topic after topic
of the Aristotelian Encyclopaedia — hitherto the preserve of
medieval theologians and philosophers — was taken over and made
the object of one or other of the ever-growing branches of modern
science : moreover, these topics were treated after a fashion
wholly unknown to Aristotle and the School, and in many in
stances blossomed out into sciences that horrified the upholders
of traditional learning. And while this was happening in natural
science, modern philosophy was launching system after system
in opposition to the philosophy of Aristotle and the School. Our
only concern, however, is with the fate of those portions of the
Physics that embody the science and philosophy of matter. It
was against that part of the Aristotelian line that the modern
world flung its shock troops. And as I shall record hereafter, (16)
that part failed hopelessly to withstand their attack. The first
result of this successful revolt against Aristotelian Cosmology was
the identification from an opposite point of view of the science
and philosophy of matter : Aristotle identified the science of
matter with the philosophy of matter because he held no con
clusion to be scientific that was not syllogistically demonstrated ;
these early modern anti- Aristotelians identified the philosophy of
matter with the science of matter because they held no truth was
discoverable about matter other than the facts and laws and
theories of empirical science. A baptised and experimentally
enlarged edition of Greek atomism thus became rehabilitated in
Europe as the last word of science and of philosophy on matter
and its properties. Descartes was too keen a mind to share this
naive outlook, but he was unwilling to disillusion the many :
apparently, his desire to curry favour for his kineticism was
stronger than his sense of candour. (17) Leibniz fastened on
this chink in the armour of Descartes and made the unmasking of
the popular delusion a central aim of his life's work as cosmologist.
The talents of Descartes and of Leibniz as mathematicians and as
physicists made it impossible for students of the new physical
sciences to ignore this little rift in the lute ; the controversies
between them on the principles of Mechanics agitated every
university and every learned academy in Europe. The result was
that even experimentalists began to realise there may be two
views of matter and its properties : the view of the physicist and
the view of the metaphysician. That stage of mental develop
ment ushered in the period of human thought which acknow
ledged a complete divorce between the science of matter and the
philosophy of matter ; at least in the sense, that henceforth any
thinker who was aware of the actual state of this problem felt
bound to give his reasons for denying the existence of a philosophy
of matter as distinct from a science of matter. Thereupon, a
fresh division of the branches of philosophy was adopted outside
the Aristotelian school. Logic, formal and real, continued to be

20 COSMOLOGY

for these anti- Aristotelians, as it had been for Aristotle, a pro
paedeutic to philosophy : it is impossible to argue consistently in
philosophy or elsewhere unless one obeys the rules of Formal
Logic ; moreover, the kind of systematic thinking that one aims
at in philosophy or elsewhere depends on the conclusions reached
about the scope or value of human knowledge in Keal Logic
(alias Criteriology, Epistemology). All speculative philosophy
came to be called Metaphysics. This modern Metaphysics is
subdivided in General and Special. General Metaphysics, which
is also called Ontology, studies being as such and the attributes
of being as such. Special Metaphysics is the application of the

Erinciples of General Metaphysics to the three great classes of
eings : Nature, Soul, God. Rational Cosmology is the title of
the special metaphysics of Nature. Rational Psychology is the
title of the special" metaphysics of Soul. Rational Theology is
the title of the special metaphysics of God.

This modern division was later still accepted by the Aristotelian
School. Its adoption is largely a question of practical convenience,
for, it is obviously of little importance what titles you give to
the subdivisions of any branch of knowledge or how you distribute
its problems amongst these subdivisions, provided you take care
that all the problems are treated somewhere or other. There is,
however, a slight difference of opinion among contemporary
scholastics as to the scope of Cosmology. Some scholastics make
Cosmology the philosophy of Nature and treat therein not merely
of inanimate but of living bodies : a usage that has the advan
tage of being upheld by modern non-scholastic schools. Other
scholastics make Cosmology the philosophy of matter and treat
therein only of inanimate bodies : leaving the study of all sorts
of living beings to Rational Psychology for the reason that
plants and animals have souls of a sort. In this book, I adopt
the second usage for the purely personal reason that the discussion
of the philosophy of matter apart from the philosophy of life has
taken on, in the course of my inquiry, a wholly unforeseen length.

PHYSICAL SCIENCE AND MODERN PHILOSOPHY.

Descartes is rightly acclaimed the pioneer of the explanatory
ideal which has in recent centuries dominated Physical Science
in its attempt to explain matter and the qualities of matter. To
him it is due that modern theoretical physics denies the existence
in matter of everything which Aristotle and the School regarded
as quality : the primary qualities of modern science or modern
philosophy were, for Aristotle and the School, not qualities but
quantities. To him is it due that modern theoretical physics
attempts to solve the problem of non-living bodies by matter
and motion. For all that, his physical investigations were
infected by the same methodical error as were those of Aristotle :
a minimum of experience sufficed for a maximum of inference.
He started from clear and distinct ideas. And having satisfied

PHYSICS AND MODERN PHILOSOPHY 21

himself rather hastily that extension is the only attribute which
the mind cannot abstract from bodies he concluded that extension
was the essence of matter. Now, Geometry deals with the laws
of extension as embodied in geometrical figures. Again, Arith
metic and Mechanics deal with the laws of the measurement of
extension and of motion. Hence Descartes concluded that by
the study of these sciences man can unlock the secrets of matter
and explain the composition, the properties, and the mutual
relations of lifeless bodies. This method of scientific inquiry was
obviously as a priori as the method used by Aristotle.!18) And
the only reason why it led Descartes to conclusions apparently
more conformable to the results of all subsequent theoretical
physics was, that extended particles and motion formed his
initial data. But the history of modern science proves that
physics could have made no genuine progress, had not the a priori
methods of Cartesian physics been contemptuously set aside
by the experimental pioneers : Galileo, Huygens, and Newton.
These pioneers agreed with Descartes in denying the extra-mental
reality of the proper sensibles ; that is, they explained away these
proper sensibles as subjective illusions due to the action on our
sense-organs of purely quantitative particles. But while they
and their successors refused to admit any material forces save
those which cause local motion, they never reached a unanimous
view on the nature of these motive forces ; one group held that
some of these forces were inherent active powers in matter ;
another group held that all these forces were really invisible
motions of invisible particles. For a long time, however, all
physicists continued to speak of the particles of matter as sub
stances and of the forces (real or fictitious) of matter as causes.
But the older metaphysical interpretation of substance as self-
subsisting being and of cause as active being became, by degrees,
less and less attractive to the students of a science that boasted
of being concerned with the real facts of nature and of scorning
with all its migjht the hobgoblins of metaphysics.

Fate was kind to these troubled physicists. Modern philo
sophy stepped in to rid them, apparently for ever, of the only
traces of metaphysics embedded in the Cartesian ideal of physics.
Hume set out to prove that the notion of substance as self-
subsisting reality was but an irrational instinct — something akin
to the social convention which insists that we may not use cups
without saucers : that the notion of cause as activity was another
irrational instinct of preceding ages — something akin to the rus
tic's terror at the play that the villain is going to murder the
hero. The metaphysicians were naturally furious with Hume.
But, by one of these ironies of history that occur in every depart
ment of life, the pro-metaphysical champion that caught the
attention of the public s was Kant. It took the metaphysicians
and the physicists a long while to disentangle from Kant's cum
brous and obscure terminology the gist of what he himself styled
mental Copernicanism. But when the physicists did learn what

22 COSMOLOGY

Kant was driving at, they realised that they need not trouble
further in physics with the bugbears of substance and causality.
Kant had taught unmistakably that substance and cause — and
indeed every other fundamental concept in systematic thought —
were simply dress-suits made by man's mind for extra-mental
realities in order that these ragged and unruly urchins of the
outer darkness might be transformed into well-groomed and
orderly members of the world of science. Hume and Kant took
the world of their day by storm. Physicists would be less than
human did they not avail themselves of this turn of events in
philosophy to fling to the wind all further scruples about the
traditional meanings of substance and cause. Thereupon, what
is sometimes called the positive age of science was ushered in :
scientists profess to mean by substance simply a sensibly-per
ceived or perceptible fact or a group of such facts ; scientists
profess to mean by cause simply the invariable succession of
sensibly-perceived or perceptible facts. Hegel attempted to
stem the rising tide of radical empiricism in science and in phil
osophy by the metaphysics of Objective Idealism. He was
successful in exhibiting the flimsy basis of Humian scepticism
and of Kantian agnosticism. But his constructive ideals were
lost on the physicists owing to a popular belief that he was trying
to replace the experimental investigation of matter by the
ancient and totally discredited methods of metaphysical deduc
tion.

Physicists and mathematicians are, of course, perfectly
justified in ridding their own sciences of any metaphysical ideas
which they find useless or worse in these branches of learning.
They are not justified on that account in treating these ideas as
wholly illusory in reference to the world of facts." This question
is at least further arguable. To treat it as closed, simply because
of the advantage occurring to physics and mathematics from the
exclusion of such ideas, is to adopt the outlook of the student of
shorthand who imagines phonetic spelling ought to satisfy the
purposes of orthography.

THE EVOLUTION OF MODERN PHYSICS.

Prior to the advent of Planck and Einstein, the progress Of
physical science had centred about five leading theories : the
theory of attractive and repulsive forces, atomism, kineticisrn,
the laws of energy, and the theory of electrons.

Newton (1689) gave the first progressive impulse to modern
physics by abstracting from the mechanics of Galileo and Huygens
ani the astronomy of Copernicus and Kepler the formula of
universal gravitation. A hundred years later, the continental
development of Newtonianism found its most complete and
confident expression in the system of Laplace : a system in
\)fhich atoms with attractive and repulsive forces were offered as
the ultimate explanation in astronomy, physics, and chemistry

EVOLUTION OF MODEKN PHYSICS 23

of all interaction both between molar and molecular bodies.
And so satisfying was this system to a certain type of continental
physicist that, despite the popularity elsewhere of kineticism,
this view prevailed there till the close of the nineteenth
century.(19)

The atomic theory of Dalton (1803) introduced into chemistry
a consistent exposition of the laws of fixed and multiple propor
tions, and this became the fulcrum of all subsequent advances in
that science. But Dalton's theory had to undergo, especially in
the first half of the nineteenth century, so many changes for the
purpose of adapting itself to newly discovered facts that many
eminent chemists of the time looked on chemical formulae as
nothing more than a convenient symbolism. It was only when
the kinetic theory of gases was domiciled in Physics by Clausius
and Maxwell about the middle of that century that these doubts
of the chemists were definitely set aside and replaced by a belief
in the physical reality of atoms. Thereupon, structural chemistry
and stereo-chemistry began their popular career : chemists, no
longer content with a knowledge of the relative weights of atoms,
attempted to discover the geometrical arrangements of atoms in
the compound. And this ambition fixed their attention on the
most difficult problem of all : chemical affinity.

While these problems were being tackled in chemistry, a big
revolution had been wrought in Physics by a return to the
unpopular ideals of Cartesian kineticism : unpopular, I say,
because despite the triumphal progress of continental Newtonian-
ism, kineticism had ever had its admirers — among them Huygens,
Euler, Kumford, Young. The nineteenth-century herald of
kineticism was Fresnel, the Newton of Optics. He made kineti
cism popular by his undulatory theory of light and by reminding
his contemporaries of the value of kineticism in Acoustics. These
kinetic successes in Acoustics and in Optics led to a renewed
belief in the Cartesian ideal of a thoroughly kinetic interpretation
of every physical property of matter : of heat, of electricity, of
magnetism, and even of gravitation. This belief received a great
impetus through three independent branches of research of a

Sirely theoretical nature : the researches of Joule, Clausius, and
ax well on the kinetic theory of gases, the researches of Helm-
holtz and Kelvin on vortex motions and vortex atoms ; the re
searches of Faraday and Maxwell on electricity and magnetism.
This wave of kineticism involved enthusiastic discussions first
about the existence of ether, then about its nature, and then
again about its existence : discussions whose unsatisfactory
result has since been emphasised by the uselessness of this entity
in Einstein's scheme. Nor was this problem about the nature of
ether the only thorn in the side of the kineticists : gases never
became thoroughly kinetic ; Kelvin acknowledged publicly the
failure of the vortex atom ; in electro-magnetism, Maxwell
abandoned physical and real models for illustrative and symbolic
ones,

24 COSMOLOGY

The Idnetic revival was affected towards the middle of the
nineteenth century by a discovery of more general application
than either gravitation or atomism or kineticism : that of a real
quantity called Energy — the power to do mechanical work.
Mohr, Mayer, Joule, Clausius, Kelvin and Helmholtz discovered
and developed the laws of the conservation and degradation of
Energy. These laws revolutionised the theoretical side of physical
science : a new vocabulary had to be created ; the old text books
had to be rewritten ; well-known and approved theories had to
be revised and restated ; new and promising fields of research
such as physical chemistry became possible. But the most
piquant result of all was the emergence of a scientific heresy under
the name of Energetics. These Energists were a band of scien
tists who condemned all atomic and ethereal hypotheses as useless
and mischievous chimera of the scientific imagination : indeed,
some of them went the length of condemning matter itself as a
chimera, and of seeking to prove by balance and calculi the
existence of nothing but Energy. The attitude towards these
scientific dissenters of the majority of the upholders of that branch
of learning, which rarely lost an opportunity for centuries of
ringing the changes on Galileo, must ever prove a delightful study
for sardonic theologians : there is a lot of human nature even
in scientists. Energetics, unless I be mistaken, has not made
good : it was born out of due time. For just as the Energists
were delivering their sledge-hammer blows on atoms and ethers,
the discovery of the electron fixed the old idols more firmly than
ever in men's minds. But the electron brought the atomic model
of Rutherford and Bohr (1911-22) postulating that all of the
positive and about half of the negative electricity of the atom is
concentrated at the centre, forming a very small body called
nucleus ; postulating also that energy exists in little parcels, the
quanta of Planck. Add to Rutherford and Bohr and Planck the
relativity theories of Einstein and their unknown consequences
in physics, and one realises why from the physicists themselves
there has arisen at long last a cry for a thorough overhauling of
the principles and methods and purposes of physics : in short,
for an epistemology of Physics as an experimental and mathe
matical science.

THEOEETICAL PHYSICS AND ABSTRACT MECHANICS.

Descartes thought to reduce all physics to a geometry of
motions on the assumption of a created indestructible motion.
But this was, as Leibniz pointed out, to forget that Mechanics is
possible only on the condition that the positions of bodies are
determined in their mutual dependence by a relation of force, a
function of time. That is why modern Mechanics was able to
enter on a fruitful development only when the Cartesian view
was replaced by the views of Galileo, Huygens and Newton.
Now this fruitful outlook in Mechanics was permeated from the

PHYSICS AND MECHANICS 25

start by two rival methods which have never since been able to
come to terms : some theoretical physicists have been content,
as occasion arose, to make use of both methods without facing
the question of the superiority of one to the other ; other
theoretical physicists have sought vigorously century after cen
tury for the supremacy of one or other of these two methods.
These rival methods are known as the Galileo-Huygenian and the
Galileo-Newtonian. The Galileo-Huygenian operates almost ex
clusively with the notions of work, mass and vis viva ; the Galileo-
Newtonian operates almost exclusively with the notions of force,
mass and momentum. The one method regards the momentum
of a system of bodies as determined by forces ; the other regards
the vis viva of a system of bodies as determined by work. The
individuality of each student determines largely his choice between
these methods. That is why at the close* of the nineteenth
century, Helmholtz, in the preface to the posthumous work of his
pupil Hertz, acknowledges the logical consistency of Hertz's plea
for the Galileo-Huygenian system of mechanics, but declares his
own preference for the Galileo-Newtonian system. But long before
Helmholtz and Hertz had agreed to disagree on this point, two
facts of importance for the future of theoretical physics had
emerged : the peculiar psychological satisfaction aroused in
men's minds by thinking of matter and motion as the ultimate
explanation of the activities of non-living bodies ; and the
astonishing progress of the science of abstract mechanics.

These two facts secured for Descartes as mechanist a triumph
even greater than his failure as physicist. The pioneers of modern
physics had no sooner discovered, by observation and experiment,
by hypothesis and verification, a number of laws of nature, than
they naturally set about the theoretical explanation of these laws.
Now, explanation must stop somewhere. And what is more
satisfying or more simple than extended particles and local
movements ? Moreover, the success of abstract mechanics was
based solely on the motion of mass-points : the Galileo-Huygenian
mechanics admitted nothing else ; and the force of the Galileo-
Newtonian mechanics was really a mass-acceleration. Hence, the
path seemed clear for explaining everything in the world of matter
by mass and motion, and the task of reducing all physics and
all chemistry to abstract mechanics became a dominant ideal in
theoretical physics. It was always allowed — even prior to the
emergence of contemporary electro-mechanics and of the quantum
theory — that this reduction of Physics and Chemistry to Mechanics
was not complete : still, there was no doubt about its being a
thoroughly sound ideal whose value was continually enforced by
the assimilation of old facts and the discovery of new facts.
The advent of electro-mechanics and of the quantum theory has
made this dominant ideal more difficult. But hope springs
eternal in the human breast : and although at the moment these
divergences in Mechanics are threatening to become, if anything,
rather more than lessjundamental and mysterious, the leaders

26 COSMOLOGY

all look forward to a stage of scientific thought when classical
mechanics and electro-mechanics and the quantum theory shall
be expounded as consistent parts of a homogeneous whole.

THE PKACTICAL INTEREST OF PHYSICAL SCIENCE.

' There always have been, and always will be, several (non-
scientific) interests which induce men to study nature. Some are
driven to it by curiosity or a pure love of nature. To those who
belong to this class the end of the study of nature is to describe
and to portray the objects which surround us, to see and know
them better. . . . This is the genuine love of nature, the con
sciousness that we lose all power if, to any great extent, we sever
or weaken that connexion which ties us to the world as it is — to
things real and natural : it finds its expression in the ancient
legend of the mighty giant who derived all his strength from his
mother earth and collapsed if severed from her. In its extreme
and purest form this interest probably lies at the root of all poetry
and all art, and it accordingly governs a great part of the literature
and thought of the (nineteenth) century. At present it interests
us only as far as it asserts itself also in science. In the study of
natural science we meet with a class of students who are attracted
by things as they are : not so much by those which we artificially
prepare in our laboratories, as by the infinite variety of real
forms ; not so much by the geometrical types which allow us to
bring them together under some abstract formula, as by the
apparent disorder and divine confusion in which real things are
scattered about in the heavens and on our globe. It is not the
general equation which in its complete solution contains all real
and many unreal instances merely as special cases that interests
them, but the individual examples themselves. . . .

" It would seem as if to such minds the scientific formula, the
so-called law of nature, must be distasteful and probably useless.
Nevertheless the scientific view, of which the mathematical
formula is an extreme expression, has reacted, though not always
beneficially, upon the labours of those who confine themselves to
observation and description ; it has given to their efforts gene
ral interest and encouragement, indicated new directions, and
frequently opened new fields. Thus the new formula of Coper
nicus and Galileo gave a great impetus to star-gazing, which was
greatly increased by the almost contemporary invention of the
telescope. ... It seems as if the purest love of nature, the
greatest devotion of the observer and the collector, lead only a
little way in finding out the hidden paths of natural things or the
behaviour of natural objects ; and however grateful we must be
to those pioneers of knowledge who with unrewarded patience
amass the material for later theorists, it is ... to the formulae of
a Newton or a Gauss, followed by the calculations of their pupils,
that we are indebted for a real grasp, for a comprehensive know
ledge, of great masses of natural phenomena,

THE PRACTICAL USE OF PHYSICS 27

" Next to the pure love of nature, the desire to apply natural
knowledge, and to make it useful for practical purposes, has
rendered in return great services to science. The Royal Society
and the Royal Institution had both from their infancy a large
admixture of the practical spirit. These were founded, more
even than the academies abroad, to a great extent upon the
desire to make knowledge useful. . . . The Governments of
England and of France promoted the study of the ' mechanics of
the heavens ' by offering large prizes for scientific and practical
means of determining the longitude at sea. The lunar theory,
which has occupied the attention of the greatest mathematicians
since Newton . . . was an outcome of this. It still engages the
attention of scientific minds, involving as it does all the most
delicate astronomical calculations, whilst for practical nautical
purposes the moon has ceased to be the great timekeeper and has,
since 1763, been replaced by the wonderful chronometers of
Harrison and his successors. A similar stimulus both to abstract
scientific research and to the perfection of the practical instru
ments of measurement was given in this (nineteenth) century by
the development of submarine telegraphy : in this case both sides
of the problem, the scientific and the practical, were attacked and
carried to a high degree of perfection by one and the same mind —
an almost unique instance of abstract reasoning and practical
inventiveness." (20) That mind was Kelvin's : he failed — and
acknowledged failure — at a comprehensive theory of matter, but
he succeeded in patenting more than seventy practical inventions.
" How much science owes to the practical interests of navigation
can be seen at a glance at the subjects contained in the third
volume of Lord Kelvin's Popular Lectures and Addresses. The
Tides, Deep-sea Sounding, Cable-Laying and Terrestrial Magnetism
all furnish important practical as well as highly abstract theoretical
problems, the solution of which demands new instruments and
new methods of calculation . . . ." (21)

c There has always existed one great interest in which nearly
all the descriptive branches of human knowledge have found a
common rallying ground and a uniting purpose — namely, the art
of healing, the alleviation of human suffering and the curing of
disease. During long ages, when the purely scientific interest was
almost dead, physical and chemical research was created and kept
alive by the physician, the alchemist and the apothecary ; medical
works like those of Celsus and Galenus in antiquity have been the
encyclopedias of the existing knowledge of nature, and celebrities
like Boerhave, Linnaeus and Haller in more modern times have
been the living centres of all the natural sciences. The same
uniting bond has not been wanting in our (nineteenth) century,
when it has again, as many times before, manifested its powerful
influence, has brought together researches which were on the point
of falling asunder, and ^infused new life and interest into the
driest of studies. . . . The modern school of medicine originated
in the attempt — begun by Lavoisier in France, but carried out

28 COSMOLOGY

on the largest scale in the chemical and physiological laboratories
of Germany — of making the new discoveries in physical science
and chemistry fruitful for medical purposes and the treatment
of pathological cases." (22)

In all the arts and industries this practical usefulness of mathe
matical and experimental researches is evidenced. " In these
[arts and industries] we do actually abstract the possessions of
nature from their proper hiding-places ; we drag the minerals
from the bowels of the earth ; we cut up the timber of exotic
growth into artificial fragments ; we break up that natural
equilibrium in which electrical and chemical agencies have, for
thousands of years, evaded our discovery and our regard. Having
done so, we create an artificial world of our own making which
ministers to our wants, comforts, pleasures, and supplies that
most inestimable of all commodities of civilisation, varied and
stimulating work for ready hands and active brains. The wants
and creations of artificial life have thus proved the greatest
incentives to that abstract and artificial treatment of natural
objects and processes for which the chemical and electrical
laboratories of the mathematician on the one side, and the
workshop and factory on the other, have in the course of the
(nineteenth) century become so renowned." (28)

These two interests — that of the naturalist and that of the
practical man — are the chief stay of the popular confidence in
Physical Science. At the beginning of the twentieth century
specialists discussed amongst themselves whether the hypotheses
which are at the base of the scientific theories now most generally
accepted were to be regarded as physical realities or convenient
fictions. This momentous discussion ended in hopeless confusion :
one set of specialists held that the atomic and ethereal hypotheses
were convenient fictions — " a person who thought a river was
really a streak of blue paint might learn as much about its
direction from a map as one who knew it as it is " (24) ; another
set of specialists held that the atomic and ethereal hypotheses
were physical realities — " the wreckage of rejected theories is
appalling, but a knowledge of what actually goes on behind what
we see or feel is surelv if slowly being attained " (25) ; a third set
held that atomic and ethereal hypotheses were a blend of fact
and fancy, but that it was difficult to say where the one ends and
the other begins — " a man peering into a darkened room and
describing what he thinks he sees may be right as to the general
outline of the objects he discerns, wrong as to their nature and
their precise forms." (28) And apart from all these groups, you
had the Energists denouncing atoms and ether as utterly mis
leading fictions of the scientific imagination. But the public
heeded not and heeds not these worries of the master-minds of
Physical Science. So long as Physical Science describes the
beauties of lifeless bodies as they are, so long as it calculates and
foretells accurately the happening of perceptible events, the

IKK AT I <>Nf A 1 1 SCIENCE 29

pi 1 1.1 ie \M content : the naturalist and the practical worker take
no interest in the deeper aspects of Physical Science.

THE MANUFACTURE AND DIFFUSION OF IRRATIONAL SCIENCE.

-ir William (Kelvin) "—writes Professor Thompson, quoting
I h II it < hinson, " in my time had three favourite subjects, on
each of which he was sure to go off at a tangent whenever the
smallest opening was presented* One of these was the Cambridge
•in of examinations. . . . Equally severe he was on our
in i ilar barbarous system of weights and measures. . . . Bat
Si i William's anger on these two subjects was as nothing compared
with what it was on the third. This was— Hegel. If vou wanted
to see an illustration of pure white heat you should have seen
Sir William castigating Hegel for the audacity of his assaults on
the Newtonian philosophy. I remember on one occasion he sent
over to the library for the learned volume containing Hegel's
criticism of Newton in order that we might hear the iprisrinut
verba, the downright nonsense of this arrant impostor*. I
remember the expression perfectly both from its native force and
the vehemence with which it was uttered. . . . In my time nothing
was more characteristic of Sir William than the thoroughness
with which he thrashed out every subject he took up. His
students were persuaded that he knew everything about a subject
that could be known, and they felt he was perfectly justified in
his sometimes rather unsparing language about charlatans,
'showmen/ mere brilliant experimenters who wished to [..»;.• as
philosophers. In fart, our faith in him went so far that I h;»ve
neard some of the best students say they were hardly satisfied
with anv philosophical theory till it had Sir William's imprimatur,
and were almost content to accept it as all ri^ht if it got that.

11 The particular passage" — continues Professor Thompson
after eoneludiiiL: this ouotation from Dr. I lnt«-hinM»n " in Hegel
which aroused Sir William to scorn was the attack on Newton's
theory of planetary motion around the sun : * The motion of the

his u-a;i or fix it (such as

motion ; they go along at

celestial <-urfnn-eii>/ fe >mt

r motion external 'to itself.

consist* of stones, and tie

kes the properties of the whole the tame as those of the
lse, Pressure, Resistance, Friction, Attraction, and the

I onli/ for tin existence of tnattcr other than celestial. . . .'
ords ! ' Sir William would sav. 'If, gentlemen, these
ics, think what his metaphysics must be.' It was

perhaps lir^ haired of tin- school of thought whieh exalt-- wordv

description about rigid demonstration, that gave Lord Kelvin

more or less of a bias against all metaphysics, and to some extent
a-jain t .ill DOM ^vmliolie philo-ophv. Herein lie (liiTered greatly

30 COSMOLOGY

from Helmholtz. whose habitual philosophical thought was of far
wider sweep. He did not even appreciate the achievements of
the greatest of contemporary English leaders in philosophy, for
he wrote : I have never been of opinion that the philosophical
writings of the late Mr. Herbert Spencer had the value or impor
tance attributed to them by many readers of high distinction. In
my opinion a national memorial would be unsuitable.

" Lord Kelvin's contempt for metaphysics was often expressed
in the interjected obiter dicta of his class-room. ' Mathematics
is the only true metaphysics,' was another saying. . . . The
following story was narrated by Lord Kelvin himself when dining
at Trinity Hall. A certain rough Highland lad at the university
had done exceedingly well, and at the close of the session gained
prizes both in mathematics and in metaphysics. His old father
came up from the farm to see his son receive his prizes, and
visited the college. Thomson was deputed to show him round
the place. ' Weel, Mr. Thomson,' asked the old man, * and what
may these mathematics be, for which my son has getten a prize ? '
I told him, replied Thomson, that mathematics meant reckoning
with figures, and calculating. ' Oo ay,' said the old man, ' he'll
ha' getten that fra' me ; I were ever a braw hand at the countin'.'
After a pause he resumed : ' And what, Mr. Thomson, might
these metapheesics be ? ' I endeavoured, replied Thomson, to
explain how metaphysics was the attempt to express in language
the indefinite. The old Highlander stood still and scratched his
head. ' Oo ay, maybe he'll ha' getten that fra' his mither. She
was aye a bletherin' body.' " (27)

I hold no brief for Hegel or Hegelianism. But it is worth the
reader's while to give some attention to this illuminating account
of the manufacture and diffusion of irrational science in the nine
teenth and twentieth centuries by men whose physical and mathe
matical achievements rightly won a world-wide reputation. This
extract cannot be dismissed as the fabrication of an enemy of
science : it is taken from a biography begun in 1906 with Lord
Kelvin's co-operation, and based at every stage of its progress
upon the accounts of many prominent colleagues and old pupils
of Kelvin. It is, then, an authentic account furnished by men
who lived and worked at some of the most famous centres of
contemporary scientific thought. Now, Kelvin was an out
standing figure in his own special domain of work. So was his
biographer, Professor Silvanus P. Thompson. Both of them
spent their lives at pursuits in which extraordinary patience of
judgment and rigorous accuracy of research are essential to that
genuine success which was theirs. We might reasonably expect,
then, that even the obiter dicta of such men in branches of study
wholly distinct from their own would show some trace of that
profound veracity which, is the secret of the truth-seeker in every
department of research.

But, in their attitude to Hegel and to Metaphysics, we find
ourselves confronted with an exhibition of prejudice that is

IRRATIONAL SCIENCE 31

redolent of the methods of the Homeric and Hesiodic poets.
Lord Kelvin refutes Hegel's system of Objective Idealism by
quoting for the raw youths of Glasgow University an extract of
less than a dozen lines. With the skill of a practised showman,
he strives to add solemnity to this farce played upon a callow
audience by sending from the class-hall to the library for a volume
of Hegel. Dr. Hutchinson, a Glasgow Headmaster, regales the
readers of the Glasgow Herald with picturesque details concerning
this gigantic intellectual feat. Kelvin entertains his colleagues
in Hall with the verdict of a Highland peasant on the value of
" metapheesics." Kelvin spurns Spencer. Poor Spencer ! His
evisceration of the philosophy of matter ought to have been
complete enough for Kelvin the kineticist. Probably, his views
in biology and in anthropology had angered Kelvin the theologian.
Then, we have Professor Thompson piously retailing these
doughty characteristics of his hero : giving in a note Hegel's
passage in the original German, in order, as he tells us, that readers
may better understand its illogical silliness ; contenting himself
with a perfunctory admission of the vastly greater mind of
Helmholtz ; betraying his own mentality by styling Spencer the
greatest contemporary English philosopher. Nor are those
irrational scientific prejudices limited to Kelvin and his associates.
Anyone who reads the obiter dicta of other militant scientists
about metaphysics cannot doubt but that, in this short and easy
method of damning metaphysics, Kelvin had and has a large
following in the English-speaking world among the zealots of
physics and mathematics. And in our full-crammed and much-
examined generation, irrational science of this kind spreads as
quickly and as widely as influenza.

The kind of solemn nonsense that is manufactured and spread
by methods like these may be aptly illustrated by applying them
to the astronomical achievements of Sir Isaac Newton. " If
Sir Isaac Newton," says Sir David Brewster,(28) writing at about
the time Kelvin began those famous onslaughts in class on Hegel,
" had not been distinguished as a mathematician and a natural
philosopher, he would have enjoyed a high reputation as a
theologian." And Sir David mentions first among the principal
theological writings of Sir Isaac, the work : Observations upon the
Prophecies of Daniel and the Apocalypse of St. John. The student
who has the curiosity to unearth this volume from some old
library will get the lesson of his life about the worth that ought
to be attached to the studies of a physical and mathematical
genius when off his beat. This vaunted book is a mine of
seventeenth-century Protestant fables about the Pope and the
Catholic Church presented adroitly under the gmse of a historic
vindication of the truth of certain prophecies in Daniel and in
St. John.(29) All the strong phrases of Daniel that used to
appeal so much to Protestants are emphasised by Sir Isaac : the
eleventh horn of the fourth Beast who speaks great words against
the Most High and wears out the Saints until a time, times and

32 COSMOLOGY

half a time ; the king who reigned with a look more stout than
his fellows, and into whose hands times and laws were given ; the
judgment that is to sit after a time, times and half a time, and
the transference by degrees unto the people of the Saints of the
Most High whose kingdon is to be everlasting ; the king who
shall exalt himself above every god and shall not regard the god
of his fathers, nor the desire of women, and shall honour with
gold and silver and precious stones and pleasant things a god
whom his fathers knew not ; etc., etc. Sir Isaac emphasises in a
similar manner the favourite texts of primitive Protestantism in
the Apocalypse : at the opening of the fifth seal, the woman
clothed with the sun and moon but who is beginning to go astray
and to need admonitions ; the change in this glorious woman
owing to her arrival at temporal dominion on the back of the
Beast where she is fed from the face of the serpent, is nourished
by the merchants of the earth, made drunken with the blood of
Saints until at last she is clearly recognisable as the iniquitous
eleventh horn of Daniel's fourth Beast ; the second Beast who
rose out of the earth and had horns like the Lamb but spoke like
the Dragon and was, therefore, of the Dragon's religion ; the
final apostasy of the woman when her corruption is signalised by
her being divided into the great whore of Babylon and the two
horned Beast ; at the opening of the seventh seal, the prevalence
of the Great Apostasy and the revelation of the Man of Sin ; the
excommunication of all who had not the mark or name or number
of the Beast ; and so on — until we come to the 144,000 who are
sealed out of the twelve tribes of Israel and become the Two
Witnesses of the true Church in all times and places. Sir Isaac
delighted the heart of the Kensitites of his time by the unfailing
accuracy with which page after page he pointed out the unmis-
takeable fulfilment of all these iniquities in the superstitions
of the Roman and of Greek Churches — the Papacy, celibacy,
purgatory, image-worship, ghost- worship, demon-worship, relic-
worship : his skill never fails him for a moment in showing
exactly which one of these superstitions was present to the minds
of Daniel and of St. John as they wrote line after line of their
prophecies. And when this labour tires himself or his readers
he enlivens his pages with delectable tales about the temporal
intrigues of the Pope, about the source of the splendid oblations
made at Rome, and about the origin of the practice of kissing the
foot of the Pope. All this mischievous nonsense was food and
drink to Newton himself as well as to his contemporaries. There
is no more dogmatic or testy mortal than the mathematician or
the scientist who starts writing on topics which his special studies
never permitted him to explore thoroughly. Newton was no
exception. When Halley once ventured to jest with Sir Isaac
about these theological by-products, he curtly repulsed him with
the remark : "I have studied these things ; you have not ! "

Kelvin was, despite his extraordinary talents, no Newton.
But he had. just as Newton had, a streak of the lay theologian in

IRRATIONAL SCIENCE 33

his temperament. He was a conscientious bible-reader and, late
in life, became President of the Largs and Fairlie Auxiliary of
the National Bible Society of Scotland. " Of sacerdotalism and
ritualism in all its phases and forms he had an unconcealed
detestation. He even went so far as to write that the only sense
in which he could regard the High Church as high, was the same
as that in which game is said to be high — when it is decom
posing." (30) Moreover — and this is apparently another uncon
scious portraiture of a delightful trait — " he was strongly opposed
to the secular solution of the religious difficulty in primary educa
tion. He was equally strongly opposed to denominationalism in
schools, particularly in Ireland." (31) This being our man once
he left his laboratory, it is not safe to assume that Kelvin would
dissent from any of Newton's conclusions in the Observations.
Happily, the truth or falsehood of these conclusions is nowadays
of no practical concern. And, at any rate, our chief interest lies
in the method of proof by which the giant mind of Newton
reached these conclusions. Newton employed of course all the
cabbalistic arts of preceding Protestant interpreters : time is a
calendar year of 360 days ; locusts are Turks ; the lives of locusts
are five months ; but the locusts of the prophecy had two lives —
five months at Damascus and five at Bagdad ; thus we arrive at
ten months or 300 prophetic days which are the years from 637
to 936 inclusive ; and so on ad nauseam. But his chief proof of
the historical allusion of these prophecies had the simplicity of
genius : he quotes in italics a text of Daniel or of St. John ; and,
at intervals, he interpolates in non-italicised letters such words
as make each text refer to the superstition at which he decrees
it must have directed. Ah uno, disce omnes. Here is his proof
that celibacy was prophesied to be an unscriptural superstition in
Daniel (xi. 37) : " Neither shall he regard the lawful desire of
women in matrimony." (32) Proofs like these — there are none
other in this volume of Newton — must appear to the profane eyes
of every unprejudiced reader to be bare shams : yet, Newton's
anger with Halley shows that, in the seventeenth century, these
shams, naked but not ashamed, paraded in the highest scientific
circles of Protestant England. Now if Kelvin's prejudice against
sacerdotalism and ritualism had not deprived him of the use of
reason, he ought, had he ever read this volume of Sir Isaac, to
have been shocked at the silliness of mind which professed to
reach truth by these childish sophistries. Suppose he was thus
shocked, can you imagine him interrupting his class-work and
sending to the library for Sir Isaac's Observations in order that
Dr. Hutchinson and the others " might hear the ipsissima verba,
the downright nonsense, of this arrant impostor " ? And when he
had read proofs like those just quoted would he exclaim heatedly :
" Hear his words ! If, gentlemen, that be his way of proving
facts about human beings, think what the value of his celestial
mechanics must be ! " ? Not he. And would Kelvin when dining
in Hall, tell his colleagues about the old Highlander who, on

34 COSMOLOGY

hearing of his son's success in Protestant Prophesying and in
Newtonian Astronomy, said : " He'll ha' getten the gift of inter-
pretin' prophecy fra' me, I were ever a braw hand at No Popery ;
maybe he'll ha' getten the star-gazing stuff fra' his mither, she
were aye a bletherin' body " ? Not he. Had Kelvin been foolish
enough to amuse his students and his colleagues by exposing the
sham proofs of Newton, would Dr. Hutchinson on the occasion
of Lord Kelvin's elevation to the peerage retail such feats amongst
his lively reminiscences for the entertainment of the readers of
the Glasgow Herald ? Would Professor Thompson reverently
gather them all into the official biography ? Would he quote the
original text of Newton's Observations in order to show his readers
more clearly its illogical silliness ? No : if Professor William
Thomson had signalised his teaching at Glasgow by meting out
to Newton the kind of treatment he found popular in the case of
Hegel, Othello's occupation was gone. There never would have
been a Baron Kelvin of Largs whose metaphysical prejudices
might safely be boosted and endorsed by Dr. Hutchinson and
Professor Thompson. Not he. Not they. There is honour
among thieves. But Kelvin and the Kelvinites make no scruple
of attempting to wield, against Hegel, controversial methods so
utterly unfair that they might be employed far more successfully
to blast, in the minds of the half-educated, the fame of the author
of the Principia. Yes : any stick is good enough to beat a dog
so long as you know the onlookers to be either uncritical or
indolent.

But what about the extract from Hegel ? Many who would
disdain to take any personal part in that kind of propaganda
against Hegel, which was carried on so long and with such gusto
by Kelvin and his admirers, will urge that, after all, the incrimin
ated extract deserved some kind of public castigation at the hands
of the votaries of mathematical physics. That is not so. Read
the passage for yourself in the original, and you will see that this
academic lynching was initiated and pursued on a bogus charge.
The mathematical and physical implication of the extract is
simply that gravitation is not an ultimate property of matter.
That view — from a different standpoint — was the guiding idea of
every kinetic theory which Kelvin, at different periods of his life,
either suggested or supported. The scientific and mathematical
proof of such a view eluded the scientific experts of Kelvin's day.
Some think that Einstein has brought it within the reach of our
generation. But, whether gravitation be or be not an ultimate
property of matter, there is not a word in the incriminated
extract, or indeed elsewhere in Hegel, that puts the slightest
restriction on the free play, in its appropriate sphere, of the
methods and achievements of mathematical physics.

The upshot of all this discussion about the "manufacture and
diffusion of irrational science is, that, despite the genius of the
one and the extraordinary talent of the other for mathematical
and scientific research, we have discovered in Sir Isaac Newton

THE PURPOSE OF MODERN COSMOLOGY 35

as lay interpreter of Daniel and the Apocalypse and in Sir William
Kelvin as lay interpreter of Hegel and Metaphysics, the immortal
cockney of ^Dickens. " ' God bless me, what is the matter ? '

cockney

This last was an ejaculation of irrepressible astonishment, occa
sioned by seeing Mr. Pickwick, in his enthusiasm for discovery,
fall on his kness before the little stone and commence wiping the
dust off it with his pocket handkerchief. . . . The astonishment
of the village may easily be imagined, when (the little stone having
been raised with one wrench of a spade), Mr. Pickwick, by dint
of great personal exertion, bore it with his own hands to the inn,
and after having carefully washed it, deposited it on the table.
The exultation and joy of the Pickwickians knew no bounds,
when their patience and assiduity, their washing and scraping,
were crowned with success. The stone was uneven and broken,
and the letters were straggling and irregular, but the following
fragment of an inscription was clearly to be deciphered :—

t

B I L S T

U M
P S H I

S. M.
A R K."

THE PURPOSE OF MODERN COSMOLOGY.

These sketches of modern physics and modern mechanics may
help the beginner to realise the genuine meaning of the methods
and results of modern physical science. But the present volume
shall introduce him only to thinkers who had none of the worries
raised by the enormous progress in its own domain of modern
science. The thinkers of Greece were at once scientists and philo
sophers. The thinkers of the Middle Ages went one better : they
were scientists, philosophers and theologians. Those days, — when
knowledge despite its originality and depth was so limited in
extent that anyone who had brains enough to be an expert in
anything might, if he chose, be an expert in everything — are over
centuries ago : Leibniz was the last to make any kind of successful
attempt at this kind of encyclopaedic learning ; he did not succeed
wholly, and every later attempt was that of a charlatan. Modern
progress in knowledge has become possible only since men began
to realise that this boasted mastery of all knowledge was really
an obstacle to mental progress. For centuries past, the funda-
mefttal condition of progress in research has been the division of
labour, the restriction of individual inquirers to limited provinces
and the investigation of those provinces as a life-work. That is

36 COSMOLOGY

why nowadays the philosopher ought to be simply a philosopher
and the scientist simply a scientist : ne sutor ultra crepidam.
" It is true, of course, that other things being equal, the better
stored the mind of the philosopher with scientific facts, the
sounder will be his judgment on the interpretation and implica
tions of the whole body of facts. But, at the same time, the gifts
which make a successful experimentalist and investigator of facts
are not altogether the same which are required for the philo
sophical analysis of the implications of facts, nor are both always
conjoined in the same man. There is no reason, on the one hand,
why the able experimenter should be compelled to desist from the
discovery of the facts of nature until he can solve the philosophical
problems presented by the very existence of a world of physical
facts : nor, on the other, why the thinker endowed by nature
with powers of philosophical analysis should be forbidden to
exercise them until he has mastered all the facts which are known
by the specialists. "What the philosopher needs to know, as the
starting-point for his investigation, is not the specialist's facts as
such but the general principles which the specialist uses for their
discovery and correlation. His study is a ' science of sciences '
not in the sense that it is a sort of universal encyclopedia of
instructive and entertaining knowledge, but in the more modest
sense of being a systematised reflection upon the concepts and
methods with which the sciences, and the less methodical thought
of everyday practical life work, and an attempt to try them by
the standard of ultimate (reality) and intelligibility." fa)

Cosmology, then, means the critical examination of the con
sequences involved in the recognition of matter as a distinct
class of existent and of the more general hypotheses, employed by
popular thought and scientific reflection respectively, for the
explanation of matter and its properties. Hence the work of
Cosmology may be said in modern times to begin where that of
the empirical and mathematical sciences leaves off. Its data are
not so much the particular facts directly amassed by experiment
and observation, but rather the hypotheses used by the experi
mental and mathematical sciences for the co-ordination and
description of these facts. And it examines those hypotheses
not for the purpose of modifying their structure so as to include
new facts or to include the old facts in a simpler way, but purely
for the purpose of estimating their value as an account of the
ultimate reality of matter. Whether these hypotheses are ade
quate as implements for the purposes of the natural scientist is a
question which Cosmology, as I understand it, leaves entirely to
the professors of physics and of mechanics. Whether these
hypotheses can claim to be more than this, whether they can
claim to give us a grasp of the ultimate nature of matter and its
properties, is a problem that can be dealt with only by that
science which professes to attempt a systematic analysis of the
real meaning of matter — Cosmology.

The empirical and mathematical sciences of matter differ from

THE PURPOSE OF MODERN COSMOLOGY 37

one another not because they deal with different parts of the
world of matter but because they deal with all that world from
different points of view. Physics deals with the weight, sound,
light, heat, electricity, magnetism, and local motion of matter.
Crystallography deals with the geometric shapes of matter.
Mineralogy deals with the minerals of which the crust of the
earth is composed : classifying them physically, chemically, and
geologically. Chemistry deals with the factors and conditions of
chemical change in matter. Geology investigates the manner of
formation of our globe. And so on. There is no need, then, for
Cosmology to pretend to deal with facts that lie outside the
province of these and cognate sciences of matter. It shall have
verified its right to be accepted as a science alongside these others,
provided it can show that it deals with matter and its qualities
from a point of view which is not that, of any one or of all, of these
sciences. The only sufficient answer to those who deny the
possibility of this cosmological point of view is to work out a
systematised body of conclusions distinct from those reached in
these modern sciences of matter. This I shall endeavour to do
in the second volume of this work. All that can be done here is
to utilise the information already given, in this Introduction, for
presenting the kind of questions which, modern Cosmology claims,
can and ought to be raised about matter and its properties.

The world of matter appears to the plain man to be composed
of a multitude of apparently independent, inanimate, bodies :
each of these bodies appears to him to be in some sense a unitary
being ; each of them appears also to possess an indefinite number
of qualities ; each of them appears to be caught up in a web of
connexion with the others — acting on these others and being in
its turn acted on by them in a variety of ways. The student of
Physics or of Mechanics has a different view of that same world
of matter. The classical Physics aimed at accounting for that
world in one or other of several ways : mobile massive particles
without indwelling central forces ; mobile massive particles with
indwelling central forces ; protons and electrons with varying
and extrinsic mass. The classical Mechanics aimed at accounting
for that world by mass and mass-acceleration ; "in abstract
dynamics, matter is considered under no other aspect than as
that which can have its motion changed by the application of
force " (34) ; in abstract dynamics, force answers to the differential
coefficient of the distance as a function of the time, or " is no more
an objective entity than say 5 per cent, per annum is a sum of
money." (35) And when we pass from the classical Physics and
the classical Mechanics to their respective " romanticisms " as
represented at the moment by Rutherford and Bohr, by Planck
and Einstein, stranger tales still are suggested of what lies behind
the plain man's view of material bodies and their qualities : tales
not yet fully told by their authors, tales whose consequences no
scientist or mathematician can foretell.

These views of the plain man, the physicist, and the mechanist,

38 COSMOLOGY

are as far apart as the poles. Add to these existing chasms, the
possible volcanic eruptions consequent on the developments in
Physics and Mechanics which I have styled romantic. Immane
quantum discrepant ! Now the vital question in Cosmology is the
simple one — How far and in what sense can any. or all, of these
views be true of the reality of matter and of the reality of its
properties ? And here are some of the questions that must be
asked in trying to face that simple problem. What is the genuine
reality corresponding to the mass-points of the classical mechan
ists or the non-massive electrons of electro-mechanics ? The
most widely supported views in our days, outside the Scholastic
School, come as a shock to common sense : these non-scholastic
theorists tell us that the ultimate entities of the mechanist are
either purposive beings or unextended forces. Can either of these
be true ? Both, apparently, fit in admirably with all that Physics
and Mechanics can and do teach. So it is little use to appeal to
such sciences for a solution. The next question of paramount
interest is the existence or non-existence as formal extra-mental
realities of the proper sensibles. Democritus, Descartes, and
nearly all modern scientists declare these to be sense-illusions.
Aristotle, the School and many modern Hegelians declare them
to be objective realities. Where is the truth ? And if the proper
sensibles are not mere sense-illusions, what is their relation to
material substances : are they separable accidents or are they
inseparable modes of substance ? ^Then, the question arises of the
apparent unity of the ultimate particles of matter. If these
particles are either psychic entities or unextended forces, that
worry is easily solved. But for the man who sticks to formal
extension, this worry looms large. How can that, which is
neither living nor conscious and yet has parts outside parts, be in
any genuine sense a self-subsisting being ? That problem was
obvious to Aristotle and the School : for them every paving-stone
was a single substance — not to talk at all of the Rhine or the
Atlantic. But it is not got rid of by being buried in the ultra-
atomic entities of contemporary Physics. A scale model of an
atom as big as the dome of St. Paul's in London would, we are
told,(36) display its electrons as little larger than pin-heads, and
its protons as dust particles invisible to the naked eye. The
nucleus of 1iis_atom is said to consist of all the positive electricity
and about half of the negative electricity : that is, of all the
protons and about half the electrons. This nucleus is extremely
small compared with the whole atom : thus, if we represent the
nucleus of the atom of helium — consisting, it is alleged, of four
protons and two electrons — by a rather large pea, its planetary
electrons may be represented on the same scale as two rather
small peas revolving round it at a distance of a quarter of a mile.
This is tininess with a vengeance. Still, if any part of the nucleus
or of the planetary electrons be formally extended that part has
a North and a South, an East and a West, as truly as the continent
of Europe. Now the continent is only a unit of matter in a

THE UTILITY OF COSMOLOGY 39

metaphorical sense : but those who refuse to declare formal
extension a sense-illusion must allow the ultimate continuous
infinitesimal particles of matter to be a substance, that is, to be
a unitary centre of existence and of activity. How can this be ?
How can this extended manifold exist and act as a unitary being ?
Science does not worry about the fact. Cosmology must so worry
or else cease chattering about the existence of extended substances.
And when the cosmologist is done with the question of substance,
that of cause engages his attention. The plain man believes in
the interaction of material bodies. Science accounts for that
interaction by the communication of motion from one body to
another. The fact is undeniable, but how can it occur ? Do
bodies when they collide share their motions as men exchange
moneys when marketing ? Can bodies shed their motion as
snakes slough their skins ? Is motion a kind of internal liquor
which bodies can emit and pass on to their neighbours, just as
restless spiders in autumn emit from their spinnerets those fine
separate threads of silk that speed through the air as showers of
gossamer to settle down on hedge-row and moor ? And if to
escape these absurdities, the alarmed student plumps for indwell
ing central forces, he appears to be stepping gently from the frying-
pan into the fire. Motion is motion ; there is no gainsaying that.
But force — what is that ? A cause of motion ? Where does it
reside ? In the protons or electrons or some infinitesimally small
lump of matter ? And how ? Are forces stuck in substances
like currants in a cake ? And when a force is diminished by
action and reaction, does this mean that the force is extracted
from the substance somewhat after the manner in which a currant
is picked out of a cake by a child ?

These are some of the questions that arise out of the simple
problem set the cosmologist of finding out whether and how far
the plain man, the physicist, or the mechanist, is speaking the
ultimate truth about matter and its properties. With the single
exception of that one about the reality or illusion of the proper
sensibles, none of these questions is ever discussed in Physics and
Mechanics or any of their sub-branches. There is, then, a big
field for the cosmologist. And if it be said that all these questions
of the cosmologist, intelligible as they are, are unanswerable, the
answer is obvious. You never know till you try, and you cannot
make that trial without wading through the pages of Cosmology.
Even should that trial convince you that the quest of the cosmolo
gist, alluring though it seem, is nothing else but a chase after a
will o' the wisp, your labour is not lost. You have crossed the
chasm between ignorant learning and learned ignorance.

THE UTILITY OP COSMOLOGY.

Where ignorance is bliss, 'tis folly to be wise : this is appar
ently the most powerful piece of heavy artillery in the armour of
certain critics of Cosmology. In showing its feebleness, St.

40 COSMOLOGY

Thomas takes high ground : a sound philosophy of matter is
essential to a sound philosophy of theism, and a sound philosophy
of theism is essential to a sound defence of Catholicism. But
before citing this argument of St. Thomas and the commentary
thereon by Leo XIII. and his successors, I would suggest other
considerations more level with the mental outlook of this kind of
critic : there is no accounting for tastes : beggars can't be
choosers.

There is no accounting for tastes. There are men to whom
Hunger and Love, Work and Play are the only things worth
while. There are men whose supreme interests are State and
Church or either of these. There are men whose supreme interests
are Art and Literature and Science or one of these. Similarly,
there are men whose supreme interests in life are speculative :
men for whom the effort to give some rational account of the
riddle of the universe is an irresistible passionate desire. Re
vealed Religion knows in the realm of intellect no more powerful
friend, no other foe, than these rationalistic seekers after the
Infinite : the metaphysics of St. Thomas and Duns Scotus saved
the Catholic universities of medieval Europe from the paganism
of Averroism ; the metaphysics of Spinoza and Kant left the
Protestant universities of modern Europe an easy prey to every
form of revived Paganism. Now, it is from such seekers after
the Infinite that Metaphysics gathers age after age its votaries :
for them, the" study of Metaphysics is its own justification and its
own reward.

Beggars can't be choosers. Lazarus must eat of the crumbs
and must allow his sores to be licked : if he eat not, he dies ;
if he be not licked, he rots. Every man is in a similar plight
with reference to Metaphysics. The most complacent non-meta
physician and the most virulent anti-metaphysician accept or
advocate some particular solution or no-solution of the riddle of
the universe : they may never be aware of the existence of such
a branch of learning as Metaphysics, or they may never have
given a moment's thought to its value ; yet, the existence of
Metaphysics is at the root of all those safeguards against facile
and random theories of life and life's aim, which tend to destroy
the spontaneous moral vigour of that environment in which our
critics live and whose standards they accept. It is puerile, then,
to talk of the uselessness of Metaphysics : every child of Adam
is, in reference to Metaphysics, a Dives or Lazarus or a something
between these extremes. None of us can avoid having some kind
of Metaphysics : if our Metaphysics be not conscious and rational,
it will certainly be unconscious and will run the gravest risk of
being irrational. Our one hope is to be as metaphysical as our
talents and our opportunities permit : otherwise the likelihood is
that, on the great problem of the ultimate purpose of human life,
we may be but travelling " from the smoke into the smother."

Metaphysics at the root of the gravest issue in human
existence ? Perhaps, when it deals with the soul or with God

METHOD IN COSMOLOGY 41

but — Cosmology, the Metaphysics of sticks and stones, of clouds
and rainbows ? " No man dare despise," writes St. Thomas,!37)
" the science treated in this book (Meteor, iv.) or indeed any part
of the science of nature : in fact, he who despises natural science
despises himself. It is true that many writers make little of the
natural sciences on the ground that such sciences are useless for
that speculation about divine truth which is, as the Philosopher
says in the tenth book of the Ethics, the happiest and most
desirable life for man. Such writers, however, are mistaken.
The science of this book and all the sciences of nature — not
merely those which deal with general truths but also those which
deal with particular facts and the properties of each being — are
helpful in making God known to us : for we arrive at a knowledge
of causes by starting from those obvious and natural facts which
are their effects. That is why the Philosopher in his Metaphysics
begins with perceptible substances and in the twelfth book
proceeds to prove by astronomical reasoning the nature of
separated substances. That is why no matter what science we
are studying, we study it for the purpose of a knowledge of divine
things : indeed, any other motive in the study of science is
perverse except in the case of those who have to study science
for a livelihood." This is the language of a metaphysician who
was also evidently a man of common sense. Leo. XIII. and his
successors are never weary of reminding the Catholic schools of
this broad outlook of St. Thomas. These Pontiffs insist that all
hopes of the Catholic Church ever recovering that ascendancy
which she has lost over the intellect of Europe depend on a sound
Philosophy, and that all hopes of a sound Philosophy depends
to-day on an alliance with Physical Science. If that be so,
Cosmology — the philosophy of matter — must be worth a good
deal to the Catholic student.

METHOD IN COSMOLOGY.

" There are three different ways in which the criticism of
philosophic, of all speculative opinion whatever, may be con
ducted. The doctrines of Plato's Republic, for instance, may be
regarded as so much truth or falsehood, to be accepted or rejected
by the student of to-day. That is the dogmatic method of
criticism ; judging every product of human thought, however
alien or distant from one's self, by its congruity with the assump
tions of Bacon or Spinoza, of Mill or Hegel, according to the
particular mental preference of the particular critic. There is,
secondly, the more generous, eclectic or syncretic method, which
aims at a selection from contending schools of the various grains
of truth dispersed among them. It is the method which has
prevailed in periods of large reading but with little inceptive force
of their own, like that of the Alexandrian Neo-Platonism in the
third century, or the Neo-Platonism of Florence in the fifteenth.
Its natural defect is in the tendency to misrepresent the true

42 COSMOLOGY

character of the doctrine it professes to explain, that it may
harmonise thus the better with the other elements of a pre
conceived system.

" Dogmatic and eclectic criticism alike, have in our century,
under the influence of Hegel and his predominant theory of the
ever-changing ' Time-spirit ' or Zeit-geist, given way to a third
method of criticism:, the historic method, which bids us replace
the doctrine, or the system, we are busy with, or such an ancient
monument of philosophic thought as the Republic, as far as pos
sible in the group of conditions intellectual, social, material amid
which it was actually produced if we would really understand it.
That ages have their genius as well as the individual ; that in
every age there is a peculiar ensemble of conditions which deter
mines a common character in every product of that age, in business
and art, in fashion and speculation, in religion and manners, in
men's very faces ; that nothing man has projected from himself
is really intelligible except at its own date, and from its proper
point of view in the never-ending ' secular process ' ; the soli
darity of philosophy, of the intellectual life, with common or
general history ; that what it behoves the student of philosophic
systems to cultivate is the ' historic sense ' : by force of these
convictions many a normal, or at first sight abnormal, phase of
speculation has found a reasonable meaning for us. As the
strangely twisted pine-tree, which would be a freak of nature on
an English lawn, is seen, if we replace it, in thought, amid the
contending forces of the Alpine torrent that actually shaped its
growth, to have been the creature of necessity, of the logic of
certain facts ; so, beliefs the most fantastic, the ' communism ' of
Plato for instance, have their natural propriety when duly corre
lated with those facts, those conditions round about them, of
which they are in truth a part." (38)

Pater — from whom I take this excellent account of the three
different ways of studying philosophical opinions — was mistaken
in thinking that Hegel introduced the historic method of criticism
into the study of philosophy : being probably led to this con
clusion by the fact that, as Descartes and Kant had neglected
the historic method, Hegel's reintroduction of a method as old
as Aristotle seemed to many the invention of a new way of
philosophising. Chief among Aristotle's services to rationalism
was his insistence on historic criticism as a necessary preliminary
to systematic study of any subject : he did this in Politics ; he
did this in General and in Special Metaphysics. He opens his
First Philosophy, his first treatise on Physics, and his Treatise on
the Soul with detailed historic criticism of his predecessors. The
introduction to his First Philosophy consists of a whole book
containing nine chapters devoted solely to the historical exposi
tion of the views of his predecessors in Ontology and Rational
Theology. The introduction to his first treatise on Physics
consists of a whole book of nine chapters similarly occupied with
the views of his predecessors in Rational Cosmology. The intro-

METHOD IN COSMOLOGY 43

duction to his Treatise on the Soul consists of a whole book of
five chapters devoted to nothing else but a historical account of
preceding Kational Psychology. And as the metaphysical
treatises of St. Thomas and of Duns Scotus are really line-to-line
commentaries on the text of Aristotle, they and theirs also made
the historic method of criticism the basis of their studies in
philosophy. Passage after passage of Aristotle, of St. Thomas, of
Scotus explain why philosophy should be grounded on the historic
method. (39) Here are some passages from St. Thomas. " He
(Aristotle) tells us the reasons why here and elsewhere he discusses
the opinions of others. ... It is necessary for the truth-seeker
to solve doubts because, as is laid down in the third book of the
Metaphysics, the solution of doubts is the discovery of truth.
And that is why the arguments of our adversaries are a great
help in the search after truth. ... He (Aristotle) gives four
reasons for this plan of his (of making the historic method of
criticism an essential feature of all his Metaphysics). The first
is that anyone who seeks after truth must begin by doubting
stoutly : because the finding of truth is nothing else but the solving
of doubt. Every one knows that a man who cannot see where the
knot is cannot untie a bandage. But a doubt in one's mind is
like a bandage on one's body and produces the same effect : the
doubter suffers inconveniences analogous to those of the bound.
When a man's legs are tied he cannot march forward, and when
a man has his mind tied up by a doubt he cannot make any
progress in speculation. That is why he who wishes to solve any
doubt must begin his work by examining all pertinent difficulties
and their causes : just as anyone who wishes to untie a bodily
knot must begin by studying the knot and the way it is made.
His second reason is that those who wish to investigate truth
but are unwilling to start with doubting may be likened to
travellers who do not know where they are going. The reason is
that just as the goal of his journey is intended by the pedestrian,
so the overcoming of certain doubts is the goal of the truth-seeker.
But it is clear that anyone who does not know where he is going
cannot go straight — except by chance : therefore, no one can
keep on the right road in the search for truth unless he knows
beforehand the doubts of the question. His third reason is as
follows. He says that just as anyone who knows not where he
is going cannot know when he really arrives at the goal, whether
he is to stop there or go farther, so the person who does not know
beforehand that doubt whose solution is to be the goal of all his
searching can never be sure whether he has found the truth or
not : for he does not know the goal of his enquiry — a goal that is
manifest to the man who starts with a knowledge of the (pertinent)
doubts. His fourth reason is based on the needs of the hearer.
It is the function of the hearer to pass judgment on the cases
that are at hearing. But just as in the courts no one can act as
judge who has not heard all sides, so the hearer of philosophy is
better able to act as umpire if he has been told all that the

44 COSMOLOGY

doubting adversaries have to say for themselves. . . . He
(Aristotle) says also that if having begun by stating the views of
others and the reasons that induced them to hold such views, we
are able to refute their arguments, then it will be clear to everyone
that we are not condemning our opponents without grounds as
those do who reject the views of other people solely on the grounds
of hatred or dislike. Conduct of that kind would be unbecoming
in philosophers whose boast it is to be truth-seekers. Those whose
aim is to discuss truth and truth only must not take up an attitude
of hostility to any of the disputants on whose claims they are
about to sit in judgment : their proper attitude towards all
parties is that of an impartial investigator and umpire. . . . Note,
then, that these are the reasons why Aristotle has the habit — in
almost every book of his that deals with the enquiry into and the
proof of truth — of beginning with an account of all pertinent
doubts."

Aristotle and the Schoolmen did not use the historic method
simply for the purpose of following intelligently but with strict
indifference the mental processes of their predecessors or adver
saries. Their aim as philosophers was to settle the score between
reason and unreason as guides of human life. That is, they were
as keen on dogmatic and eclectic criticism as on historic criti
cism : they heard all sides simply because they wished to winnow
the grain from the chaff. " We admit," writes Aristotle (40) in
the Ethics, " that the subsequent inquiry is disagreeable to us on
account of the fact that our friends (Plato and his School) have
adduced therein (unsatisfying) views. But we must be loyal to
truth even to the extent of setting aside their conclusions — especi
ally as we also are philosophers. For although our friends and
truth are both dear to us, it is our sacred duty to set truth above
friends." " He shows," comments St. Thomas,(41) " that this (his
friendship for Plato) must not be allowed to hinder him. For it
is better and more virtuous — nay, an inevitable duty — to oppose
a friend in the interests of truth. This is so essential to morality
that morality is impossible otherwise : for if a man does not
estimate truth higher than his friends, he will be led to deliver
false judgments and false testimonies in defence of his friends.
And that would be immoral. And although this duty of pre
ferring truth to one's friend binds all men as rational beings,
it is particularly binding on philosophers who are teachers of
wisdom, that is, of the knowledge of truth. Then, he goes on to
prove that man must prefer truth to friends by the following
arguments. We must honour most our greatest friend. And
since we are friendly with both — that is, with truth and with a
certain man — we must love truth more than this man because
our principal reason for loving the man ought to be the truth
that is in him and because our reason for loving truth is itself
and nothing else, as shown in the seventh book of this treatise.
Truth is, in sooth, a super-excellent friend to whom is due a reveren
tial honour. For, truth is in a sense divine : it is found funda-

METHOD IN COSMOLOGY 45

mentally and primarily in God. Hence Aristotle concludes that
it is a sacred duty to love truth more than friends. Sanctity — as
Andronicus the Peripatetic says — makes people staunch and
inflexible in the service of God. Plato is of the same mind. For
when setting aside an opinion of Socrates who was his master, he
declares that one must be more careful of truth than of anything
else. And he says elsewhere : Socrates is a friend but truth is a
greater friend. And in another place he writes that one may
make little of Socrates but one must make much of truth." The
pith of this rigorous rationalism cannot be put with greater
precision and terseness than in another text of St. Thomas.
" The purpose of philosophy is to know, not the thoughts of men,
but the truth of things." (42)

The present treatise has been written on this plan so familiar
to the student of Aristotle and the School : it aims at placing each
cosmological system as far as possible in the intellectual conditions
amid which it was actually produced ; it regards all these con
tending systems chiefly as so much truth or falsehood to be
accepted or rejected as such by the student of to-day : it strives
to select from the welter of systems the various grains of truth
dispersed among them. As I went ahead with the enquiry, I
found the fruitful development of Cosmology fell naturally into
two periods : an ancient and a modern period. The ancient
period stretches in Greece from Thales to Aristotle, and in Europe
from Albert the Great to Suarez and his first disciples. That
earlier period marks the victory and the consolidation of Aristo
telian Cosmology. The modern period in Cosmology opens with
the rise of modern physics and modern mechanics, and still
continues. Its chief characteristic is a double bias against
Aristotle and the Schoolmen : the dominant views in experi
mental and mechanical science are wholly anti- Aristotelian ; and
the modern fashionable philosophies of matter pay little or no
attention to Aristotelianism.

The volume that is here presented to the reader covers the
ancient period of cosmological speculation : roughly from Thales
to Suarez. It begins with an account of the growth and maturity
of Aristotelian cosmology in Greece. Passing from ancient
Greece to medieval Europe, it proceeds to unfold the complex
cosmological speculation of the Aristotelian Schoolmen. And in
the final chapter, it gives an account of the downfall of medieval
cosmology. The second volume, which is fairly advanced, will
give the sequel of that downfall. It will open with a review of
physical and mechanical science from Galileo to Einstein. This
review will be followed by an account of the philosophy of matter
from Descartes to our own time. I shall merely repeat the tale
of the scientists as they themselves speak it : the cobbler must
not quit his last. But in reviewing modern philosophies of
matter, I shall unfold the grounds for my conviction that the
Cosmology of contemporary Scholasticism embodies the best
attested results of modem science and modem philosophy.

CHAPTER I.
PRE-ARISTOTELIAN THEORIES OF MATTER.

THE problem of the constituents of matter was the first philo
sophical problem that attracted the Greek mind : it emerged as
soon as the Greeks, grown sceptical of popular mythology, turned
to reason for light on the mysteries of experience. It had,
therefore, been debated for two centuries before the time of
Aristotle : thinker after thinker contributing his item to an
ever-growing store of observation and speculation. Asked and
answered in the beginning with the frankness and confidence of
every fresh mental effort, it had been thrown in later days into
almost all possible shapes : and by the close of the fourth century
B.C. had received almost all available replies. Some of these
replies are as puerile as might be expected of the first attempts of
human thought : others carry us forward to the most recent
solutions of modern science ; all alike claim our attention in this
opening chapter because of their bearing on the subsequent
development of Cosmology. (J)

THE MILESIANS.

Wonder is the root of all philosophy. Surrounded by the
universe in all its varying manifestations of earth and air and sea,
the Milesians, these earliest philosophers of Greece, asked them
selves what all things were made of. A child's question : yet
one that like the rude flint betokens expanding powers of intellect ;
and one, too, that will worry to the end the mind of man. In
propounding their answers, the Milesians relied partly on observa
tion, partly on reasoning. Their observations were prescientific.
They believed in some kind of identity between ice and water
and steam with, on the one hand, earth and stones, and with, on
the other, air and fire. Water froze as ice, and vaporised as
steam ; ice when frozen harder seemed to become earth and stones ;
steam when further evaporated seemed to turn to air and fire —
the blue of the Mediterranean sky. Then, rain sinks into the
ground, becoming earth and all earthy products ; and the sun
draws up water giving it back as rain ; facts like these were taken
as proving a ceaseless cycle of transformations. The sun is
lighted up afresh each morning in the east ; and as he traverses
the heavens, is fed by watery exhalations from earth and stream
and sea ; sometimes he restores these gifts as rain ; and every night

46

THE MILESIANS 47

he is put out in the west. Such was the naive scientific outlook
of these first philosophers. The principle that lay at the root of
their reasoning was the indestructibility and improductibility of
reality : creation and annihilation were for them unthinkable.

Thales (fl. 585-4 B.C.), the first Greek cosmologist, was the
founder of the Milesian school. Water was, according to him,
the primary principle of which all other things were mere transient
forms. The reasons which led him to this conclusion are not
known. " He (Thales)," writes Aristotle,(2) " was, perhaps, led to
this conclusion by observing that the nutriment of all things is
moist ; that heat itself, by which living things are kept alive, is
educed from moisture — but that from which another thing is
derived is the principle of that other ; and further, by observing
that the seed (from which living organisms spring) is of its nature
moist — but the principle which makes moist objects moist is
water." Aristotle is obviouslv guessing at the arguments of
Thales. Others have taken a similar liberty and have suggested
that Thales was influenced by the fact that of all things we know
water seems to take the most varied forms : it hardens into ice
and rarifies into steam ; drawn up as moisture from the sea by
the sun, it is made into the fire of the heavenly bodies, and
later sent back as rain to earth ; and in these days, the alluvial
deposits at the mouth of rivers made it natural to think of water
becoming earth ; and the return of earth to water was the nearest
explanation of dews and night-mists and subterranean springs.

Anaximander (fl. 565 B.C.) succeeded Thales. He was so
struck by the infinite changes of things that he believed only a
spatially endless stuff could account for this inexhaustible supply
of new realities. But if the primary stuff must be thus infinite,
it cannot be identified with a particular reality like air : for the
qualities of air would be so dominant that no other particular
reality could have existed. Accordingly, his fundamental stuff is
a boundless mass out of which our world of perceptible things
emerge by separation. This theory is a compost of mysteries :
Anaximander has left us no clear utterance on the nature either
of this boundless mass or of this process of separation. As for
the mass,(3) the ancients are fairly unanimous in emphasising
the distinction between it and the bodies afterwards known as
the four elements — earth, air, fire, water ; some interpret this
boundless mass as a medium between water and air, others as a
medium between air and fire ; again, others interpret it as a
kind of mixture in which all particular bodies are contained ;
others as a primitive matter without qualitative determinative
ness. This last view seems most consonant with the text and
context of Anaximander. Hence we may picture to ourselves
this principle of Anaximander as a homogeneous bodily mass,
indeterminate in quality, and infinite in extent. Out of this
boundless stuff, particular bodies emerge by separation. But
what exactly this process may be is not explained. Being a
hylosoist, Anaximander thinks of matter as self-moved and

48 COSMOLOGY

alive ; and it has been suggested that this separation may be
a kind of shaking up and down which sorts out the opposites
from the infinite mass. The first result of this shaking is the
emergence of heat and cold : the mixture of these produces water,
and, though Anaximander rejects the view of Thales that water
is the ultimate stuff out of which all things are made, he regards
it as the immediate stuff and calls it the seed of the world.

Anaximenes (fl. 546 B.C.), the third and last great Milesian,
combines in a new synthesis the theories of his predecessors. He
takes over from Anaximander the animation and the infinity
of the primary stuff ; he reverts with Thales to its definite
qualitativeness. Air is the primal substance out of which all
things are made. But air meant more for Anaximenes than for
us : it means for him as for us invisible air — the breath and the
wind ; but it means also for him visible air — mist, vapour,
darkness. He bases his choice of this primary stuff on an analogy
between the universe and living beings : " just as our soul being
air, holds us together, so do breath and air compass the whole
world." (4) Animal life becomes extinct when breathing ceases ;
and similarly, earth and water and fire, which exist as islands in
that boundless ocean of air surrounding them on all sides, would
cease to exist did not the living air hold them together. . . . Sim-
plicius (5) suggests another motive for this choice of air : it is more
mobile, more volatile than water, and therefore more fitted for
those changes of quality which must be undergone by the primal
substance. It is likely also that the popular belief in rain, hail,
snow, and fiery phenomena as products of air influenced Anaxi
menes. His fame rests not on this choice, however, but on his
suggestion as to the process by which all things were produced
out of air. That process was one of condensation and rarefaction.
And although our author did not read into these words all their
modern meaning, he certainly made a hit in inventing a phrase
that was to have an immense future. Nor is the value of his
discovery lessened one whit by its ludicrous basis : the air of the
whistle is cold, that of the yawn warm. Rarefaction, then, is
heating ; condensation cooling. Rarefied air changes into fire ;
condensed air changes gradually into wind, cloud, rain, earth,
stone ; and from these simple bodies arise all compound bodies.

THE PYTHAGOREANS.

The Pythagorean mathematicians were led, Aristotle (6)
writes, by fanciful analogies between the properties of numbers
of those of visible things to the view that physical things are
made of numbers and that the constituent principles of numbers
—the Even and the Odd or the Unlimited and the Limited— are
the ultimate principles of things. This doctrine is difficult to
grasp, owing both to the lack of historical data and also to the
two-fold development of views with the Pythagorean school :
none of the earlier writings and only fragments of the

THE PYTHAGOREANS 49

later writings of this school are extant ; there is an early or
pre-Eleatic Pythagoreanism and a later or post-Eleatic Pytha-
goreanism.

The gist of early Pythagoreanism — Pythagoras " flourished "
532 B.C. — turns on the meaning of three words : the Unlimited ;
the Limit ; Number. Aristotle (7) says explicitly that the
Unlimited of the Pythagoreans is not a quality of any qualita
tively determinate "body such as fire, water, air or any inter
mediary ; that it is an infinitely extended reality ; and that it
is outside our world ; that this infinitely extended something is
not extension as a mathematical abstraction. He tells us
further (8) the Pythagoreans held that there was boundless
" breath " outside the world ; that this " boundless breath "
was inhaled by the world ; that after the first unit had been
formed, the nearest part of the Unlimited was drawn into the
process of world-development ; that this " boundless breath "
thus inhaled kept the units separate from one another ; and that
the Unlimited is identical on the one hand with the void and
on the other with this " boundless breath " : an identification
supplemented by other suggestions which confound air and
vapour, air and darkness. All these hints seem to imply that
the early Pythagoreans meant by the Unlimited a boundless
extent of breath or air : air, visible and invisible, and therefore
including vapour, mist and darkness as well as ordinary air. If
this be so, there is a close connexion between the Pythagorean
Unlimited and the primary substance of Anaximenes. But in
explaining how particular substances are developed out of the
Unlimited, these Pythagoreans set aside all suggestions of con
densation and rarefaction and teach that the Limit gives definite-
ness to the Unlimited. They seem to have discovered this
function of the Limit in their musical and medical studies. In
music, they showed that the concordant elements of the scale — in
melodic progressions — could be expressed by simple numerical
ratios. Music, then, the purge of the soul, depends on a blend
of high and low notes which can be numerically determined.
Medicine, the purge of the body, also depends on a fixed blend of
opposites : it is the duty of the physician to produce a proper
temperament in human bodies " of the warm and the cold, the
dry and the moist and things of that sort." Attunement and
health, apparently the most elusive realities within human
experience, were accordingly viewed by the Pythagoreans as the
result of blends that can be expressed in numbers. And if num
bers express the inmost secret of music and of medicine, why
should they not hold the philosophic secret of the world's brew ?
But the Unlimited is space-filling. Its limitation, then, must
consist in marking it off into regular parts. It would be natural
on this hypothesis to regard the point, the line, and the surface,
as forms of the Limit. It was characteristic of early Pytha
goreanism, however, to think of the point as the first product of
the Unlimited and the Limit. The point is a unit having both

4

50 COSMOLOGY

position and magnitude. (9) Two points by enclosing a portion
of the Unlimited determine a line : Pythagorean lines have
therefore breadth. At least three lines meeting together to form
angles determine the enclosed Unlimited to a surface : Pytha
gorean surfaces have thickness. Finally, at least four surfaces
joined together at their corners are necessary to determine the
enclosed Unlimited to a body. Everywhere, both the Unlimited
and the Limit are essential : any two line-forming points would
coincide but for the intervening Unlimited ; without two such
points, the Unlimited would have neither beginning nor end nor
direction ; but once the presence of the enclosed Unlimited is
taken for granted, bodies come from surfaces, surfaces from lines,
lines from points. Points, however, are units ; consequently all
bodies are a sum of units and things are numbers.!10) Numbers ?
Yes : but from a point of view long since obsolete. The numerical
symbolism of these Numbers was quite distinct from the ordinary
notation by letters of the alphabet and from the Euclidean
representation by lines. It is best illustrated by our present
marking of dice and dominoes : numbers were represented by
dots arranged in symmetrical and easily recognised patterns ;
and each pattern was regarded as a fresh unit. A number for
such thinkers was a figure or pattern expressing the sum
a series of different kinds : triangular numbers were a series
of integers; square numbers a series of odd numbers; oblong
numbers a series of even numbers. It is true that this usage has
partially survived ; we speak as these old Greeks did of square
and cubic numbers. " All that we mean by these phrases is that
the products stand to their factors in the same proportion as the
spatial content of a plane or body to the key-numbers of the
lines containing its superficial area or corporeal volume." (n)
But these early Pythagoreans apparently took the symmetrical
figure to be identical with the number summing up its spatial
contents. The dots which stood for the units within these figures
or patterns were called terms or boundary stones, and the spaces
marked out by them were known as fields. And in this way,
number came to be regarded as the principle whence proceeded
all reality ; the seed out of which things grew. To what depths
of puerility this confusion of symmetrical patterns with physical
bodies could lend itself is evidenced by the extraordinary methods
of Eurytos, one of the foremost leaders in the later Pythagorean
school. " Let us assume,!12) for example," he says, " that 250
is the number which defines man, and 360 that which defines
plant. Having laid this down, he took 250 counters, some green
and some black, and others red, and all sorts of other colours ;
and then, smearing the wall with plaster and sketching on it a
man and a plant he proceeded to fix some of the counters in the
outline of the face, some in that of the hands and some in that of
other parts ; and thus he completed the outline of the man he
had imaged by a number of counters equal in number to the
units which he said defined man." And as soon as number had

HERACLEITUS 51

been thus exalted as the source of physical reality, it took possession
of the spiritual universe ; one, because unchangeable, was reason ;
two, because variable and indeterminate, opinion ; three or five
because a union of odd and even, marriage ; four or nine, because
square numbers and suggesting an eye for an eye, justice ; eight,
because the harmonious octave, love and friendship ; and so on
ad nauseam. Abstractions — as ever in uncritical minds— issued
forth from the depths of human consciousness to become for their
makers full-blooded realities.

Later Pythagoreanism (13) was cast in a different mould. Its
distinctive features were, first, a practical acknowledgment of the
force of Zeno's dialectics and, secondly, an attempt to assimilate
the then current theory of the four elements. Pythagoreans of
the time of Socrates held that things were like numbers, not that
they were numbers. Moreover, they accepted in a sense the
theory of the four elements : this acceptance meant the rejection
of the older view of the Unlimited as air. But, like Plato, they
denied that the four elements were ultimate : they seem to have
held that these elements were made up of particles which had the
shapes of the five regular solids — thereby apparently interpreting
the Unlimited as an extended body. And since Zeno had proved
that lines cannot be constructed out of points, they admitted that
the actual triangles, out of which the four elements were ulti
mately made, were not triangular numbers, but likenesses of these
numbers.

HERACLEITUS.

The philosophy of Heracleitus (fl. 504 B.C.) is dominated by
the thought of the continuous change going on in the world :
nothing remains what it is ; everything passes into something
else ; and that something else is called by Heracleitus its opposite.
This means not only that all individual existences are transitory
but also that the matter composing any individual is never
altogether the same for two consecutive moments of time.
Plato (14) is explicit : " nothing ever is, everything is becoming ;
all things are in motion like streams ; all things are passing and
nothing abides." " Heracleitus says somewhere that all things
pass and naught abides ; and, comparing things to the current of
a river, he says that you cannot step twice into the same stream."
Aristotle is equally clear : "all things are in motion ; nothing
steadfastly is." And though the phrase " all things are flowing "
is not found in any of the fragments of Heracleitus, everyone of
his fragments emphasise the transitoriness both of man and of
nature : any real thing, however stable in appearance, is merely
a section in an ever-flowing stream and the stuff composing it is
never the same at any two consecutive moments.

Flux rules the life of man : waking or sleeping, youth and age,
life and death. " Man is kindled and put out like a light in the
night-time." (15) " And it is the same thing in us that is quick
and dead, awake and asleep, young and old ; the former are

4*

52 COSMOLOGY

shifted and become the latter, and the latter in turn are shifted
and become the former." (16) " Upon the same stream we do
and we do not embark for we are and we are not." (17) This
Flux never ceases : from life death and from death life through
food ; from youth age through lapse of years and from age
youth through procreation ; from waking sleep and from sleep
wakefulness. It rules also in nature : night follows day, day
night ; winter follows summer, summer winter. " The sun is
born afresh every morning " (18) and dies every night : clouds
change into rain — e water lives the death of air " ; rivers form
at their mouths alluvial deposits — " earth lives the death of
water." (19) ' You cannot step twice into the same river, for
fresh waters are ever flowing in upon you." (20) This way of
regarding man and nature make it necessary for Heracleitus to
seek out a new primal substance. He needed a world-stuff of
such a nature that it would be always passing into everything
else while everything else would be returning into it. Fire seemed
to satisfy these requirements. A steady flame appears to retain
its identity although its contents are continually coming and
going : it seems to have a fixed thinghood because what is passing
away as smoke is being always replaced by fuel. It is also likely
that the ancient belief in fire as the source of life influenced
Heracleitus : a belief based on the warmth of living bodies and
the stiffening of corpses, the vivifying influences of summer and
the deadening effects of winter. " This world," he writes,
" which is the same for all, no one of gods or men has made ; but
it was ever, is now, and ever shall be an ever-living Fire, with
measures kindling and with measures going out." " It (fire) is
the thunderbolt that steers the course of all things." (21)

The universe is, therefore, a huge fire that burns incessantly :
the world of nature — as well as we who contemplate it — is in a
state of perpetual flux. Nothing is at rest : every apparently
permanent being is changing ; at every moment, some matter is
passing out of and other matter is coming into the structure of
all beings. The ceaseless movements of fire bring about these
untiring changes of things : fire assumes through qualitative
change a different form in each thing, bringing into existence the
multitudes of individuals, urging them forward to their own
destruction, and thus introducing ever new forms of being only
to return ultimately to fire. " All things are exchanged for Fire
and Fire for all things just as wares for gold and gold for
wares." (22) This exchange follows a regular path (*3) : fire
becomes water and water earth ; earth liquifies into water, and
from water are derived all other things by evaporation, and
ultimately fire. Fire, water, earth constitute what Heracleitus
calls the downward path ; earth, water, fire the upward path.(24)
At any given moment, each of these three forms of matter is
made up of two equal portions, one of which is pursuing the
upward path and the other the downward (25) : for instance, half
the sea is for ever taking the downward path and has just been

HERACLEITUS 53

fiery storm-cloud, and the other half has just been earth and is
pursuing the upward path ; when rain falls, a proportionate part
of the sea turns into earth ; when the sea evaporates, a propor
tionate part of the earth turns into water. The same is true of
man.(26) He is made up of fire, water and earth ; the fire —
which alone is conscious — is perpetually becoming water and the
water earth ; but, as the opposite process goes on simultaneously,
man like a candle flame appears to remain the same. " The soul
is fully alive only when awake ; sleep is a stage between life and
death. Waking and life are due to warmth and fire : the dry
soul is the wisest and the best." (27) " Sleep and death are due
to the advance of moisture : the drunkard is led about by a
beardless boy, not knowing whither he goes, for his soul is wet ;
it is death to souls to become water." i28)

The simultaneity of the upward and downward paths is the
secret of the apparent stability both of things and of men and
of the whole universe. Moreover, the fact that the two halves
of everything are being drawn in different directions explains
the underlying order of the universe : the accuracy of the arrow
is due to the opposite tension of the hands to each other and to
the different parts of the bow ; the sweet note of the lyre is
due to an analogous tension and retention. " Men do not
know how what is at variance agrees with itself : it is an
attunement of opposite tension like that of the bow and
lyre." (29) "It is the opposite which is good for us." (30)
" Man is the father of all and the king of all ; and some he had
made gods and some men, and some bond and some free." (31)
" Homer was wrong in saying : Would that strife might
perish from among gods and men. He did not see that he
was praying for the destruction of the universe ; for if his prayer
was heard, all things would pass away." (32) The upward and
downward path are two inseparable halves of one and the same
world process : if either were to cease, the other would cease also ;
what explains the one explains the other. " The way up and the
way down is one and the same." (33) Thus does the fire-flame
figure, to the mind of Heracleitus, those deeper subtly disguised
currents of universal change that are ever stealthily withdrawing
the apparently solid earth itself from beneath our feet. Despite
his childish analogies and his paradoxical explanations, this Greek
divines that doctrine of flux which is the burden of Hegel and
Darwin and Kelvin : mind and life and matter make an ever-
flowing stream which knows no rest. Modern evolutionism has,
however, no fulcrum : the system in which all things live is
for many moderns in ceaseless movement nowhither. Not so,
Heracleitus : the way upward and the downward path is not
merely a circle ; at the upper end, where both paths meet, he
puts that pure fire which is not differentiated into parts, Zeus.(34)
The one permanent reality in this endless cycles of change
is the all-embracing law that governs them. Nothing remains
what it was as regards its ingredients : there is ceaseless loss and

54 COSMOLOGY

ceaseless gain. " This world was ever, is now, and ever shall be
an everliving Fire with measures kindling and measures going
out." (35) But " the sun will not transgress his measures : were
he to do so, the Erinyes, abettors of Justice, would overtake
him." (36) Accordingly, the truly permanent reality in the
universe is fixity in the rate of exchange between the various
substances : the advancing and retreating streams of matter in
each substance proceed in definite directions and in definite
proportions. There is no caprice, no arbitrariness : everywhere,
a uniform rule holds sway over the endless currents of change.
But this fixed law of exchanges admits, as facts show, of alternate
variations. Sleep is caused by the encroachment of those dark
exhalations from the water in the body which cause fire-con
sciousness to burn low : wakefulness is restored each morning by
an equal advance of the bright exhalation. Again, when either
fire or water gains the upper hand, death ensues. It is death
to souls to become water : hence the folly of such pleasures
as drunkenness or wantonness.!37) Excessive fire also causes
death : the heroic death which makes a man a god.!38) But
whether men die the fiery or the watery death, their souls begin
once more the unceasing upward and downward paths : " gods
are mortals, men are immortals, each living in the other's death,
each dying in the other's life." (39) Day and night, summer and
winter involve similar variations in the fixed measures of Nature's
changes. Night is ca.used by the rise of darkness from the earth
and sea : a moist darkness that so increases the watery element
as to put out the sun's light. Darkness, however, can no longer
rise upwards when the sun is extinct : accordingly, a fresh sun
can kindle and nourish itself at the expense of the moist element.
But this fresh sun burns up the bright vapour and thus digs its
own grave. Thus the sun is born afresh every morning and dies
every night : for it is nothing but a mass of burning vapour
kindled at sunrise by the dry vapours of earth and sea, burning
up and consuming those ascending vapours in its motion by day
through the heavens, and paying the penalty of extinction at
sunset owing to dark exhalations from earth and sea. The
alternation of summer and winter arises from similar causes : the
sun's retreat southwards is due to the gradual advance of the
moist element caused by the very heat of the sun : its return
northwards is but the search for that nourishment which . owing to
diminished evaporation, fails it in the south. But oscillate as
they will, neither fire nor water can wholly prevail : "so long as
things are as they are, fire and water will always be and neither
will ever fail." (40)

Another feature of Heracleitean philosophy has aroused so
much interest in modern times as to call for special referenced41)
A number of extant fragments assert in the most emphatic manner
the identity of various things which are usually regarded as
opposites : God is day and night, winter and summer, war and
peace, surfeit and hunger ; day and night are one ; the way up

HERACLEITUS 55

and the way down are one and the same ; good and evil are one ;
mortals are immortals and immortals are mortals ; it is the same
thing in us that is living and dead, awake and asleep, young and
old ; what is at variance agrees with itself, couples are things
whole and things not whole, what is drawn together and what is
drawn asunder, the harmonious and the discordant. These are
the most startling expressions of a thought that pervades certain
fragments of Heracleitus : the thought, namely, that each thing
is a unity of opposites. What exactly Heracleitus meant by this
correlation of opposites has been long and vigorously disputed.
Aristotle (42) in certain passages condemns such utterances as a
denial of the principle of contradiction; Hegel?(43) on the other
hand, welcomes them as the first historical admission of the iden
tity of being and non-being. It is more consonant with Hera
cleitus' s position as thinker to regard both the Aristotelian censure
and the Hegelian praise as undeserved : Heracleitus never
dreamt of maintaining that opposite qualities belong to the same
subject at the same time and under the same respect. The unity
of opposites in the concrete is a totally different doctrine from
that unity in the abstract ; and the former doctrine alone is
asserted in fragments of Heracleitus. His fundamental teachin
is that the ever-living fire ceaselessly passes into all things,
assuming in each of them different qualities, producing in this
way particular individuals, and yet finally returning into itself :
accordingly, each thing becomes what it is only through the
perpetual emergence of the opposites between which it stands.
His varied expressions of the coincidence of contraries are but
aspects of this central doctrine. There are, first of all, the obvious
consequences of a theory of perpetual flux : day is not night,
summer is not winter, strife is not peace, good is not evil, but
these and all similar contrasts are inseparable halves of that
restless process which is the life of the world : were either to
cease, so would the other, and with them the universe. Then,
there are single beings which are kept in equilibrium by the
tension of antagonistic qualities and conflicting principles : man,
for instance, is a compost of fire and earth and water. Most
intelligible of all are those fragments that speak of a thing dis
playing opposite qualities when brought into relationship with
different bodies : sea- water is good for fish, bad for men ; straw
is worthless for men, precious for asses ; gold precious for men,
worthless for asses ; bitter vetches a joy to oxen, a disgust to
men ; the wisest of men an ape compared to God, just as the
most beautiful ape is ugly compared to man ; and so on. Equally
intelligible are other fragments which speak of a coincidence of
opposites in two or more agents that produce a single effect :
high and low must unite for concord, male and female for pro
creation. The Heracleitean unity of opposites is, therefore,
purely relative. And as we have already noted, this relativity
disappears at that upper end where the two paths meet : men

56 COSMOLOGY

think this right and that wrong, but to God all things are fair and
good and right.

Such is the outline of the Heracleitean theory of the universe :
fire the world-element, flux the world-process, definite sequence
and equivalence the world-law. Heracleitus believed that he had
got rid in this way of all permanent reality — the one invariant in
all these changes being the all-embracing law ; the universe is at
once One and Many — the opposite tension of the Many consti
tuting the unity of the One. And though he did little for the
scientific and methodical discovery of the causes which bring
about change, his insistence on the fact of perpetual flux in our
world gave a definite bent to the speculations of his successors.
After his day, the character of pre- Aristotelian Cosmology changes :
the problem of the stuff out of which all things were made yields
place to the somewhat different problem of the agencies that
produce all things. And a first reply, developed at least contem
poraneously, was that of the Eleatics : the denial of the very
possibility of such production.

THE ELEATICS.

" I hold thee back . . . from that course also, upon which
mortals knowing naught wander two-faced ; for helplessness
guides the wandering thought in their breasts, so that they are
borne along stupified like men deaf and blind. Undiscerning
crowds, in whose eyes it is, and it is not, the same and not the
same, and all things travel in opposite directions." (44) This
panting invective is hurled at Heracleitus by garmenides
(fl. 474 B.C.). He had been in his youth of the school o± Jfyttfa-
goras and had brought thence a vehement conviction of the power
of thought. Accordingly his solution of the problem concerning
the nature of things turns on the answer to the question — what
is thinkable ? His predecessors had taken for granted that one
or other primal substance could assume different forms. How
was this possible ? Anaximenes had suggested by rarefaction
and condensation. Whether rarefaction and condensation im
plied in the mind of Anaximenes particles and interstices, we do
not know. But they certainly did imply both in the mind of
Parmenides. And when his Pythagorean teachers spoke of the
world as inhaling empty space or air from the boundless mass
outside it and spoke of this empty space or air as entering into the
world to separate the units, the problem of the possibility of
empty space became a pressing one. Now the whole strength of
the Parmenidean theory lies in its denial of the possibility of
empty space whether within or without our world. And his one
proof runs : empty space is nothing and nothing is unthinkable ;
only that which can be thought can be.(45) He proceeds, then,
to unfold in a thorough-going fashion the consequences of this
starting-point. (46) What-is can never have come into existence :
for it could come only from nothing and there is no such thing

THE ELEATICS 57

as no thing. (47) What-is can never pass out of existence : for
it could only pass into nothing and nothing does not exist.
What-is is unchangeable, for every kind of change involves a
transition from nothing to something. What-is is unique : for
there is no empty space in which anything else beside itself could
come into existence. What-is is continuous and indivisible : for
there is nowhere anything else distinct from itself by which its
parts might be divided. What-is is homogeneous : for were it
not at all points equally perfect there would be somewhere a
streak of nothingness. What-is is, therefore, a continuous,
undivisible plenum : the body or matter of popular language
provided we remember that, at this stage of Greek thought, matter
had not been distinguished from life and mind. This continuous
indivisible plenum is, for Parmenides, finite : hemmed in by the
real on every side and no empty space outside it. It is spherical ;
for it is equally real in all directions. In short, this Parmenidean
world may be pictured as a uniform, unchangeable, limited whole,
without parts, without beginning, without end, resembling the
bulk of a well-rounded and equally weighted ball : a finite sphere,
at once spiritual and material, always and everywhere identical
with itself ; but a sphere of matter that is sterile because immov
able and a sphere of spirit that is powerless because inactive. It
is true that our senses attest a world of multiplicity and of motion :
a world of birth, and decay, and death. So much the worse for
our senses, retorts Parmenides. Sense appearances are illusions :
thought alone is trustworthy ; and thought tells us that a world of
multiplicity and motion is an utter impossibility. (48) Thus did
this first Eleatic make a clean sweep of the Many — all these
things and persons that press so closely on eye and ear and heart
at every moment ; and establish in their place the rigid, inalterable,
One.

Naturally this denial of so ubiquitous, so tyrannical, so irre
sistible a fact as the world of experience sent a peal of laughter
ringing through Greece. But Zenp (fl. 449 B.C.) would not see
his master vanquished with a grin : turning on the scoffers, he
paid them, as Plato says, " to the full in their own coin and
added not a little." His pithy dialectics fill but a single page of
Aristotle or Simplicius : yet so compact are they with difficulties
that they have puzzled generation after generation of thinkers.
His method is to take one of his adversary's fundamental postu
lates and deduce from it two contradictory conclusions : and thus
he tries to show that assumptions like multiplicity and motion
lead to even greater absurdities than the theory of Parmenides.
Four of his famous arguments are directed against multiplicity.
If there (49) were a plurality of bodies each of these bodies would
be at once infinitely large and infinitely small ; infinitely large,
because each body can exist at all only if it has magnitude and
this magnitude implies extended parts outside extended parts and
other extended parts between these parts to infinity ; infinitely
small, because the ultimate parts of these bodies can be true units

58 COSMOLOGY

only if they be indivisible, unextended realities and no multiplica
tion of such units can result in magnitude. If there (50) were a
multiplicity of bodies, these bodies would form simultaneously a
finite number and an infinite multitude : a finite number, because
there are so many of them, no more and no less ; an infinite multi
tude, because two things are two only when separated by a third
and this separation in turn involves something between the third
and each of them and so on to infinity. If there (51) were a multi
plicity of bodies, there would be an infinity of spaces because,
everything real being in space, space itself unless it lacks reality
must be in another space, this secondary space in a tertiary
space and so on to infinity. If a bushel (52) of corn were made up
of thousands of separate grains, each of these grains, when let
fall singly to the ground, ought to make a noise, because otherwise
how explain that great noise caused by the fall of the bushel as a
whole ; and yet — each ought not to make a noise because our ears
testify that a single grain when falling separately sinks noiselessly
to the ground. More famous still are Zeno's paradoxes concerning
motion. (53) The first is the impossibility of ever reaching the
end of a racecourse : a body can move to the end of any distance
only by first traversing half that distance ; but to traverse half
that distance, it must traverse half of that half, and so on ;
motion involves, therefore, the transition of an infinite number of
points in a finite time. His second paradox is the impossibility of
Achilles overtaking a tortoise : if Achilles gives the tortoise a
start, then, before he reaches its starting-point, it will have got
a little way-on and the same thing repeats itself with regard to
this little way-on to infinity. The next paradox refers to the
flying arrow at rest : if the arrow measures one foot in length
and is launched at the rate of ten feet a second, then, it occupies
a space equal to its own length in every tenth part of that period
of time ; but the sum of an infinite number of positions of rest
cannot constitute motion. His last paradox is that the motion
theory makes half the time equal to double the time : if three
bodies exist, one lying at rest and the other two of equal length
moving past it with equal velocity in opposite directions, then one
of these moving bodies will pass in the same time twice the
number of points in the other moving body that it passes in the
body at rest ; therefore, the time it takes to pass the moving body
is twice as long as the time it takes to pass the body at rest ; but
the time which both moving bodies take to reach the position of
the body at rest is the same ; therefore double the time is equal
to the half.

Zeno was followed by Melissus (fl. 441 B.C.), the systematiser
of this school. His arguments for the indestructibility, imperish
ability, and immutability, of the barren static One are but so
many paraphrases of those set forth by Parmenides. Earth
and water, air and iron, gold and fire, the living and the dead,
black and white — all these, and what men say currently of such
things, are mere names and sense illusions. He departs from his

EMPEDOCLES 59

master's teaching on the question of the finite size of the One : (34)
what is temporarily infinite must be spatially infinite ; moreover,
were the One limited, it should be limited by empty space.
Lastly, he is remarkable for a forecast that is destined apparently
to immortality : "if there were many things, they would have
to be just of the same nature as the One." (55) In this sentence,
Melissus heralded unwittingly the exit of Eleaticism and the
advent of Atomism. A conclusion intended by him as the
reductio ad absurdum of pluralism was accepted afterwards as the
foundation-stone of their system by Leucippus and Democritus.

EMPEDOCLES.

Empedocles (fl. 472 B.C.) concedes to Parmenides that being
can neither begin to be nor cease to be. " Fools ! (56) for they
have no far-reaching thoughts who deem that what before was
not comes into being, or that aught can perish and be utterly
destroyed : for it cannot happen that aught can arise from
what-in-no-way-is ; and it is impossible and unheard of that
what-is should perish for it will always be wherever one may keep
putting it." He grants also the impossibility of empty space :
" in the All there is naught empty." (57) He insists, however,
on the reality of change : the senses assure us that particular
things come into, and pass out of, existence. And he reconciles
his concessions to Parmenides with his trust in sense experience
by postulating a plurality of everlasting substances : the birth
and death of particular things are but the spatial union and
disunion of these qualitatively unchangeable realities. " Hear,
first, the four roots of all things : shining Zeus, life-bringing
Hera, Aidoneus and Nestis whose tear-drops are a well-spring
to mortals " (58) ; fire, air,(59) earth (60) and water are the un-
derived, irreducible, imperishable roots of all existing substances.
Why exactly Empedocles chose these four as roots is not certain :
he may have taken them over eclectically from his predecessors
or he may have regarded the different states of aggregation as
the fundamental essence of all things. Whatever was the reason
for his choice, he explains all individual existence as a mixture of
these roots. " But when the elements have been mingled in the
fashion of a man and come to the light of day, or in the fashion of
the race of wild beasts of plants or birds, then men say that these
come into being ; and when they are separated, men call that
woeful death. They call it not aright ; but I too follow the custom
and call it so myself." (61) Whence this power of uniting and of
separating in the roots ? Here, Empedocles sides once more with
Parmenides against Heracleitus and the Milesians : there is no
impulse towards movement in the roots themselves. Accordingly,
he sets up in addition to the four roots two principles of motion
which he styles Love and Strife : Love for union, Strife for
separation. (G2) These principles are, despite their names,
spatial and corporeal, somewhat akin to the " fluids " of early

60 COSMOLOGY

nineteenth-century science. Love is said to be " equal in length
and breadth " (62)'to the four roots ; Strife is described as equal
to each of them " in weight." (62) Love and Strife are equally
powerful. Conflict is ever being waged between them, and each
in turn gradually drives out the other. At the beginning, the
roots are mixed together in a single sphere, an echo of Par-
menideism : Love is triumphant, Strife powerless. But no
sooner has Love completely ousted Strife than this latter begins
once more to enter the sphere and to grow strong there. A
period ensues during which Love is passing out and Strife coming
in : all this time, the roots are partially separated and partially
united. This period ends with the victory of Strife : triumphant
Strife completely separates the roots into conglomerate masses of
similars. Then, Love begins once more to regain the mastery :
it gradually reverses the victory of Strife and in time binds up
the roots again in a single sphere. These cycles recur perpetually,
each of them with its four periods : complete inter-mixture,
transition from this to separation, complete separation, return to
unity. A world of change like ours can exist only in the second
a.nd fourth of these periods : these periods when both Love and
Strife are in the world are the eras of births and deaths. " There
is a double becoming of perishable things and a double passing
away. The coming together of all things brings one generation
into being and destroys it : the other grows up and is scattered
as things become divided." (62) But these two principles of
Love and Strife explain only one aspect of the problem : that of
the moving cause. The question of the nature of mingling and
separating remains. Empedocles answers here that the four roots
are qualitatively changeless ; that effluxes stream off from all
bodies (63) ; that the roots run through one another (64) ; that all
differences between things are due to different proportions in the
mixture ; that just as painters by mixing only four pigments in
a variety of proportions can produce likenesses of all things,
similarly nature by skilful mixture of the fouK roots produces
countless multitudes of perishable creatures.!65) The possibility
of mixture, then, in the theory of Empedocles, depends on the
existence of particles which .can lie side by side in the compounds.
And Aristotle says that Empedocles explained mixture by the
" symmetry of the pores." (66) Mixture would seem, therefore,
to be effected by the entrance of the particles of one body into
the pores of another : the pores of some bodies are symmetrical
and these can mingle easily — hence the attraction of like for like ;
on the other hand, a fine body will run through a coarse body
without becoming mixed and a coarse body will not be able to
enter into the pores of a finer one ; in short, all combinations are
not possible — " water fits better into wine, but it will not mingle
with oil." (67) Thus, for Empedocles, bodies are a group of
particles which have openings between them : their mingling and
unmingling are reduced to the coming and going of material
particles which remain eternally changeless in quality ; and the

ANAXAGOKAS 61

distinctive qualities of the mixture, differing as they may and do
from the qualities of the roots, are due to the varying proportions
of their constituents.

ANAXAGOEAS.

Anaxagoras (fl. 460 B.C.) sought another way of reconciling
the Eleatic doctrine of unchangeable substance with the facts of
sense experience. He accepts the arguments of Empedocles
against absolute becoming and qualitative change. " The Greeks
follow a wrong usage in speaking of coming into and passing out
of existence : nothing comes into and passes out of existence ;
but there is union and separation of the things that are. The right '
usage would be to speak of coming into existence as mixture and
of passing away as separation." (68) He agrees with Empedocles
also in denying the existence of empty space.!69) But he rejects '
his predecessor's solution of the origin of particular substances.
" We use a simple nourishment when we eat the fruit of Demeter
or drink water : but how can hair come from what is not hair, or
flesh from what is not flesh " ? (70) His own theory seems to .
have been thought out along the following lines. Bread nourishes '
our bodies. Bodies are made up of parts that have distinctive
qualities : skin, flesh, bone, blood, hair, etc. Now since change of
quality is unthinkable, these qualitatively distinct parts could
never have found their way into human bodies unless they were
already present in the bread ; and for the same reason, this
richness of qualitative distinction must 'have been present in corn
and in the nourishment of corn — earth, water, air, solar fire. The
four roots are, then, most complex : storehouses of countless
qualitative particles. Moreover, what is true of man is true of
every animal, every bird, every plant, every mineral. The
qualitative parts of everyone of these, and of everything else that
ever did or shall exist, must have been extant from all eternity :
otherwise, at some moment, qualitative change would have
happened. The primal constituents of matter, therefore, are as
numerous in number as the least shades of difference perceptible
to our senses and as the multitudinously varied combinations of
qualities displayed by anv material substance. In short, the
original substances are unlimited both in kind and in number :
that is the tremendous conclusion drawn by Anaxagoras from the
premiss that birth and death are merely the union and the
separation of pre-existent parts. In the beginning, these count
less qualitative articles were mixed so thoroughly and so minutely
that no single quality was individually perceptible : that mixture,
as a whole, displayed none of the distinctive qualities of things.
" All things were together infinite both in number and in small-
ness " : " seeds of all things with all sorts of shapes and colours
and savours." (71) And he seems to have held that all possible
qualities were simultaneously in the smallest particles of that
mixture : " everything is in everything." (72) Still, even in that
first mixture, air and aether prevailed over all other things : for

62 COSMOLOGY

they were greatest both in quantity and in size, and, even though
everything is in everything, each thing has the appearance of
those tilings of which it has most.

The starting-point of our world, then, is an infinite multitude
of innumerable seeds divided into infinitely small parts. This
composite medley of qualities lasted until Nous intervened and
set up a process of continuous differentiation which gradually
formed our present world. This Nous is primarily a cause of
motion. And Anaxagoras was driven to postulate this external
cause by his acceptance of the Eleatic teaching that matter of
itself cannot move. Aristotle thinks that our author discovered
this world-forming force from experience of the power of mind
in human conduct. And he praises him for introducing mind
as the cause of all order in the world : " Anaxagoras spoke
like a sober man in contrast with the random speech of his
predecessors." (73) It is difficult, however, to make out what
exactly was meant by Nous. The most bewildering character
istics are assigned (74) to it. It is certainly distinct from all
other substances : it is infinite and self -ruled ; it is mixed with
nothing, for, were it mixed with any it should be mixed with all,
and, then, it would have power over nothing ; it is omniscient
and omnipotent for only through such knowledge and power
can it arrange and move, as it does, all things for the best.
These characteristics suggest that Anaxagoras meant by Nous
an incorporeal being like human reason but with far greater
powers. There are other characteristics, however, that suggest
a subtle kind of matter, an impersonal force : Nous is the thinnest
and purest of all things ; it has greater and smaller parts. Its
action, too, is purely mechanical : it imparts to a portion of the
original matter a rotatory motion which gradually extends over
a wider and wider space. Hence the disappointment of Plato
and Aristotle with Nous : " Anaxagoras uses mind as a deus ex
machina to account for the formation of the world ; and whenever
he is at a loss to explain why anything necessarily is, he drags it
in."(75)

Anaxagoras seems at first si^ht to be face to face with insuper
able difficulties in explaining birth and death and change in the
world of experience. For there, no less than in the original
mixture, everything is in everything. But if that be so, how can
one thing even apparently emerge from another ? His reply is
that what at any stage comes into being was in reality already
there, but that at one particular moment it becomes so prominent
as to be perceptible. Dark water comes from white snow : the
dark particles were always present in the snow ; but they were
invisible up to the melting stage owing to the prevalence of white
particles. " All things have a bit of everything " ; " the things
that are in the world are neither divided nor cut off from one
another with a hatchet." (76) " Nothing, however, is like
anything else, but each single thing is most manifestly those
things of which it has most." (77) Anaxagoras ventures a

THE ATOMISTS 63

greater paradox : " and in all things many things are contained
and an equal number both in the greater and the smaller of the
things that are separated off." (78) No extant fragment clears
up this paradox : but a comparison of two fragments excludes
both of two obvious explanations. The smaller could contain a
less number than the greater on one or other of two hypotheses :
decrease in size might result in a quality reaching its smallest
possible dimensions so that any further diminution would involve
its disappearance ; increase in size might result in such extension
that all stuffs of a particular kind would be absorbed by this
enlarged object so that none of it could remain over for any other
body. Anaxagoras explicitly rejects both of these hypotheses :
" nor is there a least of what is small, but there is always a
smaller " : " there is also always something greater than what
is great." (79) However great or small, then, a body is, it contains
a portion of everything and there are as many portions in the
smallest particle as in the greatest. And if any particular object
appears to us to contain some one quality to the exclusion of
others, this happens only because that object contains more of
that than of those other qualities : as a matter of fact, each
thing contains qualities of every kind but it gets its name from
that special quality of which it has most.

Such was the world-theory of Anaxagoras : the universe is
made up of an infinite multitude of seeds which develop from
chaos into cosmos owing to a vortex motion that is started by an
initial fillip given to one portion of its mass by Nau-s.

THE ATOMISTS.

Empedocles and Anaxagoras prepared the way for the most
important pre- Aristotelian theory of the constituents of bodies,
Atomism. Leucippus (fl. 450 B.'C.) laid the foundations of this
theory, but Democritus (b. 460 B.C.) completed the superstructure
with such gifts of erudition and style that it is only nowadays
the true significance of his teacher is being realised. (80) Aristotle
who paid Atomism the tribute of his keenest attention and criti
cism gives a clear account of its origin.(81) It arose, he tells us,
out of that denial of the void by means of which the Eleatics
sought to prove the impossibility of motion and multiplicity.
Parmenides and his school had argued : Motion and multiplicity
are impossible without empty space ; but there is no empty
space ; therefore there is no motion, no multiplicity. The
Atomists retorted : Motion and multiplicity are impossible
without empty space ; but there is motion and there is multi
plicity ; therefore, there is empty space. Atomists granted,
indeed, that empty space was not real in the Eleatic sense of
being corporeal : they insisted, however, that it existed. Since
motion was a fact, empty space cannot be identified with the
non-existent : " what-is-not " in the Eleatic corporealistic mean
ing " is " in another meaning just as much as " what-is." And,

64 COSMOLOGY

in addition to empty space, there was body or the Full. But if
the facts of experience are to be accounted for, this body cannot
be interpreted as the Eleatic One : it must be broken up into an
infinite number of parts that are separated from one another by
the void. Zeno had proved that absolute division would abolish
magnitudes : consequently, this division of matter must stop at
indivisible particles, atoms. Atoms are indivisible, not mathe
matically, but physically : and they contain within themselves
no empty space. Once an infinite extent of empty space and an
infinite number of atoms are secured, the Atomists accept and
transfer to these atoms all the properties of the Eleatic One.
Atoms are increate and imperishable : whence could they come ?
whither could they go ? They are subject to no internal changes :
not from within for they have no parts that admit of displace
ment ; not from without for they have no empty spaces. They
are all of the same nature for they all act on one another. (82)
But this changelessness and this homogeneousness refer only to
quality : quantitatively, the atoms are infinitely various.!83)
They differ in shape — and this includes size — position and arrange
ment : A and N ; A and P> ; AN and NA. Moreover, these
quantitative differences must be infinite in number : otherwise,
the atoms and their groupings could not explain the infinite
differences and changes of things in our universe. Only one
condition governs this infinity of differences : all atoms are too
small to be perceived by our senses.

These presuppositions account for everything that happens in
our universe : all properties and all changes in bodies are due to
the number, shape, size, position, and arrangement of the atoms
of which these bodies consist. Birth is a union of atoms ; death
a separation of atoms ; growth an addition of atoms ; decay
a subtraction of atoms ; qualitative alteration a change either
in number, shape, size, position, or arrangement of atoms. All
reciprocal action between bodies is a push or a pull of atoms :
there is no action at a distance. The physical properties of
bodies are explained mechanically by the quantitative relations
of these atoms. Some properties belong to the bodies themselves :
for instance heaviness, lightness, hardness, softness. The weight
of an atom depends on its size : the weight of a body depends on
the amount of atomic matter it contains ; bodies of equal size
may enclose more or less empty interspaces and thus differ in
weight. Hardness and softness are similarly conditioned by the
proportions of emptiness and fulness within a body : and even
when the number and the size of empty interspaces are equal in
two bodies, one of them may be harder than the other owing to
the manner in which these empty interspaces are distributed.
Other physical properties such as temperatures, colours, and
tastes are really sensations caused in us by the number, shape,
size, position, and arrangement of a body's atoms : one and
the same body will evoke different sensations according as it
touches our senses with atoms of such and such numbers, shapes,

THE ATOMISTS 65

sizes, in such and such a position, arranged in closer or looser,
equal or unequal order.

Thus does the assumption of empty space enable the Atomists
to shatter into an infinite number of fragments the world-sphere
of Parmenides and to scatter these fragments through the infinite
immensities of space. Atoms and the void furnish the raw
material of our universe : particles of matter, solid, indivisible,
impenetrable, eternal, unchangeable, indestructible, infinite in
number, so small as to be invisible, exactly alike in nature,
differing only in shape and size and position ; surrounded on all
sides by empty interstices as by a network of canals, constantly
impinging on one another and uniting into groups, yet com
municating with one another solely by external contact and
collision. These invisible, extended, homogeneous indivisibles
moving about in empty space, are the only existing realities :
all qualitative differences between things are illusions of sense-
perception. " In truth, there are atoms and a void : by conven
tion there are a sweet and a bitter, a hot and a cold, and according
to convention there is colour." (84) Such was the first European
theory of Atomism : in the main a speculation based on Eleatic
metaphysics, the physical facts that suggested it being but the
trite experiences that things are many and are subject to birth,
growth, decay, death.

By atoms and the void, the Atomists explained also the for
mation of our world and all its contents. The nature and cause
of the " eternal motion " of the premundane and extramundane
atoms are matters of dispute (S5) : but whether this original
motion be regarded as a confused motion this way and that or as
a perpendicular fall due to the weight of the atoms, it results in
collisions which set up in an infinite number of places a vortex
motion. Now, all atoms are not equally gregarious : some have
hooks and eyes, balls and sockets, involuted edges and so on ;
some have no handles of this kind and can be kept together only
if inclosed by others as in a shell. But when in the vortex
atoms that are fit for combination meet, they are woven gradually
into larger and larger wholes until they form a shell that shuts
in multitudes of other atoms : this shell cuts off its contents
from the infinite void, and thus serves to enclose the makings of
one of the infinite number of existing worlds. Our world is
clearly a cosmos : land and sea and heavens ; earth at the
centre, fire at the circumference. And the Atomists illustrate
its development by such analogies as the action of the winnowing
fan on grain and of the tide on stones ; lentils lie next to lentils,
barley to barley, wheat to wheat ; long stones are heaped beside
long stones, round pebbles beside round pebbles. Vortex motion
produces similar results in cosmic processes : it segregates and
brings together atoms that are alike in shape and size, — flinging
watery particles beside watery, earthy beside earthy, and so on
until it forms the four large distributions of water, earth, air and
fire. Moreover, in every eddy of wind and water, larger bodies

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66 COSMOLOGY

make their way to the centre and smaller bodies are squeezed
out towards the circumference ; that is why the large atoms of
earth congregate at the centre and the small atoms of fire at the
circumference in our world. Thus was the formation of our world
and all its contents formulated for the first time in kinetic and
materialistic terms ; " naught happens by chance, everything by
law and necessity." (86)

PLATO.

Plato (427-346 B.C.) denies that there can ever be a science — in
the true sense — of Cosmology : the world of experience, including
matter, belongs to the realm of becoming and is therefore merely
a copy of that true reality, the world of Ideas. " And in speaking
of the copy and the original we may assume that words are akin
to the topic which they describe ; when they relate to the lasting,
the permanent, and the intelligible, they ought to be lasting and
inalterable, and, as far as their nature allows, irrefutable and
immutable — nothing less. But when they express only the copy
or likeness and not the eternal things themselves, they need only
be likely and analogous to the real words. As being is to becom
ing, so is truth to belief." (87) Every theory of the ultimate
constituents of matter deals with what is always becoming and
never is, not with what always is and never becomes. Becoming
for Plato, however, cannot be an object of scientific knowledge :
it is merely an object of belief. " Enough if we adduce (on this
question) probabilities as likely as any others ... we ought to
accept the tale which is probable and enquire no further." (87)
Plato gathers these probabilities from his predecessors : the
perpetual flux of Heracleitus ; the four roots of Empedocles ;
the Unlimited and the Limit of the Pythagoreans ; the invisible
indivisibles of Leucippus and Democritus. But he fashions
these borrowings after a method all his own. He is no mere
syncretist : he opposes to that world of perpetual flux, the world
of Ideas ; he challenges the irreducibility of the four roots ; he
denies the existence both of atoms and of the void ; and though
in identifying forms with numbers, he leads his readers through
a labyrinth where it is confessedly difficult to find one's way,
he himself kept his head sufficiently well throughout all these
meanderings to destroy once and for all two insuperable obstacles
to the progress of Greek arithmetic and Greek geometry — the
hypotheses that the numerical series has the unit as its origin
and that the point was a unit having position.

The fountain-head of all Platonism is the theory of Ideas.
For our present purpose, it is sufficient to recall that the world of
Ideas is a superphysical world of eternal and immutable types :
that the objects of scientific definition and scientific truth are
these unchanging forms ; and that the objects of sense experience
are merely approximate and imperfect copies of these types or
forms, and get from them their class-names. The Ideas, then,

PLATO 67

are the only true existents : sensible objects are but a shadow,
a mimicry, a copy of these Ideas. And that is why there can
be no science of Cosmology : its subject is sensible matter and
sensible matter is not, for Plato, a full-blown reality.

Let us see, however, what Plato thinks we may believe about
the ultimate constituents of sensible matter. Part of his treat
ment of this problem consists in a deductive proof of the existence
of the four elements and an empirical proof of their reducibility.
That deductive proof (88) runs. What is created is of necessity
visible and tangible : visible and therefore made of fire ; tangible
and therefore made of earth. But in order that fire and earth
be combined into a unity such as our world, there must be a
proportional mean between them ; solids are always connected
by two middle terms. Accordingly, God added to earth and
fire the two other elements air and water. His empirical proof
of the reducibility of four elements is set forth in the following (89)
words. '' We speak of fire and the rest of them . . . and we
maintain them to be the first principles and letters or elements of
the whole although they cannot reasonably be compared by a man
of any sense even to syllables or first compounds. ... In the first
place, we see that . . . water, by condensation, I suppose, be
comes stone and earth ; and this same element, when melted
and dispersed passes into vapour and air. Air again, when
inflamed, becomes fire, and again fire, when condensed and
extinguished, passes once more into the form of air ; and once
more, air when collected and condensed, produces cloud and
mist, and from these, when still more compressed, comes flowing
water, and from water comes earth and stones once more ; and
thus generation appears to be transmitted from one to the other
in a circle." This empirical proof of the reducibility of the four
elements, which was later used by Aristotle as the basis of Hyle-
morphism, is used by Plato chiefly for the purpose of refuting
Empedocles.

Plato's own theory of matter grows out of his theory of Ideas
rather than out of the empirical facts of the transmutation of the
elements. He sets up on the one side that world of Ideas — the
prototype, the truly existent, the immutable, the self-dependent,
the one : and on the other, the world of sensible objects — the
copies, the non-existent, the mutable, the mutually-dependent,
the many. Then, the problem is : how can imperfection issue
from perfection, becoming from being, manifoldness from unity ?
His solution is that a special principle, the direct contrary of the
Idea, must be assumed as the basis of all sensible existence : a
principle which is the cause of non-being, of change, of depen
dence, of divisibility. The fullest description is given in the
Timceus. There this principle is called the receptacle, and in a
manner the nurse of all generation ; the universal nature which
receives all things and never assumes a form like any of those
things which enter into her ; the invisible and formless being
which receives all things and, in some incomprehensible way,

5*

68 COSMOLOGY

partakes of the intelligible ; the formless receiving principle
which may be likened to a mother, the impressible mass which
is to receive, perpetually and throughout its whole extent, the
copies of all eternal beings, and for that reason must be devoid
of any particular form.i90) Plato's hearers use similar terms
when speaking of this Universal Recipient. Aristotle says that
Plato in his lectures reduced matter to the Unlimited, the Great
and Small — that is, to an indefinite continuum which is capable of
increase or decrease to anv extent : and again, that this Great
and Small was identified with non-being, which implies, not that
the indefinite continuum of the more or less was nothing, but
that it was not anything.!91) What, then, did Plato mean by
this Universal Recipient ? Aristotle answers, (92) space of three
dimensions : and some of our best modern scholars (93) agree
with the Stagyrite. Plato's text is their proof. In several consecu
tive paragraphs of the TimcBUsJ?*) he describes rather fully
the triad of principles that are necessary to account for our world.
In the first of these paragraphs : — a pattern, intelligible and always
the same ; the imitation of the pattern, generated and visible ;
the receptacle, and, in a way, the nurse of all generation. In the
following paragraphs : — that of which the thing generated is a
resemblance, the source or fountain-head likened to a father ;
that which is in process of generation, the intermediary nature
likened to a child ; that within which generation takes place, the
receiving principle likened to a mother. Farther on : — one kind
of being which is always the same, uncreated, and indestructible
and the contemplation of which is granted only to intelligence
another nature of the same name as this, like it but created
becoming, vanishing, and apprehended by opinion and sense
a third nature which is space and is eternal and indestructible,
and provides a home for all created things, a nature apprehended
not by sense but by a kind of spurious reason. And having
concluded this description, Plato adds : " Thus have I given
concisely the result of my thoughts ; and my verdict is that
these three, being and space, and generation, existed in their
three ways before the heaven."

This conclusion regarding the identity of the Universal
Recipient with space is confirmed by Plato's mathematical con
struction of the four elements. There is no mention of a corporeal
stufT that assumes figured shapes. Bodies are formed simply
by throwing certain portions of space into the shape of the four
elements : as is clear, from the assertion that they are com
pounded out of and resolved into planes. How and what planes
thus form the four elements is detailed at great length.(95)
Plato's guiding principle is the discovery of the four most beautiful
figures, which are unlike one another and which are capable — in
some instances — of resolution into one another. He selects on these
grounds the isosceles triangle, and that form of the scalene which
has the square of the longer side three times as great as the square
of the lesser : " out of these, fire and the other elements have been

PLATO 69

constructed." By combining triangles of these kinds and of
an infinite variety of sizes, we get certain geometrical forms :
from the scalene are formed the three first regular solids — the
tetrahedron, the octahedron, the icosahedron ; from the isosceles
is formed the cube. These geometrical forms are, in their turn,
identified with the four elements : the cube as the most immovable
and the most plastic is identified with earth ; the tetrahedron,
as the most movable, with fire ; the octahedron, as intermediary,
with air ; the icosahedron, as after the cube the least movable,
with water. This mathematical construction of the elements
furnishes in its turn the key to their transformations and their
motions. Three of the elements are interchangeable because
composed of similar triangles. That transformation consists
in their resolution into their original triangles, and a reunion of
these latter in new ways : a particle of water, when decomposed,
gives two particles of air and one of fire because the twenty
triangles of an icosahedron can form, when rearranged, two
octahedrons and one tetrahedron ; a particle of air, when decom
posed, gives two particles of fire because the eight triangles of an
octahedron can form, when rearranged, two tetrahedrons. Earth,
however, has triangles peculiar to itself : it cannot, then, be
changed into any of the other elements ; it can only be dissolved
into its original triangles.

This transformation and this dissolution (96) depend on the
distribution of the elements in space. Here, Plato postulates a
theory of natural places : fire, earth, air and water have, each of
them, a particular region in our universe assigned to them and, of
themselves, congregate there in large masses. The motion of the
external orbit of the universe acts as a check on this natural ten
dency of each element to gather into one spot : that orbit is
circular and continuous and exerts, by its revolution, sufficient
pressure on the things within it to thrust the four elements out
of their natural places. The result is incessant mixture of the
various kinds of bodies : the smaller bodies being crowded into
the interstices of the larger. And when the smaller quantities
of one element are caught thus by larger quantities of another,
the smaller must either escape or decompose : they may escape
to their natural place ; failing that, if they are portions of fire
or air or water they are changed into the larger element, if they
are portions of earth they are dissolved into their constituent
triangles. Thus is brought about and maintained a perpetual
process of circulation of the four elements : the circulation that
in its myriad intricacies makes up the motions and the changes
of the material universe.

Plato's theory of the ultimate constituents of matter may be
characterised in modern speech as mechanical : he regards all
sensible differences between bodies as consequences of more
ultimate differences in geometrical structure. Space is ever the
same, taking on with complete indifference the forms that pass
in and out of it. These forms — copies of the Ideas — are the

70 COSMOLOGY

primordial triangles and their products, the regular solids. These
regular solids are the four elements : these elements congregate
in large masses at their natural places ; three of them are trans
formable into one another ; the fourth is merely decomposable.
There is a universal attraction of the smaller masses of each
element to the larger masses of its kind : like to like. There is
no void : particles of matter are ever pushing one another round
and round. Such are the outlines of a Platonic mechanism which
rivals the doctrine on which in certain moods Plato expends his
finest irony — the Atomism of Leucippus and Democritus.

The Pythagorean (97) features of Platonism have ever proved
a mass of seething controversies : controversies fraught with
significance for the system as a whole. But the references to the
problem of the constituents of matter scattered through these
developments, whether found in the writings of Plato or of his
disciples, are mere asides that throw no new light on the doctrines
of the Timceus. Plato in the Republic, the Sophist, the Parmenides,
refers to matter as non-being ; in the Philebus, as the Un
limited ; in his oral lectures — according to Aristotle, Hermodorus,
Eudemus — as the Unlimited, the Great and Small, non-being,
the source of evil. When examined in their contexts, however,
these technical phrases do not provide any sufficient reason for
abandoning or supplementing Plato's mathematical analysis of
the corporeal into geometrically fashioned shapes of space. The
expressions are, it is true, Pythagorean : but so far as our present
problem is concerned, there is no fundamental change of thought :
the doctrines are those of the Timceus once more.

CHAPTER II.

ARISTOTLE'S CRITICISM OF THE COSMOLOGY OF HIS
PREDECESSORS.

ARISTOTLE'S criticism of the cosmological theories of his pre
decessors is based on his theory of causality.!1) He holds that,
when you ask yourself why such and such a state of things exists
in the universe, four partial answers may be given and each
of these corresponds to a cause. Consequently, a complete
theory of the causality of matter requires the enumeration of all
four. This view of causality was developed apparently from
observation of the making of artificial products and of the bio
logical processes of reproduction and growth. A coalvase is
constructed out of copper ; copper is its material cause ; it
has a special shape or structure which marks it off from all other
articles made out of the same metal — this structural shape is
its formal cause ; it gets this shape from the artificer — he is the
efficient cause ; it was made for the purpose of holding coals or
of wage-earning or of fame — coalholding, wages, fame are its
final causes. An oak starts from a particular kind of germ, an
acorn — the acorn is its material cause ; it develops perfections
characteristic of an oak and not of a plane or ash — these perfec
tions are its formal cause ; the acorn itself did not come from
nothing, it was produced by another oak — that parent oak and
its acorn-bearing activity are its efficient cause ; the whole
process of growth leads up to a final stage, in which the whole
perfection that was, at the beginning, present in the efficient
cause is fully realised in the material cause — the adult oak is
the final cause of the acorn.

ARISTOTLE ON THE MILESIANS.

Aristotle (384-322 B.C.) rejects without much ado the solutions
of the Milesians ; "it is clear that all who regard the universe
as one and assume a single entity as its material — and that a
bodily and extended entity — have fallen into error in several
respects." (2) These errors may be summed up under two
heads. One main objection is that the Milesians do not treat
of all kinds of causes ; they treat of only one kind of cause, the
material cause — hence they give no constituent principles for
incorporeal beings ; they neglect the agency by means of which
change is produced — the efficient cause ; they do not assume the

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72 COSMOLOGY

essence as the cause of anything that happens — the formal
cause ; they do not treat of the goodness or beauty of things —
the final cause. A second difficulty is their arbitrary choice
of particular bodies as primal world-stuff : they call anyone of
the four simple bodies, except earth, a principle without adver
tence to their reciprocal generation from one another : from
the point of view of generation, the most elementary ought to
be that body which is finest in texture and has the minutest
points — fire ; from the point of view of the logical superiority
of the completed result of development, water should be prior
to air and earth to water ; lastly, substances so definite in nature
as water and air exclude many physical qualities by reason of
the opposition of their own qualities to those of other substances,
and, consequently, it is impossible to derive those other sub
stance from either of them without much more machinery than
was dreamt of by the Milesians. As for that boundless mass
of Anaximander, Aristotle is not very definite about its nature,
probably because no clear statement concerning it was uttered
by Anaximander. (3) He is content to urge against the latter's
theory that spatial infinity is not essential for the incessant
production of new things ; and that " separation " was a word
whose meaning was left altogether vague. His general criticism,
if expressed, would likely have been that the qualitative distinc
tions of actually existing substances could not be derived from
that which has no definite qualities by means of Anaximander 's
meagre principles.

ARISTOTLE ON THE PYTHAGOREANS.

Aristotle urges against the Pythagoreans that their principles
are better suited to objects of mathematical study than to sensible
bodies.!4) First of all, their philosophy of nature excludes all
possibility of those motions which are the source of all natural
processes : they do not tell us how there can be motion ; or
how, without motion, there can be generation and destruction ;
or how, without motion, the stars can traverse the heavens as
they do. Neither do they explain how the first unit was con
structed so as to possess magnitude ; and what can they mean
by asserting that, when the first unit had been constructed, the
nearest part of the Unlimited began to be constrained by the
Limit. And even if it were granted or proved that spatial
magnitude is made out of the Limit and the Unlimited, how
could this method of structure account for the existence of bodies,
heavy and light ? and how are the remaining qualities of bodies
—temperature, taste, colour — to be derived from numbers ?
" Number is neither the cause as agent, nor the matter, nor the
ratio and form of things." (5) Number is not the essence " for
the ratio is the essence while the number is the matter : for
instance, the essence of flesh or bone is number only in this way,
' three parts of fire and two of earth.' And a number, whatever

ARISTOTLE ON HERACLEITUS 73

it is, is always a number of certain things, either of fire or earth
or of units but the essence is that there is so much of one thing to
so much of another in the mixture ; and this is no longer a number,
but a ratio of mixture of numbers whether these are corporeal or
of any other kind." (6) " Nor, of course, is number the final
cause " : " what good do things get from the fact that their
composition is expressible as number ? ... In fact honey-water
. . . would do more good if it were in no particular ratio but
well diluted than if it were numerically expressible but strong."
In short " these people are like the old Homeric scholars, who see
small resemblances but overlook great ones." (7) They tell us
nothing about the objects of experience — fire, earth, and the
rest — because their principles are in no way adapted to the ex
planation of these objects. Their definitions are superficial :
they regard anything to which a term under examination is first
applied as the essential nature of the object in question — " as
if one were to think that ' double of ' and * the number 2 ' are the
same thing on the ground that two is the first number which is
the double of another." (8) And the attempt to accommodate
their theory to facts results in the most glaring inconsistencies :
for instance, they explain material and immaterial realities by
one and the same number (9) : opportunity because it is seven
is in one special part of the world and a body which is seven
is also in that same part of the world ; accordingly, the question
arises whether we are to distinguish these sevens because of the
differences between the objects symbolised or whether we are
to deny the differences between those objects because of the
identity of their numbers. Again (10) they invent bodies to
suit their caprice : the number 10 is thought by them to be
perfect and to comprise the whole nature of numbers ; accordingly,
they insist that ten bodies move through the heavens, and
since only nine are visible they invent the tenth — the counter-
earth.

ARISTOTLE ON HERACLEITUS.

Aristotle urges against Heracleitus a total disregard of the
incorporeal, and an insufficient explanation of the corporeal.
The theory of Heracleitus is applicable at best only to corporeal
substances whereas there exist also incorporeal things. Even
with reference to corporeal things, Heracleitus made several
mistakes. He did not proceed in an intelligible way in his
selection of a primary body : for he did not discuss the mode of
production of other bodies from this primary body : nor did he
weigh the bearing of the respective values, in processes of develop
ment, of the temporal starting-point and the completed result.
Again, however irrefragable it be, that there is underlying the
production of anything, something out of which the product — be
it one thing or several— is formed, that truth is only one aspect
of the problem : there still remain unanswered other aspects —

74 COSMOLOGY

that of the efficient cause, that of the causal influence of the
thing's essence, and that of the final cause. So far Aristotle
does but treat Heracleitus as a thinker of the Milesian type.i11)
He has, however, special difficulties against the theory of flux.(12)
His first complaint is that Heracleitus does not say explicitly
what is the nature of that change to which all things are ceaselessly
subject. He proceeds, then, to prove that no change whether of
substance or of size or of place can go on uninterruptedly ;
that, as the changeable portion of our world is but a fraction
of the whole, it would have been more just to acquit that part
because of the other than to condemn the other because of it ;
that, even when a thing is not constant in quantity, its quality
or form — that through which we know each thing — remains ;
finally, and most trenchantly, that, if a thing perishes, there will
be present still some thing that persists and that, if a thing comes
into existence, there must be something from which it springs
and something by which it is generated.

Aristotle's attitude to the Heracleitean unity of opposites is
vacillating. He has too much good faith to misrepresent an
opponent on the strength of these paradoxical utterances, and
too much intelligence to accept the most startling fragments
in their context as the verdict of a logician. Hence, a series of
cautious criticisms : some think Heracleitus says that the same
thing can be and not be — but a man need not believe all he
says (13) ; again, Heracleitus adopted, without understanding what
he said, this opinion of the identity of opposites — if questioned, he
could be forced to confess that opposite statements can never
be simultaneously true of the same thing.!14) But Aristotle's
good faith and intelligence were often hard driven by an invete
rate habit of stating and criticizing, from his own standpoint, the
views of his opponents : and elsewhere, when speaking on this
point, he flings to the winds all hesitancy and declares the unity
of opposites to be in conflict with the principle of contradiction
" the doctrine of Heracleitus that all things are and are not,
seems to make everything true." (15)

ARISTOTLE ON THE ELEATICS.

Aristotle contests the principles, the arguments, and the
conclusions of the Eleatics. Their first principles (16) are vitiated
by obscurities both of language and of thought : the different
meanings of their favourite concepts — being and unity — are
never distinguished ; even if being had only one meaning, the
unity of all being could not be proved ; the finiteness of Par-
menides and the infinity of Melissus imply a denial of the un
conditional unity of being — in fact, every proposition about being
involves a distinction between thing and quality ; being is but
a common predicate of all things, and accordingly " what-is-not "
or " non-being " is perfectly thinkable as the denial of some

ARISTOTLE ON THE ELEATICS 75

definite kind of reality ; they attack the divisibility of being,
and yet describe it as extended in space. Then, their arguments
are as faulty as their principles. Each member of the school
in disproving the possibility of change overlooks the only ten
able hypothesis (17) : that whatever comes into existence springs
not from absolute nothingness, but from something which rela
tively to the finished product is nothing. The polemics of Zeno
in favour of his master are futile. (18) Three of the eight argu
ments hardly need refutation : one grain of corn does make a
noise when falling singly but this noise is so slight as to pass
unnoticed by our ears : the space in which each body exists is
nothing else than the surface or surfaces of surrounding bodies,
and each of those surfaces exists in its own body as substrate ;
the paradox of equalising the half and the double is due to the
fallacy that the space traversed by one body ought to be measured
according to the size of another body, which it passes, whether
that other be in motion or at rest. The other five arguments
are more puzzling : the alleged consequences of contradictory
magnitudes, and contradictory numbers, on the supposition of
pluralism ; the alleged consequences of the unfinished racecourse,
the unbeatable tortoise, and the ever-resting flying arrow, on the
supposition of motion. Aristotle allows that these paradoxes
follow logically from Zeno's presuppositions about continuous
quantities. His contention is that in every instance these pre
suppositions are false. Were a continuous body really divisible
into an actually infinite multitude of parts, it would be infinitely
large and infinitely small, and its number of parts would be
simultaneously finite and infinite. That supposition can never
be realised because it is impossible to come to the end of the
division of a continuous body : the number of parts obtained by
actual division, however protracted, is always finite ; the size
of each part decreases proportionately with the number of parts
made, and thus the sum of their extension remains always the
same ; moreover, there exists no actual distinction of parts at
all in a continuum prior to actual division ; in short, infinite
divisibility and infinite quantity are two totally different things.
Again, a finite distance in space is not composed of an infinite
multitude of successive and separate units : nor is a finite lapse
of time composed of an infinite multitude of successive and
separate moments. Hence the question can never arise of
traversing an infinite number of spatial units in a finite time.
Both space and time are continuous magnitudes that are endlessly
divisible ; and if anyone makes a difficulty of the possible
endless subdivisions of space, his opponent may fairly rebut it
by recalling the possible endless subdivisions of time. But,
as a matter of fact, finite spaces and finite times exist, prior to
division, as continua without any distinction of parts : conse
quently, there are no insuperable difficulties of a theoretical
nature, either about traversing any particular distance or about
traversing such a distance at different speeds or about traversing

76 COSMOLOGY

it in a finite lapse of time. Then, the plea of Melissus (19) in
favour of infinite space is unsound : why should infinity in space
follow from infinity in time ? and how could the real be spatially
indeterminate ? But the general conclusion of the Eleatic School
is the worst of all their many paradoxes. The alleged nullity
of the world of experience is but a cloak for their failure as a
school to solve the most pressing problem of philosophy (20) :
if, closing our eyes to the differences of things, we allow that the
Eleatics and their despised opponents whether among the masses
or the philosophers, as well as all the curious and complicated
processes at work in living beings on the earth and in the heavens,
are all one and the same, do we not assert the identity of opposites?
or, if the hills and cities of Greece and that humanity which they
house, with its busy, brilliant, fretful life, are all non-existent,
what, then, can claim to be existent ?

AKISTOTLE ON EMPEDOCLES.

Aristotle argues that the denial of change, whether substantial
or accidental, by Empedocles contradicts our experience : the
four elements are mutually transformable, and the same elements
unite in true mixture to form unitary compound substances ;
bodies, while remaining the same kind of substance, suffer changes
of quality and quantity — colour, taste, size, etc.i21) He suggests
also that the sphere of Empedocles compels an admission of real
generation : if the elements are in it completely united, their
qualitative differences must disappear — and, accordingly, the
subsequent emergence of . the elements involves their coming
into existence out of a homogeneous substance. Passing to
details, Aristotle raises sundry difficulties concerning the ele
ments and their motive forces.!22) These elements are chosen at
haphazard — no compelling reason is advanced for their accept
ance ; their number is not accounted for — why should they be
no more and no fewer than four ? their equality is not clearly
defined — is it an equality of magnitude or of power ? their
qualities do not explain such distinctive characteristics as lightness
and heaviness ; the doctrine of pores and effluences leads logi
cally to empty spaces and atoms — though Empedocles accepts
neither the one nor the other ; the pores are not accurately
described — if empty, what of the denial of the void, if full what
is their use ? Similarly, the principles of motion are not well
thought out (23) ; according to Empedocles, Love unites and
Strife separates, but, in the system itself, Love also separates and
Strife also unites ; their mode of action is more or less fortuitous ;
finally, why. in a world like ours, should their simultaneous
operation be preceded by complete mixture, and followed by
complete separation ?

ARISTOTLE ON THE ATOMISTS 77

ARISTOTLE ON ANAXAGOKAS.

Aristotle repeats in his criticism of Anaxagoras the chief
objection to the theory of Empedocles : the absurdity of denying
qualitative changes in our world. Then he marshals a number
of difficulties (24) against the special tenets of Anaxagoras. An
infinite number of primary bodies is needless, for a small number
would do equally well ; it is false, for the fundamental distinctions
of kinds are numerically limited ; it is fatal, for knowledge of
the infinite is impossible. Plants and animals have a definite
natural size : consequently their constituents — seed, hair, flesh,
bone, etc. — cannot be indefinitely big and small. Again, if
exhaustive secretion is possible, everything is not in everything —
there is no flesh in the residual water : if it is impossible on the
grounds that more always remains behind, then, you are bound
to admit the absurdity of an infinite multitude of finite magnitudes
in a finite body. Moreover, no explanation is forthcoming in
this theory of Anaxagoras of the differences in weight between
bodies. And despite his denial of empty space, the doctrine
of an infinite number of constituent parts imperils the continuity
of bodies. Finally, the original chaos is brimful of paradoxes :
things would have to exist first in an unmixed state ; nature
does not allow any chance thing to be mixed with any chance
thing ; specific qualities would be separable from their respective
substances ; motion in the original chaos subsequent to infinitely
continued rest would contradict the regular order of nature.
It is true that Anaxagoras surpassed his predecessors in setting
up Mind as the purposive cause of the world's beauty and order :
he uses it, however, merely as a stop-gap and drops it whenever
he can in favour of mechanical causation. (25)

AEISTOTLE ON THE ATOMISTS.

Aristotle regards Atomism as the most important doctrine
of matter among his predecessors : " no one before Democritus
paid much attention to the processes of bodies, but he seems to
have thought out everything about these processes." (26) He
rejects, however, on the grounds of experience all the leading
theses of the Atomists : empty space, the existence of atoms,
the homogeneity of matter, the denial of qualitative change, the
exclusion from nature of finality.

Democritus had accepted empty space as the only possible
explanation of local motion, of rarefaction and condensation, of
growth, and of the experimental fact that a vessel filled with
ashes holds as much water as one that is empty. Aristotle
retorts (27) that motion in a plenum is possible if bodies inter
change places ; that condensation is explicable by extrusion —
compressed water yields up the air it previously had ; that
rarefaction admits of one or other of two explanations — in some

78 COSMOLOGY

instances, it is due to the entrance of fresh matter into bodies,
in others, as when water passes into steam, it is due to a change
in substance which necessitates a change of volume ; that growth
is explained by change of substance ; that the conclusion drawn
from the experiment mentioned may be explained away as due
partly to the inaccuracy of the supposed fact and partly to
extrusion of the enclosed air. Having thus rebutted the argu
ments of his opponents, Aristotle proceeds to prove that empty
space would make motion impossible : no characteristic motion
of bodies can occur in empty space for it admits neither of up or
down or middle : the flight of projectiles could not occur in empty
space — there would be nothing to maintain and direct their
motion, and there would be no reason why they should come
to rest here rather than there since the void yields equally on
all sides ; bodies of equal masses ought to fall or rise with infinite
rapidity because of the infinite rarity of the void, and bodies of
unequal masses ought to rise and fall with equal rapidity because
of the lack of resistance of the void — conclusions which Aristotle
believed to be contradicted by facts. (28) For these and cognate
reasons, Aristotle concludes slyly that those who think out this
theory of empty space can see for themselves " there is really
nothing in it," (29)

Aristotle multiplies ad nauseam difficulties against the
atoms. (30) He argues that atoms cannot be indivisible — for the
division of extended matter could reach a limit only if the con
tinuum consisted of mathematical indivisibles ; that atoms, even
if they existed, need not be infinite in number and shape — firstly,
because all known differences of kinds and qualities and positions
and motions are reducible to a few fundamental types, and
secondly, because the finite or determinate is preferable to the in
finite or indeterminate, a characteristically Greek argument ; that
atoms which act on one another merely by pressure or collision
could not, even with the help of fantastic hooks and eyes, constitute
a cohesive body ; that the atoms, for instance, of water and air
can not have a distinctively fixed shape since these substances
readily adjust themselves to vessels of every shape ; that no
reason can be assigned why there should not be large as well as
small atoms ; that if the atoms are homogeneous, they should,
when brought into contact, join together into one body — just
as water unites with water ; that if the atoms are heterogeneous,
this heterogeneity of stuff, and not their differences of shape,
must be the cause of phenomena ; that if qualities like warmth,
coldness, hardness, softness, weight, are coupled with definite
shapes, atoms necessarily influence one another and cease to
be unchangeable ; that, on the one hand, atoms cannot be without
qualities — possessing, for instance, merely shape — for body is
tangible, and what is tangible must be qualitative ; that, on the
other hand, atoms cannot have qualities — for if each has only one
quality, this coldness, and that hardness, they are not homo
geneous, whereas if each has several qualities, the same indivisible

ARISTOTLE ON THE ATOMISTS 79

thing will be simultaneously hot and cold, soft and hard, active
and passive ; that if the atoms are moved by an extrinsic cause,
they are passible ; that if the atoms are moved from within
themselves, then they are either divisible into parts which are
motor and moved, or one and the same thing is at once motor
and moved ; that if the elementary atoms are distinguished from
one another only by their size, one element could not be developed
from another ; that if the atoms cannot interact, empty space
will not suffice to set bodies interacting, for these interstices
merely bring atoms into contact.

Aristotle^ chief difficulty against homogeneity of matter is
the obvious differences of bodies as regards weight : sparks fly
upwards, stones fall ; in water, large logs of timber float, tiny
lumps of lead sink.(31) The atomistic explanation of lightness
was based on empty space : the greater the interstices, the lighter
the body — fire was the lightest of all bodies, for it contained
most void : still, the lighter body must contain not only more
void but also less full — otherwise a large lump of gold with big
empty spaces would be lighter than a small mass of fire. Aristotle
points out the worthlessness of this explanation : according to it,
the absolutely heavy must be that which has most full or that
which has least void. Neither definition fits the facts : there are
surely sufficiently large masses of fire that enclose more full
than tiny clods of earth, and there are surely tiny masses of fire
that contain less void than large lumps of earth ; and yet fire,
large or small, ascends while earth, large or small, descends.
Nor does the supplementary suggestion, based on the relative
proportions in bodies of the full and the void, meet this difficulty.
Great and small masses of fire must contain relatively the same
proportions of full and void, and so, too, must great and small
lumps of lead: and yet, the greater the mass of fire the more
quickly it ascends, and the larger the lump of lead the more quickly
it falls. Finally, it is absurd to hold that bodies rise because
of the enclosed void unless it be of the nature of the void to ascend ;
and if the void of itself ascends, the full of itself must fall. And
should that be so, the problem of the differences in weight between
bodies is merely transferred from these bodies to their alleged
constituents : there, it meets us in all its difficulty once more.
Why does the void ascend ? Why does the full fall ? And how
is it that the void and the full do not exist, wholly apart, in separate
regions of space ?

Aristotle insists also upon the reality of qualitative changes
in bodies : changes of substance in generation and destruction,
changes of qualities in alteration, changes of size in growth and
decline. (32) Atomists admitted only changes of spatial position,
and attempted to reduce all other kinds of change to this : gene
ration and destruction were the union and the separation of
atoms ; growth and decay, the addition and subtraction of
atoms ; alteration, spatial redistribution as regards order and
position and number of atoms ; in Aristotle's words, the most

80 COSMOLOGY

contrary things were said by the Atomists to be constructed out
of the same atoms somewhat as tragedies and comedies can be
constructed by transposition of the same set of letters. In this
connection, the trump card of atomism was its suggestion that
bodies enter into and influence one another through the pores :
it certainly gained popular sympathy for their theory because,
to the thoughtless, once indivisibles are invisibly entangled in one
another everything seems possible. Aristotle stresses from the
start the weakness of this appeal to the pores : if atoms are
incapable of influencing one another reciprocally when they
come into contact, pores cannot relieve this incapacity for pores
merely facilitate contact. His strong point, however, on this
problem of change is experience ; the four elements come into
and pass out of existence ; true mixtures are formed by the
union of the four elements ; some bodies completely absorb
others ; substances often gain new qualities and lose pre-existing
ones. Consider, first of all, the births and deaths of the four
elements : earth becomes fire ; fire becomes water ; water
becomes air ; air becomes water ; water becomes earth. How
are these facts explicable on the atomic hypothesis ? The elements
cannot be formed from elementary atoms that differ merely in
size, for, then, how could their distinctive sets of qualities arise ;
nor from an incorporeal substance for a similar reason ; nor from
a body different from the elements themselves, for this body
could have neither weight nor natural location, and, accordingly,
could not exist in space. The only remaining solutions are
development from one another either by substantial generation
or by extrusion. Extrusion would mean, for instance, that
when air is formed by evaporation from water, a group of atoms
hitherto imprisoned in the water would emanate therefrom :
how can one accept this view who knows that water can be so
completely resolved into air as to leave behind no insoluble
residuum ? and then, there is the other equally adverse fact that
the evaporated air occupies so much larger a space than the original
water that unless allowed to escape it will burst the containing
vessel. Hence the only satisfactory solution of these facts of
experience is the admission of substantial generation : water
with its distinctive qualities ceases to exist and air with its dis
tinctive qualities begins to exist. This same solution is needed
for other mutual transformations of the elements, for difficulties
somewhat similar in character block the way of explaining the
changes that occur as cases of extrusion : when fire becomes
water, and water earth, in both instances bodies which are heavier
than their sources come into existence ; when earth becomes fire,
there is an enormous increase in volume ; and when earth be
comes water, this must mean on the atomic view that some atoms
are extracted from the earth — but if such extraction can go
on forever, there must be an infinite number of particles in a
finite body. Substantial generation occurs also in cases of absorp
tion and of the formation of true mixtures. Absorption is the

ARISTOTLE ON THE ATOMISTS 81

complete conversion of one body into another : the merging
of a drop of wine in a hundred gallons of water, and the changing
of food into living flesh. True mixture is the formation of a new
substance from the union of the four elements : the living tissues
of plants and animals were the examples best known to Aristotle.
And by arguments similar in kind to those urged in favour of
the transmutation of the elements, he proved that neither
absorption nor true mixture is a mere mechanical juxtaposition
of elementary atoms : in the light of the characteristics of weight
and touch and activities, which mark off flesh and bone from
every kind of food, who can really believe that grass and bread
and meat are merely inset in plants and animals like bricks in a
chimney stack ? Nor is alteration merely so much spatial change
among the parts of a substance ; when water freezes and ice
melts, the whole substance changes from liquid to solid and back
again from solid to liquid, and the consequent changes in volume
are due neither to a coming together nor to dividing off of par
ticles, for the continuum is everywhere equally solid or equally
liquid. The alterations of living bodies are still more inexplicable
on the atomistic hypothesis, for they — to quote Aristotle's illus
tration — change from health to sickness, from non-musical to
musical, from ignorance to knowledge. Again, growth is not a
mere addition of new parts to those already there, nor decay a
mere subtraction of old parts : the one implies the increase,
the other the decrease of the preexistent as a quantitative unit.
Accordingly Aristotle concludes that the evidence at our dis
posal is overwhelmingly in favour of qualitative changes both
in substances and in accidents. Nature is not a collection of
comedies and tragedies cunningly contrived out of the spatial
transpositions of an alphabet infinitely homogeneous in quality.
Finally the Atomists (33) had explained everything that happens
in the heavens and on the earth as due to the fortuitous collision
of material antecedents : rain falls because the clouds cool and
thicken, and not at all in view of the ripening of corn, as is clear
from the fact that, later on, this same rain rots the corn ; when
teeth are formed, some incisive, others molar, and thus adapted
to their respective functions, that result is also due to the fortui
tous concurrence of various circumstances ; in short, all things
happen fortuitously, but those of them that are lucky hits,
in the sense of being able to triumph over their foes from within
and from without, live on and perpetuate their kind. Aristotle
thinks this account of natural processes incorrect. " Democritus,
however, neglecting the final cause reduces to necessity all the
operations of Nature. Now they are necessary, it is true, but
yet they are for a final cause, for the sake of what is best in each
case. Thus nothing prevents teeth from being formed and shed
in this way ; but it is not on account of these causes but on account
of the end ; these are causes only in the sense of being the moving
and efficient instruments and the material. So is it reasonable
that Nature should perform most of her operations using breath

6

82 COSMOLOGY

as an instrument, for as some instruments serve many uses in
the arts — the hammer and the anvil, for instance, in the smith's
art — so does breath in the living things formed by Nature. But
to think that necessity is the only cause is as if we should think
that the water has been drawn o££ from a dropsical patient on
on account of the lancet, not on account of health for the sake
of which the lancet made the incision." (34) And against the
Atomists, Aristotle holds that everything in nature works for a
fixed goal. He supports this view mainly by four arguments (35) :
nature is overwhelmingly regular in its processes, and what hap
pens always or even usually cannot be assigned to fortuitous
concurrences ; wherever you discover a series of changes always
leading up to some last stage you think of those changes as
directed toward it as product — now, the heavenly processes recur
in strict order and with unbroken regularity, and all living
beings periodically reproduce their kind ; art either perfects or
imitates nature, and art always aims at some end — therefore, nature
aims at ends ; the natural instincts of ants and bees are obviously
helpful to them and theirs, and the same fact is evidenced by
close study of the tendencies of plants — but ants and bees and
plants are the products of nature. This Aristotelian theory of
finality is neither extrinsic nor anthropomorphic : it means
simply that the natural activities of bodies — their constant modes
of acting — are not governed wholly by fortuitous external con
tacts and collisions but partly, and indeed principally, by deter
mining internal principles : bodies, whether living or non-living,
are directed by their respective internal qualities to definite ends.
In every case this definite end is the development of " form " :
its results vary, however, according as we are dealing with
accidental processes that take place in an existing substance or
with those processes that lead to the production of a new sub
stance.!36) In the first case, the activities of the individual act
for its own good — bringing it, as far as circumstances permit, by
stages of progress from imperfection to perfection, its essential
type remaining unchanged throughout the process : thus, anyone
of the four elements when produced seeks its natural place ; a
true mixture, even after formation, gradually " digests " its con
trary qualities and extrudes all excess ; the germ of plant or
animal advances step by step to maturity. In the other case, the
new individual comes from a progenitor of similar species — man
begets man, for everything in the universe is arranged for the
conservation and perpetuation of species : all natural activities
are just what they ought to be to secure for each existing species
its regular development in cycles that comprise myriads of indi
viduals. And this immanent teleology within each species,
whether living or non-living, accounts for the general order of
the universe (3?) : that unity in multiplicity which manifests itself
in the equilibrium and immortality of the universe as a whole,
is but the grandiose result of that unity in multiplicity which
governs the activities of individuals within each particular

ARISTOTLE ON PLATO 83

species : in short, it is simply the regular recurrence of the
general phenomena of nature. The whole conserves itself through
the multitudinous activities of parts, that possess an independent
individuality, and yet are, in relation to that whole, mostly
ephemeral realisations of fixed species whose orderly interre
lationships permit each and all to be perpetuated. The whole
is eternal because of the perennial vitality of its parts : and thus,
the destruction of the individual is but the expression of the
larger world-teleology. (38)

ARISTOTLE ON PLATO.

Aristotle rejects Plato's denial of all qualitative variety in
matter, and his reduction of all sensible differences between bodies
to the number, shape, and size, of their constituent planes. He
urges (39) that a theory which maintains that bodies are composed
of planes or indivisible surfaces involves the contradiction of
indivisible lines ; that since lines are constructed with points,
Plato's view resolves solids into points ; that since the primary
triangles cannot be divided, Plato denies the divisibility of bodies ;
that Plato's geometrically shaped planes cannot fill all space
within our world although their propounder rejects empty space ;
that the fact of bodies like air and water assuming the shape
of their containing vessels cannot be reconciled with the fixed
shapes of their planes ; and that as a continuum cannot be
formed by composition nor out of planes subject to composition,
flesh and bone or any compound body cannot come into existence.
In addition to these mathematical objections. Aristotle urges
a number of physical ones. Bodies (40) that have weight cannot
be constituted out of imponderable surfaces : nor does the
explanation of the Timceus that the heavier consists of many,
the lighter of fewer, constituents of the same kind meet such a
fact as the existence of absolutely light and absolutely heavy
bodies ; and if this explanation were valid with reference to the
other two elements, there ought to be large masses of air which
are heavier than small masses of water — a conclusion that is
contradicted by experience, for the greater the mass of air the
more quickly it rises and even tiny particles of air ascend upwards
out of water. Further, experience assures us of the mutual
transformations of all four elements, whereas Plato's theory
compels him to deny this transformation in the case of earth :
even in those transformations allowable on Plato's theory,
superfluous triangles may be left over owing to inequality in
the multitude of constituent triangles ; lines may be super
imposed on, as well as juxtaposed to, one another and since
planes may be put together in the same way, a superimposition
of surfaces which would not form either elements or compounds
is not excluded by Plato's principles. Fire (41) is said by Plato
to be made of pyramids because of its mobility, earth of cubes
because of its immobility : but fire will not leave its natural

84 COSMOLOGY

place — it ought, then, be a cube there ; and earth will strive
to escape, and rapidly too, from the regions of fire, air and water
— it ought, then, be a pyramid in these regions. Fire is supposed
to heat and burn because of its corners : if that be so, the other
three elements ought to heat and burn for their constituent
triangles have corners. Fire is supposed to change fuel into
itself, but pyramids do not change what they touch into pyramids
any more than do swords or saws. If heat be united with a
particular shape, then its contrary, cold, ought to be united
with a contrary shape : shapes, however, have no contraries.
For these and similar reasons, Aristotle dismisses Plato's theory
of matter as unsatisfactorv.(42)

CHAPTER III.
PERTINENT ARISTOTELIAN VIEWS IN NATURAL SCIENCE.

ARISTOTLE'S conclusions in those branches of knowledge that
are now known as physics, chemistry and astronomy are a
necessary prelude to a clear grasp of his philosophy of matter.
And as these conclusions are reached by means of the Aristotelian
method of scientific proof, it will be useful to begin our present
chapter with an outline of this method.

ARISTOTLE'S THEORY OF SCIENTIFIC PROOF.

Aristotle bases his theory of scientific proof (*) upon the
fundamental conviction that there exists such a thing as science.
By science, moreover, he means something very different from
much that has come to be known by that name in modern times.
Science was, for him, a system of truths valid always and abso
lutely for every thinking mind and a system in which the various
members are connected by a bond of logical necessity. Another
fundamental conviction of Aristotle's was that geometry was a
model of what every science should be. An easy approach to
the Aristotelian view of science may be got, therefore, by an
analysis of geometry. Geometry can be analysed into three
constituents. A special class of objects form the subject matter
of its inquiries : the initial definitions of the figures about which
it reasons. A number of first principles are enunciated as its
tools of reasoning : some of these are common to other sciences ;
some are special to geometry. A number of conclusions are
reached by the application of these first principles to the initial
definitions : these conclusions are scientifically proved truths.
All this analysis is summed up in the significant Aristotelian
phrase that geometry starts with essences and proves properties.
" Science consists in the knowledge of causes and the cause of
a phenomenon is that from which it of necessity arises. Proof,
therefore, and apprehension by means of proof are only possible
when something is explained from its original causes. Nothing
can be the subject of proof except that which is necessary. Proof
is a conclusion from necessary principles. That which is ordin
arily, though not without exception, true can be included under

85

86 COSMOLOGY

matters of proof only in a limited sense. On the other hand, the
contingent cannot be proved — cannot even be known scientifically.
And since necessary truth is that only which proceeds from the
essence and the idea in the subject, while everything else is con
tingent, so it may be said that all proof relates to and is founded
exclusively upon the essential characteristics of things and that
the concept of each thing is at once its starting-point and goal. . . .
All demonstration hinges on the concept of the thing. Its pro
blem consists of determining, not only the properties which
attach to any object by virtue of the conception of it but also
of the media by which they are attached to it. Its function is
to deduce the particular from the universal, phenomena from their
causes." (2)

Aristotelian science involves, then, two main processes : a
process of discovery of definitions and first principles : a process
of proof of properties by means of these definitions and first
principles. This second process, that of proof, need not detain
us. Admirers and opponents are agreed that Aristotle both
initiated and completed the theory of the scientific syllogism :
none of his predecessors had ever done this work ; none of his
successors has ever succeeded in adding anything of importance
to this part of his work. The first process, that of the discovery
of definitions and first principles, is the crux of Aristotle's theory
of scientific proof. He insists that definitions and first principles
are not demonstrable : if they were, demonstration would result
in the endless regress. He insists that they cannot be proven
necessarily true from the data of sense-perception : the essence
of a thing and the necessity of a first principle cannot be grasped
by any accumulation of empirical facts. How, then, does Aris
totle propose to discover these initial data of all scientific proof ?
He proffers three suggestions : perfect induction, intellectual
intuition, and dialectical reasoning. Perfect induction would
prove a proposition to be universally true by showing empirically
that it is true in each particular case. This method involves a
complete enumeration of individuals and hardly commends
itself to a sane man : the best that can be said for Aristotle, in
this connexion, is that the example he gives does not start with
particular facts at all but with lowest kinds — and these are
limited in number and can be cited. Had he recognised no other
way of discovering the requisite initial data, his theory of scien
tific proof would have fallen to pieces. Aristotle was not as big
a fool, however, as Francis Bacon and other critics would have
us believe. In actual practice, he relied on intellectual intuition
and dialectical reasoning rather than on perfect induction. His
theory of intellectual intuition was that when a sufficient number
of instances of sense-perception have been recorded in our ex
perience, a psychological process occurs in our intellect revealing
truths that go beyond these actual facts of sense-experience.
This process consists in an infallible intuition by the intellect
of the essences of the various kinds, and of the necessity of first

ARISTOTLE'S THEORY OF SCIENTIFIC PROOF 87

principles. His third source of initial scientific data was dia
lectical reasoning. Dialectic investigates the definitions and
principles of particular sciences by means of principles of universal
application. A man whose mind is stocked with principles of
universal application has points of vantage from which he may
attack or defend the scientific man's claim to lay down special
premisses. This dialectical reasoning is a favourite means with
Aristotle of testing prevalent opinions : those of the populace
and those of the experts. He confronts these opinions with a
series of ingenious difficulties based partly on logic and partly
on known facts. The consequence is that the opinions in question
seldom come through this ordeal without being either wholly
exploded or considerably modified. The residue is — in Aristotle's
view — a stock of reliable definitions and special principles for the
various sciences.

This theory of science and scientific proof has its difficulties.
Nowhere in his writings, does Aristotle betray an appreciation of
the differences between the subject matter of geometry and that
of the empirical sciences ; he failed to see or forgot to state that
the discovery of essences was not as easy a task in physical and
biological science as in geometry. Moreover, dialectical reason
ing, consisting mainly, as it does, in answering problems raised
by a disputant, tended to inculcate the habit of testing scientific
truth by interrogating your opponent rather than by interrogating
nature. But the weakness of Aristotle's theory need not have
led to unsatisfactory discoveries in empirical science. John S.
Mill was the first to raise the crucial question regarding the theory
of induction : and subsequent thinkers have been very much
divided as to the value of Mill's and of one another's solutions.
Yet, before and after Mill, modern scientists have been busily
doing the work of induction and doing it with ever increasing
success : solvitur ambulando. Aristotle's theory, then, would
not have prevented him from making valuable inductions if he
were in practice a careful and untiring observer. This he
undoubtedly was. An anthology (3) of extracts, inculcating the
most rigid cult of facts and the deepest distrust of mere speculation,
might be compiled from his writings. What is far more impor
tant, he practised what he preached. He outstripped predecessors
and contemporaries by his unwearied patience in research and
by his enormous accumulation of facts of observation. Further,
this ancient Greek, who busied himself about everything, out
stripped, even in their own domain, some of the greatest modern
specialists : so remarkable was the accuracy of his studies in
biology and so astonishing the extent of his achievements, that
Darwin speaks of Cuvier and Linnaeus as schoolboys in com
parison with the author of the " History of Animals." (4) A
similar enthusiasm for facts marks his historical studies. This
being so, the question arises how did an observer of this calibre
go at times so lamentably astray ? His mistakes are as amazing
as his discoveries. Side" by side with difficult biological details

88 COSMOLOGY

that have been rediscovered only late in the nineteenth century
are catalogued some extraordinary malobservations in bio
logical matters quite easy of access. (5) And everyone knows
that Aristotle's long ascendancy over European thought is mainly
to be regretted owing to his outlook in Physics, Chemistry and
Astronomy. I think we must distinguish between these two
sets of mistakes. These rare but atrocious errors in biology may
be accounted for by the fact that he collected more facts than
he could personally verify : he was too credulous regarding
famous authors and popular traditions — who was not until his
torical criticism, the latest born of the sciences, opened our
eyes ? This explanation has a partial application, also, to his
failure in those other sciences. But another factor intervened
here : the lack in Greece of crucial experiments, a lack necessarily
consequent on the non-existence of our modern mechanical
appliances. It is too often forgotten that the Greeks had little
more than their unaided senses, their imagination, and their
intellect to aid them in empirical discoveries. Their merits
as scientists must be weighed from that point of view. It has
been said, for example, that Aristotle foolishly rejected the
atomism and copernicanism of some able predecessors. He
certainly rejected root and branch the kineticism and the atomism
of Democritus. Modern science in the main has approved,
albeit unwillingly, of his rejection of thorough-going kineti
cism : it has never, up to the present, succeeded in re
ducing all force to motion : and in our day, it has grown
careless about this ideal. As for atomism, there is little more
than the name in common between the ancient and the modern
varieties of atomism : the Democritean atom had all sorts of
puerile attachments for grappling its neighbour; moreover, it
was supported solely by a series of speculations. Aristotle
grappled with these speculations, showed their unsoundness
from the standpoint of actual knowledge, and clenched his
thesis everywhere by an appeal to the facts of experience. Few
readers who recall the actual circumstances of this debate will
deny the weight of Aristotle's objections to ancient atomism.
The accusation about copernicanism is even more flimsy. The
only trace of copernicanism known in Aristotle's time was a sug
gestion (6) of some Pythagoreans — and possibly of Plato — that
the earth was not at the centre of our universe and that it was
in motion : but, in the existing state of astronomical knowledge,
these suggestions were simply wild guesses. In short, the reader,
who keeps steadily in mind the imperfect conditions of scientific in
vestigation amongst Aristotle's predecessors and contemporaries,
and weighs impartially the grounds of Aristotle's opposition
both to Democritus and these alleged pre- Aristotelian precursors
of Copernicus, will be led, I believe, to the conclusion that the
Stagyrite missed the path of progress in Physics, Chemistry and
Astronomy simply because, in branches of knowledge now ranged
under Natural Science, he was the most genuine empiricist

TERRESTRIAL AND CELESTIAL UNIVERSE 89

amongst the thinkers of Greece. That conclusion need not
blind any reader to Aristotle's one big defect in his handling
of the empirical sciences. For, despite a union of talents so
eminent and so diverse as to rank him amongst the master
minds of all time both in natural science and in philosophy,
there is that in Aristotle which makes the modern gorge rise.
It is this. He is not readily content with the observation and
enunciation of facts of experience : he is ever anxious to show
not merely that these facts exist but also that they follow neces
sarily from their causes ; in one word, he is obsessed with the
geometrical ideal of science. And in attempting this task, he
often starts from assumptions which are known nowadays to
have been the merest conceits, and proceeds to spin lengthy
webs of reasoning in order to prove, between a fact and its alleged
cause, a bond of logical necessity which is known nowadays to
have been a mere figment of his own brain. In instances of this
kind where Aristotle is trying to transform a fact of observation
into a metaphysical necessity, he is sometimes trapped in the
snare against which he warns others : " It is not difficult to set
up random hypotheses, to spin them out to great length, and to
weave them together." (7)

THE TERRESTRIAL AND THE CELESTIAL UNIVERSE.

Aristotle teaches the division of the universe into two essen
tially distinct parts, sublunary and heavenly, on a variety of
grounds : tradition, experience, speculation. Century-old astron
omical doctrines of the Egyptians and the Babylonians have
attested the imperishable nature and the regular motions of the
heavenly bodies : moreover, both Greeks and Barbarians make
the heavens the abode of the gods, and believe in its immortal and
nobler nature.!8) Our senses support these traditions : they
make us aware of the contrast between the immutability and
regularity of the heavens and the mutability and irregularity
of sublunary bodies and therefore of an impassable chasm be
tween the things of heaven and the things of earth. Aristotle,
however, is rarely content with empirical evidence ; and accord
ingly he proceeds to prove that the stuff out of which heavenly
bodies are made must be different from that of sublunary bodies.
His first argument (9) to that effect is based on an analysis of
motion. All natural bodies move in space. Simple motion is
of two kinds, rectilinear and circular. There must, then, be two
kinds of simple bodies : one to which rectilinear motion is nat
ural ; another to which circular motion is natural. Circular
motion, he argues, exhibits no contraries : it always returns on
itself. Hence the body to which it is natural has no opposites,
and is beyond birth and death and change : it cannot begin
and it cannot end, for generation and corruption imply oppos
ites ; it cannot increase and it cannot decrease, for either implies

90 COSMOLOGY

more or less of that matter out of which the thing has grown ;
it cannot in any way alter, for alteration implies either increase
or decrease. And since such a body has no rectilinear motion
it cannot rise or fall : it is not, then, either heavy or light. A
heavenly stuff, therefore, must exist — he calls it aether : a simple,
uncompounded, changeless matter which of itself rotates ; a
something godlike in the realm of body, and therefore fit to be
the makings of the heavenly bodies. His second argument (lo)
toward this conclusion is one of elimination : the heavenly bodies
cannot possibly be made of the four elements — fire, earth, air,
and water. It is obvious that heavenly bodies are not made of
earth or of water. Neither are they made of fire or air : for
if the heavens and its contents were constructed out of fire or
air, the other elements would long since have been swallowed
up by the hugely disproportionate bulk of either ; furthermore,
there is not enough air in the world to form the azure vault
over our heads ; even if one imagines all the waters of the world
changed to air and all that air in turn to fire, how insignificant
would be the volume thus obtained in comparison with the
immensities of the heavenly spaces. Once more, then, there
must be a special fifth element for the heavenly bodies — sether.
His scientific theory of sublunary bodies is an equally amazing
medley of observation and dialectics. Before and after Empe-
docles, the theory of the four elements — fire, earth, air, water —
was popular in the schools of Greece : popular but, as we have
seen, not uncontested. It is not easy to explain the origin of
this belief. The ancients seemed to have paid great attention
to two frequently recurring facts : ordinary combustion and
animal decomposition. A stick when burned gives off air and
flame, occasionally water, and leaves a residue of ashes : a rotting
corpse gives off air gases and turns into dust — while it evidently
contains water. Facts of this kind probably prompted the
popular view that all sublunary bodies were made up of the
four elements. But whatever particular facts first suggested
this theory, it owed its subsequent extraordinary longevity to
the apparent metaphysical necessity claimed for it by Aristotle.
That necessity was grounded firstly on the analysis of motion,
and secondly on the analysis of qualities. Circular motion gave
him a necessary argument of aether : rectilinear motion gave
him a necessary argument for the four elements. (11) Rectilinear
motion, he argues, has two directions, up and down : the body
which tends naturally downwards is heavy ; that which tends
naturally upwards is light. This opposition of the heavy and
the light is fundamental and qualitative : for reasons already
recorded, Aristotle emphatically rejects all attempts to explain
weight by quantitative differences of magnitude or shape or
density. And on general principles, there must exist two ele
mentary bodies corresponding to these two primitive directions
of rectilinear motion — one tending towards the centre, the other
away from the centre, of the universe ; also, a pair of inter-

THE STRUCTUKE OF THE HEAVENS 91

mediate bodies, one of which approximates to the former and the
other to the latter. In short, earth is absolutely heavy ; fire
absolutely light ; water and air relatively heavy and, therefore,
also relatively light. Such is Aristotle's first must-be in favour
of the theory of the four elements. His second (12) must-be
is based on an analysis of the qualities of matter. All tangible
qualities are reducible, he claims, to four fundamental ones, the
favourites of ancient Greek philosophy : the hot, the cold, the dry,
the moist. Four terms when taken in pairs yield six combinations :
ab, ac, ad, be, bd, cd. Opposites cannot be combined : conse
quently the hot and the cold, the dry and the moist, are impos
sible combinations. Hence we have four pairs : and as warmth
and cold are active qualities, dryness and moisture passive quali
ties, each pair of the four has both an active and a passive quality ;
warm and dry or fire ; warm and moist or air ; cold and moist
or water ; cold and dry or earth. But while each element
possesses two essential qualities, one is in each instance dominant
and characteristic : earth is distinctively dry, water cold, air
moist, fire warm.

All four elements act upon and are acted upon by one
another through their active and passive qualities : these
changes are accidental or substantial. And of the substantial
changes the most important are the mutual transformation
of one element into the other, and the union of all four to
form compound substances. Mutual transformation is more
difficult in the case of those elements that exhibit greater quali
tative opposition : elements which are but partially opposed
in quality are transformable directly ; elements which are wholly
opposed in quality are transformable only indirectly. The
union of the elements in proper proportions gives rise to com
pound substances : minerals, plants, animals. (13) Every com
pound substance contains all four. Their habitat proves that
they contain earth : earth is not cohesive without water ; and since
the contrariety of elements is the source of the production of
other bodies, compounds that contain earth and water must
contain also air and fire. This argument is confirmed as regards
living substances by an appeal to the facts of nutrition and
decomposition : they feed on and rot away into all four. Thus
does Aristotle portray the sublunary world as a self-contained
cycle of generation and corruption, the substances of which are
incessantly subject to mutual transformation according to
definite laws.

THE STRUCTURE OF THE HEAVENS.

Aristotle's astronomy was in the main a reproduction of the
teaching of his time : modified here and there by the needs of
his personal theories. The guiding principles of the majority of
ancient astronomers were, that the earth is at rest in the centre
of the universe and, that the heaven! v bodies revolve round it

92 COSMOLOGY

in circles and at a uniform rate. The facts familiar to everyone
were sun, moon and stars moving in an azure vault which rises
high above our heads and curves down on every side to the
horizon. Astronomers studied as intently as their opportunities
allowed the contents of this vault : watching them for hours,
they saw those in the east rising upwards, those in the south
moving westwards, those in the west sinking out of sight ; watch
ing them for days, they saw them apparently revolving as on
an axis once in twenty-four hours ; watching them for years
and for centuries, they noticed and recorded that the vast majority
of the stars preserved unchanged their relative position in the
firmament. How were the motions of the fixed stars explicable ?
Not by free motions in space of the stars themselves : Newton
and Einstein lay centuries and centuries ahead. (14) In Aris
totle's time, each star was thought of as set in a sphere. Now,
both the azure spheres and the stars appear to move. And
their motions cannot be independent of one another for their
speed rates correspond with invariable regularity. Perhaps, the
stars move and the spheres rest ? That cannot be, for, then,
the rate of motion of the stars ought to correspond to the
size of their circle. Aristotle concludes, therefore, to motion
less stars inset in moving spheres. (15) And he finds con
firmation of his conclusion in suggestions like these : the
stars cannot move because they have no locomotive organs ;
they could not progress by mere rolling and they do not — as
the moon proves — spin ; if they did move, their motion through
the aether would create a horrible din. All these fixed stars,
then, are set like rubies in a hollow sphere of crystal that revolves
daily around our motionless earth. But what of those other
seven heavenly bodies whose motions seemed to observers hope
lessly irregular : Saturn, Jupiter, Mars, Venus, Mercury, Sun,
Moon.(16) The sun showed an annual,, the moon a monthly,
as well as a daily motion : both moved from east to west ; and
these motions among the stars when combined with their diurnal
motions resulted in courses that were spirals, not circles. For
all that, both sun and moon moved always forward. Not so
the other five wanderers. Mercury, for instance, seems at one
time to go forward, at another to go backward, and at another
to remain stationary. To square these and like irregularities with
the prevalent view of uniform circular motions for heavenly
bodies, was the great problem of ancient astronomy. The only
solution lay in assigning a plurality of crystal spheres to each of
these seven. But how many ? Plato proposed the problem to
the Academy, and Eudoxos of Cnidos — one of the most eminent
astronomers of all time — analysed these non-circular planetary
wanderings as resultants of the rotations of twenty-six concentric
spheres : three apiece to the sun and moon, and four to each of
the five upper planets. The outer sphere of each planet ex
plained its daily revolution in concert with the heaven of the
fixed stars ; the second, which was fastened into the outer,

THE STRUCTURE OF THE HEAVENS 93

revolved in an opposite direction ; the others, likewise carried
around by their surrounding sphere, but differing in direction
and speed of rotation from them, were meant to explain the varia
tions which are observable between the apparent motion of these
wandering stars and that produced by the two first spheres ;
and the lowest or innermost sphere of each planet carries the
planet itself. A theory of this kind was bound to undergo ever-
increasing elaboration : as observation grew more exact, the
discovery of apparent anomalies became more frequent and the
demand for a greater number of spheres more urgent. Calippus,
for instance, added seven.

Aristotle in refitting this theory of concentric spheres to his own
theory of motion added many more.(17) The outstanding features
of his theory of motion were : all motion depends on the contact
of the moved and the mover ; one moving body can produce only
one kind of motion in the same matter : every motion proceeds
ultimately from an unmoved cause — and when eternal from an
eternal cause. He was, in consequence, obliged to assume as
many eternal and unmoved movers for the production of spheral
motions as there were spheres (18) : spiritual beings that bear
much the same relation to their respective spheres as the human
soul does to the body. Each sphere has a motion of its own
that is communicated to it by its spheral spirit : in all cases,
this motion is axial, uniform, and eternal; but from sphere to
sphere, there are variations of direction and of rapidity. Each
inner sphere is so connected with the outer that it is carried
round by it just as if its axis were inserted at its poles in this
outer one : each sphere, therefore, communicates its own motion
to the one next below it. This connection of all the upper
spheres with those contained within them is peculiar to Aristotle (19),
and forces him to insert additional spheres between the lowest of
each planet and the highest of that planet which comes next
underneath : otherwise, the motions of the lower planets would be
disturbed by those of the higher. These inserted spheres move at
the same rate as those they are destined to neutralise but in an
exactly opposite direction : twenty of these regressive or retarding
spheres were accounted necessary by Aristotle. His heavens (20)
consisted, accordingly, of a system of fifty-six concentric spheres,
so placed within each other that there is no empty space and so
linked together that each without losing its own proper motion
partook of that of its enclosing sphere : each of these spheres was
of crystal, hollow and transparent, with the result that stars set
in the outer spheres were visible through all the inner ones. Of
these fifty-six spheres, the first heaven, the heaven of the fixed
stars, is the most perfect (21) : it is stationed next to the motionless
Prime Mover ; it accomplishes its purpose by a single motion ;
it carries round countless hosts of stars ; it starts from the better
side, and follows the better direction — the right ; it moves without
beginning, without end, without trouble, and thus rejoices in the
most perfect bodily existence. Not so the planetary spheres (22) :

94 COSMOLOGY

many of them are necessary for a single star ; they start from
the left side ; they are not so self-sufficient — carried round and
disturbed as they are by their enclosing spheres. All spheres,
hbwever, are part of the olivine portion of the visible universe (23) :
the stars admit neither birth nor death, neither growth nor
alteration ; they are made of finer stuff than the sublunary
elements ; and they possess a nature far more godlike than man
does ; in fact, they are divine bodies, and their spheres are set
and kept revolving by gods of the second order.

INTERACTION OF TERRESTRIAL AND CELESTIAL BODIES.

All the motions and changes of our sublunary world take
place under the influence of the heavenly bodies. It is true that
the terrestrial elements by their very nature move in opposite
directions, display opposite qualities, act on and are acted on,
pass into and mingle with each other. Still this reciprocal
causality needs impulse and maintenance from without (24) :
everything non-living that is moved is put in motion, and kept
in motion by something else. Generation, for instance, arises
from heat, corruption from cold.(25) But since cold arises from
want of heat, the same explanation accounts for the external
conditions of generation and corruption. Heat is due to the swift
motions of the heavenly bodies. Not indeed that the spheres and
stars get hot : aether is not subject to the law of contrariety.(26)
Spheres and stars, however, heat by their movements those
layers of air that are nearest to them : just as leaden points
melt on an arrow when it speeds through the air. There must
be, however, periodicity in this action of the heavens : otherwise,
generation would not alternate with corruption. Aristotle
traces this periodicity to the oblique motion of the sun.(27)
The sun, in advancing through the signs of the zodiac, approaches
and warms some parts of the earth, retreats from and leaves
cold other parts : thus bringing about nature's birth and growth,
decline and death — springs that pass into summers, and through
summers and autumns into winters. Aristotle employs those
same general principles to explain particular instances of gene
ration and corruption. Changes of warmth and of cold are
the most universally active forces in the processes of the four
elements.!28) By progressive cooling, fire becomes air and water
earth ; by progressive heating, earth becomes water and air fire.
Those mutual transformations prevent the elements from accumu
lating in their respective regions : there exists a never-ceasing
stream of them, downwards from above and upwrards from
below.i29) These endless processes, whereby each element
passes into all the others and finally returns upon itself, com
municates to the sublunary world a sort of infinity of becoming :
a perpetuity that mirrors, to Aristotle's mind, the indestructible
existences of the heavenly world and helps to bridge the chasm
which separates these two parts of our universe.!30)

THE UNIVERSE AS A WHtLE 95

THE SHAPE OF THE UNIVERSE.

The universe is spherical in shape. It looks so to the eye.
It must be so. Aristotle undertakes to show, first of all, that the
four elements are grouped in spherical layers, one above the other.
The elements uniformly strive to reach their natural places.
These places are determined by their distance from the centre
of the world. All four must, accordingly, be grouped into
spheres which are everywhere equidistant from that centre. In
the middle lies earth (31) : a solid sphere for the reason just
given ; and this spheral shape is confirmed by facts of experience —
its lunar shadow during eclipses, the differences of the stars
visible in the north and in the south, and the fact that bodies
falling on the earth move not in parallel lines, but at similar
angles. This solid sphere of earth is motionless (31) : specu-
latively, because circular motion is contrary to its essential
nature and because the world's rotation needs a fixed centre ;
empirically, because heavy bodies when thrown upwards in a
straight line return to their starting-point and because stars
always rise and set in the same place. Water with an upper
surface of spheral shape fills the hollows on the earth's crust (32) :
and as water always accumulates in the deepest parts, it must
flow towards the centre until its surface is at all points equidistant.
Hollow spheres first of air and then of fire surround those of water
and earth. (33) In much the same way, observation and specu
lation are employed to prove the spheral shape of the celestial
regions.!34) Empty space is an absurdity : consequently, the
celestial bodies are everywhere in contact with the fiery sphere.
The heavens, he argues, look spheral. They must, he adds, be
spheral : the sphere is the most perfect figure and is, therefore,
the appropriate shape for the noblest bodies ; it is also the only
figure that can revolve within the space it encloses ; finally, it
affords the shortest return route in lines that enclose a space
and is, therefore, best suited for bodies which, like those in the
heavens, move most rapidly.

THE UNIVERSE AS A WH^LE.

Our universe is the only universe. There is no empty space (**) ;
consequently, there cannot exist other universes separated from
ours. The visible sphere of sky which overarches our head
is, thus, for Aristotle the limit of the universe. His strong
point, here, is the doctrine of natural places : since each element
has its own natural place, there can be only one region of earth,
of water, of air, of fire, of aether. He dismisses the suggestion that
a body may be forcibly detained in a locality beyond the world
with the remark that any such locality must be the natural
place of some other body : all bodies have their natural places

\
I

96 COSMOLOGY

in this one world of ours and there can be, therefore, no space
beyond it.(36) Much subtler depths are foreshadowed in another
argument (37) of his that several worlds would presuppose several
first causes of motion, specifically similar, materially different :
but, there can be no matter in the First Mover. Accordingly, the
world that is moved by the single and complete First Cause
must itself be single and complete. Here Aristotle has to fight
down a spectre of his own — are we ever justified in believing
anything unique, ever justified in supposing a " form " realised
in only one individual ? His reply (38) is that all available
matter has been exhausted in the formation of our world : ac
cordingly, its uniqueness is absolutely inviolate ; it was. and is,
and ever shall be, unique. He appeals, also, to the unicity of
the first heaven in favour of the unicity of our world.!39) The
unicity of the first heaven is doubly assured : it has the one and
only primary circular motion ; it has an essence which excludes
birth, death, reproduction and, consequently, numerical plurality.
But if there can be only one first heaven, there can be only one
world, for everything that exists is enclosed within the first
heaven.

This unique world of ours is finite, stationary, and eternal.
It is finite because it is a sphere : an infinite sphere is impossible ;
it would have no circumference and, consequently, neither radius
nor centre. This finite sphere is stationary. Where could it
go ? And by what route ? There is nothing existing outside
it. Again, how could it be displaced — above or below, right or
left ? All these notions are due to lightness or heaviness : but the
first heaven, which encloses and dominates everything else in
our universe, is imponderable.!40) Finally, this unique, sta
tionary world is eternal.!41) The heavenly bodies are indefect
ible : aether cannot change in nature for it has no contrary ;
aether cannot change in motion for it moves under the essentially
immutable influence of the motionless Prime Mover. The
heaven has always been, and shall always be, what it is : its eternal
youth never wanes. It is true that the sublunary world is a
theatre of ceaseless changes : there, death alternates with life,
age with youth. But these alternations never had a beginning
and never shall have an end (42) : for primordial matter is
eternal, and so, also, are the motions of the heavenly bodies —
especially those of the sun — which generate and corrupt the
inexhaustible potencies of that matter. If it must be allowed,
then, that sublunary individuals are mortal, it cannot be denied
that their species are immortal.

Such was Aristotle's scientific theory of our universe. The
supralunary portion is made of the best material, is utterly
changeless, and moves in a perfect way. The sublunary portion
is made of inferior material, and given over to birth and death
and every kind of change. At the centre of the whole is the
motionless earth ; around that earth in concentric spherical
layers lie water, air, and fire ; then come the crystalline spheres

THE UNIVERSE AS A WHOLE 97

and their inset stars. Everything that happens in the sublunary
world is conditioned by the constant motions of these spheres.
That motion is imparted to each sphere by an eternal, incorporeal
substance — a soul or spirit. But the outermost sphere of all,
the first heaven, is moved by the motionless Prime Mover : the
deity which is touched but does not touch. Finally, arguing
from this view of the contents and interrelations of our world,
Aristotle concludes to the unicity, the fmiteness, the stationariness,
the eternity of the Whole.

CHAPTEK IV.

ARISTOTLE'S THEORY OF THE ULTIMATE CONSTITUENTS
OF MATTER : HYLEMORPHISM.

ARISTOTLE'S method of scientific proof has been already outlined.
It consisted in the completion of the method employed by the
Pre-Socratics and by Plato ; intellectual intuition and dialectical
criticism of the results of methods of observation which were wide
rather than deep. We need not expect, then, to meet in Aris
totle's attempt to elucidate the philosophy of matter particularly
accurate empirical foundations. He was unrivalled in every
empirical device that was possible without experiment. But the
circumstances of the age in which he worked denied him the
means of crucial experiment in physics, chemistry, and astronomy.
He excelled, however, in speculative reasoning : and despite the
drawbacks occasioned by the impossibility in certain branches
of accurate experiment, his philosophy of matter abounds in
theoretical considerations of permanent value.

The exposition of his theory of the ultimate constituents of
matter centres round the following topics : proof of the possi
bility of change ; facts and factors of accidental change ; facts
and factors of substantial change ; primordial matter ; sub
stantial form ; substance and attribute. Then, I shall close
this review of Greek Cosmology by a few words on post- Aris
totelian Greek theories of matter.

PROOF OF THE POSSIBILITY OF CHANGE.

Aristotle prepares the way for his own explanation of change
by emphasising two valuable suggestions of his predecessors.
He accepts whole-heartedly the principle that nothing can come
from nothing : the production of something from absolute
nothingness is unthinkable. (x) Next he recalls that second
principle, dear to Greek thought, according to which all change
takes place between contraries (2) : for some pre- Aristotelians,
these contraries were the hot and the cold, the dry and the moist ;
for others, the odd and the even, the limit and the unlimited,
love and hate ; for others, the thick and the thin, the full and
the empty. Aristotle admits a kernel of truth in this second
principle : fundamentals are underivable and are the starting-

PROOF OF THE POSSIBILITY OF CHANGE 99

points of everything else ; moreover, the primitive contraries
are obviously not derivable from each other or from any ante
cedent ; and lastly, Aristotle's own analysis will show that
the terms between which change occurs must be contraries.
Of themselves, however, contraries cannot explain change : therein
lay the error of the Pre-Socratics.(3) Contraries as such can
neither act upon nor pass into each other ; a hot body can act
on a cold body but heat itself cannot act on cold ; a hot body
can become cold but heat itself does not become cold. The
justification of this physical principle is found in the identification
of the Aristotelian " form " with the Platonic Idea : contrary
Ideas may be realised in the same object, but they cannot be united
with each other ; one Idea never passes into another. And yet
there is no denying facts : cold bodies do cool hot bodies that are
in their neighbourhood, and vice versa. Accordingly, Aristotle
postulates a third reality whose function is to act as intermediary
between the contraries : a persistent substrate in which the
contraries that yield place to each other may inhere. In every
kind of change, a distinction must be made between something
that persists from start to finish and those contrary determina
tions, of which one disappears in favour of the other : this per
sistent substrate is something different from the determinations
that successively qualify it. Aristotle called this substrate
" matter " (4) : but this word has become so fixed in its ordinary
meaning that it needs to be marked by inverted commas, when
used in its technical Aristotelian sense of persisting substrate.

At this point in the Physics, Aristotle abandons history in
order to establish by argument his own view of change.!5) Change
implies that a body passes from a state in which it lacks a par
ticular perfection to a state in which it possesses this perfection.
The various steps involved in this process are carefully distin
guished and named : the substrate, which is the recipient of
whatever succession occurs, is callejd " Matter " ; the previous
absence in the substrate of the particular perfection acquired
as a result of the change, is called Privation ; the result of the
change, the newly acquired perfection is called Form. But since
Privation consists merely in the absence of Form from " Matter,"
it is neither a positive reality, nor an independent principle :
accordingly, the principles of change are reducible to " Matter "
and Form. Aristotle illustrates his analysis by a man's progress
from ignorance to knowledge : the starting-point of such progress
is an individual substance who presents two aspects — humanity
and ignorance ; by means of education, one of those disappears
and is replaced by its contrary — ignorance yields place to know
ledge ; the individual man persists during and after the process
of education — he is the substrate in which this interchange of
contraries happens. The difficulty of basing big conclusions on
this seemingly trivial illustration jumps to the eye. Aristotle's
scruples arise out of the deep-seated differences between sub
stantial and accidental change.!6) A substance is an individual

100 COSMOLOGY

with an existence and activity of its own — Plato or Socrates :
an accident is a diminutive sort of reality which can exist only
by inhering in a substance — qualities such as colours and tastes,
actions such as building and killing. Now Aristotle's illustration
refers only to accidental change : Socrates is successively ignorant
and educated. It is not surprising, then, that the chasm which
separates this kind of change from that by means of which
substances originate should give our author momentary pause.
He satisfies his scruples for the nonce by insisting on the general
application of his analysis to every kind of change. He admits
the greater obviousness of " matter " in the lesser kind of change :
accidents are predicated of substances, and this grammatical
relationship involves physical inherence in them as substrate.
But this substrate is not one whit less necessary in substantial
changes : plants and animals come from seed. However, his
immediate obsession is the need of a substrate in all kinds of
change : hence, he introduces instances of artificial products —
houses, statues, etc. — which clearly imply a substrate. Con
sequently, this general analysis applies to all changeable beings :
whatever undergoes change is compounded of " matter " and
form. He has not altogether forgotten the third principle —
privation — for he interpolates some valuable hints on its applica
tions. Privation, he writes, may be an opposition either of
contraries or of contradictories : an opposition of contraries
when a substance loses one positive perfection and acquires in
its place another positive perfection, v.g. a hot body cools or a
white body darkens ; an opposition of contradictories when there
is question solely of the successive absence and presence of one
and the same form, v.g. an illiterate becomes learned, a plant
or animal is born. Neither has he forgotten the distinctive
features of the deeper kind of change. Realising as it were
the baldness of his passing reference to the origin of all living
beings from seed, he hints at the necessity of a special kind of
substrate for the generation of substance. This hint is merely a
comparison expressed as a ratio : the " matter " of substantial
generation is to the produced substance what bronze is to the
statue, wood to the couch, raw material to the finished product.(7)
Some lines farther on, Aristotle refers to another solution of
the problem of change based on the distinction between potency
and actuality : this solution which is more fully expounded in
the Metaphysics, concludes also to " matter." (8) Change as
the realisation of what is possible implies a distinction between
the possible and the actual : once you admit the fact of change,
you admit the reality of that which can exist but does not yet
exist. That out of which something comes into existence is,
therefore, a presupposition of change. It is only one of these
presuppositions, for in order that a thing be made you require
as a second presupposition, the efficient cause. Aristotle terms
the mutual presence of these presuppositions of new realities,
potency. This kind of potency is different from logical possi-

PKOOF OF THE POSSIBILITY OF CHANGE 101

bility or mere absence of contradiction, for it implies a physical
capacity or power. And as capacity and power are different,
physical potency is double : active and passive. Active potency
is the power of "the efficient cause to produce an effect. Passive
potency is the capacity of anything to receive into itself a new
perfection. This passive potency is identical with " matter " :
for, in every kind of change, the being of the substrate and the
non-being of the privation are united in such a way as to constitute
the passive potency of the reality which is afterwards produced.
All change may, accordingly, be described as a transition from
potency to actuality : " matter " is being in potency, and the new
reality brought into existence by the change is actualised being
or being in actuality.

These are the outlines of the solution offered by Aristotle to
that problem which had baffled the wits of philosophers since
the time of Parmenides. Change is possible because our world
contains a reality that is neither absolute being nor absolute
non-being : its presupposition is something which may be de
scribed, on the one hand, as being that is relatively non-being
and, on the other, as non-being that is relatively being. According
to the Physics, " matter " is being that is relatively non-being :
it is being because it is a substrate with a reality of its own existing
prior to the change ; it is relatively non-being because, prior to
the change, it had not that perfection which accrues to it owing
to the change. According to the Metaphysics, " matter " is non-
being that is relatively being : it is non-being because that out
of which anything comes into existence cannot already be what
it is on its way to be ; it is relatively being because that out of
which anything comes into existence must contain the makings of
what comes out of it — and Aristotle boldly calls that-which-makes-
being-possible potential being, so that " matter," although
actually non-being, is potentially and relatively being. Both
solutions are employed in accepting Parmenides's challenge to
to prove the possibility of change.!9) How, asked this latter,
could any new state of things arise ? Not out of nothing for
nothing can come from nothing : still less, out of something for
what exists, exists, and it is absurd to speak of what already
exists as a something coming into being. The conclusion of this
dialectic had provoked an outburst of mirth among the Greeks :
ridicule that was repaid mercilessly by the scornful Zeno. But
laugh as the populace would, this solvitur ambulando attitude
was beggarly fare for keener minds. Aristotle was the first to
hoist Parmenides with his own petard : " matter " provides
a dialectical solvent for all the puzzles of Parmenides. Consider
it, first of all, as the substrate of contraries. That from which
anything comes cannot be absolute nothingness : no Greek
doubted this. But being can spring from relative non-being :
it can spring, for instance, from a privation which is of itself
non-being, but is an aspect of some substrate ; the being or product
starts in its process of becoming from this non-being or privation,

102 COSMOLOGY

and yet, this ancestry is accidental for Aristotle because the
privation is in no wise part of the result — an educated man is
not a compost of ignorance and knowledge. What-is, is : that,
also, is incontrovertible ; what already exists cannot be identical
with any reality that is only on its way to existence. But being
can spring from being or what already exists, if this pre-existent
includes as part of itself a condition capable of fusing with a new
reality emerging out of change — an ignorant man can become'
educated because he is a substrate having a predisposition
towards education ; and here, also, the ancestry is accidental
for Aristotle because there is no contradiction between pre-
existent and product. Again, consider " matter " as potency
and see how it rebuts the dialectics of Parmenides. His dilemma
is disjunctively incomplete : neglecting as it does the factor
of potential being. A thing cannot come from nothing for the
makings of anything must be something : true, retorts Aristotle,
but, as a matter of fact, that from which the thing comes is
potential being, and this is something. Neither can being, adds
Parmenides, come from being : I agree in a way, replies Aristotle,
but that out of which the new being comes is not actual being,
but the makings of actual being, potential being.

Many and divergent views are held concerning the value of
Aristotle's analysis in its application to facts, but there is practical
unanimity about its complete success as a dialectical refutation
of Parmenides. Aristotle's consciousness of this success makes
him dwell complacently on the importance for the philosophy
of Nature of the concept of " matter." Eleaticism had given a
new direction to all subsequent thought : even those who did
not dare outrage common- sense by an out-and-out denial of
multiplicity and motion, felt themselves compelled by the argu
ments of Parmenides to restrict change to the local motion of
eternally unalterable particles. Aristotle thinks that henceforth
these half-way houses, these frail resting-places between Eleati
cism confident of its dialectic and Common-sense confident of
its experience, must collapse. Hylemorphism, or the theory of
" matter " and form, satisfies the claims both of dialectics and
of experience. It solves all problems of change, be those changes
accidental or substantial. It solves, moreover, the problem of
the ultimate constituents of non-living bodies, for in pulling
body to pieces you lay bare its inner springs of structure and
activity. There is, of course, a difference between the principles of
being and those of becoming ; privation is a strong point in the
polemics of becoming, but, as it is absent from the product of
change, it is unimportant as a principle of being. It is true
moreover, that any individual is in a state of privation with
regard to those perfections which it might have but has not :
yet, such a way of looking at things is too far-fetched when you
are seeking for these factors of any particular process which
led to the production of a new reality. (10)

These are the essential points of Aristotle's first sketch of

FACTS AND FACTOKS OF ACCIDENTAL CHANGE 103

the principles of being and becoming. Few moderns are likely
to read it with the zest with which it was penned by its author.
To many, a solution of this kind, brimful of dialectics and scanty
of facts, must appear the merest logic-chopping. Two pleas may
be made in its favour : one psychological and purely extenuating,
the other metaphysical and decisive. Aristotle tackled this
problem dialectically because of training and environment :
factors that emerged from the historical development of Greek
philosophy. He was dialectical for the same reason that Augus
tine was allegorical, Aquinas abstract, Kant critical, Hegel
absolutist ; contagious influences of age and race. The meta
physical plea is, I would urge, decisive. And by this I mean
that those, who can penetrate through the husks of these Aris
totelian abstractions to the kernel of thought within them, will
find themselves face to face with choices that mark in philosophy
the parting of the ways : choices at varying levels and with
proportionate consequences — the choice between mechanism and
anti-mechanism in the realms of matter and of life, and, beyond
these limited spheres, the grave choice between theism and its
rivals. A serious issue this latter, far too serious seemingly, to
take its rise in the analysis of such a commonplace occurrence
as a child's study of its first lessons ! And yet who that has ever
got to the heart of the problems of philosophy dare deny the
ultimate significance of this and similar iotas.

FACTS AND FACTORS OF ACCIDENTAL CHANGE.

Aristotle's general conclusions so far is that bodies which
change are composed of " matter " and form. There are, how
ever, several kinds of change I11) : change of substance in gene
ration and corruption ; change of quantity in growth and dim
inution ; change of quality in alteration ; change of place in
local motion. Accordingly, Aristotle distinguishes several kinds
of " matter " and several kinds of form : but as the four kinds
of change are reducible to change of substance and change of
accidents, the leading implications of hylemorphism will be made
sufficiently clear by discussing separately accidental and sub
stantial change. Aristotle refuses on principle to prove the
existence of change in the universe. There are facts which no
sane mind calls in doubt : and amongst them, are the existence
of bodies and of, at least, some kind of change in some of those
bodies ; the fact of change is made evident by experience. Even
Parmenides, he asserts, was compelled to account for the facts
of sense-perception : thereby mistaking, it would seem, the genuine
import of the second part of the poem of the founder of Eleatic-
ism.(12) It is true that the mechanical physicists had attempted
to reduce every kind of accidental change to mere spatial change.
But, as we saw, Aristotle had grappled boldly with, and, as he
believed, had overthrown these formidable opponents. His
conclusion was that the sensible qualities of bodies were, each

104 COSMOLOGY

of them, genuine accidents distinct from the accidents of shape
and of motion : qualitative change is not a mere disguise which
mechanical motion wears for our senses.!13) On these pre
suppositions, there was no need to labour the obvious. Accidental
change abounded everywhere in the universe : in the elements
— in cooling and heating water or air, in drying and soaking
earth, in kindling and flaming fire ; in true mixtures — in the
hardening of diamonds, in the dimming of the lustre of gold,
in the heightening of the sheen of bronze ; in living beings —
in the growth and withering of trees, in the blooming and fading
away of flowers ; in animal life — singing itself away on the tree
and through the grasses, or lazily feeding in the fields ; in human
life — working out hour by hour the future destiny of each of
us by myriad processes in our bodies and in our minds ; above
all, in the artistic processes of human handiwork — topics rarely
absent from Aristotle's mind when he is discussing the problem
of change. (14) These innumerable facts of accidental change
are classified under the three heads already given — alteration,
augmentation and diminution, local motion. By a choice of
words which was, in view of modern usage, to prove unfortunate
he called all kinds of accidental change " motion." (15) And
in accordance with his conclusions on the possibility of change,
he naturally explains all accidental changes by his theory of
"matter" and form. In such changes, the " matter" is always
an existing individual and the form is always an accident/16)
Within these cycles of accidental change, then, Aristotle looks on
existing individuals as fixed and permanent factors : individuals
are the invariants of existence within this sphere — processes go
on in them and processes take place among them : they are the
bearers of all qualities and of all quantities — fluctuations of these
accidents occur in them ; they are the agents and patients of
all accidental reaction — they act on, and are acted on by, one
another without impairing the identity of their respective sub
stances.

FACTS AND FACTOKS or SUBSTANTIAL CHANGE.

Aristotle did not think it necessary to give elaborate proofs
of the existence of substantial changes. (17) This is easily under
stood: the Eleatics had, indeed, denied the existence of any
kind of change and some of their successors had admitted changes
only of quality or of location, but the majority of Aristotle's
predecessors had accepted substantial change as a fact of daily
and hourly experience. He was naturally content, therefore,
with rather meagre proofs of a fact admitted almost by everyone.
First of all, he illustrates by examples the distinction between
accidental and substantial changes : for instance, the contrast
between the processes involved in an act of intelligence and those
involved in the birth of things. In the next place, he recalls
and confirms Plato's admission of the mutual transformation

FACTS AND FACTORS OF SUBSTANTIAL CHANGE 105

of three of the elements ; and, then, he extends this mutual
transformation to all four elements. The keynote to this part
of his theory is his acceptance of sensible qualitative differences
as fundamental : bodies exist in as many different kinds as our
senses testify. This plain-man outlook runs through every age
of the Aristotelian text : each bodily substance has its own
distinctive set of sensible qualities, and a total change of that set
involves a total change of substance. This attitude was not
accepted without critical examination of the facts : witness
his exhaustive criticism of the contrary views of his predecessors.
But once it was accepted, our world became for him a theatre of
countless substantial changes. Consider the mutual transforma
tion of the four elements : every sheet of water at the earth's sur
face is being evaporated continually under the influences of the
sun ; part of that evaporation becomes more and more heated until
it turns to fire — forming, Aristotle thought, comets, meteors and
the Milky Way ; another part of it is being gradually cooled
until it becomes water once more and descends as rain ; fire
itself is being constantly destroyed by water, while earth can be
destroyed either by fire or water. Every perfect mixture in
the sublunary world is a compound of the four elements (18) :
his a priori and a posteriori arguments in favour of that con
clusion have already been expounded. As far as his knowledge
allows, he pieces together thread by thread the facts of this
interweaving of the four elements to form compound substances.
These compounds must not be thought of as they were by
Empedocles : a mere juxtaposition of the smallest parts of their
constituents just as barley and wheat lie side by side in a granary
or stones and mortar in a wall. In a perfect mixture the four
elements are so completely changed that every part of the mix
ture is homogeneous with the whole : the smallest particle of
flesh is as much flesh as the whole. Aristotle is aware, of course,
of the existence of mechanical mixtures : not every union of
the elements results in perfect mixture. But he is confident that
when the four elements meet under appropriate conditions of
quantity, interaction, and divisibility, they cease to exist as
elements and combine to form homogeneous compounds. Perfect
or true mixture is due to the fact that the elementary qualities
act and react on one another in such a way as to produce a
qualitative mean, that is incompatible with the existence of the
elements as such and, therefore, leads to the formation of a totally
new substance : the elements exist not actually but potentially
in a perfect mixture. The homogeneous compounds thus formed
may be inorganic or organic : copper, silver, gold, zinc, iron,
stone, etc., in the world of minerals ; root, wood, bark, leaf, etc.,
in the world of plants; flesh, bone, skin, hair, etc., in the world
of animals. This formation of perfect mixtures is a different pro
cess from the absorption of one substance by another. Absorp
tion is the total conversion of one body into another under the
influence of which it comes (19) : for instance, a drop of wine is

106 COSMOLOGY

absorbed in a hundred gallons of water ; food is absorbed by living
bodies. It is clear that absorption also implies change of sub
stance : the wine ceases to exist as wine ; and foods like bread and
meat cease to be such and become part and parcel of living flesh.
These facts, and others of the same calibre, are at the root of
Aristotle's hylemorphic theory in the non-living world. On
them he bases two arguments. Here is the first.!20) Changes of
substance occur in the mutual transmutation of the elements,
in the formation of perfect mixtures, in all instances of absorp
tion : for, all these happenings involve the disappearance of the
distinctive sets of qualities bound up with particular substances
and the production of a totally different set of qualities bound
up with other substances. But a change of substance is impossible,
unless, on the one hand, some portion of the old substance remains
and, on the other hand, some portion of it passes away and yields
place to an incoming portion of the new substance : unless you
admit this much, you have to maintain annihilation of the old,
and creation of the new, substance. Now the results show that
the portion which persists during the change is an indeterminate
principle capable of uniting successively with that other portion
of various substances whence springs their characteristic and
specific qualities : that indeterminate principle of substance was
called by Aristotle " matter " or substrate ; thanks to the
Schoolmen, it has lived in history as primordial matter.!21)
The results also show that the portion of the old substance which
disappears and the portion of the new substance which takes
its place are, each of them, a specific principle — each of them,
when present, is the source of all those qualities that make the
substance belong to a particular species ; this principle was
given by Aristotle a variety of names — oftenest, " form " ;
thanks to the Schoolmen, it has lived in history as substantial
form. Bodies that undergo substantial change, therefore, are,
in spite of their unity as substances, made up of two constituent
principles : primordial matter and substantial form. Aristotle
supports this fundamental argument by a second.!22) All
sublunary bodies come into and pass out of existence : they
possess within them, therefore, some principle capable of existing
or not existing. That principle must be distinct from whatever
it be in them that gives them actual existence and specific
activity. Consequently, all sublunary bodies are composed of
two principles, one which makes them neither necessarily existent
nor necessarily non-existent, and another which makes them
for a time actually existing and specifically active substances :
and these principles are identified by Aristotle with primordial
matter and substantial form.

PRIMORDIAL MATTER.

Aristotle has left us three general descriptions (23) of primordial
matter : the famous negative description in the Metaphysics—

PRIMORDIAL MATTER 107

" I call (primordial) matter that which in itself is neither a sub
stance, nor a certain quantity nor any other of those determina
tions by which being is specifically determined " ; a positive
description in the Physics — " I call (primordial) matter that
which is the first substrate of each thing in such a way as to be
no mere accidental portion of it while the thing exists, and as to
remain on afterwards as an ultimate when the thing is des-
stroyed " ; an analogous description, also in the Physics —
" (primordial) matter is to the individual substance what bronze
is to the statue, wood to the couch, raw material to the finished
product." Primordial matter (24) is, then, a medium between
nothing and actualised existence, between non-being and being :
it is not sheer and mere nothing for every existing thing contains a
portion of it ; and whenever any particular substance is destroyed,
its primordial matter is not destroyed but persists in some other
substance as a real part of our universe. It is the sole invariant
of generation and corruption : a substrate that precedes the birth
of each individual, persists during existence as one of its essential
constituents, and survives as ultimate residue the death of that
individual. It must be, then, a wholly indeterminate reality:
something that is neither substance, nor quantity, nor quality ;
a substrate whose essence is pure potency, and, as such, not any
thing definite but capable of becoming everything ; a subject
to which not one of the thinkable predicates belongs, and hence
equally receptive of them all ; a centre of indifference to all
opposites ; a purely passive, absolutely structureless, reality
at the root of all things. This accumulation of negatives is,
indeed, the only means of describing primordial matter : but
descriptions of this kind always raise doubts. Long ago, Alexander
was puzzled by the difficulty of distinguishing between substrate
and privation in this wholly indeterminate reality : and nine
teenth-century critics whose sympathies are strongly Aristotelian
have denied the possibility of making any such distinction —
primordial matter seems to them nothing but the privation
itself.!25) But it must not be forgotten that this substrate is
a reality present in all existing individuals nor that, however
complete be the indetermination affecting any subject, the dis
tinction between that which is undetermined and its lack of deter
mination remains. Primordial matter is not then identical with
privation : as a persistent substrate of every substance that
comes to birth, its indeterminateness involves the capability
of being made determinate ; and owing to the cycle of substantial
changes that goes on, it is so completely indeterminate as to be
capable of every kind of specific determination. Its incapacity
of existence by itself is due solely to the absence of a determining
principle : as a potency, it is a positively real. How real primor
dial matter was for Aristotle is shown by his occasional willingness
to style it substance, nature : always however with the expressed
or implied restriction — potential.!26) It is potentially substance,
potentially nature. It is not actually a substance for it cannot

108 COSMOLOGY

of itself exist : yet as one of the two constituents of substance,
it is a principle without which no substance can exist and may,
therefore, be termed a potential substance ; and for practically
the same reasons, primordial matter, which of itself is incorporeal
and possesses not a trace of activity of any kind, is spoken of,
betimes, in the Aristotelian text as a potential nature.

Aristotle assigns to this primordial matter a number of pro
perties : incorporeality, incapacity of existence by itself, pas
sivity, unity, infinity, eternity, unknowableness, appetency for
substantial form, and the role of principle of individuation.
Primordial matter is incorporeal, (27) for it is not a body but the
potency of body : physical bodies are perceptible to our senses
by their qualities — but were primordial matter cold or hot,
moist or dry, it would be already one or other of the four elements ;
mathematical bodies have no weight and as such cannot exist
in a place — but the elements and compounds of which primordial
matter is a constituent do exist in a place. Primordial matter
is incapable of existing by itself (28) — " all alone before a rag of
form is on " : the simplest order of existing substances is that
of the four elements. Yet, it is never absent from our world,
for the corruption of one substance is the generation of another.
And just as it has no existence of its own, so it has no activity
of its own (29) : it is a passive principle destined solely for the
reception of substantial form. Its unity (30) consists in the fact
that it is one and the same kind of reality in all bodies : though
of course it is broken up into as many portions as there are separate
substances in the sublunary world. It is infinite, not actually
or spatially, but potentially (31) : in the endless circle of sub
stantial changes that encompasses bodies it is transmitted from
one to another and is never exhausted. It is eternal (32) — never
having come into, and never passing out of, existence : did it
come or go thus, it would have a whence and a whither and could
not be accepted as an ultimate principle. It is unknowable!33) :
unknowable to the senses for it has no determinate quali
ties ; unknowable to the intellect for it is not a determinate
essence ; the only way of knowing it is by analogy. It has an
appetency (34) for substantial form — a striving or longing or
inclination that is not conscious desire but natural impulse :
union with substantial form is the purpose of whatever reality
it has got. It is, finally, the principle of individuation. (35)
Aristotle in his theory of knowledge makes the substantial form
the object of intellectual knowledge, the abstract concept. No
difference of content can exist between the substantial forms
of individuals within the lowest species : " they (Callias and
Socrates) . . . are the same in form for their form is indivis
ible." Individuals, however, do differ : Callias is not Soc
rates. Consequently, the principle of individuation must be
sought in primordial matter : " thy matter is not mine." Callias
differs from Socrates because the substantial form of humanity
is united in each of them with a distinct portion of primordial

SUBSTANTIAL FOKM 109

matter. Primordial matter as pure potency does not exclude
division into parts ; and since it is the recipient of substantial form,
specifically the same form may unite with, different portions of it.
In this way the multiplication of individuals within the species
is explained. This fact, also, explains the transitoriness, of the
individual : primordial matter being indeterminate has no
necessary grip of any particular substantial form. And while
Aristotle speaks as strongly almost as Plato about the incorrupti
bility of substantial forms, he teaches explicitly their birth and
death.(36) He whittles down, in practice, his words about the
eternity of substantial form to the level that substantial forms
of themselves are increate and immortal, but their union with
primordial matter brings about their accidental subjection to
birth and death.

SUBSTANTIAL FORM.

The main clue to the Aristotelian doctrine of substantial form
is to be found in our author's criticism of Plato's theory of know
ledge. Plato and Aristotle start from similar presuppositions
on this point (37) : first, the existence of science, that is, a system
of reasoned deductions from indemonstrable but certain defini
tions and principles ; secondly, the existence of objects of sense
experience that are constantly undergoing all sorts of incalculable
changes. And their common problem is to adjust these two
facts : the world of science with its systematic truths that are
valid everywhere, always, and for everyone, and are connected
with one another by the bond of logical necessity ; and the world
of experience with its indefinitely variable bodies that rarely
endure for long in the same state, that often at the same moment
provoke conflicting and even contradictory beliefs, and that
apparently lie side by side without being welded into any kind of
system. Plato's solution was that the world of science refers
to a world of realities distinct from the world of experience —
the world of Ideas ; that opinion or unsystematised knowledge
refers to the world of experience ; and that the world of experience
" participates " in the true reality of the world of Ideas. That
solution has provoked endless controversies : are those Ideas
of Plato metaphysical or mythical or logical ? Aristotle, at least,
never dreams of construing the theory of Ideas as a flight of poetic
fancy or a doctrine of logical predication : he accepts it as dog
matic metaphysics, implying the separate existence of a super-
physical world of eternal and immutable entities which are the
sole objects of scientific definition and scientific truth. And
whether Plato did or did not defend so crazy a doctrine, Aris
totle's incisive attack helps to emphasise the part played by the
Idea in his own theory of knowledge. He urges against the
Platonic view the fallacy of all those proofs that are advanced
to prove the separate existence of the Ideas : then, he insists
on the worthlessness of separately existing Ideas as an explana
tion of the existence and activity of the objects of experience.

110 COSMOLOGY

Plato's arguments are not conclusive (38) : " for according to
the arguments from the existence of sciences there will be Ideas
of all things of which there are sciences, and according to the
argument that there is one attribute common to many things
there will be Ideas even of negations, and according to the argu
ment that there is an object of thought even when the thing has
perished, there will be Ideas of perishable things — since we can
have a memory image of these. Further, of the more accurate
arguments, some lead to Ideas of relations, and others involve
the difficulty of the ' third man.5 And in general, the arguments
for the Ideas lead to the denial of things for whose existence
those who maintain the Ideas are more anxious than for the exis
tence of the Ideas ; for it follows that not the Dyad but number
is first, i.e., that the relative is prior to the absolute — besides all
the other inconsistencies between the consequences which have
been drawn from the theory of Ideas and its principles. Further,
according to the assumptions on which our belief in the Ideas
rests, there will be Ideas not only of substance but also of many
other things . . . and yet according to the necessities of the
case . . . there must be Ideas of substance only." Aristotle
goes farther and insists that the Ideal theory, even if it were
better founded, is useless. (39) "Above all, one might discuss
the question what on earth the Ideas contribute to sensible things.
. . . For they cause neither motion nor change in them. Again,
they help in no wise towards the knowledge of the other things
(for the Ideas are not even the substances of things, else they
would have been in them) ; nor do they contribute to their being,
since they are not present in the things which participate in them.
. . . But further, all other things are not derived from the Ideas
in any of the usual senses of the term — derivation. To call them
archetypes and to say that other things ' partake ' of them is
to use empty words and poetical metaphors. For what is the
agency which actually constructs things with the Idea as its
model ? . . . And . . . there will be many archetypes and
consequently many Ideas for the same thing. . . . Further, the
Ideas will be archetypes not only of sensible things, but of Ideas
themselves. . . . So, one and the same thing will be both arche
type and copy. Again, it is impossible that the substance of a
thing and the thing of which it is the substance should exist apart ;
. . . Yet when the Ideas exist, still the things that share in them
do not come into being unless there is some efficient cause ; and
many other things come into being (v.g. a house or a ring) of which
Platonists say there are no Ideas." For these and similar
reasons, Aristotle declares that Plato's Theory of Ideas multiplies
instead of solving the problems of knowledge : in his effort to
account for the things around us, Plato duplicates them — giving
us two worlds of stars, of men, of animals, of plants and of
minerals ; " this is just as if one who wished to count certain
things should fancy that while they remained fewer he will not
succeed, but should first multiply them and then count." (40)

SUBSTANTIAL FORM 111

Despite this incisive polemic Aristotle sticks to Plato's dis
tinction between the non-sensible essence of things and their
sensible appearance : scientific knowledge must have for its
object an unchangeable and necessary reality. Ideas will explain
the world of things around us if they are dethroned from their
Olympus, and made immanent as principles of knowledge and
being in the particular objects of sense experience : humanity
is not a thing apart from and outside of all existing men — if it
were, how could knowledge of it contribute in any way to our
scientific knowledge of man as they exist in the sensible world.
But if the Platonic Ideas are embowelled in sensibly existing
substances, they account both for the object of science and for
the reality of things. Science requires not Platonic " Ideas or
a One which is something over and above the Many " but the
right to predicate one term of many objects : a right allowable
in Aristotle's eyes only if the universal concept expresses what
belongs to existing individuals by reason of their nature, and
therefore, necessarily and always. (41) Once this conclusion
was accepted in the interests of scientific truth. Aristotle was
compelled to identify the class-concept of the lowest kinds with
the substantial form. This concept represents the specific
essence : that which makes Callias, Socrates, and Plato be men.
But the analysis of substantial change has shown that the sub
stantial form fulfils this same function : it is that constituent
principle within each substance which by its union with the
passive and indeterminate primordial matter forms an individual
of a particular species. Aristotle accordingly identifies the
two (42) : substantial form and essence are frequently used by him
to express from different points of view one and the same reality :
the essence is distinguished from the sensible object by that
permanence and unity which makes it an object of science ;
and in a similar way the substantial form is both a unitary
principle that marks off one species from another, and a permanent
principle that is eternally reproduced within the same species.

A secondary but helpful clue to Aristotle's doctrine of sub
stantial form is to be found in two well-known habits of thought :
his tendency to illustrate natural by artistic processes and his
predeliction for biological study.(43) Art realises a figure or
form in raw material or " matter " : the sculptor chisels bronze
into the shape of Socrates. Now Aristotle lays down that
nature works after the analogy of art in production of substances :
new substances are produced by the realisation of substantial
form in primordial matter, after the manner in which statues
are sculptured by the realisation of human outlines in bronze.
He does not readily forget, however, the limits of this analogy :
artistic skill results at most in a change of accidents. And his
biological cast of thought leads him to develop in the de Anima
a famous definition of the soul as substantial form (44) : the
soul is there described as the substantial form of living beings
and, also, as the first actuality or perfection of a natural body

112 COSMOLOGY

endowed with the capacity of life. A body capable of life, he
adds, is one that readily serves as an instrument for the fulfilment
of living functions : and thus the soul is the first actuality or

Eerfection of a natural body endowed with these instruments,
ubstantial form is called actuality or perfection because it per
fects or completes primordial matter : it is called first actuality
because it precedes all those qualitative perfections that are found
as specific attributes in the fully formed substance ; finally, it is
called the first actuality or perfection of a natural body capable
of life to remind his readers that substantial form, as such, has
no existence and no activity outside of or apart from that pri
mordial matter with which it is united to constitute living sub
stance. These two peculiarities of outlook — the artistic and the
biological — affect also Aristotle's treatment of substantial form
in the world of non-living bodies. In that world substantial
form bears to primordial matter the relation of the determining
to the determinable principle : the form is actuality, the latter is
potency. And as primordial matter is pure potency, it owes the
actualisation of all its potencies, whether of existence or activity,
to the substantial form.

Substantial form may, then, be likened to a hidden architect
within the composite unifving and actualising its indeterminate
co-principle into a determinate substance. All definiteness, all
activity, all intelligibility come from the substantial form.W
It is the principle of all definiteness : dominating the divisibility
of extended matter so as to bind its various parts into the single
ness of a unitary substance. It is the principle of all activity :
through it the composite, although consisting in part of utterly
passive primordial matter, becomes capable of action and reaction.
It is the principle of all intelligibility : through it the composite,
although consisting in part of unknowable primordial matter,
becomes an object of thought and of science — everything that
precedes it is indeterminate and unintelligible, everything that
follows it and does not come from it is purely contingent. In
short, substantial form actualises primordial matter, and thus
produces a substance that has a determinate existence, a natural
activity, and an intelligible essence. Hence its superiority to
primordial matter. (46) It is more being, more substance, more
nature, more cause, more beautiful, more divine : more being
and more substance for it is actuality ; more nature and more
cause for it is the source of all activity ; more beautiful for it
implies greater perfection ; more divine for it is more like the
highest form, God. Hence,(47) too, the wealth of synonyms by
which Aristotle strives to convey the richness of this determin
ing principle: evreAe^eia, because realised substantial form im
plies the completed perfection of substance ; ei/c/>yeia, — more
loosely — because certain processes, those of generation, result
in the manifestation of substantial form ; ctSos, because
substantial form fixes a substance in a definite species ; Ao'yos, be
cause substantial form is the object of intellectual knowledge ;

SUBSTANTIAL FORM 113

because substantial form is the essence of a thing ; TO ri
—probably, for no one pretends to be sure about this mysterious
phrase — because substantial form expresses the abstract essence
of a thing ; </>vo-t?, because substantial form is the principle of
activity ; ftop^r;, because substantial form fixes the species
and the natural kinds are often distinguishable by their figure ;
re'Aos, because substantial form is the result of generation
and the goal of primordial matter ; bpio-pos, because the
definition is a complete enumeration in proper sequence of the
essential characteristics of a thing.

The properties of substantial form are appetency for pri
mordial matter, incapacity of separate existence, immutability,
causality, origin from the potency of primordial matter. Sub
stantial form has an appetency (4S) for primordial matter but
this appetency is not to be interpreted as conscious desire :
substantial form is the essential correlate of primordial matter,
and this implies a natural inclination for union with it in the
formation of substance. Substantial form — at least, the sub
stantial form of non-living bodies — cannot exist alone (49) :
as one of the essential parts of a single substance, it is necessarily
immanent therein, and can no more exist apart from primordial
matter than can vision apart from the eye or can roundness apart
from the sphere. Substantial form is immutable (50) and cannot
turn into something else : addition and subtraction, as regards
the content of a substantial form, would result in a change of
species ; tack on sensation to the substantial form of a plant
and the result is an animal, take away life and the result is a
non-living substance. Substantial form is the principle of
causality in each substance.!51) Its proper causality is formal,
and consists in the immediate communication of itself to pri
mordial matter for the purpose of forming a substance : this
formal causality must not be interpreted as the production in
the substrate of any reality distinct from the substantial form
itself ; it implies not efficiency but communication, and is the
mere clothing of the substrate with its own perfections. But
once embowelled in that substrate, the substantial form may be
regarded as a source of efficiency and finality. Its efficient
causality is manifested, within the substance, as a principle
fashioning unto its own ends the primordial matter ; and, without
the substance, as a principle fashioning to the same end other
substances. This doctrine is brought out most clearly in Aris
totle's views upon the soul.(52) The soul acts as efficient cause
within and without the organism : within the organism it brings
about nutrition, growth and decay in plants, and these plus sen
sation in animals ; without the organism it reproduces its like,
plant begetting plant and animal begetting animal. And as all
eificient causality, for Aristotle, is towards a definite goal, this
efficiency of the substantial form becomes forthwith final causality.
This finality is best observed in living beings. Every living
being is a microcosm the parts of which subserve the whole :

8

114 COSMOLOGY

and that adjustment of means to ends within each organism is
effected by its substantial form or soul. It is ever regulating
and directing all living processes to its own definite purpose.
It not merely grows the organs as efficient cause, but it shapes
them when growing them towards fixed results. And if its
regulating activity met with no obstacle, it would bring forth
in all fullness its perfections, and would result in a substance
finished in its kind and, thereby, harmonious with the universe
as a whole. Both this efficient and this final causality are also
at work, according to Aristotle, in non-living substances : in
them as in living bodies the substantial form exercises its three
fold causality. Still this ontological identification of the formal,
the efficient, and the final cause must not lead us to confound
the three : the substantial form, as such, exercises only formal
causality, that is, actuates primordial matter ; and it is not in
its function of substantial form that it acts efficiently and finally.
The question of the origin of substantial form remains. Aris
totle's modification of Platonism compels him to abandon Plato's
theory of the unity and eternity of the Idea. Individuals are
many, and accordingly the substantial form, despite its identity
of contents within the same species, becomes numerically mul
tiple : " just as your matter is different from mine, so is your
form different from mine." (53) Individuals are born and die,
and accordingly their substantial forms cannot be unproduced
and imperishable : " causes in the sense of forms are simultaneous
with their effects." (54) Still Aristotle retains a hankering after
Platonic phrases : substantial form is one and eternal — within
the species. (55) It is one notwithstanding its numerical mul
tiplicity in individuals because the species is one : every individual
of the species possesses a substantial form alike in nature. It
is eternal : unproduced, notwithstanding the birth in time of
individuals, because the species has always existed ; imperishable,
notwithstanding the death in time of individuals, because the
species can never perish. Phrases apart however, Aristotle
holds that substantial forms come into and pass out of existence,
and has to face the problem of their origin.!56) And since
substantial forms cannot be pre-existent like the Platonic Ideas,
they must come from primordial matter. (57) They pre-exist in
primordial matter : not as preformed miniatures nor as latent
germs ; but in potency, awaiting the stimulating influence of the
efficient cause. When the composite is produced, its substantial
form originates from the potency of primordial matter ; when
the composite is destroyed, its substantial form lapses into the
potency of primordial matter. And the secret of our world's
rhythmic succession of substantial forms (58) ? That secret lies
in efficient and final causality. Each composite is an efficient
cause, active through its substantial form and reproducing that
form in other beings : hence the renewal of forms. This re
newal follows a law of perfection in the order of finality : nature
aims at what is best ; and this best, which is nothing else than the

SUBSTANCE AND ATTRIBUTE 115

hierarchical organisation actually existing amongst the sub
stantial forms of our world, governs the ceaseless generation and
corruption of these forms.

SUBSTANCE AND ATTRIBUTE.

Aristotle waxes lyrical in his description of the union of
substantial form and primordial matter. " (Primordial) matter
co-operates like a mother with the (substantial) form in bringing
about everything that happens. . . . There is in all things some
thing divine, excellent and desirable, and (primordial) matter is
of its nature destined to desire and seek after this divinity. . . .
The (substantial) form cannot possibly desire itself, for that self
is never lacking : neither can its contrary (privation) desire the
(substantial) form, for contraries mutually destroy each other.
Herein lies the special feature of (primordial) matter : it may be
likened to the female desiring the male, the ugly desiring the
beautiful." (59) The union of the two gives a complete sub
stance : and so complementary are they that one cannot exist
apart from the other. Their union is not due to the mediation
of an intermediary : they aTe to each other what the wax is to
the impressed seal, the edge to the axe, the vision to the eye.
" Proximate matter and form are one and the same thing, the one
in potency, the other in actuality. Consequently to ask the
cause of their unity is like asking the cause of unity in general ;
for each thing is a unity and the potential and the ^actual are
somehow one. Therefore there is no other cause here unless
there is something which causes the movement from potency
into actuality." (60) Aristotle does not mean to deny by these
words the real differences between primordial matter and sub
stantial form. To maintain that primordial matter and sub
stantial form are but different ways of regarding one and the
same reality would contradict Aristotle's whole system and his
explicit assertions.!61) These two principles are the same
substance in a totally different way : substantial form is the
actuality of the substance and primordial matter, the substrate,
coexists with it as the potency of the same substance ; thus
each substance is, in spite of this dualism of objective principles,
an absolute unity. (62)

But the substances, of which Aristotle is thinking, are existing
individuals : minerals, plants, animals, with their respective
attributes. Attributes, then, are factors in existing substances ;
and they are not extraneous additions like clothes. Aristotle
admits as many kinds of attributes as there seem to be irreducible
methods of modifying a substance without injury to its identity ;
he classifies their multitudinous modifications under nine heads
— quantity, quality, relation, place, time, situation, possession,
action, passion. All these attributes of existing individuals have
not, however, the same connexion with the specific essence of their
respective substances (63) : some are properties, others accidents.

116 COSMOLOGY

Properties in the strict sense are those attributes which, although
they are not part of the essence, are common, necessary and
peculiar to the species. All other attributes are adventitious
realities which may or may not belong to an existing substance —
they are present merely by coincidence in a particular individual,
and have no necessary connexion with the specific essence of
that individual. Properties, then, belong to individuals as
existing and active members of a definite species : they are the
natural concomitants of the substantial form, and come into
existence with it the moment a substance is generated. Aristotle
has exemplified such properties in the case of animals with a
masterly wealth of details in his various biological treatises. His
meagre knowledge of those sciences that deal with non-living
bodies did not permit of his illustrating this theory of a concomi
tant resultance of properties from the substantial form in the
realms of physics and chemistry : but it is taken for granted,
everywhere, in his treatment of non-living bodies. The accidental
attributes are distinguished from these properties by the fact
that, although when present they inhere in the substance, they
have no necessary connexion with, and do not come into existence
concomitantly with, the substantial form. The individuals of
certain species, for instance, have eyes — and these are properties ;
but these eyes may differ in colour — and this greyness or blueness
is, for Aristotle, an accident traceable to the stuff out of which
the eye is made. This stuff is itself the result of an eternity of
inextricable interactions : hence, he speaks of the patient and
of the efficient cause as the makers of accidents.(64)

A word about quantity. Every bodily substance exists in
space and is measurable : hence it has quantity. But what
Aristotle understood by the essence of quantity led, as we shall
see, to controversy between Averroes and the Schoolmen. Here,
it is worth noting that quantity is not, for Aristotle, an unchange
able attribute of matter in the sense that the same non-living
matter always occupies the same volume. Quantity, as a pro
perty of matter, depends on the substantial form.!*55) Now in
the living world, all natural kinds have definite limits of less and
more in size : cabbages never attain the stature of oaks ; men
do not turn the scale with elephants, nor do they rub shoulders
with giraffes. This way of regarding quantity led Aristotle
when dealing with non-living substances to conclusions that
are totally foreign to modern views. The quantity of non-living
bodies, also, depends on their substantial form. When a large
volume of air is generated out of a small volume of water, the
increase in quantity is not due to the intrusion of extraneous
matter ; but the pre-existing quantity of matter passes under
the influence of the new substantial form from small to large —
passes from potency to actuality as regards enlargement. This
instance is typical of all substantial changes : in them, the quan
tity of the corrupted body disappears with the outgoing sub
stantial form and the quantity of the generated body is totally

POST-AKISTOTELIAN GREEKS 117

new, coming into existence for the first time with the incoming
substantial form. But in absorption or growth, the already
existing quantity does not disappear : the fresh material that
becomes part of the absorbing or growing body loses both its
substantial form and its pre-existing quantity, and is changed
by the power of the new substantial form into a definite volume
of the absorbing or growing substance.(66) The ordinary facts
of contraction and expansion of matter are also explained in a
way wonderful to moderns : contraction is for them a closer
crowding together of immutable particles, expansion the separa
tion from one another of these same particles. Aristotle thinks
that contraction and expansion are due to the actual thickening
and thinning of non-living matter itself (67) : a brick could, he
believed, occupy a volume of twice its previous volume by real ex
pansion, that is, by its quantity passing from potency to actuality
in greatness of size ; and the same brick could occupy a volume
of half its previous volume by real contraction, that is, by its
quantity passing potency to actuality in smallness of size.
Another remarkable consequence in this connexion, arising out
of Aristotle's opposition to atomism, was his view of the individual
unit in the non-living world. (6S) Each sensibly homogeneous
and continuous lump of non-living matter possessed in his eyes
unity of being, and was a single substance : a block of marble,
a log of wood, a lump of stone, a bar of iron, provided it was
not perceptibly divided, was, however enormous its dimensions,
just as truly a unitary individual as the tiniest visible chip that
might be broken of? it ; and apparently, an ocean was just as truly
a single substance as each jet of spray thrown off from its breakers.

POST-ARISTOTELIAN GREEK THEORIES OF MATTER.

Our detailed review of Greek Cosmology comes to an end with
Aristotle. A sufficient reason for this closure is that there is
little new in the cosmological theories of his successors, the
Epicureans, the Stoics and the Neoplatonists (69) : and that this
little new is but a hint of a modern theory of matter which must
be hereafter fully discussed. Epicurus revived the atomism of
Leucippus and Democritus : he modified it by attributing weight
to the atoms, and by allowing them an indefinite rather than an
infinite number of shapes and sizes ; he spoiled it by assuming
that, at certain moments and for no assignable cause, atoms
when falling in the void may swerve very slightly from the
perpendicular path. The Stoics in attempting a compromise
between Aristotle and the earliest thinkers reached a view new
to the Greeks. Those earlier philosophers had said that all
bodies were made out of one or other of the four elements ;
Aristotle had said that bodies were made out of primordial
matter and substantial form ; the Stoics taught that bodies
were made out of unqualified body and determinate qualities.
Unqualified body meant for the Stoics that inert, triply-extended,

118 COSMOLOGY

corporeal stuff destitute of shape and of qualities, which underlies
every existing body. This unqualified body was said to be a
substance in the true sense : a self-subsisting reality. And on
this account, every addition to it by way of shape and of quality
was said to be an accident. The Stoics taught, however, that
unqualified body is never actually present in our universe without
a definite shape and without definite qualities : these two con
stituents, unqualified body and the qualifying accidents, are
inseparably united in every actual body. In addition, the
Stoics admitted change of qualities in body ; they denied change
of substance — there is never a fusion of distinct bodies into one
homogeneous mass ; their distinctive doctrine in this connexion
was their assertion of " universal mingling " — a mixture in which
every part of one body is interpenetrated by every part of another,
but a mixture in which each body still retains its own qualities.
Plotinus attempted to unite the cosmologies of Plato and Aris
totle. His view was that bodies are made of primordial matter
and substantial form. Bodies have primordial matter as Aris
totle says : but it is inaccurate to contrast this primordial
matter with the " matter " of Plato — Plato's matter is not
space but the potency of body. Bodies have also a substantial
form in the Aristotelian sense : but for Plotinus, as for Plato,
these substantial forms of sensible bodies are but copies of the
Ideas. Thus we see that the only novelty, in Greek Cosmology
after Aristotle's time, is the Stoic approach to the theory known
in the nineteenth century as dynamic atomism. There is, then,
no need to enter on the details of these Greek post- Aristotelian
theories of matter. Even if there were, I should hardly do so
for the thesis of this book is, that Aristotle has really answered
the question first asked by Thales : of what are bodies made ?

CHAPTER V.

THE ARISTOTELIAN SCHOOLMEN ON THE HYLEMORPHISM
OF MATTER.

" IN judging of the Schoolmen we must remember," writes Fr.
Rickaby, Scholasticism (pp. 9-11), " how destitute they were of
those instruments of study and research without which any
modern student would consider the progress of his work impossible.
Not that the privation was altogether a dead loss. Devoid of
helps from without, men thought harder. For physics they de
pended upon their unaided senses. No telescope, no microscope,
no battery, no chemical reagents ; no museums, nor collections
either. For the literary student there were books, manuscripts
of course. He had in his hands, and by frequent quotation
showed his diligent use of, most of the Latin Classics, Cicero,
Virgil, Horace, Terence, Juvenal, Seneca, Quintilian; Pliny's
Natural History he knew at least by extracts. Knowing no
Greek ... he had in his book-chest no Greek manuscripts.
Supreme importance is therefore attached to the translation of
Aristotle : indeed, it is not too much to say that had Aristotle
never been put into Latin, scholastic philosophy never would
have arisen. Abelard in 1136 had in his hands translations of
what was quaintly entitled the Perihermenias (Aristotle on In
terpretation) and the Categories. The second half of that same
century possessed the whole of the Organon but no more. Had
you asked a clerk of our own King John's Court who Aristotle
was, he would have answered with a shrug of the shoulders,
' Oh, a crabbed logician.' The throne of the Stagyrite was not
yet firmly planted in the West. By the middle of the thirteenth
century, however, besides versions from the Arabic, a translation
from the Greek of nearly the whole of Aristotle was achieved by
two Dominicans, Henry of Brabant and William of Moerbeke.
(The History of Animals does not seem to have been translated,
nor the later books of the Generation of Animals, nor the end of
the Metaphysics. To Aristotle the later Middle Age attributed
a work, really by Proclus, known as Liber de Causis, extraordin
arily popular.) All that the Schoolmen had of Plato was a
fragment of the Timceus translated by Chalcidius, also the Phcedo
and M eno ; further information about the philosopher was
gathered from St. Augustine and sundry Neoplatonists. Chief

119

120 COSMOLOGY

of these latter was the Pseudo-Dionysius, the Areopagite (prob
ably a monk of the sixth century), whose treatise Of the Divine
Names and Of the Heavenly Hierarchy had a great hold on the
medieval mind. A still greater treasure was the works of Boethius,
who was long the chief authority on Aristotle. Many fragments
of the ancient learning were found embedded in the works of the
Latin Fathers, notably St. Augustine, St. Ambrose, St. Gregory
the Great, St. Isidore, Lactantius, and Latin versions of Clement
of Alexandria and Origen. There was also a sort of Cyclopaedia,
the work of Martianus Capella, bearing the title of The Nuptials
of Mercury and Philologia. Last but not least, diligently conned
and continually transcribed, there was the Bible according to
the Latin Vulgate." The result of these limiting conditions for
progress in the empirical and the metaphysical sciences was that
the medievalists were, in these branches of learning, men of one
author. Not, indeed, of the whole of that author. St. Thomas,
Scotus and the others commented on less than half the writings
of Aristotle for the simple reason that only so much of these
writings refers to metaphysics and to those portions of empirical
science which are the basis of metaphysics. That half of Aris
totle comprises about 750 double-columned pages in Bekker's
standardised text. The whole basis of medieval science, both
empirical and metaphysical, lies, therefore, within a surprisingly
narrow compass. It must not be forgotten, however, that the
conciseness and obscurity both of Aristotle's style and of his
subject made the understanding of this half of his text a very
difficult task. It is in their commentaries on this text and
rarely elsewhere that we find the philosophy of the leaders of the
School : each succeeding leader, however, added to his commen
tary on Aristotle a concomitant commentary on his predecessors ;
that is why the two volumes — Disputationes Metaphysicce — of
Suarez embodies the philosophical opinions of the whole School.
These commentaries were extensive treatises : the lectures of
St. Thomas on Aristotle, for instance, exceed in bulk his Summa
Theologica.

The salient points of medieval Cosmology will be expounded
in five chapters : two dealing with substance and three dealing
with accidents. All that Cosmology is based on Aristotle : it pre
supposes, then, the scientific views outlined in the third chapter ;
it presupposes, also, Aristotle's cosmological criticism of his
predecessors. But so little has hitherto been explained of Aris
totle's Cosmology regarding material accidents that the medieval
doctrine on quantity, quality, and motion, has to be built from
the ground up. Not so the medieval doctrine of inanimate
substance. A full account has already been given in the fourth
chapter of Aristotle's theory of inanimate substance. With the
exception of some important divergences that shall be pointed out,
the Schoolmen endorsed every line that Aristotle wrote in refer
ence to non-living bodies about the proofs of hylemorphism, the
existence and nature of primordial matter and substantial form.

THE PROOFS OF HYLEMORPHISM 121

It would be meaningless, then, to repeat all this in two chapters
that follow immediately a detailed account of Aristotle's teaching
on these topics. Hence the fifth and sixth chapters must be
read as extensive supplements to the fourth : they simply put
before the reader points in the Cosmology of inanimate substance
where the Schoolmen, pondering over the doctrine outlined in
the fourth chapter, either developed more fully the implications
of the Aristotelian text or discovered certain inconsistencies in
that text.

THE PROOFS OF HYLEMORPHISM.

The Schoolmen endorsed Aristotle's view of primordial matter
and substantial form as the ultimate constituents of inanimate
bodies. And as he was their guide not only in philosophy but
in empirical science, they accepted the proof of hylemorphism
drawn from substantial change. For them as for him, the change
of one inanimate substance into another substance was a fre
quently occurring and easily observable fact of experience. This
change of substance was due sometimes to the absorption of
one body by another : " when anything small is mixed with any
thing much greater, there is no true mixture . . . but the specific
nature of the small is destroyed and becomes part of the great —
this happens when a drop of wine is added to a thousand pitchers
of water." 0-) The mutual transformations of the elements are
also instances of absorption. But change of substance is due
sometimes to the fact that the four elements combine to form a
single substance different from the components : this happens only
when none of the components is greatly in excess of the others ;
thus, the four elements combine in varying proportions to form
true mixtures. Both of these instances of substantial change
were in their eyes irrefragable proofs of hylemorphism. They
accepted also the proof based by Aristotle on the contingent
nature of all sublunary bodies. As both of these Aristotelian
proofs have been already expounded, there is no need to repeat
them here : they appear in all the medieval commentaries on
the Aristotelian text.

Some of the Schoolmen, however, developed a proof of hyle
morphism that was not formulated by the Stagy rite. He held
that the heavenly bodies did not undergo substantial change :
and with that view all the School agreed. It is not quite certain
whether he concluded from this fact that the heavenly bodies
were not composed of primordial matter and substantial form :
some Schoolmen thought he did ; others thought he did not.(2)
But whatever about Aristotle, the majority of the greater School
men did teach the hylemorphic composition of the heavenly
bodies, and, in striving to prove this composition developed a line
of argument that betrays prevision of a problem which has be
come since the days of Leibniz one of the central problems of
Cosmology : that of the conditions under which alone extended
matter can exist as substance.i3) The following quotations

122 COSMOLOGY

give an outline of their reasoning. " If," says St. Thomas,(4)
" he (Aristotle) means that a heavenly body has in no way matter
or subject, he is clearly wrong. It is evident that this kind of
body is actually existing : otherwise, it could not act on sublunary
bodies. Everything that actually exists is either an actuality
or possesses an actuality. But a heavenly body cannot be
an actuality because, then, it would be a subsisting form
and an object of intellectual not sense perception. There
fore, there must be a substrate in a heavenly body underlying its
actuality." This and similar texts have even been the source
of the Thomist theory of the heavenly bodies : according to that
theory, a heavenly body cannot be primordial matter alone,
because it is active ; nor substantial form alone, because it is
not spiritual ; hence, each of the heavenly bodies must be com
posed of primordial matter and substantial form. This argument
gets a slightly different twist with the leaders of some of the other
schools. " Since no body lacks extension," says St. Bonaven-
ture,(5) " and since extension implies a corporeal nature, no
body can exist without matter and no body can exist without
form." Aegidius(6) is more detailed. "It must be composed
of true matter and true corporeal form . . . because the accident
must be rooted in its substance. Accordingly, the quantity
and the quality of a heavenly body must be rooted in substance
of some kind. Put yourself the question whether that substance
be simple or compound. Simple it cannot be, for, then, it should
be matter alone or form alone : but it cannot be matter alone
for matter cannot exist without form ; nor can it be ... form
alone, for immaterial forms cannot possibly receive and be the
subjects of sensible accidents. Therefore the accidents of a
heavenly body prove clearly that its substance is made up of
matter and form." Three centuries later, Suarez (7) winds up
his review of the arguments and authorities for and against
this hylemorphic theory of the heavenly bodies by an admission
of its probability. " And yet, as far as we can judge from signs
and from effects, each of these heavenly bodies is probably
composed of matter and form. First of all, everyone of those
accidents that flow from matter — with the exception of corrupti
bility — is found in it : quantity is there, for instance, and it
springs from the same root in every body. Then, rarity and
density are present in heavenly bodies and they necessarily
connote matter : density consists, in fact, in the presence of
much matter in what is quantitatively small. . . . Again, some
accidents of the heavenly bodies are merely of the receptive kind
— for example, quantity which makes these bodies physically
movable ; whereas other accidents are of the active kind — for
example, light and any powers they may have for influencing
(terrestrial bodies) ; therefore, just as these latter accidents
point to the presence of form, so do the former accidents indicate
the presence of matter." The discoveries of modern astronomy
have long since put an end to all this guess-work about the stuff

PRIMORDIAL MATTER— WHAT IT IS NOT 123

out of which stars and planets are made. But for the student
of hylemorphism, this non- Aristotelian argument, in every variety
in which it appears from the days of St. Thomas to those of Suarez,
proves that, in the minds of some of the ablest medievalists,
the fate of hylemorphism was not absolutely dependent either
on the occurrence of changes of substance or on the contingency
of sublunary substances.

PRIMORDIAL MATTER — WHAT IT Is NOT.

Primordial matter is neither one nor all of the four elements.
Aristotle had already proved this : and the Schoolmen (8) re-echo
his agreements, stressing in our present reference the impossi
bility on such a supposition of substantial change. Albert the
Great, whose peculiar theory of mixture has made him suspect
on this topic, admits this explicitly. (9) " We teach that there
is one (primordial) matter distinct from the four elementary
sensible bodies : but we teach that this (primordial matter)
never actually exists distinct from all four bodies but is separated
now from one of them and now from another of them — that out
of it as matter those bodies which are called elements are gene
rated." For exactly the same reasons the Schoolmen (10) re
fused to identify primordial matter with either the atoms of
Democritus and Epicurus or the seeds of Anaxagoras. They
rejected also the Arabian attempts to thicken the fibre of primor
dial matter. Avicenna held that the ultimate substrate of sub
stantial change was a primordial matter which was inseparably
united with an incomplete and quasi-generic form, the basis
apparently of extension and division. None of the greater
Schoolmen (n) admitted this view : there was not the slightest
trace in the activities of bodies of this inseparable and incomplete
form ; there was no sufficient reason in the processes of sub
stantial change for its assumption ; its presence would destroy
the unity of subsequently formed substances ; finally, its presence
would make changes of substance impossible. Averroes fastening
on certain texts of Aristotle held that primordial matter was a
substance with indeterminate, inseparable, ingenerable, incor
ruptible dimensions that were at most accidentally changeable :
in other words, a quantified substrate that had no special density
or rarity, no special size or shape. And he implied that this
indeterminate quantitativeness was moulded into the various
special dimensions of existing bodies by the substantial form.
St. Thomas (12) apparently accepted this view of primordial
matter in his youth, but he changed his mind later on and, in the
de Natura Materice, he marshals against it almost a score of
arguments. He points out that this view of primordial matter
cannot be reconciled with Aristotle's explicit teachings on the
indivisibility of primordial matter. He argues that these in
determinate dimensions are either educed from the potency of

124 COSMOLOGY

primordial matter or not ; if educed, they must have been previ
ously in potency and, hence, primordial matter could be deprived
of them — a supposition that Averroes denies ; moreover, if educed
they can have been educed only by a change in the primordial
matter under the influence of the substantial form and, hence,
they cannot be indeterminate — a supposition that Averroes cannot
admit ; therefore, these indeterminate dimensions are not educed
from the potency of primordial matter by the form — a conclusion
that involves an absolute contradiction for Aristotle because it
implies that there are three principles of substance, primordial
matter, the substantial form, and the alleged indeterminate
dimensions. He urges also that quantity, whether indeterminate
or determinate, supposes always the presence of substantial form.
Suarez and some of the Jesuit Schoolmen did not admit as certain
that bodies in changing their substance lost everything except
their primordial matter, but they spoke of this alleged permanent
core of reality as primordial matter plus certain accidents :
thereby assenting with St. Thomas and Scotus to the rejection
of this Averroist interpretation of primordial matter. The
Schoolmen, then, stood loyally by Aristotle's famous negative
description : for them as for him, that which is of itself a complete
substance, or that which has of itself either quantity or quality
or any other kind of accident, cannot be identified with primordial
matter.

PRIMORDIAL MATTER — WHAT IT Is.

St. Thomas, when commenting on this negative definition,
insists that Aristotle in denying that primordial matter is either
a complete substance or an accident, either a substantial form
or the privation of substantial form, does not thereby deny that
it is a positive reality.!13) Primordial matter cannot be absolute
nothingness for it is one of the essential constituents of those
undeniable realities, material bodies. Moreover, if it were nothing,
there would be neither generation nor corruption but creation
and annihilation in the world of matter. It is, then, a genuine
reality of some sort. Further, it is a reality distinct from sub
stantial form : realities which are actually separable are cer
tainly distinct from each other, but primordial matter persists
during those substantial changes that involve the disappearance
of the old substantial form and the appearance of a new sub
stantial form ; realities which are essentially simple cannot owe
their intrinsic being to anything outside themselves, and primor
dial matter, even when united with substantial form in a sub
stance, preserves its own essentially simple reality. Hence St.
Thomas approves that other Aristotelian description of primordial
matter as the first subject of which each substance is made and
which persists in each substance after it is made, but which, neither
before nor after the making of the substance, exists as an accident :
as first subject, it does not presuppose any other substrate ; as
the subject out of which the substance is made, it is distinguished

PKIMOKDIAL MATTER— WHAT IT IS 125

from substantial form, for this is the goal of generation ; as some
thing that perseveres after the substance is made, it is distinguished
from privation for this is but an accidental principle of generation.
Despite its distinction, then, from substance, accident and sub
stantial form, primordial matter as one of two ultimate consti
tuents of bodies must be a genuine reality. It was for the purpose
of emphasising its genuine reality that Aristotle sometimes
spoke of primordial matter as substance : an inconvenient usage
even when the qualification — potential — is added. The School
men defend this usage on the ground that primordial matter, being
a principle of substance, cannot belong to the category of accident,
and must be somehow linked up with the category of substance :
A substance is a self-subsisting reality of a definite species : hence
a full-blown substance implies completeness of self -subsistence
and completeness of species. Now, primordial matter cannot
by any stretch of language be put down as an accident : it does not
need anything distinct from itself as subject of inherence in order
to exist. But the Schoolmen spoke of it as an incomplete sub
stance : it is incomplete in regard to self-subsistence because,
although it does not need a subject of inherence, it cannot exist
without the co-existing principle of substantial form ; it is in
complete in regard to definiteness of species because, although it
is one of the two constituents of any specific substance, it is that
indeterminate constituent which lacks all specific determination
either of essence or of activity. This medieval terminology
about " incomplete substances " is not popular nowadays : it has
its obvious difficulties. But whatever about the elegance of the
term, the use of it in reference to primordial matter proves
beyond cavil that the Schoolmen believed this factor of substance
to be something real.

The Scotists and the Suarezians are above suspicion on this
question : as we shall see, they declared that primordial matter
had, of itself, an entitative actuality. The Thomists objected
to the application of this term — actuality — to primordial matter.
But that linguistic objection does not imply that they differed from
their opponents on the problem of fact : the positive reality of
primordial matter. Any representative selection of the texts of
St. Thomas proves this.O4) Take the following. " Matter of
itself is potential being." "The actuality towards which pri
mordial matter is in potency is subtantial form ; and therefore
the potency of matter is none other than its essence." "It is
true that matter has its exemplar idea in God, but this idea is
not different from that of the composite : for matter of itself
has neither being nor knowability." " Matter exists for the sake
of things ; it is in some sense a thing because it is the potency of
things ; it is also in some sense the substance of a thing because
it enters into the make-up of substance." " In whatever bodies
there is composition of potency and actuality, that which holds
the place of the primary potency or primarv subject is incorrupt
ible. That is why primordial matter is incorruptible even in

126 COSMOLOGY

corruptible bodies." " Primordial matter was created neither
wholly without form, nor under one common form, but under
distinct forms." " Primordial matter receives substantial being
by means of the form, and, therefore, it must be created under
some particular form — otherwise it would be in actuality. But
while existing under any particular form, primordial matter is
in potency towards other forms." ' The destruction of a body
cannot result in primordial matter in the sense that this matter
would continue to exist without a form because matter of itself
cannot exist." " Primordial matter is that first subject which
does not exist in any other." " The very nature of primordial
matter demands that it cannot be in any other but that it should
be itself the first subject." :; You must know that primordial
matter is said to be numerically one in all things." " That is
called matter which has being from some other conjoint reality,
for matter of itself has incomplete being or rather none at all."
" Although primordial matter cannot exist by itself it can be
considered by itself." " Activity is proportionate to the grade
of actuality in being, and, therefore, the greater the defect of
being, the less the activity : this is clearly seen in reference to
primordial matter for, since it embodies the lowest grade of being,
it has no active power." " Since matter is, as such, potency,
the primordial material principle must be foremost in potency,
and, thus, most imperfect." " That is called primordial matter
which is in the category of substance as a potency of some kind
distinct from species and form and privation, but yet capable
of receiving forms and privations." " Primordial matter, al
though without form, is an imitation of the First Form : for,
however feeble be that being which it has, it is, despite its feeble
ness, an imitation of the First Being." " When Avicebron argues
that since there is a Being which, itself unmoved, is the cause of
motion, namely, the First Maker of all things, there must also be
something which is merely moved and passive, his conclusion
is sound. But this being is primordial matter which is sheer
potency just as God is sheer Actuality." " Primordial matter
which is the first recipient holds in reference to passive potency
that same place that God, who is First Agent, holds to active
potency ; accordingly, matter is its own passive potency just
as God is His own active potency." " If a definition of the essence
of primordial matter could be framed, the differentia would be
its own relation to form, the genus its own substance." " Strictly
speaking, that which is in potency to substantial being is pri
mordial matter." " You must know that although primordial
matter has not of itself any form ... it is never stripped of
form. It cannot, however, exist of itself : for, since it has not
of itself any form, it cannot be in actuality because actual being
results only from form ; it exists (of itself) only in potency."
" The form is a part of the composite and the composite as a
whole is made up of it and of the matter." " Matter in its essence
must be distinct from all substantial forms and their privations

ORIGIN AND UNITY OF PRIMORDIAL MATTER 127

which are the terms of generation and corruption." " Matter
has not strictly an essence but is part of the essence." " When
we observe that what is air sometimes becomes water, we must
admit that something existing under the form of air sometimes
exists under the form of water : and in this way, that which is
something distinct from the form of air and the form of water
holds the same relation to these material substances as bronze
does to the statue, wood to the couch, and everything raw and
unfinished to the form ; and this something is what we say to
be primordial matter." " Primordial matter has of itself potency ;
and since potency is a good, it follows that good is included in
primordial matter of itself." Who can read these texts and doubt
that St. Thomas held the positive reality of primordial matter ?
Some of them read thin, some of them read thick, but none of
them in their context casts the slightest doubt on the positive
reality of primordial matter. Nor was this reality denied by
any of the Thomists : they never attempted any far-fetched
explanation of those texts that read thick ; and they conducted
the controversy about primordial matter as sheer potency on
grounds that never infringed the claims of primordial matter as
a positive reality. " Matter has a proper essence distinct from
form : hence the form is extrinsic to it ; still, that essence of
matter implies an essential relationship to actuality or to form,
a relationship, I mean, that is not prsedicamental but transcen
dental." These are the words of a seventeenth-century Thom-
ist.(15) And Bannes, the supposed enfant terrible of Thomism,
writes towards the end of the sixteenth century. " Matter is a
true incomplete substance. Matter is the prior incomplete sub
stance. Therefore it is not an accident. It is a real being : it
is the subject of real transmutation, that is, of generation : it is
not an accident in another subject for it is the first subject.
Therefore, it is a substance. No substance can be made out of
what are not substances. But substances are made out of matter.
Therefore (matter is a substance)." (16)

ORIGIN AND UNITY OF PRIMORDIAL MATTER.

The Schoolmen taught, in opposition to Aristotle, that pri
mordial matter was created at the beginning of the world : rather
con-created, for the term of God's creative activity was a world
of substances. But once created, they held it to be ingenerable
and incorruptible ; meaning thereby that it persists unchanged
through all changes, whether of accidents or of substances. (17)
This identical persistence throughout change was the basis of
their belief in its unity : everywhere and everywhen, its nature
was the same ; it was a substrate of itself absolutely indifferent
to the comings and goings of either substantial or accidental
forms ; whenever the necessary extrinsic causes were applied
to any portion of primordial matter, the results were the same as
regards the subsequent product of generation. Moreover, every

128 COSMOLOGY

portion of primordial matter displayed the same natural need
for union with substantial form. And the Schoolmen built on
this appetency of matter for form a theory of passive evolution.
This theory meant merely that primordial matter may pass
unchanged through all the cycle of sublunary substances : be
ginning with the transmutation of the four elements and ending
with man, an advance that gradually prepared its potency at
each stage for higher and higher forms. " There are varying
levels of actuality among substantial forms. Primordial matter
is first in potency towards the forms of the elements. And when
existing under these elementary forms, it is in potency towards
the forms of mixtures ; and that is why elements are the makings
of mixtures. And when existing under the forms of the mixtures,
it is in potency towards the vegetative soul because this kind of
soul is the actuality of a body. In the same way, the vegetative
soul is in potency towards the sentient soul and the sentient soul
towards the rational soul. . . . Elements exist, then, for the sake
of mixtures ; mixtures for the sake of living beings ; among
living beings, plants for the sake of animals and animals for the
sake of man : because man is the end of all generation." (18)

A WAR OF WORDS.

A doughty controversy was waged over the question whether
potency or actuality was the more fitting term to apply to pri
mordial matter : Thomists plumping for the use of the term,
potency ; Scotists and Suarezians allowing, according to the
occasion, the use of both terms. Thomists (19) insisted that
primordial matter was of itself mere and sheer potency : that is,
a reality whose essence consists solely in its relation to the act
uality of substantial form. They meant by actuality of essence
that which makes a thing be in a determinate species or genus ;
and they refused to allow any other meaning to actuality of
essence. They concluded, then, that since primordial matter
was a reality which was specifically determined only by some
thing else, namely, the substantial form, it ought not in strictness
to be termed an actuality of essence. Scotus and Suarez (20)
fastened on the fact that primordial matter even in union with
substantial form preserves its own simple reality, and concluded
that it has an actuality of essence of its own distinct from that
actuality of completed essence which results from union with the
form. They concluded that, while in reference to the actuality
of complete essence it might be rightly called mere and sheer
potency, it ought to be called, in reference to its own intrinsic
indeterminate and incomplete reality, a distinct actuality of
essence. Thus both parties to this dispute recognise the same
dose of reality in primordial matter. The source of their quarrel
lies solely in the different meaning they give to essential actuality.
" I ask our opponents," writes Goudin,(21) " what they under
stand by essential actuality. Either they mean by it everything

DISTINCT EXISTENCE OF PRIMORDIAL MATTER 129

that is not nothing in the sense that actuality is opposed to
nothingness, and that whatever is not nothing may be called an
actuality ; and according to this meaning, (primordial) matter is
certainly an actuality because it is something and not nothing.
But this use of the word, actuality, is a wrong use : for potency
is also a reality and enters into the make-up of created being.
Or they mean by essential actuality something determinate in
the order of being and something expressing a special mode of
being — which is the meaning of St. Thomas when he says act
uality is that which determines potency ; and in this meaning,
(primordial) matter is not an actuality because it is of itself
something indeterminate, and something indifferent in reference to
all species of material being."

THE DISTINCT EXISTENCE OF PRIMORDIAL MATTER.

The cosmological question whether primordial matter has of
itself an existence of its own is really an offshoot of the dispute
about the distinction between essence and existence in concrete
individuals. All the Schoolmen admitted some kind of distinc
tion between essence and existence in a concrete being : but they
contended fiercely about the nature of that distinction.!22) St.
Thomas and the Thomists maintained this distinction was real ;
Henry of Ghent, Durandus, Suarez and a host of disciples main
tained it was purely conceptual although founded on something
real ; Scotus and the Scotists maintained it was a formal actual
distinction based on something real. The consequences of this
dispute in Ontology were logically accepted by the respective
Schools in Cosmology. All the opponents (23) of a real distinction
between the essence and the existence of a concrete being held
that primordial matter had of itself an existence of its own
distinct from the existence of substantial form : for Scotus, this
existence of primordial matter is independent of the existence of
substantial form ; for Suarez, this existence of primordial matter
is so dependent on the existence of substantial form that it cannot
be realised naturally without this latter. On the other hand,
Thomists (24) deny a distinct existence of its own to primordial
matter. Unity of existence is necessary, they urge, to unity of
being. Had primordial matter a partial distinct existence of its
own, this existence should be conceived as potency both in
regard to the form and in regard to the partial existence of that
form : existence, however, is the ultimate actuality, and accord
ingly cannot be thought of as a potency ; therefore, primordial
matter must owe its existence to the existence of the substantial
form. The Thomist view, then, is that a single actuality of ex
istence actuates primordial matter and substantial form. The sub
stance which results from the union of matter and form involves
a double relationship : one of matter and form ; another of this
composite and the actuality of contingent existence ; the con
tingent existence of any substance is neither its form nor its

9

130 COSMOLOGY

matter but a distinct actuality that accrues to the substance
by means of the form. Distinct realities can concur in a single
actuality of existence only when their nature is such that one
cannot be realised apart from the other. Primordial matter is
irrealisable without form because it is of too indeterminate a
nature to exist by itself : it could not exist without some specific
degree of being — unless it would exist simultaneously as being
and non-being. Moreover, a substantial form that is intrinsi
cally dependent on primordial matter cannot exist without this
latter. Existence is the actualisation of a specific essence : and
a specific essence is the result of the union of matter and form.
This union is, consequently, a presupposition of the actuality of
existence. Hence the Thomist concludes that existence belongs
strictly neither to matter nor to form : it is a third reality distinct
from these constituent principles of substance: a third reality
which results from an extrinsic cause. " Existence," writes
St. Thomas,(25) " is the proper actuality not of matter, but of
the whole substance : for that actuality belongs to that of which
we can predicate existence ; existence, however, is not predicated
of matter but of the whole. Hence matter cannot be said to
be that which exists : it is the substance itself which exists."
As we have already noted, Suarez is much nearer Thomism here
than is Scotus. " Scotus, Henry and Gregory seem to deny
that this existence of matter depends in any way on the form
and its union with matter: but the contrary view/' continues
Suarez,(26) "is generally admitted because although matter has
a proper existence of its own, yet it is so imperfect that it cannot
naturally exist without the help of the form : and this is what is
styled the dependence of matter on form." And of course, the
Thomists, admitting as they did the distinctive reality of pri
mordial matter even when united with the substantial form,
did not deny that, in one sense, the actuality of existence which
fell on primordial matter after union was distinct from the act
uality of existence which fell on the substantial form.

With this controversy, we may link up the problem whether
God could preserve primordial matter in existence without sub
stantial form. St. Thomas and the Thomists held that the iso
lated existence of primordial matter was as great a contradiction
as a square circle, and consequently impossible of accomplish
ment even by God. " If unformed matter had been created
first, it would thereby have been in actuality. Creation implies
this, for the term of creation is being in actuality. But that which
is actuality is the form : therefore, to hold that matter had a
previous existence apart from form is tantamount to holding
that actual being exists without actuality — and this is contra
dictory." " God cannot secure that a reality should simultane
ously be and not be, nor anything else that involves contradiction.
The existence of primordial matter apart from substantial form
would be a contradiction, because everything that is in actuality
is either an actuality itself and a potency that shares in some

ACCIDENTS IN PKIMOKDIAL MATTER 131

actuality. . To be an actuality is, however, contrary to the nature
of primordial matter for its proper nature is potential being.
Therefore primordial matter cannot be in actuality except in
so far as it shares in some actuality. The actuality in which it
shares, is, however, none other than the form. To affirm, then,
that matter is in actuality is really to say that it has some form.
That is why to speak of matter as in actuality apart from a form
is to affirm'that contradictories can co-exist. (Therefore, this can
not be done by God.") (27) Scotus, Suarez and their followers took
a different view of this possibility : Scotus held that primordial
matter apart from substantial form can be kept in existence by
God ; and Suarez agreed with him to the extent of affirming that
it is impossible to prove the contrary.!28) Their contention is that
primordial matter has sufficient reality of its own to be kept hi ex
istence by Omnipotence. The solution depends on man's grasp of
what is possible and what is impossible : a grasp that dwindles
away almost to nothing in difficult problems. And even those who
are thoroughly convinced of the logical strength of the Thomist
view will recognise the source of Soto's diffidence here. " It is
probable," writes this able Thomist,(29) " that God can keep matter
in existence apart from form. And in saying this, I trust I am
not forgetting the respect due to the grave authority of St. Thomas :
first, because the point at issue is of little importance ; secondly,
because I have no intention of denying that his solution best
accords with the principles of Aristotle and. can be strongly
defended. It is possible, also, that I am mistaken. There is
one argument, however, that appeals particularly to me : my
intellect cannot but hold that, since primordial matter and sub
stantial form are distinct realities and since neither of them is a
part of the other, God can keep in existence one of them apart
from the other, for we must not deny God's power except there
be irrefragable proof of contradiction : and certainly, no such
proof is forthcoming in this present controversy."

THE POSSIBILITY OF ACCIDENTS IN PRIMORDIAL MATTER.

The vast majority of the Schoolmen (30) held, with St. Thomas
and Scotus, that all the accidents of the elements are destroyed
when these elements are corrupted in the generation of an inani
mate true mixture, and that all the accidents which are present
in that true mixture when it is generated have been produced
anew. " Accidents (31) do not pass from subject to subject, in
the sense that the same numerical accident which existed pre
viously in one subject can be found afterwards in another : for
the accident owes its numerical identity to the subject." " When
this fire is made out of this air, specifically the same heat remains
but in greater intensity : still, numerically the same heat does
not remain because the same subject does not remain. . . . (The
same numerical heat) is incidentally destroyed by the corruption
of its subject." "It is impossible that accidental dispositions

9 *

132 COSMOLOGY

of any kind should pre-exist in matter prior to the substantial
form." Elsewhere St. Thomas declares explicitly that corporeity,
in a text where this word means the accident of quantity, " falls
away into nothingness when the human body rots." " It must
be held that no accident retains its numerical identity in a newly
generated body but that any previously existing accident perishes
owing to the corruption of its own subject at the moment when the
substantial form disappears ; and that a similar accident is born
in its stead as a result of the generation of a new substantial form."
The basis of this view was the Aristotelian doctrine of the nature
of the accident. Substances, and they alone, are self -subsisting
realities ; accidents are not self-subsisting and can exist ordinarily
only by inhering in some kind of self-subsisting reality. " Forms (32)
and accidents and all such realities are not said to be beings
in the sense they can exist alone but in the sense that by reason
of their presence something exists : whiteness is said, for instance,
to be a being because its presence makes a subject white. Hence,
according to the philosopher, accident may be said more strictly
to belong to, than to be, being. That is why accidents and forms
and realities which are not self-subsisting, are rather co-existences
than beings." " The nature of accident is imperfect because it
implies inherence in, dependence on, a subject and consequently
implies union with that subject." " In strict language, that which
is in potency to substance is called primordial matter, that which
is in potency to accident is called a subject. The reason is that
the subject gives being, i.e. existence to the accident — the accident
receiving being only through its subject : hence accidents are
said to be in their subject whereas the substantial form is not
said to be in its subject. This is also the difference between the
subject and the primordial matter : the subject is a reality which
does not receive being by means of union with some reality other
than itself, it has being, complete being, of itself. ... In short,
substantial form gives being to primordial matter, but the acci
dent does not give being to its subject : it is the subject which
gives being to the accident." Moreover, Aristotle (33) in several
texts seems to assert that change of substance involves the dis
appearance of every reality except primordial matter. And,
therefore, when some thinkers proposed the contrary doctrine
most of the Schoolmen rejected it. Primordial matter, these
Schoolmen argued, is of itself neither adapted as a potency for
the immediate reception of accidents nor capable as a substrate
of ultimately upholding them. " No accidental disposition can
intervene between . . . any substantial form and its matter.
The reason is that matter is in potency to various actualities
according to a definite order : hence that which is absolutely
first in the order of these actualities must be admitted to be the
first actuality of matter. But the first of all actualities is being.
Therefore, matter cannot be thought of as warm or quantified
before it is actual being. Actual being comes, however, from the
substantial form, for that form causes being absolutely. . . .

ACCIDENTS IN PKIMOEDIAL MATTER 133

Therefore no accidental disposition of any kind can pre-exist in
matter prior to the substantial form." (34) Thomists supported
this argument by their thesis that primordial matter has no
independent existence of its own. A substrate that has not of
itself self-subsistence cannot ultimately support realities like
accidents which need to inhere in something else for the purpose
of subsistence. Finally, if accidents of any kind exist in and are
proper to primordial matter, they must somehow emanate from
this latter : a consequence that would be incompatible with the
generally received doctrine of the passive nature of primordial
matter. For these and cognate reasons, St. Thomas and Scotus
taught that all material accidents really and physically inhere in
the inanimate composite substance and receive from it their
actuation. The student must not be led astray by the fact
that Thomist and Scotist speak betimes of certain accidents as
flowing from primordial matter and of others as flowing from
substantial form : thus quantity and certain passive qualities
are said to flow from primordial matter, while active qualities
are said to flow from the substantial form. This language is
based on the affinity in nature between certain accidents and one
or other of the ultimate constituents : all it means is that the
presence of such and such an ultimate constituent is the basis of
such and such accidents in the composite : it never means that
either primordial matter or substantial form is a sufficient sub
strate for any material accident.

This unity of view regarding the destruction of all the accidents
of the four elements at the moment of the generation of a true
mixture was rendered more emphatic by a startling variety of
opinions as to the exact nature of the newly produced accidents.
The first difference of opinion arose between Scotus and St.
Thomas. St. Thomas (35) held that the accidents of the four
elements remain virtually in the true mixture ; and he declares
this virtual permanence of these accidents is secured by the origin
of qualities that are specifically the same as those of the destroyed
accidents. Scotus also held the virtual permanence of the acci
dents of the elements in the true mixture : but he denies that
this virtual permanence is explicable by the origin of qualities
that are specifically the same as those of the destroyed accidents.
" The elements do not persist as substances in the true mixture :
nor ought one to say that they remain by reason of their qualities
— extreme qualities do not exist in a mean quality. Therefore,
elements remain in the true mixture somewhat after the fashion
in which sentiency and life remain in the rational soul." (36)
In short, Scotus holds that the virtual permanence of the elements
in a true mixture is to be explained by that fact that the sub
stantial form of this mixture contains in a more perfect way all
the perfections of the substantial forms of the elements. The
reply of the Thomists is to deny the parity : the rational form is
superior to the animal and vegetable forms ; moreover, the
characteristic activity of the elements is far less perfect when in

134 COSMOLOGY

the true mixture than when the elements exist alone. But the
Thomistic School,!37) while accepting St. Thomas's view that
the virtual presence of the elements in the true mixture is explic
able by the accidental qualities of the latter, never succeeded in
reaching unity of opinion on the details of this virtual presence.
Many held that the four qualities of the elements are replaced
in the mixture by a single quality : a mean quality that bears the
same relation to the nature of the extreme qualities of the elements
as pale does to black and white. This mean quality is the proper
quality of the mixture : it varies however in different mixtures
owing to the different proportions in them of the elements.
Some of these Thomists spoke of that mean quality as actually
simple : it is not really made up of the different qualities of the
elements — it is not partially hot and partially cold and so on,
but it contains virtually all the qualities of the elements ; and
it differs from the qualities of the elements, not merely in intensity,
but in kind — just as redness differs from whiteness and blackness.
Other Thomists spoke of that mean quality as really composite
— it has in it something of heat and something of cold and so on ;
and when one of these contraries within it grows more intense,
the other grows less intense. Another group of Thomists held
that the four qualities of the elements were represented in the
mixture by two simple qualities : one a mean between the hot
and the cold ; the other a mean between the dry and wet. A
fourth group held that the elements were represented in the
mixture by all four qualities formally : but while maintaining the
specific likeness between the qualities of the elements and of the
mixture, they denied, as loyal Thomists, the numerical identity
of these qualities.

Gregory, Auriol, Marsilius, Aegidius, Suarez, Toletus and many
of the later Jesuit Schoolmen opposed this teaching of the Thom
ists and Scotists regarding the destruction of all accidents in
changes of substance.!38) These illustrious dissenters held that
certain accidents may persist unchanged during processes of sub
stantial generation and corruption : for instance, the accident of
quantity and other accidents that are not specially connected
with the outgoing substantial form and are necessary dispositions
for the incoming substantial form. And when challenged for a
sufficient substrate for these persisting accidents, they retorted
that primordial matter had sufficient essential and existential
actuality of its own to act as their subject of inhesion. Suarez
is the best exponent of this theory of the possibility of accidents
in primordial matter. He allows that the Thomistic and Scotistic
view is probable, but, in view of the objections that can be raised
against that view, he puts forward the opposing view as more
probable. These objections are four : certain facts of experience
suggest the persistence after substantial change of some previously
existent accidents : the need of a corporeal and extended patient
at the instant of substantial change : the need of distinctive
proximate dispositions for each incoming substantial form ; the

ACCIDENTS IN PRIMORDIAL MATTEE 135

danger of materialising the human soul. None of these objec
tions are concretely illustrated in regard to non-living substances ;
a consequence of the medieval state of physics and of chemistry.
Medievalists held that all non-living bodies were mixtures, either
apparent or true, of the four elements, but they had no detailed
knowledge of the structure of non-living true mixtures or of the
stages of their formation : accordingly, they transferred the battle
ground of this and similar disputes to the realm of biology — a
science in which Aristotle's writings were more detailed.

The facts that gave rise to the first Suarezian objection were
drawn from the likeness between the body when alive and shortly
after death : a corpse preserves for some time its heat, its flexi
bility, its colour ; and preserves even longer its quantity, its
shape, its scars. Thomists (39) reply that the testimony of the
senses cannot be accepted regarding numerical identity when
set aside by the evidence of reason : no medievalist taught the
numerical identity of motion in moving and moved bodies after
collision, and yet the senses seem to testify to the passage of the
motion from the one body to the other. They also reminded
their opponents of the accepted distinction regarding validity
in the Aristotelian theory of sense-perception : the senses are
infallible in reference to their respective proper sensibles, fallible
in reference to all the common sensibles. Now the numerical
identity of an accident at different times is one of the common
sensibles. Were God to destroy at any moment the whiteness of
a wall and instantaneously to put in its stead an exactly similar
whiteness, no human eye would be aware of the change in numerical
identity of this accident. Even the ordinary thimble-rigger can
lead the senses of the onlookers astray on this question of numeri
cal identity ! How, then, can man be assured of the numerical
identity of any part of his environment ? Not by his senses alone,
but by reasoning which supposes, on valid grounds, the uniformity
of the divine ordinances in nature and, also, the trustworthiness
in their respective spheres of sense and of intellect. Further,
when challenged for an efficient cause of these disputed accidents,
the Thomists appealed to the extrinsic death-dealing agent :
the activity of this extrinsic cause on the living body produces
the corpse-form and, with this, by way of natural resultance all
the accidents of the dead body. The specific likeness of the
accidents before and after death was said to be due to a certain
affinity between the substantial forms of the body when alive
and when shortly dead. Accidents that seem anomalous, either
in reference to the corpse-form or to the extrinsic death-dealing
agent, were said to be due to the union of the corpse-form with a
primordial matter that has been deprived — sometimes suddenly,
in all cases quite recently — of its living form : and it was added
that the corpse-form, like the embryo-form, takes time to develop
all its powers in its substrate.

Suarez's second objection is based on reasoning. A bodily
agent can act only on an extended, corporeal patient : it is not

136 COSMOLOGY

enough, then, that the patient be quantified during the whole
process of alteration ; it is necessary that this quantification
should exist at the actual instant of the generation of a new
substance because a new action, proceeding from a bodily agent
begins at that instant, namely, the production of the substantial
form. His opponents reply that primordial matter is the immed
iate but not the sufficient basis of generation : it must be previ
ously prepared by suitable dispositions for the incoming substantial
form ; and this preparation is wrought by some natural agent.
" In order that any generation may be called natural, it must
be produced by a natural agent and out of natural matter that
is thereto appropriate : should either of these be wanting, the
generation cannot be called natural." (40) Their point is that
primordial matter never exists by itself for a single instant during
the whole process of substantial change : the outgoing substantial
form remains with the varying accidents until the incoming
substantial form with appropriate accidents takes its place.
It is possible to hold, then, that in generation the patient must
be corporeal and extended and yet to deny that quantity or any
analogous accident persists numerically unchanged during this
process. The generating cause by acting on the patient gradually
alters the qualities of this patient in such a way as to dispose
its primordial matter for a new substantial form : a stage is
reached in this gradual alteration when these qualities are so
changed as to be no longer fit properties for the elementary sub
stantial forms ; and as soon as that incompatibility is effected, the
substantial form of the elements and their qualities disappear
out of existence and, simultaneously, the substantial form of the
true mixture is born bringing in its train those quantitative and
qualitative accidents which make up the properties of the newly
produced substance.

Suarez's third objection touches the most difficult point of
the whole controversy : the doctrine of his opponents that, when
the generating agency actually produces the new substantial form
of the mixture, none of the previous dispositions which brought
about the corruption of the four elements are present in that
primordial matter into which as substrate this substantial form
is received. To appreciate the strength of this objection the
whole process of substantial change must be recalled. That
process begins when circumstances of one kind or another bring
together the four elements in certain proportions. Thereupon
alteration sets in : due to the interaction of the four elements
on one another as influenced, of course, by their environment.
During the interval that precedes the eduction of the new
substantial form, this alteration produces changes in the active
and passive qualities of the elements which are more and more
abnormal and, therefore, more and more provocative of the dis
appearance of the elementary substantial forms. Uncongenial
and incompatible qualities of this kind that are produced prior to
the instant of generation are called previous dispositions : there can

ACCIDENTS IN PRIMORDIAL MATTER 137

be no controversy about such dispositive accidents for they exist
in and are supported by their respective elements. A moment
comes, however, when the resulting incompatibility between
these accidents and the existing substantial forms is so pronounced
that they and the forms can no longer co-exist in the same sub
stance. The problem is — what happens at this moment ? St.
Thomas and most of the Schoolmen hold that at this moment, the
instant of generation, the substantial forms and all the accidental
forms of the elements cease to exist. Suarez and his supporters
allow that at this moment, the instant of generation, the sub
stantial forms of the elements cease to exist, but urge that certain
dispositive accidents persist in the primordial matter : they
demand this persistence of these dispositive accidents on the
grounds that otherwise primordial matter would not be disposed
for the reception of this rather than that substantial form ; and
they explain the possibility of their persistence on the ground
that primordial matter may be a sufficient substrate for certain
accidents. The gist of the Thomist reply is that primordial
matter is prepared at the instant of generation for the reception
of this rather than that substantial form by certain accidents
that are technically termed " ultimate dispositions." These
ultimate dispositions do not exist in the four elements ; neither
do they exist in the primordial matter of these elements prior
to the advent of the substantial form of the mixture ; they are
introduced into this primordial matter at the instant of generation
concomitantly with the incoming substantial form ; in fact, they
follow by way of resultance from that new substantial form.
Suarezians naturally object that qualities which follow from and
after a substantial form cannot prepare a substrate for the recep
tion of this form. Thomists insist that whether accidents inhere
in primordial matter or in the complete substance, these ultimate
dispositions can never exist simultaneously with the elementary
forms for the simple reason that, being specifically incompatible
with these forms, they expel them : " the substantial form of
water is expelled by heat of the highest kind " (41) — the specific
heat of fire. They insist, also, that these ultimate dispositions
are, even in the Suarezian theory, introduced into the primordial
matter by the incoming substantial form : " heat of the highest
kind is introduced simultaneously with the form of fire." (42)
In every theory, then, the ultimate dispositions exist only with
the substantial form of the mixture. But the difficulty of St.
Thomas and his supporters is to explain how such ultimate
dispositions can be said to prepare primordial matter for the
reception of a particular form. St. Thomas's explanation is
that these ultimate dispositions precede materially the incoming
form. The ultimate disposition is the effect of the incoming
substantial form from the point of view of formal causality, and
yet it precedes this latter form from the point of view of material
causality. " The like happens in natural bodies with reference
to that disposition which is necessary for a form : that disposition

138 COSMOLOGY

in one sense precedes (substantial) form, namely from the point
of view of material causality, for material dispositions refer to
matter : but in another sense, namely from the point of view
of formal causality, the substantial form comes first for it perfects
both primordial matter and the material accidents." . . . "Another
kind of disposition prepares something for its form : for instance,
it prepares primordial matter for the reception of its form in
such a way that it pre-exists in matter before the form does, not
in the order of existence but in the order of production : heat, for
example, acts as a disposition for the form of fire, not because
it intervenes as intermediary between substantial form and
primordial matter but because primordial matter becomes
possessed of the form of fire by means of the advent of heat." (4S)
St. Thomas adds that these ultimate dispositions exercise no
efficient causality on the form. " This disposition does nothing
for the form efficiently : its action is purely material and consists
in the fact that primordial matter is by means of this disposition
rendered fit for the reception of the form. . . . More dispositions
are necessary for the removal of contrary forms and the intro
duction of a form than for the mere introduction of a form." (44)
All this is explicit, but, when later controversies arose, the diffi
culty of those who endorsed St. Thomas's view lay in pointing
out the linkage between the accidents of the four elements that
perish at the instant of generation and the accidents of the true
mixture that at the same instant take their place. The general
answer was that the accidents of the true mixture are the term
and the consummation of all preceding accidents : whatever be
the generating agency at work, the ultimate dispositions are in
the circumstances the necessary sequel of all the previous dis
positions, " heat of the eighth degree (the property of fire) is of
the same nature and species as that heat of the sixth or seventh
degree which, prior to the instant of generation, disposes wood
for the substantial form of fire, and in this way the ultimate
disposition is the term and consummation of the (antecedently
dispositive) heat." (45) It was usual, also, to look on the ultimate
dispositions as forming with all previous dispositions a single
dispositive material cause on the plea that the same instant
which marked the death of the latter set of dispositions marked
the birth of the former set : " just as a thing may be said to be
produced at that instant in which it exists for first time for the
reason that this particular instant, which is the term of the time
occupied in producing the thing, gathers up into itself whatever
was accomplished during the preceding moments." (46)

The final objection of Suarez is based upon the hylemorphic
theory of man. He asks how can a spiritual soul be informed by
quantity ; and concluding that this is impossible, he lays down
that, at least in man, primordial matter must be the subject of
quantity and of analogous material accidents. But if this must
happen with regard to man, he urges that it may happen in all

ACCIDENTS IN PRIMOKDIAL MATTER 139

other substances. The Thomists retort that the human soul
is the subject neither of inhesion nor of receptivity in regard to
material accidents : that its function is to actuate primordial
matter and thereby constitute a complete human being ; and
that there is little difficulty in explaining how a spiritual soul
can be one of the two constituent principles of a substance that
has corporeal accidents. Their argument is that quantity,
being an accident, lies outside the essence of every kind of body :
it emerges simply as a necessary concomitant of corporeal sub
stance — inherent in but extraneous to, and logically subsequent
to, the formation of this latter. And they insisted that a higher
substantial form can accomplish by virtue of its greater perfection
everything which can be done by a lower substantial form :
hence, the human soul can give being and corporeity and life and
sentiency as well as reason ; but whereas reason inheres in the
soul alone, all those other powers inhere in the composite of soul
and body and owe their origin not to the fact that the soul is
spiritual but to the fact the soul is the substantial form of man, a
corporeal being. No substantial form has, of itself, quantity :
but if the lower substantial forms can introduce this and other
material accidents into the composite which they form by uniting
with primordial matter, why should not the highest kind of sub
stantial form in terrestrial beings be able to do at least as much ?
" A more perfect form virtually contains whatever is proper to
inferior forms : that is why it, although remaining one and the
same, endows matter with different degrees of perfection. Thus
it is essentially one and the same form by which a man is actual
being ; by which he is body, by which he is living, by which he
is animal, and by which he is man. Now it is plain that the
appropriate accidents accompany each grade of being. And as
matter is thought of as perfected in being before being thought
of as perfected in corporeity — and so on for the other degrees
of perfection — similarly, the accidents appropriate to being are
thought of as present prior to those appropriate to corporeity." (47)
" One form, for instance, constitutes matter merely as a body.
. . . But another more perfect form constitutes matter not merely
as a body but also as a living being. Again, another form gives,
in addition to corporeity and life, sentient being ; and so on.
. . . Now matter when regarded as substantially complete in
being according to the standards of any inferior grade, can, in
consequence, be regarded as subject to accidents. For substance
of that lower grade of perfect must necessarily have accidents
proper to itself and necessarily inhering in it. ... Hence it is
that since the human soul is a substantial form and constitutes
man in a definite species of substance no other form intervenes
between this soul and primordial matter : man is completed by
the rational soul and by it alone in his various degrees of perfec
tion, to wit, body, living being, rational animal." (4S) " In so
far as the human soul surpasses the perfection of corporeal matter

140 COSMOLOGY

and is capable of subsisting alone and of energising alone, it
is a spiritual substance ; but in so far as it is brought into contact
with, and communicates being to matter, it is the form of the
body." (49) " A second opinion lays down that there can be
only one substantial form in each individual ; and in accordance
with this, it follows that each individual owes to that substantial
form which is human the possession not merely of reason but
also of sentiency, life, corporeity, substance and being. Hence
no other substantial form precedes in such a man his human soul
and, consequently, no accidental form precedes : for in this last
hypothesis, one would have to admit that matter was perfected
by an accidental form prior to the substantial form : a view
utterly inadmissible since every kind of accidental reality must
be based on a substance." (50) " No accident can survive the
destruction of its subject. Hence when the composite (human
substance) is corrupted, these powers (of sentiency and nutrition)
do not remain actually : they remain only virtually in the soul
as in their principle or root." (51) " Those faculties are said
to remain in the disembodied soul as in their root : not that they
are actually in it but that the separated soul has the power, if
it be united (again) with the body of causing these faculties in
that body just as (it would again cause) life." (52)

On the totally different question as to whether one accident
can naturally be the ultimate subject of inhesion for another
accident, St. Thomas and Scotus and Suarez were of one mind :
one accident cannot be the ultimate subject of inhesion for another.
Thomist and Scotist and Suarezian allowed, however, that one
accident may sometimes be prior to another in its reception into
its ultimate substrate. (53) They appealed confidently to facts
of experience : heat is received into a body through its surface ;
colour, rarity, density and figure are quantitatively diffused
through bodies. They appealed, also, to the state of existence
of the sensible qualities of consecrated bread and wine : the
substances have disappeared, yet these sensible qualities per
sist ; unless one insists, then, on the multiplication of miracles,
the natural conclusion is that these qualities are sustained by
the quantity. " It must be held to be necessary," writes
St. Thomas ,(54) " that the other accidents which remain in this
Sacrament, should subsist as in a subject in the dimensive quan
tity which remains of the bread or of the wine." Scotists and
Suarezians interpreted this teaching about the priority of quan
tity as implying that quantity received into itself these other
accidents, terminating, thereby, proximately their inherence and
their subsistence : in short, that quantity was a proximate
subject of these other accidents. The Thomists refused to admit
that quantity was a proximate subject of this kind : they held
quantity to be a necessary link by which these other accidents
inhere in and are sustained by their connatural substance ; in
short, these other accidents are not truly inherent in or truly
sustained by quantity.

THE NATURE OF SUBSTANTIAL FORM 141

THE NATURE or SUBSTANTIAL FORM.

Aristotle had sufficiently unfolded the nature of substantial
form as the first actuality of primordial matter which, by union
with the latter, forms a complete essence. The Schoolmen had
nothing to add to this portion of his doctrine : and we shall find
them emphasising that role of the form again and again in this
and the next chapter. In consequence of that r61e, they spoke
of primordial matter and of substantial form as, each of them,
an incomplete substance : an expression which is to be under
stood, Cajetan says, only reductive.^}

But, for reasons peculiar to their age, they were more explicit
than Aristotle on the distinction between the substantial form
and accidental active principles. Centuries before Aristotelianism
had become the dominant philosophy of the Church, theologians
had developed a theory about the appearances of consecrated
bread and wine which implied that body as substance was not an
object of sense-perception. In those days, every theologian was
a philosopher and every philosopher a theologian. The result
was that the Schoolmen, denying on theological grounds the
perception of material substance, denied also the perception of
substantial form, one of the constituents of substance. As
philosophers, however, they brought forward two arguments dis
tinct from that based on the current theology of the Eucharist :
one of these was due to St. Thomas, the other was due to Suarez.(56)
St. Thomas's argument is based on the intimate relation between
any potency and its appropriate actuality : diverse actualities
necessarily presuppose a diversity of proximate potencies. Now,
the actions of an inanimate substance and the existence of that
substance are totally different facts : its actions are many and
fleeting, its existence unique and relatively permanent. Anyone
of the four elements has a variety of actions but it has only one
existence : further, that existence continues even when this
element is not exercising one or other of its activities. It is one
thing for fire to cause heat, it is another and quite a distinct
thing for fire to exist : but to cause heat is the actualisation of
the heating power of fire, and to exist is the actualisation of the
essence of fire ; consequently, the heating power and the essence
are different realities. And what is true of the heating power
is true of every other active principle in fire or in any other
non-living substance. In inanimate substances, no principle of
activity is identical with the essence. Substantial form is, how
ever, part of the essence. Therefore, the active powers of non
living substances cannot be identical with the substantial form.
Substantial form is indeed the root of these active powers : but
it is not identical with these immediate principles of activity ;
it is their hidden source. Suarez reaches the same con
clusion by a different route. His starting-point is that
each non-living substance has a distinctive set of specific
properties : a stable group of qualities which are quantitatively

142 COSMOLOGY

definite and are inseparably connected with this species of body,
and, thus, easily distinguishable from those other transient
qualities that continually come and go without changing the
body's specific nature. Inseparable qualities of this kind, common
to all members of the species and never present in this definite
quantity as a group in members of other species are called —
in the strict sense — properties. There must be some unifying
principle to account for this unitary grouping of specific qualities
in individual substances. No such principle of unity is discover
able in the properties themselves : as a matter of fact, each of
these qualities is present, in different amount and with different
companions, in bodies of other species. Primordial matter, being
itself a passive potency, could not exercise the task of unifying
this group of active properties. Therefore, substantial form must
be the inner bond of association among themselves of the specific
properties. It is, then, a principle distinct from and more funda
mental than the properties of bodies. These latter are percept
ible : it is not. On these grounds, then, the medieval theory
of the imperceptibility of substantial form was based. The
existing individual — in the non-living world — is the agent that
acts : action is a development of existence and cannot be realised
apart from existence. But only a complete essence is capable
of complete existence, and in that essence while substantial form
is the mediate and remote principle of activity, the properties
which are accidental forms are the immediate and proximate
principles of specific activity. Substantial form is a remote,
regulative principle which determines the specific nature and
extent of any body's activity.

THE UNICITY OF SUBSTANTIAL FORM IN NON-LIVING BODIES.

Difference of opinion concerning the inner structure of inani
mate true mixtures led to a controversy as to the unicity or
plurality of substantial form in inanimate bodies. Aristotle had
taught that inanimate bodies were a blend in varying proportions
of the four elements. But he seems never to have reached a
definite conclusion on the permanence or non-permanence of
the substantial forms of the elements in these composites. His
text when treating directly this problem favours the theory of
their non-permanence : other texts of his favour the theory of
their permanence. (57) Accordingly, the medievalists in interpreting
these texts took different sides : some defending the permanence
of the substantial forms of the elements in true mixtures, others
defending the contrary view. Avicenna, Averroes and Albertus
Magnus defended the theory of permanence.!58) Avicenna held
that the substantial form persists in its full perfection. Averroes
held that it persists in a weakly state : his presupposition is that
the substantial forms of the four elements are, on account of
their imperfection, middle terms between accidental forms and
all other substantial forms, and that they can exist, therefore,

UNICITY OF FORM IN NON-LIVING BODIES 143

in a state of greater or less intensity somewhat like the accidental
forms. Albertus Magnus attempted a further compromise.
His starting-point is a peculiar distinction in non-living bodies
between apparent mixture and true mixture and generation or
corruption of substance ; an apparent mixture has not homo
geneous parts ; a true mixture has homogeneous parts but does
involve as complete a change of substance in its components as
does either generation or corruption ; generation or corruption
imply a complete change of substance. A true mixture is a new
homogeneous substance arising out of the alteration of the four
elements : it is neither fire, nor earth, nor air, nor water but a
distinct substance with a corresponding substantial form ; more
over, it is a distinct substance which is through and through
homogeneous ; still, it is a distinct substance that holds within
itself both the essence and the properties of the four elements.
As regards the fate of the substantial forms of the elements in
such a mixture, Albertus holds these are neither wholly preserved
nor wholly destroyed : not wholly preserved, because the same
primordial matter cannot be simultaneously actuated by more
than one substantial form ; not wholly destroyed, because this
kind of mixture certainly possesses the properties of the four
elements. In defence of this view, Albertus distinguishes two
kinds of substantial form in the elements : a primary substantial
form which gives substantial being ; a secondary substantial
form which gives existence and activity. When the elements
unite in a true mixture, this secondary form disappears but the
primary persists : and as these primary substantial forms are of
themselves incomplete, they not only do not exclude but actually
need a new substantial form in the true mixture. This Albertine
theory was accepted by a few Schoolmen. (59) It was acquiesced
in for a time by his pupil, St. Thomas. St. Thomas changed his
mind later on and initiated, in the teeth of grave opposition, the
theory of unicity of substantial form in all substances including
inanimate true mixtures. (60)

The fundamental basis of St. Thomas's theory of unicity is
that a mixture in which the substantial forms of the elements
persist can not be said to be true : " if (61) a mixture is found
in which the elementary substantial forms persist, it cannot be
true, it must be apparent and due merely to the juxtaposition of
imperceptibly small particles " ; " moreover what seems a (true)
mixture to one whose eyes do not enable him to distinguish these
parts is known by one with keener eyes not to be a true mixture " ;
" the different portions of matter as long as substantial forms of
the elements remain, are really so many distinct bodies." St.
Thomas's next point is that the suggestion of increase or decrease
in the reality of substantial form is absurd : as the specific
substantiality of any body is indivisible, addition or subtraction
would involve a change of species just as in numbers ; a hybrid
form — partly substantial and partly accidental — is impossible
because the substantial form is presupposed by the composite

144 COSMOLOGY

and the accidental form presupposes the composite. He con
cludes, then, that a new solution must be sought : "we must
discover some other solution by means of which the meaning of
the true mixture is kept intact, and at the same time the obvious
fact, that elements are not completely destroyed but are some
how preserved in the true mixture, is acknowledged." (62) This
new way of thinking is set forth in detail in the Opuscule, De
Mixtione Elementorum. " A mutual contrariety and difference
of intensity exist between the active and passive qualities : out
of differences of this nature between qualities, a medium quality
which shares the nature of its extremes can be formed, for instance,
pale is a mean between black and white, tepid between hot and
cold ; and in this way the elementary qualities when toned down
(by interaction), form a mean quality which is characteristic of
the true mixture as such ; this mean quality is different in dif
ferent mixtures owing to the different proportions in each mixture
of the elements." And as a result of the necessary connexion
between the substantial form and the specific properties of any
substance, this abnormal change of the specific properties of the
elements involves the disappearance of their respective substantial
forms : "a body cannot lose its qualities unless it itself be de
stroyed ; heat can be taken from fire, for instance, only by the
corruption of fire," " this (mean) quality is the disposition for
the substantial form of the true mixture just as the elementary
quality is that of the elementary form." Moreover, as long as
the true mixture exists its " contrary qualities are controlled
and are preserved from the work of mutual destruction by its
substantial form." If this equilibrium is sufficiently upset by
an external cause, then, the true mixture breaks down once more
into the four elements : each of the four reappearing with its
proper qualities. The principal cause of this breakdown is the
substantial form of the mixture acting through the mean quality :
" in true mixtures there exists an active principle of corruption
owing to the fact that it is built up out of contraries." This
destructive activity of the substantial form is conditioned, of
course, by the environment, immediate and remote : "if this
(the activity of the heavenly bodies) were to cease, the activity
of all terrestrial bodies would cease." (63) St. Thomas concludes,
then, that the substantial forms of the elements do not persist
actually in true mixtures : "we must hold with the Philosopher
that the forms of the elements remain in the composite, not
actually, but virtually." (64) This virtual presence means merely
that the qualities of the elements recur in the mixture tempered
by their previous mutual reaction and actuated by the new
substantial form, that of the mixture : " for the qualities proper
to the elements persist and they contain the efficacy of the elemen
tary forms : and this (mean) quality of the mixture is the proper
disposition for the substantial form of the mixture, for the form,
v.g. of a stone or a living body." " Whenever a true mixture is
formed from constituents that differ in quality either because

SIMPLICITY OF FOBMS OF NON-LIVING BODIES 145

their qualities are contrary or because their qualities, though
the same, are of different degrees of purity, then, once the mixture
is complete, neither constituent is therein with its own proper
quality : for if it were, the result would simply be a collection
of unchanged substances, in short only an apparent mixture :
hence the whole must receive a single form which is a mean." (65)
These extracts contain an outline both of St. Thomas's criticism
of the opposing view and of his reasons for the unicity of form in
non-living bodies. He mentions as opponents Avicenna and
Averroes : he does not mention Albertus Magnus, but no doubt
can be entertained by an attentive reader as to St. Thomas's
attitude towards his master's theory. Subsequently, some of
the Schoolmen sided here with Albertus Magnus. But Henry
of Ghent, Scotus and Suarez sided with St. Thomas — in reference
to inanimate substances — and brought with them the over
whelming majority of the Schoolmen.!66)

THE SIMPLICITY OP THE SUBSTANTIAL FORMS OF NON-LIVING

BODIES.

The School attributed various kinds of simplicity to the sub
stantial form of non-living substances. Substantial form is
simple in the sense of being unanalysable ; as one of the ultimate
principles of substance, it cannot be broken up into anything
more fundamental. Substantial form is simple in the sense
that it confers on every part of a body the same essence : it
communicates the same specific essence to the whole and to each
part of the substance. " The whole substantial (67) form of
wood is in every part of it : because the totality of a substantial
form does not admit of quantitative totality, as is the case with
the totality of accidental forms which are founded on quantity
and presuppose it." Finally, substantial form is simple in the
sense of being of itself devoid of quantity : it is not of itself
extended in space. " It is (68) the composite which has diverse
parts. Hence diversity of parts does not belong to the matter
or the form but to the composite." But this third kind of
simplicity was affected by that complete immersion in matter
which is the fate of the substantial forms of non-living bodies.
The Schoolmen, having rejected the Democritean atom, were
committed to the theory that every sensibly unbroken body was
a single substance : a stone, a stick, a bar of iron, a block of
marble, a river, an ocean — whatever their respective sizes. Now,
if every sensibly continuous molar bulk was a single substance,
it was actualised by a single substantial form : at least in non
living bodies. Experience shows, however, that these larger
non-living substances are being frequently broken up into smaller
substances of the same species : for instance, sticks into splinters,
stones into fragments. This division is effected by mechanical
means : none of the processes of alteration occur prior to the
resulting divisions ; and these results themselves betray no sign

10

146 COSMOLOGY

of a change of substance. The Schoolmen drew from these
facts of experience the conclusion that the substantial form of
non-living substance was divided consequent on the division, up
to a certain limit, of that substance itself. And they termed this
divisibility of substantial form incidental in order to emphasise
their view, that this divisibility was alien to the nature of
form and arose solely out of its complete immersion in matter.
" Matter (69) and form have not parts of themselves, they have
parts merely incidentally : hence they are divided merely inciden
tally, that is, owing to the division of the whole." " When a
line is divided there is no new reality in the divided parts but
that same linear essence which was previously one in actuality
and multiple in potency is made by division multiple in actuality.
. . . Exactly the same thing occurs in stone and in fire and in
all non-living bodies that are generable and corruptible : for
that form, owing to which they have unity of nature side by side
with unity of quantity, is present in all its perfection in every
part of such substances. The result is that when these bodies
are split up the essence of the same form remains in the separated
parts : each part of the fire is (when separated) a fire, each part
of a stone is (when broken of?) a stone. . ." " This (divisible)
totality can be attributed to forms only incidentally inasmuch
as they are incidentally divided by a division of the quantity :
as, for instance, whiteness by division of the surface. But this
(incidental division and subjection to quantitative totality) is
found only in those forms that are coextended with matter :
and this coextension is due to the fact that such forms have similar
matter in the whole as in the parts."

THE ORIGIN OF SUBSTANTIAL FORM.

The Schoolmen held that in the beginning God created
certain material substances and, with these, their substantial
forms. But the subsequent perpetually recurring changes of
substance involve a production of a new substantial form for each
newly produced substance. The question arose, then : whence
come these newly produced substantial forms ? Aristotle (70)
illustrated this question by reference to the production of works
of art : the substantial form is developed in primordial matter
by the action of the generating cause in the same way as the
shape of a statue is developed in wood or marble by the activity
of the sculptor ; the only difference being, that this shape existed
previously merely in the mind of the sculptor while each newly
made substantial form is received by its substance from a pre
existing material substance. St. Augustine crystallised this
doctrine in the famous formula : form is educed from the potency
of matter. The great value of this formula to his mind was its
marking off of finite propagation from creation : creation, the
work of God, is the making of something out of nothing ; pro
pagation, the work of finite beings, is the making of something

THE ORIGIN OF SUBSTANTIAL FORM 147

out of the potency of a pre-existing substrate. Pithy formulae
lend themselves to various interpretations. In his own day,
St. Thomas (71) was confronted with three unsatisfactory
interpretations : that of Anaxagoras, involving the latent pre-
existence from eternity of all substantial forms ; that of Plato,
attributing the origin of such forms to the action of the Ideas ;
that of Avicenna, referring their origin to the activity of finite
spirits, the Intelligences. Anaxagoras got short shrift : his
theory would make substantial change an illusion, and would
postulate in the first created bodies countless multitudes of forms,
hidden as in a conjuror's box and awaiting there the appropriate
moment for their emergence. St. Thomas rejects also the sup
position on which the theories of Plato and Avicenna are based :
to wit, that material agents merely prepare primordial matter
for the reception of a form which is produced by an immaterial
being — the Idea or the Intelligence. " They (Platonists and
Avicenna) appear to have been led into this error because they
considered a form to be something produced in itself : so that it
must proceed from some formal principle. But — as the Phil
osopher proves in the seventh Book of the Metaphysics — that
which is, properly speaking, produced is the composite. For it
alone, strictly speaking, exists, inasmuch as it is subsistent.
But the form is not called being in the sense of that which exists
by itself, but in the sense of that by which something exists.
The consequence is that the form is not, strictly speaking, pro
duced : production pertains only to that which has a being of
its own because production is nothing else but a making of
being. Further, it is clear that the thing made bears a likeness
to its maker : because every agent produces an effect like to
itself. Wherefore, that which produces natural things bears a
likeness to the composite : either because it is itself a composite
as when fire generates fire; or because the whole composite,
both as regards matter and as regards form, is virtually contained
in the agent — which belongs to God alone. Therefore all infor
mation of matter is immediately due either to God or to some
bodily agent, and not immediately to Angels." (72) " These
theories (of Plato and Avicenna) deny that natural power which
exists in every natural principle of producing its like so far as
the substrate on which it acts is capable of receiving this like.
And this power follows from the fact every agent acts up to its
own actuality. Therefore whatever is actualised in a particular
way can after a fashion produce this actuality : accordingly,
every natural principle is intended to reproduce itself by its own
actuality." (73) In short, St. Thomas contends that two errors
underlay this doctrine of Plato and of Avicenna : by maximising
the nature of material substantial forms, they unfitted these
forms for their purpose of actualising material substances ; by
minimising the generative powers of material substances, they
denied the very purpose of the existence of such substances.
' The third opinion, that of Aristotle, is a mean between these

10*

148 COSMOLOGY

(the opinions of Anaxagoras, Plato and Avicenna) : according
to it, all forms are in potency in primordial matter — not, as is
said by the defenders of latent forms, actually ; and according
to it, the natural agent by reducing matter from potency to
actuality produces, not the form, but the composite. This
natural agent is in its activity a kind of instrument of that God
who both made matter and gave it its potency to form. There
fore, in this theory, there is no need to hold that the generating
cause creates the form or makes something out of nothing :
because he produces, not the form, but the composite." (74) And
to those objectors who stressed the point that substantial forms
were new realities and must, therefore, be created anew each
time, St. Thomas retorted that accidental forms were also new
realities and that the logical consequence of this line of argu
ment was Occasionalism. " If for these reasons, it be necessary
to resort to creation in order to account for the origin of sub
stantial forms, the same reasoning would be equally valid in the
case of accidental forms. For just as the substantial form per
fects a substance at the moment of origin, so the accidental form
adds a reality to the substance already made. Consequently a
natural agent would be in no sense a generating cause, neither
by perfecting nor by disposing, and this would involve the utter
denial of all natural activity. For when a thing is said to be
made out of nothing this means a denial of any material substrate :
but a material cause can never be absent from either substantial
or accidental generation." (75)

There were, however, other dissentients (76) besides Anaxa
goras, Plato and Avicenna. Soto attributes to Albertus Magnus
the view that all forms pre-exist in an undeveloped state in pri
mordial matter. This suggestion was set aside as multiplying
rather than solving the difficulties of eduction : substantial
forms differ from one another as do the cardinal numbers, and
consequently to speak of them as existing in an incomplete
stage is absurd ; moreover, even were this inchoateness thinkable,
the genuine difficulty of eduction recurs in explaining the progress
from rudimentary to finished substantial form. Durandus men
tions without names authors who tried to cut the Gordian knot
by inserting in primordial matter certain possibilities of substan
tial forms. Soto attributes to Auriolus the suggestion that the
form partly pre-exists in primordial matter and is subsequently
made perfect by the action of the generating cause, and, thus, is
not a production from nothingness. These suggestions won little
support. If the alleged possibilities imply merely the potency
of matter, that particular view differs merely in words from the
general teaching of the Schoolmen. But if this alleged possi
bility and this alleged partial pre-existence are really intended
to relieve the seeming mystery of eduction, they necessarily
imply the presence in primordial matter of some reality other
than itself. Now, every thinkable interpretation of that reality
is open to serious objection : that reality cannot be an accident,

THE OKIGIN OF SUBSTANTIAL FORM 149

for an accident is useless to explain the emergence of a substantial
form : that reality cannot be either a full-blown substance or
any of the two constituents of substance — not the coming com
posite for ex hypothesi it does not exist at this stage of the process,
not primordial matter, for ex hypothesi this reality is something
added to primordial matter, not the full substantial form for
ex hypothesi it is only in the making so far ; this reality must,
then, be nothing else than an inchoate stage of the substantial
form — a revival of the inadmissible view fathered on Albertus
Magnus. The uselessness of all these attempts to escape from
the mystery of eduction confirmed the majority of the Schoolmen
of the wisdom of subscribing boldly to the Augustinian formula
and of explaining definitely its meaning.

The eduction of substantial form out of the potency of the
primordial matter has a negative and a positive aspect.
Negatively considered, eduction implies that the form is
not so much an entity itself as the cause of entity in another ;
that the form, by reason of its imperfect entity, cannot be the
total effect of either creation or production ; that the form must
be developed out of some reality ; and that it cannot continue
in existence by itself but requires the support of another reality
as substrate. Positively considered, eduction implies that pri
mordial matter has priority of nature in respect to form in the
genesis of material substance ; that primordial matter is the
source from which the form springs, because the latter is the
substantial actuality of the former ; that the primordial matter
virtually contains the form ; that primordial matter is the sub
strate of the form and absolutely necessary to its existence.
" A clearer grasp of this eduction from the potency of matter
is available by the exposition of the five characteristics of all
forms which are produced in this way : firstly, these forms are
produced through material dispositions wrought by the actions
of material agents, that is, by dispositions, actions, and agents
which are inherent in and intrinsically united with matter ;
secondly, these forms depend in their very production upon
matter, that is, they can be begotten only within it and only in
union with it, they are not produced as independent realities,
and afterwards extrinsically attached and united to it ; thirdly,
these forms depend for their existence on matter because outside
that matter in which they were originally produced, they cannot
exist for an instant either as self-subsisting realities or even (as
co-principles) in distinct matter — for them, separation from that

E articular matter involves loss of existence ; fourthly, these
Drms depend in their activities upon matter, with the result that
the activities of such forms do not inhere in the form but in the
composite as their subject ; fifthly, these forms depend on matter
for their essence in the sense that they can neither be defined nor
fully understood except in reference to it. These five implica
tions, then, are conveyed in the doctrine that forms are material
and are educed out of the potency of matter." (77) Valuable

150 COSMOLOGY

as are these implications as giving a solid meaning to eduction,
they leave untouched the real difficulty — whence come the new
forms ? The answer seems to lie in the mystery of causality :
a cause may give what it has. In other words, the stock phrase
about eduction from potency is — as a result of the actual con
troversies waged over the origin of these lower forms — incomplete.
Attention must be fixed on the active power of the generating
cause. The generating cause reproduces its like in the patient :
and under suitable conditions, a new substantial form is one
of those realities that is realisable in primordial matter : realis
able therein with a dependency which effects its origin, its exis
tence and its maintenance. (78)

The exact nature of the efficient cause of substantial forms
led, however, to differences of opinion. Actions belong, in the
technical language of the School, to the supposit, that is, to the
existing inanimate individual. Now an existing inanimate in
dividual contains several realities : primordial matter and sub
stantial form, essence and properties and accidents, and the
existence of all these. Hence a controversy arose as to whether
the faculties, i.e. the accidental forms, were capable of producing
a substantial form. St. Thomas and the Thomists held that
they were thus capable : their view being that, strictly speaking,
accidental forms are in finite substances the sole immediate prin
ciples of action. Thomists teach that the existence of the faculties
results from the existence of their connatural subject : " the
actuality of the accidental cause is caused by the actuality of
its subject." (79) This subject, considered as abstractly pos
sible, implies those accidental forms which are as properties, its
natural complement, and it cannot exist, therefore, without simul
taneously communicating existence to these properties ; " the
subject is, in potency, susceptive of the accidental form and is,
in actuality, productive of it." St. Thomas denies, however,
that this causality between the essence and its properties is
efficient : he admits that this causality is in a sense active ; (80)
the essence by natural resultance being the scource of the exis
tence and of the nature of these properties. Starting from this
basis, the Thomists hold that the substance of finite beings, con
sidered in itself and in opposition to the faculties, exercises no
activity of its own. What would be the need of active faculties
if the finite substance itself could act ? These faculties are the
natural sources of action in each finite body : the proximate and
immediate cause of all that body's activities. Abstractly con
sidered, then, the faculty alone for the Thomists is active and is
the source of productive power : the essence is merely the ultimate
root of activity ; the substantial form is a principle of activity
merely in the sense that its nature determines the kind of specific
properties which emanate from the essence. Concretely, things
are otherwise for the Thomist : the faculty owes its existence
to that of the substance, for a single existence actualises both —
first, the substance and through it the faculty. Now, the faculty

THE ORIGIN OF SUBSTANTIAL FORM 151

must exist before it can act and, therefore, the subject concurs
in what is fundamental for the action of the faculty. If there
were no subject there would be no faculty, and, that is why all
activity belongs not to the faculty alone but to the existing
individual.

Applying to our present topic this doctrine of theirs concerning
the source of activity in finite substances, St. Thomas and his
disciples taught that the accidental forms are the proximate and
immediate causes of all newly produced material substantial
forms. " The (81) change which has a substantial form for its
term is not produced immediately by the substantial form, but
by means of active and passive qualities which act by virtue of
the substantial form." " The accidental form owes to the sub
stantial form the fact that it is a principle of action : hence the
substantial form is the primary, but not the proximate, principle
of action." " Substantial forms are not the immediate principles
of action in natural actions : they act through active and passive
qualities as their proper instruments. . . . And thus qualities
act not merely through their own power but through the
power of the substantial form. That is the reason why their
action results not merely in an accidental form but also in a sub
stantial form : in short, that is why generation is the term of
alteration. But they participate in this kind of instrumental
power for the very reason that they are caused by the essential
principles." " The efficient cause admits of a twofold division.
One division occurs from the point of view of the effect : namely,
into a disposing (cause) which produces the disposition for the
ultimate form, and perfecting (cause) which produces the ultimate
perfection. The second division occurs within the cause itself
and shows itself as principal and instrumental agent. The
principle agent is the first mover : the instrumental agent is a
moved mover. But every instrument has a twofold action :
one proper to itself and another which it receives from the prin
cipal agent. ... It must be remembered that the action of the
instrument extends to the ultimate perfection which the principle
agent can effect but sometimes does not : in all cases, however,
this action extends to something beyond that which the instrument
could of itself achieve, whether that something be the ultimate
form or disposition. For instance, the active and passive qualities
of the elements extend instrumentally to the eduction of material
forms from matter." " Thus an instrument has two kinds of
activity : one which lies within the competency of its own form ;
and another which lies within the competency of this instrument
when moved by an agent that surpasses the power of its own
form." " An active quality, like heat, although it is an accident,
acts by virtue of the substantial form, however, and as its instru
ment, and that is why it can produce a substantial form. . . . Nor
is it contrary to the nature of an accident to exceed its subject
in action : but it would be to exceed this subject in being."
" The active qualities act in virtue of the substantial forms : and

152 COSMOLOGY

in consequence a natural agent produces his like, not merely in
quality but in species." " A body acts towards the production
both of an accidental and of a substantial form. For the active
quality of heat, even though it is only an accident, acts in virtue
of the substantial form and as the instrument ; that is why it can
act towards the production of substantial form. For instance,
natural heat, inasmuch as it is the instrument of the soul, leads
to the generation of the flesh : but it leads to the generation of
accidents by its own power." " The action of an accidental
form depends upon the action of the substantial form in the same
way as the being of an accident depends upon the being of sub
stance." " It is to the substantial form that the accidental form
owes the fact of its being a principle of action, and, therefore,
the substantial form is the primary, but not the proximate,
principle of action." These and similar texts are the basis of the
Thomist view. The upshot of that view is that a created sub
stance can never be an immediate principle of activity. " Activity
is identical with substance only in God. And that is why the
power which is in God the principle of activity is the very essence
of God : but the like cannot happen in the case of soul or of any
other creature." (82) In consequence, Thomists are committed
to the theory that the accidental form, which is united with the
substantial form in a manner that does not imply the reception
of any power from this form, can produce not merely forms which
are like itself — namely, accidental forms — but also a form that
is higher than itself, the substantial form.

Scotus (83) and his disciples fastened on this anomaly. " An
instrumental form of itself and without any actual influence from
the principal form," urges Suarez, repeating the main contention
of Scotus, " cannot be a sufficient proximate cause of the pro
duction of a higher form. This principle seems to me to be
manifest almost from its very terms ; for, if the lower form is
not actually aided by the higher, it works only by what it actually
has in itself ; and since this is an entity of a lower order, it can
never of itself produce anything more perfect." And the Scotists
concluded that an accident cannot produce a substantial form
either as principal or instrumental agent : accidental forms can
prepare a body for the reception of a new substantial form by
producing therein certain pre-disposing qualities ; but these
accidental qualities cannot produce the incoming substantial
form. In reply to this objection of the Scotists, the Thomists
urge the already quoted texts of St. Thomas. The value of
these texts as a reply depends on the perpetually recurring
phrase : in virtue formce substantialis. But Cajetan and all the
Thomists insist that this phrase does not connote the giving of
any power by the substantial form to the active qualities. And
in that case, the Scotist objection remains unanswered. Suarez
suggests that this phrase of St. Thomas might be reasonably
interpreted as implying, at the moment of substantial change, a
real aiding of the active qualities by the substantial form. This

THE ORIGIN OF SUBSTANTIAL FORM 153

suggestion seems to meet the point of the Scotist objection :
the production of the new substantial form is the effect of the
immediate action of both kinds of form, the action of the sub
stantial form as principal agent, the action of the qualities as
instrumental agents. Suarez admits, then, that accidental
forms may be instrumental causes in the proximate and direct
production of a substantial form : otherwise, in those instances
where the substance is not actually present — instances that the
medievalists believed to be frequent — you can give no philosophical
explanation of natural facts except you adopt for these instances
a theory of Occasionalism. He refuses to admit any special
difficulty in this suggestion of the active influence of a substantial
form : accidental forms are universally admitted to be active
because this theory is necessary to explain the facts of everyday
causality ; why, then, not admit the activity of substantial
forms in regard to those facts that cannot be explained without
it except one falls back on the theory of Occasionalism ? He
urges with Scotus that if an accidental form can produce its like,
why may not a substantial form also produce its like ? and that
if finite substance is of itself utterly inactive, it is a remote
principle of action only in the vicarious sense that its powerlessness
is supplemented by that of its active accidents. Scotists argue
against Suarez that if the substantial form is proximately active
in the production of new substantial forms, there seems to be no
need at that moment for the activity of accidental forms. Suarez
replies that this activity of the accidents seems to be necessary
for many reasons : in certain instances, substantial forms are
generated even though no substance is immediately present :
substantial form is never of itself a sufficient principle of action
because it is an indifferent and quite general principle — and just
as an incoming substantial form postulates preparatory accidental
dispositions, so any substantial form requires for its activity
the accompanying stimulus of accidental forms as its instru
ments. He sets little value on the Thomist objection that the
purpose of the faculties as principles of action is endangered by
his admission of the activity of finite substance : alteration is
carried out by these faculties ; it is only when their power ob
viously fails us that the activity of finite substance is admitted
for the purpose of avoiding Occasionalism. And though Suarez
admits, in the conditions specified, the activity of the finite sub
stance, he and his make abundantly clear that this activity of
finite substance affects the inviolate supremacy of divine activity
as little as does the activity of finite accidents.

A word about the medieval explanation of the disappearance
of substantial form. At the beginning, substantial form was con-
created with primordial matter in the first substances produced
by God : ever since, substantial form has been educed from the
potency of primordial ma,tter by the action of finite agents.
" Form can be considered in two ways : in one way as existing
in potency — and in this way it is concreated with matter by God

154 COSMOLOGY

apart from all intervening and disposing action of nature ; in
another way as existing in actuality — and in this way it is not
created but is educed from the potency of matter by a natural
agent." (84) Thus once form was concreated, its subsequent
appearances and disappearances were spoken of by the School
as exits out of or entrances into the potency of matter. " Matter,
then, in itself must be regarded as in potency to the forms of all
those beings of which it is the common matter. Each particular
form does not make it actual save as regards that particular form.
And. therefore, it remains in potency with regard to all other forms.
And this further potency is not excluded by the fact that one of
these forms is more perfect and virtually contains in itself the
others because potency, considered in itself, is equally indifferent
to the perfect and to the imperfect. And that is why that just
as when it is under an imperfect form it is in potency to a perfect
form, so when it is under a perfect form it is in potency to an
imperfect form." " Although forms and accidents do not possess
matter as part of themselves they have matter in which they
exist and out of the potency of which they are educed. Therefore
even when they cease to exist, they are not completely anni
hilated but remain, as heretofore, in the potency of matter." (85)
The Schoolmen taught, then, that substantial forms pass out of
existence by receding into the potency of primordial matter.
The substantial form is not corrupted : the substance alone is
corrupted and, when it is corrupted, the substantial form dis
appears. But its disappearance is not annihilation for the same
reason that its appearance is not either creation or production : the
composite alone is created or produced. The disappearance of the
substantial form is simply its recession into the potency of matter :
it is no longer actually existing, but it is in matter in such a way
that, on the recurrence of the appropriate circumstances, it can
be educed therefrom by natural agents.

CHAPTEK VI.

A MEDIEVAL METAPHYSICAL AUDIT OF THE INANIMATE
INDIVIDUAL.

THE union of primordial matter and substantial form results
in the formation of a single essence that belongs to a determinate
species. Primordial matter and substantial form are so inter
mingled that the form takes complete possession of the matter
and that the matter receives into all parts of itself the form ;
and from this total cornpenetration arises a single specific essence
which is capable of becoming a unitary nature, that is, an indivi
sible source of specific properties and activities. This unit of self-
subsisting being can as a whole exist and act for itself : it is, in
short, an existing individual. The union which produces this
individual is not, however, an instance of efficient causality : an
efficient cause is distinct from its effect, but the specific essence
is not distinct from its two constituent principles. Neither is
this union hypostatic : the constituent principles of substance
have not distinct properties and distinct activities. It is an
intrinsic union and, thereby, different from all artificial unions
wherein realities are held together by some extrinsic bond and
merely coalesce in their diverse activities. But the attempt
to elucidate the varying phases of this union from the formation
of the essence up to the finished product of the inanimate in
dividual launched the Schoolmen on many subtle controversies.
A cursory sketch of the more important of these controversies
will enable us to realise the developments wrought in this portion
of Aristotelian Cosmology by his medieval disciples.

PRIMORDIAL MATTER AND THE ESSENCE.

Aristotle's theory of substantial form was, apart from the
embodiment of these forms in the objects of experience, largely
Platonic. It is not surprising, then, to find him laying down in
certain texts that the substantial form was the quiddity of the
composite substance, and that composite substances are dis
tinguished solely by their forms. Averroes made these texts his
guiding principles,' and held that primordial matter was not a
part of the essence of substance : he was supported in this view
by Jandunus, Albertinus, Zirnara, and Pereira.l1) Durandus

155

156 COSMOLOGY

compromised : lie allowed, in the abstract, that primordial matter
was part of the essence, but he denied that the particular portion
of primordial matter in each composite was part of the essence
of that composite. The Master of the Sentences compromised,
also, but in a different fashion : he admitted that primordial
matter was part of the essence of all non-living substances ;
but being puzzled by the ceaseless changes in living bodies, he
held that only the portion of the primordial matter which came
to the progeny from the parent was part of the essence of a living
composite ; his argument in favour of this view was that, if all
the food which is assimilated by plant or animal were during
its stay part of the essence of that living being, the numerical
identity of embryo and the adult could not be defended. In
opposition to such views, the majority of the Schoolmen taught
definitely that primordial matter was part of the essence of
substance. (2) They urged that the argument from substantial
change which proved substantial form to be a part of the essence,
also proved primordial matter to be part of the essence. Sub
stantial change consists in the destruction of one specific essence
and the production of another specific essence : but that change
involves nothing else except the union or separation of primordial
matter and substantial form ; therefore, a specific essence is
composed of those two principles. They referred their opponents
to other texts of Aristotle which suggest that the physical com
posite consists of primordial matter and substantial form — a
doctrine he denies of the accidental composite ; that primordial
matter and substantial form are partial natures which coalesce
to form the integral nature of the composite — but the nature is,
for Aristotle, the essence of the composite ; that the substantial
composite is definable by primordial matter and substantial
form — but definition is of the essence. They confirmed this
philosophy and exegesis by an appeal to theology : certain phrases
of the Athanasian Creed that refer to man as composed of body
and soul ; a canon of the Council of Trent on transubstantiation
that says the whole substances of bread and wine are destroyed.
There can be no doubt of the soundness of this view of the
majority of the School. But they explained away rather than
explained the Aristotelian texts urged against them simply
because the School never realised — or at least never confessed
— those inconsistencies of the Aristotelian text which are due to
the fact that Aristotle never got wholly free from the Theory of
the Ideas. They explain away the text referring to definition
either, by saying that Aristotle mentions one constituent without
denying the other or, by saying that Aristotle refers therein not
to the substantial form but to the " metaphysical form," by
which is meant the essence as an abstract whole considered in
relation to supposit in general. Similar tactics are employed in
shelving the text which distinguished composites solely by their
form : Aristotle is said to have mentioned merely the more im
portant constituent. The truth is that the School were uncon-

THE PROBLEM OF UNION 157

sciously evolving from the Aristotelian text the full consequences
of the revolt of Aristotle against Plato : a task which was much
easier for writers living centuries later than for one who had sat
so long at the feet of Plato. There is no need to deny the Platonic
significance of the texts quoted by Averroes, but there is no need
to accept them as decisive of the logic of hylemorphism. As for
the plea urged by the Master of the Sentences, it was reputed of
little worth : some believed that a portion of the body remained
unchanged during life and regarded this as an ever-existing stock
on which the changing portions could be grafted ; others insisted
on the continuity of the processes of growth and decay, and on the
fact that the living being of each day is the progeny of that of
each yesterday ; all of them urge that the soul, being the principal
part of any living body, suffices throughout all sorts of changes
to guarantee numerical identity during life ; and most of them
add the typical medieval illustration of the persistent identity
of a river which, though its waters are ever rushing away, abides
ever the same !

THE PROBLEM OF UNION.

The nature of the union between the two constituent principles
of substance gave rise to various opinions. Some of these opinions
met with little support : the opinion, that this union consisted
formally in the intimate presence and mutual penetration, was
rejected on the grounds that these were realisable apart from
actual union ; another opinion, that this union consisted formally
in the divine decree willing it, was rejected on the grounds that
this decree is extrinsic. The real controversy centred on the
question whether union was formally some kind of reality super-
added to the constituents : something which acted as a link
between them. Scotus, Suarez, their followers, and some of the
Thomists pleaded that union was a superadded reality of this kind :
the Suarezians and these Thomists interpreting this reality as
a substantial mode, the Scotists interpreting it as an extrinsic
supervenient relation.i3) Further controversies arose concerning
the number and the location of these superadded realities. Suarez,
the Complutenses, Rubius, and Aversa admitted only one such
union : Suarez planted it in the substantial form alone ; the Com
plutenses in both primordial matter and the substantial form ;
Rubius and Aversa in the primordial matter alone. Scotists
postulated at least two partial unions : one in the primordial
matter, and the other in the substantial form. In opposition
to all such views, St. Thomas (4) and most of the Thomists
stoutly denied the need in union of a third reality distinct from the
constituents of substance : granted the requisite dispositions
and the mediating action of an external agent, primordial matter
and substantial form are immediately united to each other in
formal union without the assistance of any superadded reality
or mode. " Some (5) ancient philosophers made the mistake of

158 COSMOLOGY

asking what unites potency and actuality, evidently imagining
that these require to be linked together by some intermediary
as do totally different bodies. . . . But there is no necessity that
these should be united by a bond of the kind that is necessary
for totally different beings : hence no cause unifies those things
that are composed of matter and form except the cause which
produces the change from potency to actuality." " The form of
itself makes the matter actual being for it is essentially an act
uality : and it does not confer being by the help of any inter
mediary. Hence, the unity of a thing that is composed of matter
and form is due to the form which through itself is united to
matter as its actuality. And no other unifying reality exists
except the agent which causes matter to become actual being."
"Be it known that in the union of the human with the divine
nature there is no intermediary that causes union. . . . : just
as there is no intermediary reality between matter and form that
would be in matter prior to form, for, if there were, accidental
being would precede substantial being and this is impossible."
" In truth, the very purpose of form is to be, of itself and without
intermediary, the actuality of the body: therefore, no third
thing makes matter and form one except the agent that reduces
potency to actuality." The basis of this Thomistic view is, then,
that primordial matter and substantial form are so made for
union with each other that they need no third link to accomplish
this union. These Thomists insist, reasonably enough, that
whatever be the kind of link or the number of finks postulated,
their opponents are driven at the finish to admit immediate
union either between this link and one or both constituent
principles or between each of two such links and their respective
constituent principles together with a final linkage between the
constituent principles thus affected : in other words, the rejection
of St. Thomas's solution compels you at the start to multiply
entities which can be united at the finish only by the acceptance
of his solution.

THE PROBLEM OF TOTALITY.

Scotus set up a distinction between the composite essence and
its constituent principles considered collectively and unitedly : his
teaching was that, besides the united primordial matter and sub
stantial form, there was a distinct entity which conferred whole
ness of essence. And this Scotist contention was supported by
Hervseus, Capreolus, Cajetan, Ferrarensis and Javellus.i6) Two
main arguments were put forward : nothing can be the cause of it
self and therefore the union of matter and form cannot be the cause
of totality of essence ; predicates like integrality, generation, cor
ruption can be truly used of the composite essence but not of its uni
fied parts. This theory (7) was rejected by most of the Schoolmen :
Thomists, Nominalists, Suarezians. Aristotle expressly identifies
the united constituents with the physical whole : the whole is

ESSENCE AND EXISTENCE 159

not anything distinct from its parts ; just as pupil and sight
are the eye, so soul and body are the animal ; the inclusive whole
is its contents and these are one essence. St. Thomas is equally
explicit : " Humanity must not be thought of as a kind of form
resulting from the union of matter and form in the sense of some
thing really distinct from these . . . the reason is that matter
becomes actualised through its form and therefore this alleged
form would be accidental, not substantial." " The more correct
opinion seems to be that the form of the whole is not the form
merely of a part and that there is no other form distinct from the
form of the part, but that there is a whole which results from the
union of matter and form and includes within itself both of
these." " Man is neither the body alone nor the soul alone but
both together." " Humanity implies nothing beyond the essen
tial principles of the (human) species." The basis of this Aris-
totelico-Thomistic teaching is that substantial change reveals
nothing in the composite essence but primordial matter and sub
stantial form and these two united. There is no proof, then,
of this alleged entity of totality. Nor are the Scotist arguments
convincing : primordial matter and substantial form are not in
their collective union the causes of the composite whole but are
identical with it ; no predicates are applicable to the composite
essence which are not equally applicable to its constituents when
taken collectively and unitedly. The growing consensus of
opinion against the Scotist view became gradually overwhelming ;
and after the beginning of the sixteenth century, it was scarcely
heard of in the School.

ESSENCE AND EXISTENCE.

The Schoolmen were unanimous in holding that the essence
of a creature, considered ideally and in the abstract, was really
distinct from its existence. But a doughty controversy arose as
to how in any existing creature, its essence was distinguished
from its existence. St. Thomas (8) and almost all the Thomists
maintained that the essence of any existing finite being was
really distinct from its existence. Alexander (9) of Hales, Aureolus,
Henry of Ghent, Durandus, Gabriel Biel, Hervseus, Suarez and
Vasquez held merely a mental distinction founded on reality.
Scotus and the Scotists (10) held a distinction of a diminutive but
of a real order — distinctio formalis a parte rei : a distinction
that is real, because antecedent to our thinking, and that is formal,
because not between thing and thing but between distinct
formalities.

The basis of the Thomistic view is that the identity of essence
and existence involves self-existence. St. Thomas argues that
essence must be really distinct in finite beings from existence
because creation and production imply the reception of existence
from a source other than the essence itself . He compares essence
and existence in creatures to potency and actuality : but there is,

160 COSMOLOGY

necessarily, a real distinction between any potency and its act
uality. Elsewhere, he argues that identity of essence and exis
tence involves infinity because there is nothing within or without
such an essence to limit it : but two infinitely perfect beings are
impossible ; consequently this identity of essence and existence
can be realised only in God. " It must5(u) therefore, be held
that essence and existence differ conceptually in simple beings
but really in composite beings. . . . But there is only one simple
perfect being — God." " Every being that belongs to the genus
of substance is composite in the sense of admitting real composi
tion : the reason is that everything which belongs to the category
of substance is self-subsisting in its existence ; consequently its
existence must be different from itself, otherwise it could not
differ in existence from those others with which it agrees in
essence." This real distinction of the Thomists is obviously not
of the kind that prevails between individuals each of which has
its own existence. Neither is it a distinction between thing and
thing when you take thing — as medievalists were apt — to mean a
complete essence : " the actual reality of existence is not, strictly
speaking, a thing because it is not any kind of essence." (12) But
while denying that existence was a complete essence, Thomists
asserted that it was something really superadded to the essence.
Hence their plea is for a distinction between two realities, each
of which has a distinct value and a distinct definition : essence
is the thing, existence a something added to this thing which
makes it actual and present. This superadded reality of exis
tence cannot be an accident because existence accrues to a
complete essence, not to a complete being : as long as the essence
lacks existence, there is no actual substance ; and accidents
supervene only when the actual substance is formed. Hence
existence belongs — reductive — to the category of substance. That
is why Thomists occasionally speak of existence as one of the
factors of substance : primordial matter is actualised by sub
stantial form and thereby made fit for the reception of a single
existence. "It is wrong (13) to hold that matter and body or
matter and form have distinct existences ... for the same
existence belongs to the composite and its parts." " Just as
a luminous body has only a single light-giving quality, so there is
only one existence in a whole composite, for instance, in a tree."
Primordial matter, substantial form and existence complete one
another : each of the latter two develops a potency of its pre
decessor ; and prior to that total development, there is no existing
being. There is for the Thomists, then, only one actuality of
existence, and that belongs neither to matter nor to form but
to the composite which results from their union.

The basis of the opposing view is that existence implies
merely the placing of an essence outside its causes : actualised
essence is nothing more than possible essence realised outside
its causes. But an essence remains the same essence whether
thought of as possible or as actualised. Moreover, a being in

ESSENCE AND EXISTENCE 161

potency and the same being in actuality cannot result in real
composition : one of these two states excludes the other. There
fore, there can be no real distinction of essence and existence in
any finite existent. Another line of argument is based on the
fact that if existence was really distinct from essence, they could
be separated by God : but this is impossible for their separation
would result in an essence that exists without existence and an
existence that is the existence of nothing. Thomists retort that
these and similar arguments are the logical consequence of a defec
tive starting-point. It is true that whatever exists is outside its
causes. But the pertinent question is : how is this existence
outside the cause effected and maintained ? what keeps the
actualised essence from relapsing into nothingness ? You do
not tell what gravitation is by saying that it keeps the earth
whirling round the sun : you indicate, thereby, not its intrinsic
nature but one of its effects. For a similar reason, the definition
of existence as that which puts an essence outside its causes
is incomplete. Existence requires for its maintenance as much
energy as does action : just as action is the actuality of active
power so existence is the actuality of essence. Now the active
force is distinct from the effect which it produces. And in a
similar way, existence is really distinct from the essence which
it actualises : the actualised essence is simply the essence placed
outside its causes, but that which places it and keeps it outside
its causes is an actuality really distinct from itself ; in short,
existence is an energy of some kind whose presence keeps the
essence out of nothingness. This controversy was tossed up and
down as an apple of discord all through the medieval period.
It affected various turns of argument for and against other
scholastic theories. Whatever view one takes of the controversy
as a separate problem, it is well, in view of the large claims occa
sionally made on behalf of the Thomistic solution, to recall the
warning of Soto.(14) " There is nothing certain in Aristotle
about this first distinction (that of essence and existence in con
crete finite beings) : but St. Thomas (De Ente et Essentia, c. 5,
11 contra Gent. c. 52, and 1 p. q. 3, a. 4, and frequently elsewhere)
sets up as the essential difference between God and creatures
the fact that in God alone being and existence are of the quiddity
and essence : on the grounds that God is the primary cause and
that if existence were not due to Himself, He could not have got
it from any other source. In creatures, on the other hand,
existence is not of the essence because their essences are eternal
but receive existence from God at a definite moment as already
proved. . . . This is not the context for further discussion of
these points. I wish to add, however, that, provided a thinker
does not deny the difference between God and us which consists
in the fact that existence is of the essence of God but not of the
essence of creatures, it is of comparatively little importance
whether he admits or denies this (real) distinction (between
essence and existence in existing creatures) : just as the thinker

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162 COSMOLOGY

who denies that sitting is distinct from the sitter does not deny
anything important provided he does not insinuate that sitting is
of the essence of man ; in fact, some term this latter distinction
real, and perhaps rightly."

The Schoolmen were unanimous on this point emphasised by
Soto : namely that existence in creatures was a gift from God.
This was clear with regard to those beings that were created at
the beginning. God alone is creative. Of course, this gift of
existence was not interpreted as a reality passing from the Creator
to the created : a portion of divine substance which is given to
His handiwork. Existence in God is necessarily infinite, indivis
ible, incommunicable : existence in creatures is a something that
is given, limited, individual. All that can be said is that created
existence is due to the omnipotence of God, and, that the par
ticular gift which it is, consists in an action freely originated by
God and accomplished in His creature. But the Schoolmen
were not agreed as to the manner in which this gift was trans
mitted in regard to realities which were produced.!15) Some of
them interpreted various texts of St. Thomas as implying that
secondary causes could produce only the essence of such realities
and that God produced their existence. Others took St. Thomas
to mean that God, as principal cause, produced existence but
employed the secondary cause as instrument in that production :
the distinctive mark of this theory is that God, in producing
existence, uses the secondary cause merely as a channel through
which His power passes somewhat as a Raphael uses his brush
to convey his skill to the canvas. The third, and more general,
theory was that God communicates to secondary causes not
merely the power of producing the essence of a substance or of an
accident, but also the power of producing the existences of these
essences : the distinctive mark of this view is that creatures in
their own order, and with due subordination to the First Cause,
produce existence. St. Thomas, Cajetan, Ferrarensis, Scotus
and Suarez support this third view.(16) They argue that
secondary causes cannot be said to be truly efficient unless they
produce existence as well as essence : for, until essence and
existence are united, there can be no actual effect. And they
urge that no valid reason can be assigned for excluding existence
from the scope of secondary causality : a secondary cause can
produce an essence because it is itself an essence ; a secondary
cause can produce existence because it is itself existent ; and it
produces both with the concurrence of the Infinite.

THE PRINCIPLE OF INDIVIDUATION IN MATERIAL SUBSTANCES.

The problem of the individuation of bodily substances arose
out of the attempt to explain why one individual of a species
differs merely numerically from other individuals of the same
species. It was admitted by all the Schoolmen that the signs

PRINCIPLE OF INDIVIDUATION 163

by which individuality is recognised are extension and the quali
ties connected with it. But it was also universally allowed that
these accidents could not constitute the intrinsic reason of the
individuality of each substance : the accident presupposes the
substance. " It is said that definite dimensions in matter are
the cause of individuation. This does not mean that quantitative
dimensions cause individuality for an accident cannot cause its
own subject. What it does mean is that the individual is dis
cernible here and now by these definite dimensions : they are
signs peculiar to and inseparable from individuality." (17) The
accidents, then, cannot be the principle of individuation in sub
stance. But in the course of the controversy nearly every other
factor was suggested by someone or other as this principle of
individuation : primordial matter or substantial form or existence.
By degrees, however, medieval opinion rallied to one or other
of the three leaders : St. Thomas, Scotus, Suarez. Scotus (18)
taught that the individuation of substances was effected by some
positive reality which is formally distinct from and extraneous
to the specific nature : a reality that was styled " thisness."
Thisness is certainly neither primordial matter nor substantial
form, nor the composite, nor quantity. But it is difficult to know
what it is : if thisness means that the specific nature is made
formally individual by some kind of individual differentiation,
then Scotus does but affirm the fact whence the whole controversy
springs — the multiplication of individuals within a species ; if
thisness means the substantial entity of each substance, then
Scotus coincides with Suarez ; if thisness means some kind of
accidental reality, then Scotus advocates an insufficient reason
for the individuation of substance and assumes, moreover, an
accidental entity for whose existence no decisive proofs are pro-
f erred. Suarez (19) and the majority of his School taught that
each substance is individualised by its actual entity, in short,
by the fact of its existence : once a substance exists, be it simple
or composite, it is a reality undivided in itself and divided off
from everything else, in other words, an individual. Suarez
does not deny that the common nature of each individual is
logically distinct from its individual entity ; nor does he deny
that individuality adds to the specific essence some distinctive
seal which, from a metaphysical point of view, functions as an
individualising difference ; but he does deny that this individual
ising difference has any basis, in the existent, distinct from the
entity of the substance : hence, his view that each substantial
existent is of itself and through itself the principle of its own
individuation. This thesis of Suarez can hardly be contested.
Each existing being is an individual : that incommunicability
and that distinctiveness from others which results from individ
uality belongs only to substances that exist ; all existing sub -
stances have a distinct and an undivided existence. There is no
dispute about the fact that an undivided existence makes a unit
of every existing individual. But since the existing individuals,

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164 COSMOLOGY

of each species are repetitions of the formal type, the question
remains as to what it is that distinguishes them as numerical
patterns of this species. Thomists contend, then, that the
Suarezian theory is incomplete : the problem remains why the
existence of a particular individual is its own and not that of
another individual of the same species ; if several individuals
belong to the same species, why is not their existence the same ?
Their own view is that the principle of substantial individuation
is to be found in primordial matter as affected by quantity :
substantial form cannot be the principle of individuation because
it is, of its nature, communicable to many ; primordial matter
cannot be this principle because it is, of its nature, neither incom
municable nor distinct. This Thomist theory is the express
teaching of St. Thomas (20) : his principle of substantial individ
uation is materia quantitate signata. But, as he was not explicit
on what he meant by this formula, various interpretations arose
in the Dominican School.

One group of Thomists (21) interpret this formula as implying
the actual information of primordial matter by the accident of
quantity : individuality, those argue, implies incommunicability
and distinctiveness, and the incommunicability is given by pri
mordial matter, the distinctiveness by quantity. Many of their
brethren object to this interpretation : quantity informs the
composite, not primordial matter ; moreover, quantity as actual
formal principle bestows merely accidental perfection. Hence
other Thomists (22) suggest that this individual determination
of primordial matter is effected by a mode of some kind which is
distinct from quantity : in their view, primordial matter is deter
mined by some real mode — perhaps accidental, perhaps substan
tial — that is naturally distinct from it, and that precedes the
introduction of substantial form with its quantity and other
accessory properties. Their brethren object that the assumption
of such a mode is gratuitous, and that the question arises whether
this mode or the primordial matter is the principle of individ
uation : if the matter, then the mode is useless ; if the mode,
then St. Thomas's formula is abandoned. There remain two
further interpretations of the formula : both defended by Cajetan
and both popular with Thomists. (23) Cajetan's first interpre
tation was that the sealing of primordial matter by quantity,
which St. Thomas taught to be the principle of individuation,
consists in the fact that primordial matter is intrinsically fashioned
beforehand for the reception of this quantity to the exclusion
of that : this predisposition of primordial matter towards a
particular quantity is effected by the agent that disposes it
for a particular form because the form in question postulates
this, and not that, quantity. Primordial matter is intrinsically
individuated by its connotation of a particular quantity : it, in
turn, individuates the substantial form ; the substantial form, in
its turn, individuates the whole entity of the substance ; and from
this whole entity, thus individuated, arises thisness or the individ-

PRINCIPLE OF INDIVIDUATION 165

uating difference within each species. On this view, individuated
primordial matter is not a principle of individuation in the sense
that it is itself the individualising difference, but in the sense
that it is the fundamental cause of thisness or the resulting
individuation of the substance. The argument for this theory
is its sufficiency : primordial matter is an intrinsic substantial
principle, and its determination is not an accident but a relation
ship with a particular quantity : this determination is the source
of incommunicability because matter, thus determined, is capable
of this quantity and not of any other ; this determination is
the source of distinction because quantity involves juxtaposition
of parts and, consequently, distinct locations in space. When
their opponents object that primordial matter looks first to the
substantial form as subject and only subsequently to accidental
forms like quantity, Thomists refer them to the medieval for
mula — causce ad invicem sunt causce : causes, according to their
respective causalities, may bear different relationships to one
another. It is true that, from the point of view of receptive
causality, primordial matter looks first to the substantial form
and only subsequently to the accidental form. But the point
of view of dispositive causality involves a different relationship :
primordial matter is prepared for one substantial form rather
than another by previous dispositions and, among these, quantity
is of the first importance ; consequently, primordial matter from
this point of view looks first to the accidental dispositions,
including quantity, and subsequently to the substantial form.
Quantity is the first of these accidental forms and by its presence
portions off primordial matter into parts : this division into parts
leads to that separateness of parts which adapts the various parts
either for a single substantial form of a particular species or for
the several substantial forms of distinct species. For all that,
the quantity which individuates the resulting substance is not
the perfect accident that afterwards inheres In the subsequent
composite. The individuating quantity is an imperfect accident
that prescinds from definite dimensiveness : it precedes the com
posite, and is really merely a relationship of primordial matter
towards definite quantitative limits ; still, it suffices for individua
tion because it breaks up primordial matter into portions that
are numerically different from one another. So much for this
first interpretation of Cajetan which is the ablest attempt of
Thomism to grapple with the inner meaning of St. Thomas's
formula. Cajetan (24) suggested, at a later date, a subtle modi
fication of this interpretation. By determining matter he wished,
on second thoughts, to be understood not matter in potency to
quantity but matter numerically distinct : matter, not as the
receptive subject of quantity, but matter as the root of quantity
by priority of nature ; in other words, matter as virtually pre-
containing quantity. This virtual pre-existence of quantity in
primordial matter means that primordial matter is numerically
distinct in itself before it is quantified : Cajetan's argument being

166 COSMOLOGY

that, thus only, would the effect be proportionate to the cause
since the numerical distinction of individuals within any species
is not quantitative distinction but the basis of quantitative
distinction. " Determining (25) quantity and terminated quan
tity are two different things. Quantity is said to be determining
when it marks off this as numerically distinct from that and yet
leaves unsettled the further stage whether the portion thus marked
off be terminated and completed by a substantial form or have
such and such quantitative dimensions : and that is why it can
be a principle of individuation inasmuch as it is precontained in
primordial matter. But terminated quantity refers to the same
numerical portion when considered subsequent to its termination
and information by the substantial form : thus considered, it
involves definite dimensions, v.g. two cubits, and is not the
principle of individuation." Suarez confesses his inability to
grasp the alleged difference between these two interpretations of
Cajetan : he argues that primordial matter — for Cajetan — cannot
already possess quantity as an efficient cause but must possess
quantity solely as a material cause ; and he concludes that prior
possession as a material cause can mean nothing else than a
state of receptive potency ; in short, that Cajetan's second
interpretation coincides with his first. And the subsequent
neglect of Thomists to emphasise the alleged distinction between
these two interpretations of Cajetan, suggests that Suarez is right
in suggesting that they are identical in meaning.

ESSENCE AND SUBSISTENCE.

A substance that is complete, both in specific essence and in
specific nature, and that exists as a single whole in, by, and for
itself, is called by the Schoolmen a supposit. Hence in an inani
mate supposit, there are various realities : the individualised
existing essence ; the properties that flow from and are inseparable
from a specific essence ; the adventitious accidents that are caused
by external influences ; and the distinguishing characteristic of
subsisting in by and for itself as a physical intrinsic whole, which
is not and cannot be part of the being of another but is an
independent and incommunicable individual. Now that some
thing which transforms the essence into a supposit by making it
intrinsically independent of, and incommunicable to, any other
being is called subsistence. Our present question refers to the
nature of this something : what is it ? and what is its relation
to the essence ? Henry of Ghent and Durandus held, with
Aristotle, that the only difference between essence and subsistence
was that between an abstract and a concrete individual. St.
Thomas seems, in some of his works, to approach this view : he
insists that subsistence is really distinct from essence in material
substances ; but he does not interpret subsistence as a special
reality superadded to the essence ; he inclines to account for

ESSENCE AND SUBSISTENCE 167

subsistence by the individualising properties and accidents. But
the great antagonists of subsistence as a positive entity were the
Scotists : for Scotus and his disciples, subsistence consists merely
in the fact that the essence is not actually dependent on any
other being. All these thinkers (26) agree, then, in denying that
subsistence is a special kind of positive entity which is distinct
from the essence and is added to it for the purpose of making
this essence incommunicable. And all of them rely on the
following argument. When you distinguish in any existing
individual its primordial matter, its substantial form, its pro
perties, its existence, and its individualising circumstances, you
appear to have exhausted its stock of positive realities. Now,
entities are not to be needlessly multiplied. It is true that the
complete substance is incommunicable. But that incommunica-
bility seems to be sufficiently explained by the normal conditions
of individual existence. An individual is a whole in itself and
has its own independent existence. If, owing to supernatural
causes it is subsumed by another, it loses, indeed, its independence
of supposit, but there is no need to suppose that it loses any special
positive reality. To this teaching, their opponents made the
following philosophical objection. A supposit is certainly
something positive : it implies integrity and totality in substance.
Scotists, in reply, distinguished three kinds of substantial integ
rity and totality — integrity and totality of essence, of nature, of
incommunicability : certainly, the first two kinds refer to positive
realities, but the objection does not refer to them ; and the third
kind of integrity and totality, the self-centred mastery of itself
by a substance, is also in a sense something positive but it is
attained by the mere fact that a substance is not part of the being
of any other substance.

Cajetan made famous in the School the contrary view which
interprets subsistence as a special kind of positive entity : he
rallied to his side the majority of the Thomists ; his general
view was endorsed by Suarez and his disciples ; and all of these
supporters of the positive reality of subsistence claim as their
patron, St. Thomas.!27) But these thinkers were not of one
mind as to the nature of the positive reality attributed to sub
sistence. Most of the Thomists thought of subsistence as some
thing intermediary between essence and existence but really
distinct from both : subsistence, when received into essence,
makes this latter incommunicable ; existence, when received
into supposit, makes this latter actual. A few Thomists held
that supposit adds to the essence only the individualised sub
stantial existence : in other words, these Thomists identified
subsistence with the existence of the essence. Suarez and his
disciples, denying as they did any real distinction in actual sub
stances between essence and existence, interpreted subsistence as
some kind of a substantial mode which completes the essence
by rendering its existence incommunicable. The gist of philo
sophical reasoning in favour of the positive reality of subsistence

168 COSMOLOGY

ran : that mode of subsisting separately from other beings is
something negative, inasmuch as it merely excludes substantive
communication with these others : but that mode of subsisting
separately from other beings is something positive, inasmuch as
it fashions the substance into a completely rounded whole, within
which the substance reigns master of itself and independent of
all others.

This exposition touches merely the philosophy of the problem.
The graver arguments and objections were drawn from the
Mystery of the Incarnation : in the God-Man, there are two dis
tinct natures in the unity of Person. For critical appreciation of
these issues, the student must look to the science of Theology.

» THE DISTINCTION BETWEEN SUBSTANCE AND MATEEIAL

ACCIDENTS.

" Substance is being inasmuch as this being exists by itself ;
accident is that whose being is to exist in something else." " Sub
stance is a reality to the nature of which it is due that it should
not exist in another. But accident is a reality to the nature
of which it is due that it should exist in another." These defini
tions of St. Thomas (28) express the general medieval teaching :
substance alone fully is : accident has but a diminished being
inhering in substance. These definitions embody also the
accepted teaching of the School of some kind of distinction
between substance and accident : so many changes occur in
material bodies without affecting the identity of these bodies
that there must be some self-subsisting recipient of these changes ;
that recipient is substance ; its successive and different states
are the accidents. There are, however, accidents and accidents ;
and the distinctive feature of medieval Cosmology in this context
is its doctrine of a distinction between substance and certain
accidents so real that these accidents could exist, preternatur-
ally, apart from their connatural substance. Quantity and the
sensible qualities of matter were held to be absolute accidents
of this kind by Thomist, Scotist, and Suarezian.P) The
Nominalists (30) made an exception of quantity : for them, this
kind of real distinction exists between the corporeal qualities
and the substance, but not between any substance and its quantity
and not between any quality and its quantity.

Many philosophical arguments were 'put forward in favour of
the general thesis that quantity and the corporeal qualities were
absolute accidents. Thus quantity was said to be really distinct
from substance for several reasons : no a priori case can be made
for their identity because their respective concepts are altogether
different ; nor can any a posteriori case be made because insepar
ability does not necessarily imply identity ; quantity is directly
perceived by the senses, substance only indirectly ; changes of
quantity — within limits — do not involve change of substance.

SUBSTANCE AND ACCIDENT 169

Other arguments were propounded in favour of a real distinction
between substance and the sensible qualities. Suarez starts with
an appeal to induction : the four elements exercise accidental
efficiency by means of their primary qualities — and a real dis
tinction between these and their respective elements was acknow
ledged ; local motion is caused by means of qualities ; the heavenly
bodies act through qualities distinct from themselves, v.g. through
light ; non-living mixtures, such as metals and gems, obviously
exercise causality through their accidental powers, for we know
that these powers can be intensified or weakened or destroyed.
This inductive argument was confirmed by an appeal to meta
physical reasonings : an appeal that aroused a certain amount
of dissent. It was urged that since potency and actuality must
belong to the same genus, the potency which issues in the actuality
of the accident of action must itself be an accident : critics
retorted that the presupposition cannot be maintained in view
of that fact that substance is itself a receptive potency in reference
to these alleged accidental qualities. It was urged, also, that
qualities can become more or less intense whereas substance
cannot undergo such changes ; and that since active powers are
really distinct from one another, they must be really distinct
from the substance. After a review of these and other philo
sophical arguments in favour of the thesis that sensible qualities
are absolute accidents, Suarez frankly acknowledges their weak
ness : philosophy can give but probable reasons for a real dis
tinction between the substance and the sensible qualities. ^" St.
Thomas (31) with a fair amount of proof establishes, by induction,
that in every created nature the immediate principle of action is
distinct from the substance, and is, therefore, an accident. *. . . To
assign an a priori reason for this is difficult, though St. Thomas
gives several probable arguments . . . which Scotus and others
impugn, while Capreolus and Cajetan offer a vigorous and wide-
ranging defence. But I think the efforts of these two latter
writers unavailing, nor ought a wise philosopher look for demon
stration in a question as recondite as this. For unless it can be
shown to be above the degree of perfection possible to a created
substance to be the immediate and single principle of an act which
is in the order of accidents, we can assign no a priori reason why
our actually created agencies should always stand in need of an
accidental principle for actions of the kind in question.* We do
not know the special nature of these creatures sufficiently well
to be able to deduce therefrom the peculiar causes of this need or
defect. Hence in trying to develop an a priori proof, we must,
as St. Thomas wisely remarks, fall back on the general nature of the
created being as such. But if we make that general nature the
basis of our argument, we are really urging that God could not
create a substance that would be of itself an immediate principle
of action. It is difficult, however, either to render plausible or
to prove a consequence of that kind : infinite perfection in the
order of substance does not seem to be necessary in order that a

170 COSMOLOGY

creature should act proximately and solely by its own substance,
but every perfection that is not infinite seems communicable to
creatures. If that be so, how do we know that this mode of
acting has not been communicated ? or how can we prove the
alleged need (of a distinct accidental principle of action) from the
general notion of created being ? " This hesitation of Suarez
and others, concerning the value of the arguments from philosophy
regarding the nature of this distinction between substance and
the material accidents, did not affect their belief in the doctrine
itself. The thesis of absolute accidents was as certain for Suarez
and Scotus and all theirs, as it was for St. Thomas and his. For
all of them, its irrefragable basis was the current teaching about
the Eucharistic species : after consecration, the substance of bread
and wine disappear but the quantity and the sensible qualities
of bread and wine persist.

Scotus (32) and his followers, while assenting to the reality of
this distinction between substance and certain accidents, main
tained that created substance might, apart from really distinct
accidents, exercise various forms of activity. Their view was
that substance, and it alone, does produce other substances :
that substance can produce, immediately and by true physical
action, accidents in itself or in another substance ; finally, that
all active accidents can, both by real and by intentional action,
produce their like in other substances — and can do this, whether
united or not with their substrate. The grounds of this Scotistic
teaching were alleged to be drawn from experience and from
reasoning. Keasoning proves that accidents cannot produce a
substance. Experience proves that substance can produce
accidents within itself : boiling water when removed from the
fire reproduces within itself the natural accident of cold : the
four elements — and all non-living substances — when first gene
rated reproduce within themselves those respective properties
which are, confessedly, distinct accidents ; finally, reasoning con
firms these facts, for if one accident can produce another, why
cannot a substance which is a more perfect reality produce an
accident ? Experience proves that substances can produce, im
mediately, accidents in other bodies : there is no formal quality
of heat in either pepper or wine, and yet both of these substances
heat palate and stomach ; reasoning confirms this experience in
two ways — if a substance can produce accidents in itself why not
in another, and if an accident can produce an accident why can
not a substance ? Finally, facts prove that, even when the
substance is distant or absent, accidents can produce other acci
dents both by physical and by intentional action ; and if they
can do this, when distant from or separated from these substances,
afortoiri they can do as much when working with the same sub
stances. If these arguments prove anything they prove that a
non-living substance, of itself and apart from its accidents, can
cause all those effects which are normally produced by its acci
dents. All the Scotists accept this conclusion but most of them

SUBSTANCE AND ACCIDENT 171

teach, in opposition to Mastrius, that when active accidents are
united to their non-living substance, they and not it produce
similar accidents in other bodies : their plea being that when
two causes coexist, one univocal, the other aequivocal, and both
sufficient for the effect, this effect must be attributed to the
univocal cause, for it is more determined towards that result ;
and they add that though every medievalist believes the sun
can breed frogs in mud, not one of them dreams of ascribing any
particular frog to the action of the sun as soon as he is aware
that other frogs were previously in this mud. If this exposition
be accurate, the ordinary terse statement that Scotists denied a
real distinction between the active qualities and their non-living
substances is slightly misleading, ocotus and his disciples held
that a non-living substance had an activity of its own which it
may, and sometimes did, exercise apart from all accidents : but
they held, also, that this non-living substance had active powers
which were accidents and were really distinct from itself ; and
they were of one mind with Thomist and Suarezian regarding the
theological inference that justified the nature and the number of
these absolute accidents.

Ockham and the Nominalists agreed with the general thesis
of the existence of absolute accidents, but denied that quantity
was an absolute accident. Material substance has of itself distinct
extended parts, and so has each material quality : the same
reality that is substance as material subject is quantity as dis
tinction and extension of parts, and the same reality that is
material quality as colour, heat, etc., is quantity as distinction
and extension of parts ; consequently, there are in each existing
body as many distinct kinds of quantity as there are distinct
kinds of positive entities. Primordial matter has its quantity,
substantial form its quantity, and the accidental forms their
respective quantities : and as these distinct entities can corn-
penetrate one another, it follows that the various quantities can
compenetrate one another ; it was held, however, that the con
sistency and thickness of quantity was greater in primordial
matter than in substantial or accidental forms. But while thus
emphasising the denial of a real distinction between substance
and its quantity or between quality and its quantity, Nomina
lists are not explicit on what degree of distinction they would
admit in such cases : since they speak of Christ's Body existing
in the Host apart from its normal quantity, they seemed to have
admitted some kind of actual distinction between substance and
quantity. Their first argument is built on Ockham's razor :
"it is idle to do by many things what may be done by fewer."
Material substance has of itself really distinct and really extended
parts ; it has really distinct parts because just as complete
entities are distinct from one another, so are partial entities ;
it has really extended parts because distinct entities, even though
they are partial, naturally postulate distinct spatial locations ;
therefore, there is no need in material substance, and the same

172 COSMOLOGY

applies to any material quality, of a really distinct accident of
quantity. The second argument of the Nominalists is that if
God conserved a substance apart from the alleged really distinct
accident of quantity, the substance thus conserved would still
be quantified for it would still possess its distinction of entitative
parts, the union of these parts, and the locations of these parts.
A third plea was that God could conserve the alleged really distinct
accident in a substance and yet destroy the quantitative nature
of that substance : without destroying any part of the entity
of a two cubic feet body, God could reduce it to the size of one
cubic foot ; without destroying any part of its entity, He could
reduce this two cubic feet body even to a point — and clearly in
this punctual state, the body would not be quantified.

Suarez retails these arguments for the purpose of refuting
them : His attitude is that the anti-Nominalist view is sufficiently
probable from the standpoint of philosophy, and can be proved
convincingly from the theology of the Eucharist. He begins by
attacking that ambiguous assertion, in the Nominalist view, of
a difference between the kind of quantity that is in substance
and the kind of quantity that is in quality. If there be no
difference between the various consistencies of primordial matter
and of substantial and accidental forms, then, all these entities
are genuinely quantified : but then, the Nominalists have no
right to distinguish between these various kinds of quantity ;
moreover, even this theory will not explain the Mystery, for we
know that the quantity of whiteness does not of itself expel
another body from the same place, and does not of itself make
its internal parts impenetrable in their spatial positions. If the
quantities of the various forms, accidental and substantial, are
different from the quantity of matter this must mean that the
local extension of these forms is really due to the quantity that
is in matter. That is an intelligible theory. But it is a theory
that postulates several new miracles in the Eucharistic species :
first of all, it implies that there is no true quantity in the conse
crated elements, and no natural explanation of their twofold
impenetrability; next, it implies that there is nothing in the
consecrated elements to hold the sensible qualities together either
among themselves or in anything else ; again, it implies that
there is nothing in the consecrated elements to account for their
natural intensity and diminution seeing that the sensible qualities,
there, do not inhere in a subject ; consequently, miracles must be
postulated for all these purposes. Suarez continues by an attack
on the three arguments of the Nominalists. He makes prac
tically the same reply to the first and second arguments : he
grants that distinct entitative parts exist in substance apart
from quantity — this is denied by the Thomists — and also that
these entitative parts can by divine power be differently localised
apart from quantity ; he denies, however, that this divine
local spatialisation would make the substance quantified, on the
ground that even two angels can be locally separated. A sub-

ORIGIN OF ACCIDENTS 173

stance is not, he urges, quantified unless it has that within it
which excludes other substances from its own location and ex
cludes its various internal parts from the locations of one another :
and this is impossible apart from a distinct accident of quantity.
The substance, of which Nominalists speak, is not impenetrable
either in its parts or as a whole : it is one thing to exist in dis
tinct locations, it is quite another thing to exist in these distinct
locations in such a way as to exclude from them other bodies
or other parts. He replies to the third argument by denying its
fundamental assumption : a substance cannot, he holds, become
unquantified as long as it possesses the accident of quantity.
It is generally allowed that God could reduce a body of two cubic
feet to the size of one cubic foot, or, indeed, to any extended size,
however small. " God (33) would effect this reduction, however,
not by condensation of parts but by their compenetration. He
would not make these parts less quantified, He would not make
any two parts into one, He would merely localise these parts in
the same space ; a very different thing. It is controverted
whether it is possible to reduce a quantitative whole to an in
divisible space : but on the supposition of the Eucharist ... I
have no doubt about the affirmative answer. I deny, however,
that a substance, when thus confined within an indivisible space,
becomes unquantified : for the Body of Christ has its quantity
in the Sacrament although It exists there in an indivisible point.
And my reason is, that quantity is not actual but aptitudinal
extension in space : hence, a body even when not actually existing
in extended space can retain this."

THE ORIGIN OF ACCIDENTS.

Accidents are of two kinds, proper and common : proper
accidents, which are also called properties, are accidents that
are extraneous to the specific essence of the substance in which
they exist but are, for all that, the inalienable heritage and in
separable concomitant of that essence ; common accidents are
those fleeting, fortuitous accidents which result in any substance
from the interplay of surrounding circumstances and which, accor
dingly, may come or go without prejudice to the specific essence
of that substance. No serious controversy arose concerning the
origin of the common accidents : they are incidental changes
wrought by some cause ; educed as they are by external
causes out of the potency of their subject, they depend on that
subject in production, existence, conservation. Controversy did
arise concerning the origin of proper accidents. All agreed that
proper accidents originate from their respective substances by
a process called dimanation or emanation or resultance. But
they were not agreed on the exact nature of this process. Thom-
ists (34) held that resultance was not of itself real efficient
causality : once the substance is produced, its properties flow

174 COSMOLOGY

from it immediately by natural resultance but not by true causal
action. Scotists (35) and Suarezians held that the substance
produces within itself efficiently its properties. The opinion (36)
of St. Thomas is disputed : the greater number of texts seem
to imply that properties need no other cause for their resultance
than the agent which produces their connatural substance ;
other texts seem to imply that properties are produced by a dis
tinct action on the part of their connatural substance. Caje-
tan (37) suggests that properties owe their origin to the efficiency,
but not to the action, of their connatural subject : this distinction,
between causes that are efficient with action and causes that
are efficient without action, is obviously a solution of the fairy
godmother type — a cause that did not act could not be truly
efficient.

Thomists argue that the suggested causality of the substance
is needless : the same cause that produces the substantial form,
and thereby the substance, produces what is necessary for the
existence and activity of that substance, namely, its properties :
the generator ought to produce an effect totally and absolutely.
Hence their explanation of resultance : properties as resultants
are not the direct term of causal action but the inevitable sequel
of the production of substance. The theory of Scotus and Suarez,
that properties owe their existence to the causal action of their
connatural substance, leads, according to Thomists; to two in
admissible conclusions : one that finite substance is immediately
operative ; another that non-living substances are endowed with
immanent activity. Scotus and Suarez accept light-heartedly
the first of these conclusions : it is part of the general system
of Scotus ; it is the only solution of the origin of substantial
form for Suarez. As regards the second conclusion, Scotists
and Suarezians reply that non-living substances act immanently
for the one purpose of attaining their connatural state : all
non-living substances produce their properties, and the four
elements, when obstacles are removed, seek their natural places,
but their power of acting immanently stops at that ; in short,
not all kinds of immanent action are vital. The view of Scotus
and Suarez was strongly enforced by two quaint consequences
of Aristotelian physics : light and heavy bodies when out of their
natural places were thought by all medievalists to be able, when
obstacles were removed, to move towards their respective places ;
boiled water when taken off the fire was thought by all to re
produce of itself and within itself the formal property of water,
coldness. Scotists and Suarezians insisted on these alleged facts as
incontrovertible proofs of the true causal efficiency of emanation.
With Aristotelian physics and metaphysics as presuppositions,
the only reply Thomists could make to the first alleged fact was
that the generative action of the generating cause remains vir
tually in the substantial form of each generated substance and
affords, therefore, even in the absence or non-existence of that
generating cause, a sufficient explanation of the motion of the

EXISTENCE OF ACCIDENTS 175

elements to their natural places. Some Thomists make the same
reply to the second fact. Cajetan argued, however, that the
property of cold was never expelled by the heat : it was merely
hindered from continuing its action by the heat ; and when that
heat was removed, the property simply resumes its action ;
therefore, there is no need for any causal action of the substantial
form of water.

THE EXISTENCE OF THE ACCIDENT.

Three opinions were mooted in the School concerning the
manner of existence of accidents. Capreolus (38) and a few
Thomists taught that existence fell primarily on the substance and
secondarily on its accidents : in other words, that the existence
of the accident was identical with the existence of the substance.
Scotus (39) and Suarez and their followers taught that the exist
ence of the accident was not only really distinct from the exist
ence of the substance but was wholly identified with the essence
of the accident. St. Thomas (40) and the majority of the Thom
ists taught that the existence of the accident was really distinct
from the existence of the substance but that, nevertheless, the
existence of the accident was dependent on the existence of the
substance : in other words, that existence does not belong pri
marily to the accident alone, but to the individual made up of
substance and accident.

The first opinion maintains that there is but one existence
in every individual : the existence of the substance, and it is
shared by all the accidents, proper and common. Accidents add
new perfections to the substance but they do not bring a new
existence. The single existence has not the same connexion
with the substance and its accidents : it is logically subsequent
to, and completes, the substance ; it is logically prior to all the
accidents. Finally, this existence is the bond of individual
unity that welds the substance and its accidents into a concrete
unitary being. The chief arguments for this opinion are based
on the unity of the individual, and on the nature of accidents. A
unitary being cannot have two or more distinct existences : if
the substance has its own existence and each of the accidents
its own, these distinct realities remain, say and do what you will,
a mere aggregate. Again, an accident that has an existence of
its own is practically a substance for it is a self -subsisting reality.
The second opinion is prevalent amongst all who hold the two
theories of the identity in finite existents of essence and existence,
and of real distinction between the substance and accidents.
Their favourite arguments are two : essence and existence are
not really distinct in any finite reality and, consequently, accidents
cannot be really distinct from substance except they have an
existence of their own ; moreover, the existence of the accidents
of bread and wine after the consecration compels us to hold, that
these accidents have an existence of their own, apart from the

176 COSMOLOGY

existence of the substance, and if these particular accidents have
an existence of their own, all accidents ought to have it.

St. Thomas and the Thomists reject, as we have seen, the
basis of the first argument of Scotus and Suarez. Further, they
deny the consequence which their opponents draw from the
Eucharist : the miracle of the separate existence of accidents
in this Mystery consists in the fact that one of them, quantity,
receives an existence for itself as a separate reality instead of
receiving existence as part of a compound unit which comprises
substance and accidents. These Thomists start with the con
tention that accidents must have some kind of existence because
they are realities. That existence of the accidents cannot be
identical, however, with the existence of the substance for many
reasons : one is that the substance precedes, by priority of nature,
its proper accidents and, by priority of time, its common accidents ;
another is that many accidents are produced by true causal
activity, and causation implies the production of a new existence ;
a third is that an accident which shared the existence of the
substance could not be really distinct from that substance.
Neither can that existence of the accident fall on the accidents
alone : if it did, the accident would become a self-subsisting reality
extraneous to the substance. The result would be that such an
accident could not unite with the substance to form a concrete
individual. Suarez recognised this difficulty, and tried to meet
it by inventing a mode of inhesion. This mode creates more
difficulties than it solves : it is neither substance nor accident,
yet it is a positive entity ; as a positive entity it would seem to
postulate another mode for uniting itself to the accident, and so
on to infinity ; and even were this mode united with the accident,
the problem of the inherence of the accident in the substance is
left on our hands, for a mode of inhesion, that is immediately
received into an accident and is a mode of this accident, cannot
be a link between this accident and its substance. But while
holding that the essence of the accident is distinct from the
essence of the substance, and that the existence of the accident
is distinct from the existence of the substance, St. Thomas and
his disciples insist that the existence of the accident depends on
the existence of the substance. There is a dependence of origin
and of maintenance : all accidents originate in substance — by
resistance or by eduction ; all accidents inhere in, and are
sustained by, substance ; and this double dependence involves,
as a necessary sequel, a dependence in activity. The upshot of
this Thomistic theory is that the unity which results from the
union of substance and accident is unique in its kind. This
unity is different from that which results from the union of
primordial matter and substantial form : " hence (41) from
accident and subject there arises not an absolute (per se) unity
but a relative (per accidens) kind of unity, and that is why their
union does not give rise to an essence as does the union of form
with matter ; hence, also, the accident has neither the nature

INDIVIDUATION OF ACCIDENTS 177

of a complete essence, nor is it part of a complete essence but just
as it has, in a way, (secundum quid) being so it has, in a way,
essence." " Existence (41) of this kind (i.e. the existence of the
accident) can be multiplied in a single hypostasis or person, for
the existence by which Socrates is white is different from the
existence by which Socrates is musical, but that existence which
belongs directly to the hypostasis or person cannot be multiplied
in any single hypostasis or person because one being can have
only one existence." Elsewhere St. Thomas insists that this
unity is different from a mere aggregation of distinct supposits :
" for the subject (42) and the accident are not united in such a
way as to give rise to a third something : hence the subject
does not exist as a part within this union, but is a whole which is
person, hypostasis and supposit ; the accident is so linked up
with the personality of the subject that the same person and,
similarily, the same hypostasis and the same supposit is human
and white."

THE INDIVIDUATION OF THE ACCIDENT.

A diversity of opinion, analogous to that which prevailed on
the individuation of substance, manifested itself on the question
of the individuation of the accident. St. Thomas (43) and his
disciples taught that all accidents except indeterminate quantity
were individuated by their subject. " Accidents (44) are in
dividuated by their subject : whiteness is said to be a particular
whiteness because it is in a particular subject." " Just as acci
dents have existence in the subject, so they receive unity and
multitude from the subject." " It must be remembered that
accidents are not individuated by primordial matter : they are
individuated by their proper subject which is actual being just
as substantial forms are individuated by primordial matter which
is their subject." The grounds of this theory is that accidental
forms, like substantial forms, are of themselves universal and
communicable, and can be made singular and incommunicable
only by being received into some individual substrate : and the
proper substrate of the accident is a whole substance. This
individuation is due to the subject taken, not generally as a subject,
but, as a subject existing here and now under particular condi
tions : the subject individuates each accident inasmuch as it is
the patient to the same agent in the same action and at the same
time. An exception was made for that pecuniarily Thomistic
accident of " indeterminate " quantity because it was said to
be of its very nature individualised. In opposition (45) to this
theory, Scotus and Suarez and their disciples taught that acci
dents were individuated by their own entity. Accidents cannot,
these declare, be individuated by their subject as an intrinsic
principle, for the simple reason that they are distinct from this
subject. Nor can the accidents be individuated by their subject
as a term which is particularly suitable, because the same subject

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178 COSMOLOGY

can receive in succession several accidents which are merely
numerically distinct. Here, as in the problem of substantial
individuation, the Thomists partially agree with Suarez : they
agree that the accident is individuated by its own entity as
proximate and immediate principle ; they deny that it is in
dividuated by this entity as fundamental principle ; their con
tention is that you cannot help asking yourself the ultimate
explanation of the individualised entity of the accident, its
thisness, and that, when you do raise this question, you find no
answer save in the individuality of its subject.

THE INTRODUCTION or PHYSICAL INTRINSIC MODES.

The word " mode " has many meanings in the Philosophy of
the School : it is used in Logic to express certain relations be
tween subject and predicate — necessary, impossible, contingent,
possible ; it is used as the equivalent of difference — the specific
difference that contracts the genus, the individual difference that
contracts the species ; it is sometimes used as the equivalent of
all kinds of accidents but, more particularly, of modal accidents
as contrasted with absolute accidents. None of these meanings
has any connexion with our present topic : the physical intrinsic
mode. This physical intrinsic mode is alleged to be some positive
factor which is neither a substance nor an accident and yet may
concur in determining the build of either one or the other : it
is said to be some kind of diminutive entity which, in certain
instances, determines positively the manner in which a substance
or an accident exists. Most of the Schoolmen held that substance
had an existence of its own, and that accident had an existence
of its own : and on that account, they termed the substance
and the accident realities. These physical intrinsic modes are
confessedly not realities in this sense : they are said, indeed, to
exist either in the substance or in the accident but they have no
existence of their own in any way ; not even preternaturally,
can they exist apart from that reality of which they are modes.

The origin of this theory of modes is difficult to discover : Dur-
andus who flourished in the beginning of the fourteenth century is
said to have invented it ; Suarez who flourished towards the close
of the sixteenth century is credited with the fame of having made
it thoroughly consistent. He certainly was successful in popular
ising it : after his day, Scotists (46) and Suarezians rallied in
overwhelming numbers to the defence of these physical intrinsic
modes. Late medieval Thomists were less enthusiastic about
this discovery. Hueber, writing at the beginning of the eight
eenth century, declares that the majority of the Thomists reject
the theory of the modes : he admits, however, that very many
contemporary Thomists and a few of the older Thomists defend
it. " Durandus," testifies Cardinal Pallavicinus,(47) " was the
first to introduce this kind of entity called, by recent writers, a

INTRINSIC PHYSICAL MODES 179

mode : during the three centuries subsequent to his time, this
theory found only an occasional supporter ; but since Suarez
and other recent writers adopted it and confirmed it by ingenious
arguments, this upstart has become dominant in the Schools."
Vasquez (48) affirms that the mode of union was invented only
a few years previously to the time he himself was writing. And
although Vasquez defended the existence of modes, the multi
plication and invention of needless ones forced him to utter a
warning. " To multiply modes (in the way in which some
authors did, by postulating a mode of union for two partial sub
sistences in the one supposit) and to explain everything in Philo
sophy by modes and modes of modes is ludicrous : especially as
things can be philosophically explained quite well enough without
them." But once this new theory became fashionable, Mastrius
discovered it everywhere in Scotus. So far as my reading permits
me to hazard an opinion, no advocate of the theory has been able
to find a genuine trace of it in the text either of St. Thomas, or
of the great Dominican commentators on St. Thomas.

Suarez defines a physical intrinsic mode as something positive
which affects the reality either of a substance or an accident,
and bestows on that reality something distinct from either essence
when actually existing : this something ultimately determines the
state of that existence, and yet does not add any new entity but
merely modifies the pre-existing entity. Some of the modes are
substantial : the mode of union between primordial matter and
substantial form. Others are accidental : for instance, the mode
of inherence that affects an accident. Anti-modists (49) in the
School urge that this definition involves a contradiction : if a
mode is something positive and distinct from the reality which
it effects, it is impossible to maintain that the mode does not
add an entity of its own to that reality. The only reply that can
be, or has been made, to this objection is that Suarez's denial of
the entity of the mode must not be interpreted too strictly. But,
Suarez dare not consent to this suggested emendation of his
theory : when you ask why primordial matter and substantial
form cannot unite of themselves and, yet, can unite by means
of the mode of union, the strong point of his defence is that this
mode is not strictly an entity : when you ask why accident
and substance cannot unite of themselves and, yet, can unite by
means of the mode of inherence, again the strong point of his
defence is that this mode is not strictly an entity ; did he
concede that either of these modes was strictly an entity, he
would be launched on the infinite regress in both instances. Nor
are, anti-modists urge, the arguments for these modes com
pelling : Suarez suggests that primordial matter and substantial
form are indifferent to union or to separation and, therefore, need
a mode of union to overcome this indifference ; and he makes
a similar plea for the mode of inherence. But it was the older
teaching that whatever indifference may exist either between
primordial matter and substantial form, or between substance

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180 COSMOLOGY

and accident, is overcome by the extrinsic agent that brings
into existence these realities ; and that, as a matter of fact,
there can be no intrinsic indifference since these respective
realities are made for union with each other. And when the
modists invented these linkages, those who were faithful to the
older Masters urged that if these two modes brought about
immediate union, why could not union be brought about without
either of them : and that if these two modes brought about
union only mediately — that is, by the help of other modes —
modists are committed to an infinite and useless multiplicity of
modes.

The general argument in favour of accidental modes may be
summed up as follows : real changes of an accidental nature occur
in bodies which are not adequately explained by the accidents :
since these changes are real, they can be explained only by the
presence or absence of something positive ; therefore, physical
intrinsic modes, which are not accidents, must be admitted. The
examples put forward of these real changes are all of the same
type : a man must have some position, but that position is
always determinate — standing, sitting, reclining ; a body must
have some shape, but that shape is always determinate — square,
round, oblong ; an individual must exist somewhere in space,
but that somewhere is always determinate — Rome, Paris, Ox
ford ; an individual must exist somewhen in time, but that
somewhen is always determinate — Monday, Tuesday, Wednesday ;
and so on ad nauseam. The changes involved in the presence or
absence of these determinations are not mere nothings ; neither
are they illusions of our senses or of our intellect ; therefore,
there must exist, for each of them in their respective order, this
ultimate determining diminutive entity, the physical intrinsic
mode. Lessius condenses the gist of this style of reasoning in
a single argument. " Who will say," he writes, (50) " that
shape is merely logically distinct from the thing which it shapes,
or that when a body that was a sphere becomes a cube, it is changed
not really but conceptually or for our minds ? . . . Hence there
must exist modes really distinct from things and adding some
thing to these things : otherwise, the modes in question would
not be genuine, would not truly determine, would not cause
real change." The strength of this reasoning lies in the sugges
tion that if shape be not a diminutive entity really distinct from
body, there would be not a real but a conceptual change when
any particular shape is altered : That suggestion is, to say the
least, doubtful : even if a shape be not a physical intrinsic mode
distinct from the body, the juxtaposition of the various parts of
the body is real, and it is this juxtaposition that gives rise to the
shape. Again, what can be meant by the shape of rotundity, in
the sense of a physical intrinsic mode distinct from the body
which is thus modified ? Modists declare this mode and the
body to be two distinct positive somethings. On this supposition,
the question arises whether or not the body that is affected by

INTRINSIC PHYSICAL MODES 181

this mode of rotundity has its parts so juxtaposed as to give rise
to a round shape : if it has, then, the body itself is round apart
from the mode ; if it has not, if it has parts so juxtaposed as to
give to a square shape, then, how can the mode of roundness
make this square body round ? The truth seems to be that the
results attributed, in "each instance, to these alleged accidental
modes are due either to the internal relations of the various
parts of a bodily substance, or to the external relations of that
body with its surroundings. These various relations do not add
to the body any distinct reality of that kind which is meant by
a physical intrinsic mode : they are due to the action of some
extrinsic cause or term ; and they cease to exist when that action
fails.

This sketch must suffice as an account of the beginnings of
a theory which has been a fruitful source of controversy within
and without the School. Within the School, various con-
promises not always defensible in detail have long since put an
end to the acute phases of this controversy. But the older
Thomists would make no compromise. " It cannot (51) be
proved/' writes a Thomist at the beginning of the eighteenth
century, " that either Aristotle or any of the older philosophers
made any mention of this new kind of mode : it is manifest that
they accounted for all these indifferences of things without it ;
now if these indifferences were explained sufficiently without
modes in older times, they could also be explained sufficiently
in our day without modes." " I deny, then," writes another
Thomist (52) of the same period, " that anyone before Durandus
ever spoke of these modes. I grant that the authority of recent
writers is weighty and deserves serious consideration. But as in
other and even greater controversies, the upholders of the opinion
that these modes ought not to be defended in the Schools can
quote on its behalf the more important names." " Recent
writers," declares a Thomist (53) about 1753, " have made of all
things, that are neither complete substance nor quantity nor
quality, modes, and have invented a vast number of other modes.
Nor were they content thus to pile up mode on mode : they
insisted, also, that these modes are actually distinct from the
things to which they are attached. They seemed to themselves
to explain away every difficulty that arises about the determina
tion of things, and to fill up every void in nature by this class of
meticulous entities. The Scotists went further : for they in
vented, in addition to physical modes, an almost countless host
of metaphysical modes. . . . But despite the labour that all
these authors have expended on modes, not one of them has up
to the present given a blameless description of a mode, not to
speak at all of a definition. . . . And although there has been
this vast conspiracy of authors in recent centuries on behalf of
these modes, it is not true that the Thomist or Scotist School
or even the majority of the Jesuits support these modes because
the ancients never admitted modes of the kind defended in recent

182 COSMOLOGY

times. And it is worth remembering that no text of St. Thomas
can be quoted in favour of these modern modes : not even one
text of his can be safely appealed to by the Modists, despite the
general use of the word itself. Our Salisbury professors have, as
a body, rejected these modes : our Congregationists have, also, in
great numbers rejected them ; for the excellent reason that, by
doing so, they relieve Philosophy of a heavy burden, and can
devote their time to the study of things and of their natural
activities, rather than to the study of meticulous modes or re
lationships that have nothing to do with nature."

CHAPTEK VII.
THE ARISTOTELIAN SCHOOLMEN ON QUANTITY.

A QUANTIFIED reality, writes Aristotle, is one that is divisible
into parts which are in it and which are capable, after this division,
of existing as individuals. St. Thomas when commenting on
this definition points out that it, while assigning divisibility as
the chief note of quantity, excludes certain kinds of divisibility
from quantity. Quantified reality must contain formally the
parts into which it may be divided : hence, the dissolution of a
true mixture into the four elements is not a proof of the quanti
fication of that mixture. Quantified reality must be capable of
division into parts which, after division, can exist as individual
beings : hence, the divisibility of an essence into substantial
form and primordial matter is not indicative of quantity. Thanks
to this twofold condition concerning divisibility, Aristotle's defini
tion is applicable to quantitative wholes and to them alone. But
there is quantity and quantity. Quantity is discrete, when it is
made up of parts that are really distinct from one another and
have, each of them, a limit of its own ; its unity is merely mental,
and since its parts are really distinct from one another, it is a
multitude or a number of realities. Quantity is continuous
when it is made up of parts that are not really distinct from one
another and that are so united with one another that the limit
of one is identical with that of the next : its unity is independent
of the mind ; and it makes up a magnitude that is either wholly
or partially measurable according as it is finite or infinite. Now,
there are several kinds of continuous quantity : in particular,
successive and permanent quantity. Successive quantity has
integral parts that uninterruptedly follow one another according
to an order of before and after ; its principal subdivisions are
time and motion. Permanent quantity has all its parts existing
simultaneously, and these parts occupy different positions in
space : it is generally called extension. Extension is mentally
divisible into several kinds : extension of three dimensions
representing a body as it really exists, and known as volume ;
extension of two dimensions representing a body under the double
aspect of length and breadth, and known as surface ; extension
of one dimension representing a body under the one aspect of
length, and known as line.

Throughout this chapter, the only quantity that is in question
is permanent quantity.

183

184 COSMOLOGY

MEDIEVAL PRESUPPOSITIONS.

The Schoolmen developed their theory of permanent quantity
under the guidance of Aristotelian Physics and of theological
corollaries drawn from the Theology of the Eucharist. From
Aristotle, i1) the Schoolmen learned that the formal extension of
non-living bodies is an undeniable fact of sense perception ;
that the quantified body is mechanically divisible into parts each
of which is capable of existing as an individual ; that it is extended,
having parts outside parts, each in its own spatial position ;
that it is measurable and can serve as a standard of measurement
for other bodies ; that it is impenetrable in two ways, firstly
its internal parts are mutually impenetrable, secondly the whole
body as a single substance is impenetrable to other material
substances ; that it is as a whole a continuum, namely, a single
substance whose parts have not of and for themselves subsistence ;
that it has the three dimensions — length and breadth and thick
ness. This Aristotelian view of quantity was, however, affected
by consequences which were believed by medievalists to be im
plied in the theology of the Eucharist (2). This medieval modi
fication of Aristotle's theory of quantity was based mainly on
two corollaries : the separate existence after consecration of the
accidents of bread and wine ; the quantified existence of Christ's
Body in the consecrated species. A word about the history of
these corollaries is advisable.

Faith teaches that the substance both of bread and of wine is
changed into the Body and Blood of Christ. Our senses perceive
no change in the sensible appearances of either bread or wine
after the words of consecration. Now, whatever may have been
the connotation of the term " species " in the primitive doctrine
of the Eucharist, St. Ambrose explicitly interpreted this term as
referring to the accidents of bread and wine : nil falsi putandum
est in sacrificio veritatis. Thus, centuries before the Latins came
into contact with the metaphysical treatises of Aristotle, Catholic
theologians had accepted the view that the accidents of bread
and wine remain after the consecration. This doctrine of separ
able accidents, though acknowledged by all the School, was
explained in different ways : quantity and the sensible qualities
were separable for Thomist and Scotist ; the sensible qualities
and their respective quantities, as distinct from the quantity of
the substance, were separable for the Nominalist. (3)

The second important point in the medieval theory of quan
tity arose out of the question whether quantity and the accidents,
naturally connected therewith, were present with Christ's Body
in the Eucharist.!4) Most of the Schoolmen answered this
question in the affirmative. Durandus, Major, Gabriel, Ockham
and their followers dissented : but, with differences of implication.
Durandus admitted a real distinction between substance and
quantity but, as he believed the essence of quantity to consist in
local extension and impenetrability, he naturally concluded that

MEDIEVAL PRESUPPOSITIONS 185

Christ's Body was not quantified in the Eucharist ; then, he drew,
logically enough, a similar inference with reference to accidents
like heat and colour which inhere immediately in quantity.
Ockham and the Nominalists denied a real distinction between a
substance and its quantity but, since they admitted a real dis
tinction between a substance and its sensible qualities, they were
driven by their interpretation of " species " as the accidents of
bread and wine to admit in bodies another kind of quantity,
distinct from the quantity of the substance, and, peculiar to
the sensible qualities. The quantity of substance consists for
Nominalists in local extension which gives sensible mass and
natural impenetrability : hence, that kind of quantity was not
present with Christ's Body in the Eucharist ; Christ's Body was
in their view not actually but potentially quantified in the
Eucharist. They also excluded from Christ's Eucharistic Body
those other kinds of quantity that are proper to the sensible
qualities ; the sensible qualities of Christ's Body are, in the
Eucharist, without their respective quantities and inhere imme
diately in His Body. This view of Durandus and the Nominalists
was rejected by the rest of the School. All the others sided with
St. Thomas : " Since the substance of Christ's Body is not really
deprived of its dimensive quantity and its other accidents, it
follows that, by reason of real concomitance, the whole dimensive
quantity of Christ's Body and all its other accidents are in this
sacrament." (5) Suarez tells us that some believed the opinion
of Durandus to be heretical. He hesitates on several grounds
about attaching so grave a note of censure ; he has met no express
conciliar definition, and he can discover no absolutely convincing
argument based on revealed principles against it. His view is
that the strong arguments against Durandus are drawn from
philosophy : that these arguments are sufficient, almost certain,
yet not absolutely evident. He feels inclined, then, to agree
with Alexander of Hales in declaring the theory of Durandus
erroneous : he is sure that it is, at least, temerarious : it opposes
the teaching of the great theologians : it needlessly introduces
many unbecoming and absurd consequences into this Sacrament ;
it is hardly consistent on this topic with the language of Scrip
ture, of the Councils, and of the Fathers, for, all these imply in
their utterances that Christ's Body exists in the Eucharist as it
was on earth the night of the last Supper and as it is in heaven
since the Ascension. Then if you go further and ask, says
Suarez, whether the presence of other accidents is also theologi
cally certain : I am inclined to answer . . . not with regard to
all of them and not with equal certainty. For instance, local
presence and those accidents which depend intrinsically on it
such as motion, nearness, distance, are absent : Christ's Body has
not in the Eucharist that local presence etc. which It has in
heaven. But with regard to those accidents which do not depend
on local presence and yet are purely contingent, for example, the
sensible species of corporeal vision in heaven or the various

186 COSMOLOGY

degrees of temperature on earth, opinion is divided. Major
denies the presence of these in the Eucharist, because they depend
on extrinsic causes which may operate at one spot or one time
and not at another — and this denial is not as improbable as the
already rejected theories of Durandus and the Nominalists for
two reasons ; firstly, because it does not detract from the con
natural disposition and perfection of Christ's Body ; secondly,
because it is not contrary to the ordinary language of Scripture
or of the Saints. St. Thomas holds a contrary view, however,
and his teaching is more probable in itself and more widely
accepted, because the general argument from real concomitance
implies the pres.ence of these accidents and, because there is no
compelling reason for their exclusion. Medieval writers, there
fore, taught as a theological certainty the presence of the quantity
of Christ's Body in the Eucharist. " That which belongs to
Christ is in this sacrament in a twofold way : one way by reason
of the sacrament, another way by reason of real concomitance.
The dimensive quantity of Christ's Body is not in this sacrament
by reason of the sacrament itself : for only that which is the direct
term of the change (of substance) exists in this sacrament by
reason of the sacrament. But the direct term of the change that
occurs in this sacrament is the substance of the Body of Christ
and not Its dimensions : this is clear from the fact that, after
consecration, only the substance of bread passes away while the
dimensive quantity of bread persists. But since that substance
of the Body of Christ is not really divided from Its dimensive
quantity and from Its other accidents, it follows that, by reason
of real concomitance, the whole dimensive quantity and all the
accidents of the Body of Christ remain." " Since, therefore, the
substance of the Body of Christ is on the altar by reason of this
sacrament, whereas Its dimensive quantity is there concomitantly
and in a sense incidentally, it follows that the dimensive quantity
of the Body of Christ exists in this sacrament, not in its natural
manner . . . that is, not whole in the whole and each part in
each part . . . but after the manner of a substance whose nature
is to exist whole in the whole and whole in each part." (6) In
other words, the quantity of Christ's Body was present in the
Eucharist apart from all those external manifestations which had
seemed to Aristotle to be necessary : local extension, divisibility,
impenetrability, measurability.

THE ESSENCE OF QUANTITY.

By the essence of quantity the School understood that effect
which the presence of this accident confers first of all and with
absolute necessity on its subject. This essence was, accordingly,
the source of all other effects produced in the subject by quantity :
hence, it was spoken of as the primary effect, and these others as

ESSENCE OF QUANTITY 187

the secondary effects of that accident. The Schoolmen fought
vigorously over this question. Almost everyone of the alleged
consequences of quantity was set up by some Doctor as its primary
effect. In St. Thomas's day, the controversy had not begun
and, accordingly, texts of his are quoted in favour of several
views.i7) A similar doubt hangs over the attitude of Scotus
for the same reason. By degrees, the more unlikely theories
were set aside on the grounds either of reason or of revelation.
Thus, the majority of the Schoolmen refused to consider either
local extension, or divisibility, or impenetrability, or measur-
ability, as the essence of quantity : Christ's Body with Its quan
tity is present in the consecrated elements, whole in the whole
and whole in such each part thereof; actual divisibility or
impenetrability or measurability presupposes actual local ex
tension ; hence, the general view that none of these effects can
be the essence or primary formal effect of quantity. The con
troversy was, thereby, narrowed down to two opposing theories :
one asserting that quantity confers on substance distinct integral
parts, and the other asserting that quantity confers on substance .
the extension of already existing integral parts. The first theory .
has been styled the Thomist (8) view because it was defended,
mainly, by members of the Dominican order : it is, these Thom-
ists claim', the obvious meaning of the more decisive texts in
St. Thomas. The opposing theory (9) may be styled the anti-
Thomist view : it is hardly in Scotus, but it was warmly espoused
by his later disciples ; it was fully developed by Suarez, and
became popular with his disciples. Both theories agree on three
points : they agree that integral parts are parts which, when
taken together, make up the integrity of a substance, and which
can be removed, of course within limits, without destroying the
essence of the substance — for instance, the limbs of an animal,
the branches of a tree, the corners of a stone ; they agree that
the reality or entity, underlying these integral parts, is not derived
from the accident of quantity but from the substance and from
it alone ; they agree that substance, apart from the accident of
quantity, is not divisible after the manner of a quantitative
continuum. These theories differ simply on the issue, whether
the internal arrangement of the integral parts of substance
is due or is not due to the accident of quantity. Now, in
ternal arrangement means simply the entitative distinction of
these integral parts, not their separate existence as brought
about by the application of real limits. Thomists say this
internal arrangement of the integral parts is due to quantity,
and is its essence. Anti-Thomists say that this internal
arrangement exists in substance, apart from, and prior to,
quantity.

According to the Thomists, substance of itself has merely
the two essential constituents, primordial matter and substantial
form : it has of itself no actual integral parts, and is not divisible
into smaller portions each of which would contain the two essential

188 COSMOLOGY

constituents ; it has of itself nothing more than potential integral
parts, that is, the root and need of these parts. Apart from
quantity, then, substance is a composite of primordial matter
and substantial form which, while possessing within itself all the
substantial entity of integral parts, has not these parts as entita-
tively distinct : apart from quantity, the entity of these parts is
not actually distinct, one from the other, and not even God could
divide an unquantified substance into several parts of the same
kind. Substance of itself is indivisible : not because it is of
itself a point, for it is a physical substantial reality ; not because
it is a spirit, for it is made up of primordial matter and substantial
form, and it has in addition the root and need of integral parts ;
but, because it is a reality which, though capable of receiving into
itself the entitative distinction of integral parts, has not of itself
that entitative distinction. The accident of quantity introduces
into substance the distinction of integral parts, placing them one
outside the other within the whole. This mutual extraposition
of the parts within the substance is not to be confounded with
actual local extension : hence in the Thomist theory, a body can
be actually extended within itself apart from actual local ex
tension. This, then, is the essence or primary effect of quantity :
the secondary effects of quantity — the occupation of space and,
therewith, actual local extension, quantitative divisibility, mea-
surableness, and impenetrability in regard to other quantified
realities — follow naturally from it.

The strongest argument in favour of this theory is its harmony
with the theology of the Eucharist. Christ's Body has its quan
tity in the Eucharist by the mere fact that He has therein the
integral parts of His Body placed one outside the other in reference
to the Whole ; and as diffusion through space or local extension
is not of the essence of quantity, Christ's Body, even though
quantified, can be whole in the whole Host and whole in every
part of the Host. Thomists can say, therefore, that Christ's
Body in the Eucharist preserves its own real quantity because
It has the entitative distinction, the extraposition, the orderly
connexion of organs and limbs : the presence of Christ's proper
figure in the Eucharist, apart from Christ's size, emerges as a
natural sequel of the Thomist theory of quantity. The Thomists
rely, also, on arguments from reason. They argue that if sub
stance has of itself, as their opponents say, distinct integral parts
there would seem to be no need of the accident of quantity to
account for those other consequences on which these opponents
rely as proofs of the presence of that accident : if substance
has of itself distinct integral parts, then, these parts would of
themselves be naturally juxtaposed outside one another ; if
substance has of itself this juxtaposition of integral parts, these
juxtaposed parts would of themselves postulate local extension ;
and when their opponents urge that quantity is necessary because
the integral parts of that accident are of themselves impenetrable,
Thomists retort that there are no grounds for conferring impene-

ESSENCE OF QUANTITY 189

trability on the integral parts of an accident, and denying that
impenetrability to the integral parts of a substance.

Anti-Thomists urge two chief objections to this theory. They
urge, first of all, that quantity which is only an accident confers
in the Thomist view something substantial, namely, the sub
stantial entity of the integral parts : those parts are substantial,
but quantity cannot formally give anything substantial. Thom-
ists reply that the reality underlying the integral parts is, indeed,
substantial for it is the composite substance, but that the distinc
tion, the juxtaposition, the orderly connexion of these parts is
brought about by the accident of quantity : of itself, the sub
stance has only the potency of such parts ; quantity reduces this
potency to actuality, and thus makes these integral parts exist
as distinct, orderly, and juxtaposed within the substance. Most
Thomists are content to interpret this potentiality of integral
parts in substance as implying that such parts, prior to the advent
of the accident of quantity, are present merely radically and
exigitive. John of St. Thomas goes further : he interprets this
potentiality as implying that the whole reality of these parts
is present, prior to the advent of the accident of quantity, but
present in a state of fusion and confusion because ordered unity
between them is lacking. A second difficulty urged against the
Thomist theory is that no analogy can be given elsewhere of the
separation alleged in Christ's Eucharistic Body between internally
extended parts and the occupation of different spatial positions
by such parts : in other words, that the Thomists explain one
mystery by propounding another which is equally obscure.

On account of these objections and of arguments which shall
be given later, anti-Thomists contend that substance of itself has
not merely essential, but also integral substantial parts : it has
of itself the two essential constituents, primordial matter and
substantial form ; and it has of itself, also, integral parts that are
entitatively distinct. This possession of distinct integral parts
is generally spoken of as entitative composition of substance : it
implies the presence of these parts, their distinction from and their
orderly union with one another : it does not imply either the
mutual juxtaposition or impenetrability of these parts. And
since substance has of itself integral parts which are distinct from
one another, the parts are, at least absolutely, separable from
one another. This multiplicity of integral parts within substance,
prior to the advent of quantity, is also spoken of as entita
tive extension of substance. Anti-Thomists insist, however, that
substance, even with its distinct integral parts, is a reality outside
the genus of qualified continua : it has, indeed, integral parts
but those parts are intelligible, not sensible, and their distinction
from one another can be thought, not perceived. Hence sub
stance apart from quantity is not quantitatively divisible : but
if you mean by division merely the separation of one part from
another or a mutual discontinuity of parts, God can certainly
divide up these integral parts of substance into lesser parts.

190 COSMOLOGY

Now, the anti-Thomist holds that the accident of quantity
introduces mutual juxtaposition and impenetrability into these
already existing integral substantial parts. That accident has
accidental parts of its own which are distinct from and con-
naturally impenetrable with one another, and therefore, placed
one outside the other : these accidental parts inhere in the
various integral parts of the substance, and connaturally bestow
on these latter actual local extraposition. But since this actual
local extension can be prevented preternaturally, quantity
primarily confers on substance merely a proximate and positive
tendency towards local extension : proximate, because the in
tegral parts of substance have of themselves a remote tendency
towards extraposition ; positive, because the presence of this
accident confers on the integral parts of substance a real claim
to extraposition. The various secondary effects of quantity
follow naturally and easily from this primary effect.

This anti-Thomist theory also fitted the current theology of
the Eucharist. Christ's Body with its quantity is present in the
consecrated elements, for the essence of quantity is a proximate
and positive tendency towards local extension : God's miraculous
power prevents actual local extension, and thus, Christ's Body can
be whole in the whole Host and whole in every part of it. But
whereas the Thomists can allow actual internal extension to
Christ's Body in the Eucharist, their opponents cannot. Anti-
Thomists explain the presence of Christ's Body in the Host after
the analogy of the presence of a spirit in space : Christ's quantified
Body is present in the Host without actual local extension owing
to a miracle. They enlarge on this explanation in phrases suited
to their own theory : the " quantitative order " of the parts of
Christ's Body is present in the Host, but not the " situate " order :
the " quantitative distance," of these parts is present because
one part is not immediately but mediately united with some others,
but the local distance of these parts is not preserved ; the " or
ganic figure " is present because its parts are united in a deter
minate order and postulate extraposition in that order, but the
" situate " figure is not actually present.

Anti-Thomists claimed to be driven to this view of quantity
by the insuperable nature of the objections that could be urged
against the Thomist view. They alleged also a number of argu
ments in favour of their own view. Often they begin, as do the
Thomists, with the plea that if you grant such-and-such to be
the essence of quantity, you explain satisfactorily the secondary
effects of quantity and, also, all pertinent corollaries of the Euch
arist. That kind of plea, unfortunately, tells equally well in
favour of both disputants. The reason is obvious : at this stage,
Thomist and anti-Thomist are really extracting from their re
spective juggler's box the contents each of them had previously
hidden therein ; hence, this particular argument turns out to be
in each instance merely a subtle reconstruction of the mental
processes by which each party reached its view and, with dialec-

THE SECONDARY EFFECTS 191

ticians of medieval calibre, there is rarely a logical flaw in such
tactics. More marrow is discoverable in those other pleas of the
anti-Thomist which have already been mentioned as objections :
an accident cannot complete substance in any substantive way ;
besides, if integral parts be denied to material substance, the
difference between matter and spirit dwindles almost to vanishing
point. But if substance as such involves integral parts the
better alternative is, say the anti-Thomists, our view. Eucharistic
theology shows that the essence of quantity cannot consist in
actual local extension. Quantity must, therefore, be either actual
extension of the parts within the whole apart from local ex
tension, or a proximate and positive tendency towards local
extension. Anti-Thomists reject the first suggestion as un
necessary : if two bodies can by divine power compenetrate each
other, a pari the integral parts of a quantified substance can so
compenetrate one another as to remove all actual extension ;
again, spirit exists in space in an indivisible and a non-extended
way, and God could miraculously grant this mode of existence to
matter. They accept accordingly the second suggestion : quan
tity essentially confers on a substance a proximate and a positive
claim to local extension. They were led in this way to set up a
fundamental difference between two aptitudes for local extension :
a passive and remote aptitude which is basal, and is of the essence
of matter as substance : a positive and proximate aptitude which
is found in matter only as a result of the presence in its substance
of the accident of quantity ; and for the purpose of emphasising the
value of this accident, anti-Thomists taught this proximate and
positive tendency towards local extension to be so real that God
alone can prevent its realisation. This distinction of a twofold
aptitude towards extension has ever been set aside by Thomists
as indefensible. It is, Thomists urge, merely a feeble effort to
disguise the genuine relationship between the view of Scotus and
Suarez and that of the Nominalists : if substance has of itself any
kind of genuine capacity for local extension, what is the need of
this distinct accident called quantity which clearly does but
duplicate this alleged genuine capacity ? Anti-Thomists reply
that substance for the Nominalists does not postulate for its own
extension a distinct accident of quantity, because the substance
and its quantity were identical ; but substance for themselves
does postulate a distinct accident of quantity, because for them
substance has of itself only a remote tendency to local extension.

THE SECONDARY EFFECTS OF QUANTITY.

By the secondary effects of quantity the medievalists meant,
in practice, those consequences of quantity which are observable
in natural bodies but are miraculously suppressed in Christ's
Eucharistic Body. None of these secondary effects raised any
big controversies. For all the Schoolmen local extension followed
naturally on the reception by substance of quantity : quantity

192 COSMOLOGY

rendered the integral parts of substance mutually impenetrable,
and sets them one outside the other in space. Divisibility and
measurability followed naturally on local extension : an extended
body is both divisible and measurable. However, the medieval
theory of impenetrability needs watching.

Impenetrability was said to be due to the formal causality
of quantity. Experience, says St. Thomas,!10) proves that two
bodies cannot occupy the same place. Some allege, he proceeds,
that this mutual impenetrability is due to corpulency ; and by
corpulency, they mean density or impurity, or corruptibility, or,
at least, something special added to corporeity. But he rejects
all those explanations of impenetrability in favour of the theory
of Avicenna, which explains impenetrability by the suggestion
that quantity confers on each part of the substance a position in
space distinct from that occupied by its neighbour : when a
substance becomes quantified, its various parts receive and hold
different positions in space ; and the impenetrability, that exists
between distinct substances, results from this impenetrability
between the integral parts within each of them. " (Matter) is
brought (u) into relation with place by the fact of having dimen
sions ; and hence, owing to the fact that matter is subject to di
mensions, several bodies cannot exist in the same place." " That
which P2) prevents (penetration) is nothing else that those
dimensions by which corporeal matter is affected : for that which
is directly, must be, necessarily, a cause in some genus. Now,
distinct spatial position follows primarily and directly from
dimensive quantity, for this latter is defined as quantity that has
position. That is why the parts of a substance receive distinct
spatial positions from the very fact that they are subject to dimen
sions : and just as the distinction of the different parts of one
and the same body arising out of their distinct positions of space
is due to dimensions, similarly, different bodies are distinguishable
by those differences in location which they owe to their dimen
sions." Impenetrability is due, then, not to the efficient causality
of an active power but to the formal causality of quantity : owing
to the presence within it of this accident, the substance and its
integral parts occupy distinct positions in space in such a way that
no other material substance can enter therein. No other theory
received much support in the School. Sometimes, indeed, this
formal causality was spoken of as resistance, but the explanations
given of the latter word leave no room for doubt as to the author's
meaning. " In an action," writes St. Thomas,(33) " there may be
resistance in two ways : first, on the part of the agent, when, for
instance, his power is weakened by an agent to the contrary ;
secondly, on the part of the effect itself, when it is impeded by a
contrary disposition. In every action wherein the agent is not
acted on, the first kind of resistance does not occur, but only the
second. . . . But an effect is impeded more by the substraction
of the power of the recipient than oy way of contrary disposition."
Suarez (14) is equally explicit. " One thing may resist another

ENDLESS DIVISIBILITY 193

in two ways : first, formally, by immediate repugnance ; sec
ondly, radically, and, as it were, by a diminution of the others'
force. It is in this latter way . . . that amongst men one is
said to resist another, if, by anticipating his aggressor, he inflicts
a wound, cuts off the hand or diminishes in any other way the
powers of that other. Hence, this kind of resistance is nothing
else but an action. But the other kind of resistance does not
consist in action. . . . Hence, neither of itself primarily, nor by
any kind of consecutiveness, does this other kind of resistance
proceed from an active power inasmuch as it is active. . . . With
regard, therefore, to this form of resistance, it must be said not
to consist in any positive action proceeding from the power that
is called the force of resistance ; but to consist rather in the
privation of action. Hence, such resistance is rather impotence
or incapacity of some kind than a power properly so called ;
wherefore, it should not be mentioned among the divisions of
power. ... It consists, accordingly, in some formal incompati
bility or repugnance owing to which the action of the contrary
agent is either impeded altogether, or is rendered more slow or
more remiss. And, therefore, this actual resistance does not
consist in any second actuality of a positive kind that comes
from the resisting power ; but rather in the absence or retarda
tion or abatement of the contrary action. Hence, that kind of
resistive power is not a faculty of any kind that is of itself directed
towards absence or retardation of action : the reason is, that
natural power is not directed of itself towards any kind of
privation ; and that is why we say, this (kind of resistive power)
is not so much a power as a powerlessness and a kind of in
capacity."

THE ENDLESS DIVISIBILITY OF CONTINUA.

Aristotle's teaching on the divisibility of continua may be
summed up in two terse quotations (15) : " it is impossible to
form a continuum out of indivisibles, e.g. a line out of points " ;
" it is manifest that every continuum is divisible into parts that
are themselves divisible." This teaching was accepted with
practical unanimity by the earlier Schoolmen (16) : for them as
for him, a line was not resolvable into points, nor a plane into
lines, nor a solid into planes ; in each instance, however exhaus
tive the division of the continuum be, the resultant parts are ex
tended in one or more directions and, consequently, capable of
further division. The main medieval argument was a paraphrase
of Aristotle's indirect proof drawn from the impossibility of con
structing a continuum out of inextended points : were such points
to form a continuum, they should either touch or not touch one
another ; if they do not touch, they are at a distance from one
another and do not form a continuum ; if they do touch, then
since they are not extended and have no juxtaposed parts, they
necessarily coalesce and, therefore, do not form a continuum.

13

194 COSMOLOGY

" It is (17) impossible to construct a continuum out of indivisibles,
... a line out of points, if the line be truly continuous and the
point be truly indivisible. To begin with, the extremities of
points cannot unite into one for an indivisible has no extremities
distinct from parts which are not extremities. Neither can the
extremities (of points) lie together side by side for whatever has
no parts has no extremities — the extremity being necessarily dis
tinct from that whose extremity it is." " Aristotle proves that
a continuum cannot be constructed out of indivisibles either by
continuity or contact. . . . For when one thing is made out of
several either by fusion or by contact, there must be extremities
either to be fused or to lie side by side. The extremities of
points, however, cannot be fused for an extremity exists only
where a distinction of parts exists, and there is no such distinction
of parts in an indivisible. For a similar reason, one cannot speak
of the juxtaposition of the extremities of points : there can be
no extremity in what is indivisible, because the existence of an
extremity implies the existence of a something else of which it is
the extremity ; but, this distinction of parts is unthinkable in an
indivisible. Hence, pur conclusion that a line cannot be con
structed out of points either by fusion or by contact." (18)
This same conclusion was reached by an analysis of the nature
of continuity : the continuum is, as such, homogeneous — every
part within it is extended in the same way as the whole ; but the
continuum as a whole is divisible ; consequently each of its parts
is divisible : and hence, a continuum is endlessly divisible. " It is
true that a body is made less when some part of it is cut off, and
that is why some imagine this kind of cutting will finally reduce
the body to nothingness. That is not so : cutting never ends in
nothing. The reason is that every part which results is still a
body and, accordingly occupies, space : but, it could not do this
except it also had parts into which it could be cut. Hence, by
endless cutting, it can be endlessly lessened and, in that way, it
can undergo a loss and approach to nothingness : for all that, it
never actually arrives at nothingness." (19)

This early medieval thesis of the endless divisibility of con-
tinua was restricted to bodies when considered solely as extended.
Thomists taught, for instance, that even non-living substances
had a limit of smallness of size. " Although a body (20) is end
lessly divisible from the mathematical point of view, natural
bodies are not endlessly divisible. The reason is that, in a mathe
matical body, you have to think of nothing but quantity and that
does not prevent division. But a natural form exists in each
natural body, and that form postulates a certain fixity in quantity
as well as in the other accidents." " A mathematical (21) body is
endlessly divisible because extension is the only thing to be taken
into account when dealing with it, and extension does not exclude
infinite divisibility. A natural body with its form is not, however,
endlessly divisible because when the utmost limit of its size is
reached, it is forthwith changed . . . (by any further division)

ENDLESS DIVISIBILITY 195

. . . into another body." Despite a certain subtle dissent from
this general teaching, Scotists (22) may be said, in practice, to be
of one mind here with the rest of the School. Scotists denied,
it is true, that non-living bodies postulated, in reference to gener
ation, a fixed intrinsic parvity of quantity, but they admitted
that definite size limits were necessary for the conservation and
activity even of inanimate beings.

So baffling to the imagination are the consequences of this
thesis of the endless divisibility of continua that some of the
later Schoolmen (23) rejected it. These dissenters taught that
continua was formed by the union of indivisibles : many holding
these indivisibles to be finite in number ; a few holding them to
be infinite in number. Their main argument was the incredible
results of the older view : who could believe that God or an angel
might spend all eternity in breaking up a foot-rule and yet never
arrive at a fragment that was not further divisible ? further,
God must know all the possible fragments into which a foot-rule
is divisible and, therefore, its divisibility must somehow or other
have a limit. They argued, also, that as a perfect sphere can
touch a perfect plane only at a point, it follows that if such a
sphere be so continually moved and rotated over a plane as to
touch that plane everywhere, the sum of these points of touch
gives the length and breadth of the plane. Finally, they insisted
that lines are made up of points because the point is to the line
what one is to the other numbers. Those later Schoolmen, who
stood by the traditional thesis, made rather curt replies to these
arguments : a man ought to be led by his intellect and not by
his imagination — stick to facts and to principles, never recoil
from the consequences of either or both ; God knows facts and
possibilities, not contradictions ; perhaps the sphere touches the
plane at every conceivable point, but points are not realities,
they are merely mental abstractions, and the summation of
abstract entities raises no difficulty against the endless divisi
bility of extended bodies — such was one reply to this sphere objec
tion ; the sphere at rest touches only at one point, but the sphere
in motion touches in a continuous line — such was another reply ;
the final argument was usually rebutted by denying any parity
— unity is the principle of number but points cannot be, as
Aristotle's arguments prove, the principle of continuity.

A mediating theory which, Hurtado (24) says, was invented
by his master, had only a short medieval vogue. It taught that
continua were constructed out of distended points : the theory
was, in fact, a revival of that Pythagorism against which Zeno
had directed his dialectics. Continua were made up of points
indivisible in themselves but virtually extended : each indivisible
point occupies a certain volume of space and excludes, therefrom,
all other points— somewhat after the manner, in which a spirit
might occupy a space. A number of objections were urged
against this third theory by contemporary opponents : this
manner of occupying space is proper to spirits, and there is no

13*

196 COSMOLOGY

proof either of its necessity or its possibility in the case of matter ;
one might just as plausibly suggest that the whole universe is
one virtually extended indivisible point ; these points touch as
wholes, and there is nothing to prevent mutual compenetration ;
these points occupy space and ought, accordingly, to be both
sensibly percipient and absolutely unbreakable ; points distended
in three dimensions would form solids, but not planes nor lines,
points distended in two dimensions would form planes, but not
solids nor lines, points distended only in the dimension of length
would form lines but not planes nor solids : finally, it was argued
that the halving of a line made of three of these distended points,
or the division into a proportional number of parts of lines of un
equal lengths, was impossible. These objections scotched the
theory. But it seems to have been killed outright in those days
by an express prohibition of His Paternity, General Vitelleschi
(1615-1645).

THE MANNER OF EXISTENCE OF PARTS WITHIN A CONTINUUM.

Continuity, in general, implies that dimensive quantity per
vades a substance in such a way that its extended parts form a
unitary whole : this continuity was said to be perfect when
there were no pores within the extended substance ; it was said
to be imperfect when one or more pores existed within such a
substance. A continuum — or continuous substance — is, then,
a material substance whose parts hang together in unbroken
unity : and in medieval days, sense-perception was accepted as
the ordinary test of this unbrokenness. The nature of a con
tinuum excludes genuine internal limits. There are ways, how
ever, of introducing, into a continuum, limits that do not destroy
its internal singleness : a flag may be painted with various
colours ; an all-white flag may be covered here or there by a hand
or a book ; finally, apart from colours or hand or book I may,
mentally, contrast the top, the bottom, the right and the left,
of the flag. " The separation (25) (of a part of a continuum from
the whole) is rendered intelligible by any kind of marking. I
can, for example, mark off by touch or by thought any special
part and thus in a way divide the whole, and cut off a part from
that whole, saying there is less whiteness in the part than in the
whole." And apart from these methods of introducing external
limits which did not destroy continuity, the visible molar con-
tinua of medieval physics were of course being constantly broken
up into smaller separate units : stones into sand, logs into fag
gots, sheets into strips, and so on. Now, it was the common
doctrine of the School that none of these methods of division
produced the entity of the subsequent parts : division pre
supposes the entity of the parts, and merely destroys in one way
or another the link between such parts. " A continuum is
divisible into its internal parts," says Aristotle, but he adds
elsewhere, " halves are in the continuum not actually but poten-

PARTS IN A CONTINUUM 197

tially." " The parts of a line," writes St. Thomas,(26) " are
not actually two but one : still, the line itself is potentially two
and becomes actually two when divided. Mere division of a
continuum produces these actualities : hence by dividing a
line, nothing new is induced in the parts that are broken up ;
the same linear essence, which was previously actually one and
potentially multiple, becomes actually multiple as a result of the
division. . . . And the same is true of a stone or of a fire."
" Similarly, when bodies are divided, two planes that previously
did not exist begin de novo to exist." (27) Scotus repeats the
same teaching : *' The parts of a continuum had the same positive
entity within the whole as they have later outside that whole :
but, within that whole, these parts had such a continuity as
excluded all actuality that would imply their being cut of? (from
one another), whereas, outside the whole, they have this actuality
of being cut off from one another." (28) Richard of Middletown
is equally explicit. " It must not be held that division gives to
the essence of the part any reality which this part had not already :
when one part is broken off from another, what happens is that
its essence exists now as a whole whereas, previously, it existed
merely as a part." (29) There was no divergence of opinion,
then, in medieval days about the doctrine that the parts of a
continuum existed prior to any kind of division.

But when the question was raised concerning the manner of
existence of these parts, the Schoolmen divided into two camps :
St. Thomas (30) and many Schoolmen held that, prior to division,
the parts of the continuum were merely potentially distinct ;
Scotus,(31) Suarez and others held that, prior to division, these
parts were actually distinct from one another. In its later
stages, this controversy became extremely lively. Those who
supported an actual distinction in post-Tridentine days appealed
in defence of their view to the third canon of the thirteenth
session. Then, not content with strengthening their meta
physics by this theological infiltration, they indulged roundly
in abuse : Hurtado explains the existence of the opposing view
by saying that just as no one is too ugly to find a lover, so no
theory is too idiotic to find a defender ; Arriaga speaks of the
opposing view as, already, obsolete and antiquated ; some Portu
guese professors reject it as paradoxical, and speak of the argu
ments in its favour as deserving ridicule rather than refutation.
The other side did not let this abuse go unanswered : Scares
taunts Hurtado with the calibre of the Schoolmen who, in the past,
defended this alleged fatuity ; he reminds Arriaga that what is
ancient is not, thereby, antiquated ; he recalls to his Portuguese
compatriots that the view, at which they scoff, was taught by the
ablest scholastic Portugal ever produced, by him who was known
in other lands as the Aristotle of Portugal, Fonseca ; finally, he
announces to all these epigones that, according to his information,
the Thomistic view is nowadays the most prevalent in Italy,
France and Germany. These epithets and retorts point to a

198 COSMOLOGY

grim and earnest controversy. It is difficult, however, to dis
cover any big issue behind it all. These disputants agreed that
a continuum has parts ; they agree, also, that prior to physical
division none of the parts has genuine limits ; they agree, more
over, that division other than physical introduces into a con
tinuum a sufficiently useful means of marking off part from part ;
their bone of contention was the exact formula for that distinction
of parts which existed prior to every kind of division in a con
tinuum. The controversy was, then, more about words than
facts. It must be remembered, however, that the peculiar
nature of material continuity makes almost impossible the inven
tion of words precise enough to describe the distinction of parts
within it. A non-living continuum is a unique whole : it is
through and through homogeneous, and on that account allows
neither difference nor opposition between its parts ; hence the
difficulty of distinguishing within it the integral parts. The
theory of potential distinction has much in its favour ; firstly
because, prior to either some kind of extrinsic designation or to
physical division, no part of a continuum can be distinguished
from any other ; secondly, because were the parts actually dis
tinguished they could be numbered, and then for those who
admitted, as did most of the Schoolmen, the endless divisibility
of continua, the parts of each finite continuum would constitute
an actually infinite number. Further, if one recalls that this
theory of potential distinction admits the presence of whatever
entity is in those parts that can, in all the ways mentioned, become
actual, all objections can be fairly countered. A Thomist can
speak of parts within a continuum because, prior to either designa
tion or division, he admits potential parts ; he can speak of the
halves of any body because he mentally divides it ; he can speak
of entitative or material parts as actually present, prior to either
designation or division, because he admits as pre-existent in the
continuum the reality underlying all possible parts ; he can
refuse to speak of these entitative or material parts as actually
distinct at this prior stage, because that actual distinction implies
some kind of limit ; he can refuse to admit the identity of these
entitative parts at this prior stage, because a continuum differs
from an unextended substance precisely in this fact of having
parts outside parts, even though these parts are not actually
but potentially distinct. In short, the Thomists advocate for
the parts of a continuum a mean between actual identity and
actual distinction, a real potential distinction : a real distinction
because the continuum has parts outside parts within itself ; a
potential distinction because, prior to extrinsic designation or to
physical division, these parts are not actually distinct. And this
real potential distinction acts as a solvent of all objections.
Suarez urges the mere fact of one entitative part not being
another as sufficient proof of their actual distinction. Thomists
explain this lack of identity by the peculiar kind of potential
distinction which is verified of parts within a continuum, and only

LINKS AND LIMITS 199

of them. Suarez urges that this potential distinction must be
either real or virtual, and that as it cannot be virtual it must be
real : Thomists allow that this potential distinction is not virtual
in the sense in which man's sentient soul is virtually distinct
from his rational soul, but insist that it is a virtual distinction
in a unique sense of its own for the reason that it is founded on
that unique reality, material continuity, which excludes both the
identity and the actual distinction of the parts present in it.
Others urge that divisibility is an evident sign of an actual dis
tinction, for, otherwise, a reality could be divided from itself.
Thomists retort that their real potential distinction excludes
mutual identity and accounts for divisibility. Others urge that
the head, hands, trunk, and legs of a statue are surely actually
distinct from one another, and from the whole figure : Thomists
assent, but contend that these actual distinctions are consequent
on the various shapes of these parts, that is, on the introduction
from without of a number of limits. Others urge that the essence
of continuity consists in the juxtaposition of parts, and that
juxtaposition implies actual distinction : Thomists grant the
first proposition, but insist that the potential distinction of parts
suffices for juxtaposition ; they add, also, that in defending
continuity, our minds inevitably introduce limits into an object
which is, in itself, nothing more than an extended, homogeneous,
single substance.

INDIVISIBLES AS LINKS AND LIMITS IN A CONTINUUM.

The greater Schoolmen and the majority of their disciples
refused, as we saw, to admit that continua are made up of indivis
ibles of any kind. But controversies arose as to the nature of
those indivisibles that are conceivable as internal links or external
limits of formally extended bodies. These indivisible links or
limits were points, lines, and surfaces. The Schoolmen distin
guished between boundary and connective indivisibles : boun
dary indivisibles are those that terminate any special dimension —
external surfaces terminate solids, enclosing lines terminate sur
faces, external points terminate lines ; connective indivisibles are
those links that are thought of as existing within, and holding
together, the integral parts of a continuum — a line is thought of
as having its parts held together by points, a surface by lines, a
solid by surfaces. These common starting-points led to contro
versy regarding the nature of indivisibles. The genuine issues
at stake were crystallised in two theories. Scotus,(32) Suarez,
and many others held that indivisibles were positive realities
distinct from their continua, capable by divine or angelic power,
both of being separated therefrom and of being kept in existence
in this state of separation : for them, the boundary indivisible
of a solid was apparently a subtle indivisible membrane surround
ing that solid, the boundary indivisible of a surface a series of
subtle indivisible threads, the boundary indivisibles of a line

200 COSMOLOGY

two indivisible spheres at each extremity ; analogously, the
connective indivisibles within solids were surfaces without
depth, the connective indivisibles within surfaces lines without
depth and breadth, the connective indivisibles within lines
spheres distinct from the line itself and thought of as mathe
matical points. Albert the Great,(33) St. Thomas, Durandus,
Ockham and some later medievalists held that indivisibles were
negative-positive realities, that is, merely the abstract limits of
their various continua and, therefore, absolutely inseparable from
these continua : for them, a boundary surface was a solid thought
of as having length and breadth apart from depth, a boundary
line was the surface of a solid thought of as having length without
breadth, a boundary point was the extremity of the line of a
solid thought of as having position without magnitude ; ana
logously, connective indivisibles were not positive realities dis
tinct from the parts they were alleged to hold together — connec
tive points and lines and surfaces do not exist as physical separate
realities within bodies, they exist only as objects of thought for
our minds. On account of this theory their opponents accused
these writers, and especially the Nominalists among them, of de
crying points and lines and surfaces as fictions. If this accusation
means that Nominalists put these indivisibles on a par with
hobgoblins and mermaids, I should think it untrue. The Nomin
alists never seem to have denied that geometry had a real basis
for its objects of study in the position, length and breadth of
solids : what they did deny was that points and lines and sur
faces were positive realities physically separable by divine or an
gelic power from bodies, in other words, the alleged spheres and
threads and membranes of their opponents ; they seem to have
held that points and lines and surfaces exist formally only as
mental concepts, but they apparently allowed that all these were
realities in the sense of being genuine aspects of actually existing
bodies. For the Nominalists, points and lines and surfaces cannot
exist apart from solids, yet, our intellect does not lead us astray
in conceiving these indivisibles as abstractions ; these indivisibles
have a real existence but not in the insulation of their ideal form ;
a view that suits admirably the medieval Nominalistic theory of
knowledge with its blend of conceptualism and sense-realism.

Four chief arguments were advanced in favour of the separable
reality of these indivisibles : there must be something to hold
together the various parts of continua, and that something must
needs be distinct from what it holds together ; a continuum must
be limited by something positive, and that something can be only a
distinct indivisible ; one part of a line is really distinct from another
part, and that part which is at either extremity is, therefore,
really distinct from all intervening parts ; an indivisible cannot
be identical with what is essentially divisible — a formally extended
continuum. The disputants, on the other side, made short work
of these arguments. If the parts of a line are joined together
by points, the parts of a surface by lines, the parts of a solid by

LINKS AND LIMITS 201

surfaces, then, these connected parts because divisible must
consist of smaller parts, and the question arises whether these
smaller parts are or are not held together by distinct indivis
ibles : if they are not, there is no reason why larger parts cannot
be held together without these indivisibles ; if they are, then a
similar question can be raised ad infinitum about the parts of
these smaller parts ; the consequence is, that you must stop
somewhere at divisible parts which are held together without
indivisibles, or you have to envisage a continuum as a series of
indivisibles linked together by other indivisibles. The second
argument is countered by the plea that boundary indivisibles are,
according to the point of view, positive or negative realities :
positive, inasmuch as they are extremities of a real body ; nega
tive, inasmuch as they are a denial of further extension. A
similar reply is made to the third argument : a boundary in
divisible, when considered both positively and negatively, is cer
tainly not identical with that continuum which it limits : and
when considered solely in its positive aspect, it is merely a way
of thinking about one particular part of that continuum. In
reply to the last argument, it was allowed at once that the same
reality cannot in itself be divisible and indivisible : it was urged,
however, that the threefold dimensions of solid bodies offer to
our minds a basis for marking off therein aspects that prescind
from some or all of these dimensions. Side by side with these
refutations of their opponents' arguments, Ockham's razor
figures everywhere in this controversy : entities are not to be
needlessly multiplied, and every purpose, for which both kinds of
indivisibles were postulated, was sufficiently attained without
them. Boundary indivisibles are but mental aspects of the
various extremities of solids : a boundary point is a limit to
bodies that is thought of as position without magnitude ; a
boundary line is another kind of limit to bodies that is thought
of as length without breadth and depth ; a boundary surface is a
third kind of limit to bodies that is thought of as length and
breadth without depth. There is even less use for distinct
connective indivisibles : the parts of a continuum are immediately
and of themselves united — otherwise, a continuum must be
formed of indivisibles.

CHAPTER VIII.

THE ARISTOTELIAN SCHOOLMEN ON THE QUALITIES
OF MATTER.

QUALITY was for Aristotle and the Schoolmen an ultimate reality :
a something too elementary, St. Thomas warns us, to be strictly
definable. Aristotle himself i1) had spoken of quality as any
kind of distinctive trait : any reality that made a thing be such
and such. This wide definition enabled him to talk sometimes of
the substantial form as a quality. But the Schoolmen (2) grad
ually restricted the category of quality to accidental forms.
They were even unwilling to include under this category all the
accidental forms. They excluded from the category of quality
the accident of quantity and all its formal consequences, on the
ground that quantity simply extends bodies and makes them fit
for the reception of other accidents. They excluded, also, from
the category of quality the remaining categories of accidents,
action, passion, etc., on the grounds that these classes of ac
cidents determine the substance externally rather than inter
nally. The characteristic mark, then, of quality for the School,
is that it is an accidental form which exists primarily for the
purpose of disposing and perfecting internally a substance.
" Quality (3) is an accident that completes and perfects a sub
stance both in existence and in activity." " Quality is an acci
dent (4) that modifies or disposes a substance within itself."
" Although all the accidents (5) are in a sense attributes of sub
stance and are added thereto either on account of some imper
fection in it or for the purpose of supplying some defect in it,
still, there is this peculiarity about quality that-it is, of its very
nature, intended to adorn and perfect intrinsically a substance
in order to fit this latter adequately for its existence and its
activity. ... It is no use to object that some qualities are
unsuitable to some substances, for the existence of these qualities
in such substances is purely incidental : of their nature, these
qualities were made as part of the complete equipment of some
substance."

Qualities were variously classified by Aristotle and the School.
These classifications do not concern our present topic : the nature
of material qualities. In a previous chapter, the medieval theory
of a real distinction between an inanimate substance and its
material qualities was expounded. Our present chapter on the

202

ASTRONOMY AND ALCHEMY 203

nature of material qualities centres, wholly, on a different and no
less famous doctrine of the School : the distinction as formal
accidents between a material quality and all quantitative forms
of reality whether at rest or in motion.

ASTRONOMY AND ALCHEMY.

Medieval speculation concerning material qualities was based,
mainly, on the natural science of Aristotle. It is true that the
Schoolmen admitted in Astronomy and in Alchemy current post-
Aristotelian doctrines in natural science. But these post-
Aristotelian doctrines involved no fundamental breach with the
teaching of the Stagyrite.

Medieval astronomy was an amalgam of Aristotle, Hipparchus,
Ptolemy and Alphonso of Castile.!6) It differed from that
fashioned by Aristotle in two respects : the number of the prin
cipal spheres, and the introduction of epicycles and eccentrics.
Aristotle admitted only eight principal spheres : one each for the
Moon, Mercury, Venus, the Sun, Mars, Jupiter, Saturn, and the
fixed stars. Medievalists admitted two principal spheres outside
these eight : a ninth to account for what was alleged to be the
phenomenon of trepidation ; a tenth to account for what was
known as the precession of the equinoxes. And beyond these
movable spheres lay the Empyrean, the motionless heaven, the
abode of God and His angels and the glorified saints : a heaven
beyond which and above which there is nothing ; a heaven which
is known only by revelation. Again, Aristotle had postulated
an extraordinary number of minor spheres to account for the
wanderings of the planets. The growing complexity of this hypo
thetical machinery led the Schoolmen to prefer the later theories
of eccentric and epicycles : for instance, in the sixteenth cen
tury, when Fracastorius tried to revive the Aristotelian scheme,
he found himself obliged to postulate as many as seventy-nine
spheres ; on that account, the majority of the Schoolmen pre
ferred to accept the Ptolemaic scheme of eccentrics and epicycles.
In the theory of eccentrics, each planet was supposed to be
subject to two influences of revolution besides, of course, the
diurnal rotation common to all the heavenly bodies : a circular
movement of the planet itself round the centre of the earth from
west to east ; a circular movement of its eccentric not about the
centre of the earth, but about some different central point and in
the opposite direction. This theory was invented by Apollonius
of Perga (c. 230 B.C.). He soon abandoned it in favour of a more
celebrated theory that dominated astronomy for more than
1700 years : that of epicycles. The epicycle was a small revol-
ing circle to the circumference of which the planet was supposed
to be attached : the centre of this smaller sphere was situated
at a fixed point of the principal sphere of that particular planet ;
this smaller sphere rotated round an axis passing through this
centre ; finally, the principal sphere was revolving round the

204 COSMOLOGY

earth, either about its centre or, as an eccentric, about some other
centre. Ptolemy (c. 155 A.D.) accepted, in principle, these two
theories : by a combination of the opposite movements of epicycle
and eccentric, due regard being had to their relative velocity
and the magnitude of their diameters, he contrived to account
fairly well for the more obvious phenomena of planetary motions.
But, as in the case of the Aristotelian hypothesis of revolving
spheres, the progress of observation led to the need of imagining
epicycle within epicycle until Ptolemy's planetary scheme be
came as intricate and as cumbrous as Aristotle's. During the
middle ages, however, Aristotle, as modified by Hipparchus,
Ptolemy, and Alphonso, reigned supreme in astronomy.

Medieval Alchemy was mainly interested in the search for the
philosopher's stone. Its interest for the metaphysician lay
primarily in the dominant view that all bodies were composed of
mercury, sulphur, and salt. But, in those days, no one dreamt
of interpreting that suggestion as a rejection of the theory of
the four elements. St. Thomas (7) and other Schoolmen state
expressly that the theory of the alchemists is admissible if it
means that mercury, sulphur and salt are derived ultimately
from the four elements : and no alchemist of these early centuries
set up any claims antagonistic to Aristotle. Hence, despite the
advances made by Ptolemy in Astronomy and by the alchemists
in Alchemy, the natural science of Aristotle was the accepted
basis of medieval cosmology.

At first sight, it would appear that the Aristotelian doctrine
of the origin of all non-living substances out of the four elements
opened up the way for extensive medieval study of non-living
compounds. This hope is not fulfilled in the treatises of the
Schoolmen. They knew little about the inner physical structure
of non-living compounds ; they were content to distinguish
between perfect and imperfect mixtures ; when they speak of
perfect mixtures, they refer by choice to the parts of living
substances — skin, bone, flesh, etc. ; when they speak of imperfect
mixtures, they refer by choice to the obvious facts of metereology
—thunder and lightning, clouds, hail, sleet, snow, comets, etc. ;
in short, their treatment of non-living compounds is restricted
to a treatment of their qualities as perceived, or inferable from
their action on our senses or on one another, and their chief
theories in Cosmology are based on facts derived from the study
of the four elements and of the four qualities of Aristotle. There
is no mystery, then, about their method of discovering qualities
in non-living bodies. Trust in the veracity of the senses and of
the intellect was their guiding principle. Our senses make us
aware of one group of qualities, the sensible qualities of matter :
the proper sensibles or qualities which are known to one, and only
one, of our external senses — tangibles, colours, savours, odours
and sounds ; the only other qualities known as sensible are figure
or shape in all bodies, light in heavenly bodies with its effect of
brightness in terrestrial bodies. Our intellect makes us aware of

PEIMARY AND SECONDARY QUALITIES 205

other material qualities which are hidden from the senses, and are
known as virtual or occult : these virtual or occult qualities were
not of much interest to the School, and, apart from their discovery
by the intellect, were discussed after the analogy of the sensible
qualities. This meagre list contains every quality that figures
prominently in medieval Cosmology. Meagre as it is, the de
velopment of its contents in opposition to the kinetic theory of
Democritus led to a robust and unmistakable theory of material
qualities.

THE MEDIEVAL DISTINCTION BETWEEN PRIMARY AND
SECONDARY QUALITIES.

A distinction (8) was made within the proper sensibles be
tween primary and secondary qualities. Primary qualities were
said to be irreducible and prolific : they did not come from
other qualities ; they were the scource of other qualities.
This division occurs, first, in reference to the tangibles. There
are fourteen tangible qualities : heat, cold, dryness, moisture,
gravity, levity, hardness, softness, stickiness, brittleness, rough
ness, smoothness, density and rarity. Four of these fourteen
are primary : heat, cold, dryness, moisture. Thickness, brittle-
ness, and hardness are said to be secondary qualities derived
from cold. Thinness, stickiness and smoothness are said to be
secondary qualities derived from moisture. Levity and gravity,
density and rarity proved a puzzle to those writers who are stick
lers for a theory of four primaries whence originate all other
qualities : some of the Schoolmen put these four in a class by
themselves, on the ground that they play no direct part in the
processes of substantial change ; others frankly acknowledge the
impossibility of deriving them from the primaries, and classify
them as neutral, that is, neither primary nor secondary. The
division into primary and secondary qualities is said, also, to fit
the other proper sensibles : colours, savours, odours and — some
times — sounds are said to be secondary qualities derived from
the primary tangibles. The Schoolmen are aware, and on
occasion make handsome acknowledgment, of the origin of
varieties of colours, savours, odours and sounds from mixtures
of their respective fundamentals : colours form a series of which
black and white are the end-points ; savours, a series of which
sweet and bitter are end-points ; odours, a series of which the
agreeable and the disagreeable are end-points ; sounds, a series of
which musical and non-musical undertones are end-points ; and
all intermediate colours, savours, odours, sounds arise, according
to Aristotle and the School, out of a mixture of these end-points.
But this question of the production of intermediate colours,
savours, etc., by mixture of their respective end-points was over
shadowed in medieval days by the more difficult question of the
origin of colour, savour, odour and sound from the four primary
tangibles. This eduction did not prove as easy for the Schoolmen

206 COSMOLOGY

as Aristotle's passing references suggested : a fair unanimity of
view obtained about savour and odour ; but differences of opinion
arose and stayed about colour and sound. Savour was generally
held to be a secondary quality due to a mixture of the primary
qualities in which the hot and moist are dominant but in which
the hot is the more dominant of the two. Odour was held to be a
secondary quality due to a mixture of the primary qualities in such
proportions that the hot and the dry were dominant. As regards
colour, some of the School held with Plato that colour was merely
light received into the surface of opaque bodies : the more
prevalent view was, however, that colour was a quality per
manently existing in a body and resulting, therein, from the
mixture of the four elements. Sound proved in this connexion
a genuine stumbling-block : some held it was mere vibration, but
the majority held it was a quality distinct from vibration ; and
those who held it was a distinct quality failed to agree about its
subject — some suggesting the vibrating body, others the inter
vening medium, and others both of these/ This sketch will
impress on the reader the overwhelming importance attached by
the School to the four primary qualities. This importance is,
emphasised also, by the Aristotelico-Scholastic teaching about
the common sensibles. The common sensibles are aspects of
matter apprehended by more than one of our external senses.
Both Aristotle and the Schoolmen deny that these common
sensibles are qualities. (9) Aristotle, in one place, enumerates
them as five — size, figure, motion, rest, number ; elsewhere, he
adds unity ; farther on, he adds the rough and the smooth, the
acute and the obtuse. But he reduces unity to number, and the
rough and smooth, the acute and obtuse to figure : in another
place, he reduces all the five to motion ; and finally, he virtually
admits that the common sensibles are not properly objects of sense
at all. The Schoolmen followed this lead. St. Thomas regards
all the common sensibles as modifications of quantity or the
continuous ; and therewith they cease for him and his successors
to be qualities.

THE MEDIEVAL THEORY OF SENSE-PERCEPTION.

The Scholastic theory of the proper sensibles was developed
in opposition to the kinetic theory of Democritus. Demo-
critus (10) declared those sensations that are special to each of
the five external senses false, on the grounds that they do not
represent reality as it exists outside the percipient. " By con
vention there is sweet, by convention there is bitter ; by con
vention there is warm, and by convention there is cold ; by
convention, there is colour. But, in truth, there are atoms and
the void." ..." By the senses, we in truth know nothing sure,
but only something that changes according to the disposition of
the body, and of the things that enter into or resist it. " Truth
is in the depths " . . . " There are two kinds of knowledge, the

MEDIEVALISTS ON SENSE-PERCEPTION 207

true-born and the base-born. To the base-born belong all these :
sight, hearing, smell, taste, touch. The true-born is quite apart
from these." Fragments of this kind leave no doubt on any
reader's mind as to the Democritean theory of the proper
sensibles : what really exists is an infinite number of atoms
without either colour or sound or smell or taste or even tangibles,
except of course extension and mobility. Aristotle, divining in
the author of this theory a foe with a future, devotes several of
his chapters on the proper sensibles to criticism and rejection of
the view of Democritus. The School followed suit : they reject
root and branch the Democritean explanation of the proper
sensibles ; in other words, they reject the distinction made later
by Descartes and Locke between the primary and secondary
qualities of matter. Aristotle and Schoolmen use the same lan
guage — primary and secondary qualities — as do these moderns :
but, behind this identity of phrase, lurks two opposing and irre
concilable meanings. The full discussion of this topic belongs to
Psychology : here, I shall recall only its outline for the purpose
of expounding the medieval Cosmology of the proper sensibles.

Sensation is, for the School, a complex process by means of
which the percipient is affected by an external object in such a
way that his sense organs acquire for a time, as far as the nature
of the percipient permits, the quality which exists in the external
object. Moreover, the medievals (n) believed that this assimila
tion required the intervention of a medium between the sense
organ and the proper sensible : facts prove, they alleged, that,
when the proper sensible is in immediate contact with the sense
organ, sensation is impossible. There are, accordingly, three
factors in these sensations : the proper sensible ; the medium ;
the sense organs of the percipient. And there are three pro
cesses : the action of the proper sensible on the medium ; the
action of the medium on the external sense organ ; and finally
the conscious reaction within the percipient, a process that, on
the Aristotelico-medieval view, occurs in an internal sense organ
known as the common sensory.

The first factor (12) for the perception of a proper sensible is
the existence of such a sensible as an extra-mental reality outside
the percipient : vision does not see itself, it sees colours. If
matter existed while percipients did not, sensation would not
occur but those extramental realities, which cause sensations and
which are reproduced in sensations, would for all that exist.
Sensation is not the sensation of itself but of something distinct from
itself : and this distinct reality must exist prior to sensation for
the simple reason that, whatever causes change is necessarily
prior to that which is changed, a principle of universal application
and verified, accordingly, even of correlative terms such as the
proper sensible and the corresponding sensation. Of themselves,
our external senses exist only in potency to sensation : they can
no more become actually sentient apart from the stimulus of
their respective external objects than a log of wood can begin to

208 COSMOLOGY

burn of itself apart from contact with fire. Every thing that
is in potency can be acted on and changed only by something
actual and active : that is why our senses need the stimulus of
the proper sensibles ; and, as we shall see, the result of this
stimulation is to originate within them a transition from potency to
actuality in virtue of which ihey become like the proper sensibles.

The first process (13) in this theory of sense-perception is
confessedly perplexing for the psychological historian : happily,
we are not engaged on his task, and we can be content here with
alleged facts and probable interpretations. The alleged facts
are the necessity of one or more special media for each of the
proper sensibles : extrinsic media, air and water between colour
and eye, sound and ear, odour and nose ; intrinsic media,
the surfaces of the organs between tangibles and the organ of
touch, savours and the organ of taste. This bald statement
conceals, as every psychologist knows, a nest of worries. The
worst of these worries arises out of the attempt to probe the kind
of change wrought in the medium by the proper sensible. The
purpose of that change is obvious : the transmission through the
medium to the sense organ of the form of the proper sensible.
But what is the nature of this change which is described, in the
language of the School, as an intentional form, a species intention-
alis ? It is hard to say what the adjective " intentional " is meant
to convey in this context : extrinsic media like air and water are
not in any sense physiological or psychical ; then, this intentional
form can hardly be the formal proper sensible because the medium,
and not the formal proper sensible, is, for medievalists, in im
mediate contact with the external sense organ ; all that can be
said is, that this intentional form must be some kind of effect
temporarily produced in the medium by the proper sensible
owing to which this medium is capable of producing in the ex
ternal sense organ the sensible form of the proper sensible, the
medieval species sensibilis. This vague interpretation of the
intentional change wrought on the medium by the proper sensible,
for the purpose of rendering this medium fit for its r61e in the
process of sensation, must suffice : all the cosmological reader
needs to remember is that the intervention of the medium was
essential, but did not interfere with the accuracy of sensation.

The next process (14) is a passive state of alteration set up in
the external sense organ by the proper sensible acting through the
medium. This process results in a stamping by the proper sen
sible on the sense organ of a sensible form of itself : the species
sensibilis of medieval psychology. The sense organ receives
into itself the actuality of the proper sensible exactly as this
latter exists formally in its natural substrate : the sense organ
adds nothing to, and subtracts nothing from, the proper sensible ;
it reproduces the proper sensible as accurately as a mirror re
produces the face of a man who is gazing into it. The explana
tion of this actuality is that each sense organ is in potency towards
its proper object, and accordingly, is capable under normal con-

MEDIEVALISTS ON SENSE-PERCEPTION 209

ditions, of mirroring its proper sensible. So perfect is this likeness
between the sensible form within the sense organ and its proto
type or proper sensible existing outside the percipient, that the
actualities of both are in one sense identical : identical, not in
the sense that the actuality of the proper sensible in its numerical
identity passes over to the sense organ ; but, identical in the sense
that these two numerically distinct actualities are of the same
nature, for each sensible form is the facsimile of its proper sensible ;
colour, for instance, has when perceived a twofold existence, a
natural existence as proper sensible in the coloured object, and
an intentional existence as sensible form in the sense organ of
the percipient. In his anxiety to emphasise this likeness, Aris
totle had gone so far as to suggest that the eye, when perceiving
colour, became, by reason of the presence within it of this sensible
form, coloured itself. St. Thomas discounts this Aristotelian
phrase as a slight exaggeration, but grants that, as the eye has
this copy of the external colour and as the spectator is thereby
likened to the coloured object, you may, in a sense, speak of the
spectator's eye as coloured : and he adds that a similar likeness
is reproduced in every external sense organ during the process of
perceiving its proper sensible. He follows Aristotle in pointing
out, however, the difference in manner of existence that obtains
between the copy within the sense organ and its external proto
type : the sense organ receives into itself the form of the proper
sensible apart from matter, just as sealing wax receives into
itself the shape of an iron or gold seal apart from the iron or gold.
In all action, the patient receives the form of the agent : but this
reception is, in sense-perception, different from that which happens
in causality between non-living bodies. When a non-living agent
acts on an non-living patient, the latter may be disposed for the
reception of the resulting form in exactly the same way as is the
agent, and may, accordingly, receive this form just as it exists
in the agent : air heated by fire acquires a quality of heat of the
same kind as that which exists in the fire. Proper sensibles can
not be received into our sense organs after this fashion : our
eyes, ears, etc., are living tissues, and do not offer the newly-born
form that kind of substrate which its progenitor has outside us ;
the consequence is, that the copies of these proper sensibles exist
within our sense organs in a manner wholly different from that
in which their prototypes exist in their natural substrates ; the
prototypes have their natural reality, their copies have a " spirit
ual and intentional " reality. That is the reason why, although
the passive stage of change within the sense organ implies the
presence of an actuality similar to that of the proper sensible,
our sense organs are not affected exactly as are the substrates of
the proper sensibles : the eye, though receiving into itself the
sensible form of colour, does not become coloured ; similarly, the
process of perception does not make the ear sonorous, the nose
odoriferous, the organ of taste savoury, the organ of touch any
one of the tangibles.

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210 COSMOLOGY

This necessary passive stage is, in truth, the preliminary of
sensation rather than sensation itself : sensation is " a change of
the soul through the body." (15) The percipient reacts con
sciously under the stimulus of the proper sensible, and this act of
consciousness is really the sensation. St. Thomas distinguishes
expressly these two changes within the percipient : the change
made passively by the proper sensible within the sense organ and
resulting in the species sensibilis or sensible form ; and the further
change caused by the sentient reaction of the percipient, and
resulting in the conscious perception or sensation in the common
sensory. He insists, moreover, that our sense knowledge of the
proper sensibles is per se infallible : and herein he is followed by
most of the School. (16) Their argument was that no existing
reality can be lacking in those perfections that are part of its
essence : a man may have only one eye or one leg, but, as long as
he is a man, he must have all the essential perfections of man —
he must exist as a living, sentient, rational, substance ; similarly,
our senses may err regarding the common sensibles or the inci
dental sensibles, but they cannot err regarding their respective
proper sensibles for the simple reason, that the chief purpose of
each of them is to know its own proper sensible. Of course,
certain conditions are indispensable for accurate functioning of
these senses : medievalists were well aware of the illusions
caused by jaundiced eyes, feverish palates, plugged ears. They
allowed that sense inerrancy, in regard to the proper sensibles,
was perfect only when both the sense organ and the medium
were perfect. But they took up the reasonable attitude that the
organ was healthy, and the medium normal, in the overwhelming
majority of instances : the Power that begets percipient and
percept does not abound in misfits ; the universe is rationally
constructed. The upshot of this medieval theory of perception
is, then, that our external senses apprehend the proper sensibles
exactly as these exist outside us. Proper sensibles exist as
various qualities in bodies apart from, and independent of, the
percipient : prior to perception, the external sense organ is po
tentially what its proper sensible is actually ; actual perception
implies, as a preliminary, a transition from potency to actuality
within the external sense organ which results in making that
organ actually, though intentionally, of the same quality as
the external object : subsequent on this change in the ex
ternal sense organ, a conscious reaction occurs in the common
sensory in virtue of which the percipient perceives the proper
sensible exactly as it exists outside him ; under normal conditions,
none of these processes can take wrong lines and, therefore, the
resulting sensation is absolutely accurate in its report of the
external reality.

This doctrine of the likeness between the proper sensible
and the percipient's sensations is sometimes caricatured as
implying that burning coal feels its own heat, snow its own cold,
honey its own sweetness, etc. Such criticism is based on crass

DEMOCRITUS ON SENSE-PERCEPTION 211

ignorance of the medieval doctrine of sense-perception. The
wheels within wheels, that function in the medieval theory, make
this alleged identification of the extra-mental reality of the
proper sensible and the sensation of the percipient utterly im
possible. The Schoolmen insisted on the necessity of a medium
between the proper sensible and the sense-organ ; thus cutting
off, from the start, any chance of confounding the extra-mental
reality of the proper sensible with any of the processes that
arise in the percipient. They distinguished, meticulously, be
tween the action of proper sensibles on percipients and the action
of proper sensibles on non-living patients : in other words,
between the process of perception and the transient causality
of one non-living body on another non-living body. They were
careful to point out that, in certain instances of sense-perception,
the proper sensibles — in particular, the tangibles and the odours —
produce, within the external sense organ, not merely an inten
tional form but also a physical form. They never forgot to
emphasise the distinction between the inanimate manner of
existence of the proper sensible in its own substance and its
intentional existence as a sensible form in the external sense
organ of the percipient. Finally, they distinguished between
both of these kinds of existence of the proper sensible and the
conscious reaction of the percipient. That conscious reaction is
the sensation : by means of it, the percipient knows directly
and immediately the proper sensible as this latter exists in its
own substrate ; and that sensation is located by the School in
the internal sense organ known as the common sensory. But
despite all these differences between the extramental reality of
the proper sensible and the sensation of the percipient, they did
insist, for the reason already given, on the inerrancy of our percep
tion of the proper sensibles. That is why they refused absolutely
to identify the extramental reality of the proper sensible either
with quantity or the local movements of merely quantitative
bodies. For them, the proper sensibles were material accidents
really distinct from the accidents of quantity and local motion.

THE DEMOCRITEAN THEORY OF THE PROPER SENSIBLES.

Perception, for Democritus,(17) depended on the introduc
tion of tiny effluxes through the organs of sense into the soul :
these tiny effluxes were miniature likenesses of the atoms whence
they came ; the organs of sense were simply external passages,
or thoroughfares, through which the effluxes entered the soul ;
and the soul itself was a group of atoms endowed with distinctive
shapes, order, and motions. For him proper sensibles, as such,
did not exist outside the percipient : the atoms and the void
were the only extramental realities and neither of these had
colour, sound, taste, smell or, apart from extension, proper
tangibles. Proper sensibles exist, for him, only in consciousness :
the extramental causes which arouse them are merely the grouping

14*

212 COSMOLOGY

and motion of atoms that possess no internal characteristics other
than solidity, figure, size, and perhaps, weight. This kinetic
theory aroused the fiercest antagonism both of Aristotle and of
the Schoolmen. Before expounding the grounds of that opposi
tion, it is well to be clear about what Democritus held. The
extant account (18) of colour is rather full : all colours are com
pounded out of four, white, black, red, and green ; whiteness,
as an extramental reality, is merely the smoothness of certain
atoms — smoothness prevents shadows but allows penetration ;
blackness, as an extramental reality, is merely the roughness of
certain atoms — roughness allows shadows and prevents penetra
tion ; redness, as an extramental reality, is the sphericity of certain
atoms ; greenness, as an extramental reality, differs from these
others in being due not to the shape of the atom but to a par
ticular combination of the solid and of the void. Taste,(19) also,
depends on difference of shape in the tasteless effluxes that stream
off from the atoms : acid tastes are aroused by angular, small,
thin shapes ; sweet tastes by spherical shapes that are not too
large ; sour tastes by large shapes that have many angles but
very little roundness ; bitter taste by small, smooth, spherical
shapes that have hooks attached to their spherical surface ;
and, so on, in ever-growing fancifulness. As for odours, Democ
ritus does not seem to have given an explicit account of the
atomic figures proper to each kind of odour (20) : he merely
lays down that odour, as an extramental reality, is a fine sort
of matter emanating from atoms and borne to the nostril ; but
he would contradict the fundamental thesis of his atomism, did
he acknowledge odour as anything other than a subjective feeling
of consciousness awakened in the percipient by odourless emana
tions. The same must be said of sound (21) : all Democritus
says is, that sound is due to particles thrown off by the sounding
body, and conveyed by the medium of the air to the ear, and
through it to the soul ; but, it is characteristic of his thoroughness
to add that these particles enter the ear in conjunction with air
fragments that resemble them in shape and size. These details
of the Democritean theory of the proper sensibles were known, of
course, to Aristotle. They were not known to St. Thomas and
the School. But the Schoolmen follow the exposition and the
criticism of Democritus that is embedded in Aristotle : and that
account contains the heart of the problem.

The Aristotelico-Thomistic refutation of Democritus is directed,
mainly, against his explanation of the primary tangibles because
these qualities are, for Aristotle and the School, the only active
and passive qualities which explain the generation and corruption
of the four elements : " neither whiteness, nor blackness, nor
sweetness, nor bitterness nor any quality other than a tangible
produces the elements." (22) Failure here, then, spells failure
everywhere : and that Democritus failed egregiously to explain
the primary qualities, St. Thomas had no doubts. His starting-
point is that for a Democritean the only extramental reality in

DEMOCRITUS ON SENSE-PERCEPTION 213

heat must be some particular shape in an atom.!*3) Now if
the hot be one shape, the cold must be a contrary shape ; and
if the hot and the cold are explained away as mere shapes, the
other tangibles must be similarly explained away. But if, as a
matter of fact, atoms are thus hot, cold, etc., they must act and
react on one another — a consequence impossible for a Demo-
critean : moreover, shape, as such, is neither active nor passive ;
again, if each atom has only one quality, atoms are not homo
geneous and, being different in nature, are divisible ; whereas,
if each atom has several qualities, some passive and some active,
contraries would be simultaneously present in the same indivisible
atom. It is useless, St. Thomas adds, to try to reinforce this
impossibility of activity in the Democritean atom by the assump
tion of a void : if bodies affect one another by contact, their
action and reaction are due to the presence of active and passive
qualities — apart from these, bodies might lie side by side for
ever without influencing one another qualitatively ; if bodies do
not affect one another by contact, then, this assumption of vacant
spaces, whereby their internal parts may come into contact, is
worthless as a condition of action and reaction.

St. Thomas is fairly exhaustive, also, in his refutation of the
Democritean theory of colour. (24) Democritus denies, he says,
the genuine existence of colour (and other natural qualities of
the same kind) as an extramental reality — colourless atoms arouse
in us different colours solely because of changes of place or of
attitude : further, Democritus teaches that the process of per
ceiving colour is due to the efflux of particles from the colourless
object to the eye. St. Thomas does not waste time on explicit
disproof of the first proposition : he is content with his refutation
of the Democritean theory of those tangibles which were the
basis of all colour ; content, also, with the proof based on the in
errancy of normal perception as to the reality of colour as a quality
that exists in the coloured object, light or no light, percipient or
no percipient. But he dwells on the admissible consequences of
of this efflux of colourless particles from objects to the eye :
our eyes would be destroyed by this incessant bombardment of
tiny particles ; the loss of these emanating particles would
gradually lessen and finally reduce to nothingness the size of all
visible bodies ; wind and rain would play tricks incessantly
with these streams of emigrants and immigrants, and make
accurate vision rare if not impossible ; finally, colours are visible
at distances so immense that they could never be travelled over
by these alleged effluxes. In reference to savours, St. Thomas's
rejection of Democritus is tersely stated. (25) The Democritean
theory of savours as merely the shapes of atoms is impossible :
the bitter is contrary to the sweet, but to which of the polygons,
the bitter shape according to Democritus, is the sphere, the sweet
shape, contrary ? ; again, shapes are infinite in number and,
therefore, savours ought to be numerically infinite ; and if
Democritus pretends that savours are infinite in number, let

214 COSMOLOGY

him or his explain why some of them are perceptible whereas
the others are not. the absence of an explicit Democritean
reduction of odours to shapes accounts probably for the absence
of any explicit reference to this topic in the pages either of Aris
totle or of St. Thomas. St. Thomas (26) has, however, a refuta
tion of all the ancients taken from Aristotle : and this refutation
certainly includes Democritus. All the ancients, he writes,
were inclined to refer odour to exhalation of some kind ; one
group referring it to watery exhalation ; another group to smoky
exhalation ; a third group to both one and the other. He rejects
all three theories as unlikely : watery exhalation consists of water
and this, being tasteless, is odourless ; smoky exhalation cannot
exist at all in water ; finally, this exhalation theory of odours
is analogous to the emanation theory of colours and is, therefore,
to be rejected for the same reasons. Thus we arrive at last at
that proper sensible which has ever been the joy of Democriteans
and the torment of Aristotelians — sound. St. Thomas (27) knows
well that a swinging bell puts air in motion exactly as a falling
stone sets up ever- widening eddies in stream or lake.. He
stoutly maintains, notwithstanding, that sound as a proper
sensible is not merely the vibration of matter : when he finds
Aristotle defining voice as the percussion of air, he explains away
this definition as a definition not of voice but of its cause ; voice
is not percussion, but a sound caused by percussion. His view
is that sound as a proper sensible exists not in the sounding body
but in the medium — air or water : local motion, and it alone, is
in the sounding body ; sound, as quality, exists in the medium
and has, therein, only a fleeting existence ; its presence as proper
sensible in the medium, air or water, is a result of the local motion
of this medium. He allows that the colloquial language about
sounds as sharp or grave suggests a connexion between sound
and the speed or slowness of motion : this connexion is due,
however, to the fact that motion is the cause of sound in the
medium and that, when rapid, it causes sharp sounds, and, when
slow, grave sounds. Of course, this explanation of sharpness
and gravity refers only to instances where sound is caused by a
single motion. Boethius pointed out long ago in his Musica that
sound produced by several motions owe its sharpness to their
frequency, its gravity to their fewness : hence it is that the more
tense a string be, the more sharply it sounds when pulled. To
sum up, sound is a proper sensible, local motion a common
sensible : the one is known solely through the ear, and, regarding
it, the normal ear cannot err ; the other is known both by eye
and by the organ of touch, and all sorts of mistakes are prima facie
possible about it ; sound and motion differ, then, not merely as
sensations but also as external realities.

Two short sentences of Aristotle adopted by St. Thomas (28)
embody the pith of their elaborate refutations of this Democritean
theory of the proper sensibles : Democritus, in treating of sense-
perception, proceeds quite irrationally for he represents all objects

DEMOCRITUS ON SENSE-PERCEPTION 215

of sense-perception as tangibles ; Democritus reduced the proper
to the common sensibles for he reduces colours and tastes and the
other proper sensibles to size and shape. The student of Aristotle
and of St. Thomas cannot read these extensive chapters against
Democritus without realising the chasm that separates these
antagonists on this problem. There is, however, one passage in
the midst of these refutations that has led astray some con
temporary Aristotelian and Thomistic " dippers " ; writers who
quote Aristotle and St. Thomas on a particular topic without
taking the trouble to read all that these thinkers have said on
that topic. Here is the passage as it stands in St. Thomas :
and St. Thomas does but render in slightly different words the
passage of Aristotle on which he is commentating. " The earlier
speculators on nature," writes St. Thomas,(29) " were not
correct in saying that nothing is white or black except when
seen, that nothing is savoury except when tasted, and similarly
in reference to the other (proper) sensibles and senses. . . . This
doctrine of theirs is in one way right, in another way wrong. The
sense organ and the sensible object have each of them a twofold
meaning inasmuch as they may mean severally either that which
exists potentially or that which exists actually. Now the teach
ing (of these earlier speculators) is true with reference to the actu
ality of the sense organ and the sensible object : but, it is not true
with reference to the potentiality of the sense organ and the
sensible object. But they spoke absolutely, that is without
making a distinction, in reference here to topics that have more
than one meaning." To a reader whose knowledge of St. Thomas's
doctrine on the proper sensibles is limited to this extract, when
torn from its context, this reads like an endorsement of the
Democritean theory. But the reader who looks up this passage
in the original realises at once that the context excludes any
possibility of capitulation, and does but summarise, in highly
technical language, the Saint's refutation of the Democritean
theory. St. Thomas (30) had previously given two meanings
for this word " actuality " as applied to the proper sensible.
" Every (proper) sensible may be said to be in actuality in two
ways. One of these ways of being in actuality occurs when the
proper sensible is actually perceived, that is, when its form is
in the sense organ : and in this way sound exists as an actuality
when it is being heard. A second way of being in actuality, for
the proper sensible, is existence in its own subject through that
form by means of which it can be perceived : in this way, the
proper sensibles (other than sound) are in actuality in sensible
bodies — colour, for instance, in the coloured body, odour in the
odoriferous body, savour in the savoury body. The case of sound
is different : sound is merely in potency in the sounding
body; it is in actuality within the medium which is changed
by the vibration of the sounding body; and that is why the
actuality of sound is said to belong to the medium and to
hearing, but not to the sounding body." This passage is

216 COSMOLOGY

decisive : a proper sensible has two actualities ; one actuality,
as an extramental accident which is distinct from all other
accidents, exists in its natural substrate ; another actuality, as
a sensible form, exists within the external sense organ. There
is no question at all of identifying the proper sensible with that
last stage of sense-perception, the sensation.

The reason for speaking of the sensible form as in one way
an actuality of the proper sensible is the Aristotelian common
place, that whatever be the purpose for which any reality exists
is, when realised, an actuality of that reality. The proper sensible
exists in order to be perceived ; it cannot be perceived except
it imprints on the external sense organ a copy of itself ; hence
this impressed form (species impressa) may be called, in a true
sense, its actuality. Moreover, the change within the sense organ
reduces this latter form from potency to actuality. There is,
then, in sense perception one of the applications of the doctrine
that action and passion are identical with the change within the
patient, are, indeed, but different ways of regarding that same
change and that, consequently, the action of the agent is in the
patient : " just as action (31) and passion occur in the patient
as substrate, and not in the agent except as source, similarly
the actuality both of the proper sensible and of the sense organ
is in the sense organ as subject." Hence, the same reality is,
from different points of view, called the actuality of the proper
sensible and the actuality of the sense organ : the impressed
sensible form is the actuality of the sense organ because it is
one of those perfections that are realisable within it ; that same
impressed sensible form is one of the two kinds of actuality of a
proper sensible because it is an effect which the proper sensible,
as agent, in conjunction of course with its substrate, can cause by
transient action in a percipient. St. Thomas agrees with Aristotle
in lamenting that the Greek language had not, in all instances,
distinct names for these two actualities. " There are,(32) in
deed, distinct names for these actualities in certain instances :
for example, sonation for the actuality of the proper sensible
and audition for the actuality of the sense organ. In other
instances, there is only one name, namely, that of the actuality
of the sense organ : thus vision is the name given to the actuality
of sight but there is no name for the actuality of colour ; simi
larly, tasting is the actuality of the organ of taste, but there is
no distinctive Greek name for the actuality of savour." St.
Thomas did not supply in Latin what Aristotle did not supply
in Greek : had either of them done so, we might have been spared
any attempt to identify their doctrine on the proper sensibles
with the kinetic theory of Democritus.

The world of matter is, for Democritus, an infinite number of
atoms of different shapes which are solid and mobile. These
colourless, tasteless, odourless, soundless, and (save as extended
and hard) intangible realities move and jostle in the infinite void.
Heat and cold, dryness and moisture and all their derivatives,

LIGHT AND BRIGHTNESS 217

especially colours, savours, odours, sounds, exist not as distinct
extramental realities but as sensations aroused by merely quan
titative extramental realities in percipients. Quite other was
the world of matter for St. Thomas and the Schoolmen. Neither
man nor animal conferred on bodies their formal proper sensibles :
the tints of the sky, the roar of the ocean, the fragrance of flowers,
the savour of vegetables and fruits, the temperature of bodies,
exist outside the percipient as formal accidents in their own
right, distinct from all accidents of quantity and of motion. If
no percipient had ever existed on our globe, the proper sensibles
would not have been one whit lacking in intrinsic perfection as
special accidents distinct from the quantitative accidents of
matter : the skies would not be less blue, the clouds less white,
the summer air less hot ; the breezes would murmur through
the trees, the waves resound along the shore ; the grasses and
flowers and fruits would in season flaunt their brilliant colours
in the sun and load the disregarding air with their exquisite
scents ; all these wonderful perfections would exist, as such,
even if our globe had never been peopled with man or animal
— only, there would be neither eye, nor ear, nor nose, nor palate,
nor touch, to have conscious joy in this lavish profusion of
the gifts of Nature. (33)

LIGHT AND BRIGHTNESS.

The Schoolmen made a distinction between lux and lumen :
lux was the light of self-luminous bodies like the sun, lumen the
borrowed light of bodies which owed their light to any self-
luminous body. It is not easy to find suitable English words
for this medieval distinction. The best I can do is to employ,
in this section, light as the translation of lux, and brightness
as the translation of lumen : by light, then, I mean that quality
as an accident inhering in the sun as substance ; and by bright
ness, I mean the luminous effect produced in our atmosphere
by the causal action of the sun's light. And since our atmosphere
was, for the School, part of that sublunary world which is totally
different from the supralunary world, the medieval discussion
of light involves also a discussion of that medium by means of
which the light of the sun reaches our earth as brightness. There
were, then, three distinct realities : light, the medium, and bright
ness. A good deal of unanimity (34) prevailed in reference to
the nature of these three. All agreed that light was a quality
of the sun, because the only alternative was the impossible one
of its being the substantial form of that body : no substantial
form can be an object of sense-perception ; no substantial form
produces accidents in other bodies ; no substantial form is
capable of increase or decrease. There was a similar agreement
about the medium of light. This medium was called the dia
phanous or transparent. The Schoolmen (35) taught, however,
that the transparent is not something peculiar to air or water

218 COSMOLOGY

or any of the bodies which are ordinarily spoken of as transparent.
The transparent is a kind of universally diffused natural power,
that is not capable of existing apart from bodies, and subsists in
varying degrees in air and water and other bodies, particularly
the heavenly ones. Transparency of the highest kind exists
in the heavenly bodies : otherwise, the nearer crystalline spheres
would shut off our view of the fixed stars. Transparency of
lower degrees exists in terrestrial bodies : the second degree
exists in fire when this element is in its natural region, for then
it is most rarified ; the third degree in air, and the fourth in
water ; the fifth degree in any terrestrial body that has a large
admixture either of air or water. Now, the transparent has
of itself neither brightness nor colour : when not illumined by
light, it is dark, and that accounts for the darkness of the atmos
phere at night ; when not illumined by light, it is invisible and
that is why light may be said to be in one sense the " colour "
of the transparent. This use of the word " colour " is, however,
not quite accurate : true colour has its intrinsic cause within the
coloured object, and remains, therein, as a genuine reality whether
that object be in light or in darkness, be seen or not seen ; the
" colour " of the transparent comes to it from the light of an
external body like the sun, and disappears when the transparent
is no longer under the actual influence of the sun, v.g., during
the night. Now the effect of light on the transparent was bright
ness. As to the nature of this brightness, the Schoolmen (36)
agreed that brightness could not be a body : it occupies the same
place as the body which it illumines ; it spreads at dawn instan
taneously from east to west. Brightness must be, then, a quality
of the transparent. This brightness or illumination of the trans
parent was necessary in order that the latter be a fit vehicle
for the transmission of colour from the object to the eye : when
medievals speak of air or water as the medium of colour, they
speak of each of them, not as air. not as water, but as an illu
minated transparency. And in opposition to Empedocles, the
School taught, with Aristotle, that light does not reach our earth
by local motion. Local motion would imply a time sequence,
but daily experience shows that the whole horizon becomes
flooded with brightness the moment the sun rises ; and when
opponents urged that brightness may move from point to point
in the atmosphere even though we do not perceive the lapse of
time occupied by this motion, the Schoolmen replied, that such
a suggestion might be plausible were the interval that had to be
traversed a short one, but that it is utterly unlikely because the
distance between the extreme east and extreme west is so
enormous.

There was practical unanimity of opinion, then, that light
was a quality of the sun, that brightness was a quality of the
transparent, that the medium of colour was the illuminated
transparent, that light does not travel. Two further points
were controverted : the relation between brightness and colour ;

LIGHT AND BRIGHTNESS 219

the nature of the quality of brightness. A number of the School
men following Albertus Magnus (37) taught, in reference to the
first point, that colour was not distinct from brightness but was
brightness as received into the surface of opaque bodies. These
held that bodies were but potentially or materially coloured,
prior to the reception of brightness ; that this potentiality or
materiality consisted in definite blends of the constituents of
opaque bodies ; and, that the reception of light actualised this
potentiality and introduced, thereby, the formal accident of colour.
The arguments, in favour of this doctrine, were certain texts of
Aristotle and such facts as the fleeting colours of the rainbow,
of the tails of peacocks, of the necks of doves. St. Thomas (38)
and most of the School rejected this interpretation of the Aris
totelian text, and insisted on a distinction between colour and
brightness : formal colours existed in bodies apart from brightness,
and were of themselves visible ; these formal colours cannot
reach the eye, however, except the transparent medium be illu
minated. Every active form, they argued, has the power of
reproducing its like ; some forms are so perfect as to be able to
dispose the patient for the reception of their effects ; other forms
are not so perfect, and require the patient to be disposed for the
reception of their effects by a distinct agent. Their contention
was, that colour was one of these less perfect forms : it could
not reproduce its like in the medium until that medium had
been previously prepared by the presence of brightness. St.
Thomas and the others met the facts about fleeting colours by
setting up a distinction between these and permanent colours :
fleeting colours do depend on brightness for the attainment of
their complete formality as colours ; but, as long as that brightness
is present, even these fleeting colours exist as formal accidents
in the object and outside the percipient. The second contro
versy about brightness divided Thomist and Scotist. St.
Thomas (39) taught that brightness was a physical quality,
differing from light only as any physical effect differs from its
univocal cause. His proof consisted in pointing out the likeness
between them and between their effects : brightness is an object
of sense experience just as is light ; brightness illumines, heats,
and dries, just as does light. Scotus (40) taught that brightness
was an intentional quality : a representative image dependent,
both for origin and conservation, on its prototype. Cajetan with
a few others advocated a combination of both views as a full
solution of the facts. The Thomist view prevailed. Suarez
tells us that most Schoolmen accepted St. Thomas's teaching
because of the physical effects of brightness ; that they rejected
Scotus's teaching, mainly, because an intentional quality could
never become an object of sense-perception ; and that St. Thomas,
himself, sometimes spoke metaphorically of brightness as an
intentional quality for the simple reason that it is the most
subtle of all the qualities of matter.

220 COSMOLOGY

GRAVITY AND LEVITY.

Earth was absolutely heavy, and fire absolutely light ; air
was heavy relatively to fire, light relatively to water or earth ;
water was heavy relatively to fire or air, light relatively to earth ;
as for the mixtures, they, whether perfect or imperfect, were heavy
or light according to the predominance within them of one or
other of the four elements. This medieval teaching (41) was but
a' transcript of the Aristotelian theory of the natural places and
natural motions of the elements. Gravity was, then, a principle
of downward motion, i.e. of motion towards the centre or earth :
levity, a principle of upward motion or motion away from the
centre or earth. The effect of gravity or levity was to cause
local movement of an element towards its natural place under
certain conditions : these conditions were (a) the presence of an
element outside its natural place, (6) the removal of any obstacle
that prevented this natural motion. The Schoolmen taught
with Aristotle that gravity and levity, despite their derivation
from the primary qualities, were special qualities distinct from
the four primaries ; also, that gravity was a special quality
distinct from levity ; finally, that the elements were neither
heavy nor light in their natural places. They taught also that
gravity and levity were accidents distinct from their substantial
substrates : their reasons being, that the Eucharistic accidents
retain their gravity, that the same primordial matter is found
in succession in heavy or light bodies, and that the substantial
form of man, the Soul, is spiritual and cannot, therefore, be
either heavy or light. But in attempting to distinguish the
motion due to gravity or levity from the self-motion of living
beings, Thomist and Scotist fell out : Scotists (42) held that this
natural motion of non-living bodies was a kind of self-motion ;
Thomists (43) stoutly denied this, and attributed the natural
motion of non-living bodies chiefly to the generator of these
bodies. In later times, this controversy lost a good deal of its
intensity : Suarez suggested that the point at issue was mainly
verbal ; John of St. Thomas made no explicit admission, but his
treatment of the issue seems to show he was of the same mind
as Suarez.

DENSITY AND RARITY.

Density and rarity were, for medievalists, facts of sense-
experience : solids are more dense than liquids, liquids more
dense than either air or fire ; moreover, the same body undergoes
changes in density or rarity as is clear from the fact of its occupy
ing, at different times, more or less space. Hence, the Aristotelian
definitions : the dense body is one that has much matter in a
small space ; the rare body is one that has little matter in a
large space. The effort of accounting for these facts led to
several theories. One of these deserves to be reckoned the
common view, both because of the calibre of its leading exponents

DENSITY AND RARITY 221

and because of the number of its adherents : the theory of Aris
totle and of St. Thomas. This common (44) view implied that
a non-living body, when generated, owes its actual volume to a
special quality which flows from the substantial form — a quality
called rarity in rarefied bodies, density in dense bodies : it im
plied, also, that this quality is capable of being influenced by
external causes, such as heat or cold, and that, when thus af
fected, it may cause increase in volume apart from gain of matter,
or decrease in volume apart from loss of matter. The reader,
who forgets the Aristotelian denial of empty space, is apt to miss
the true significance of this theory of expansion and contraction.
This theory- means that a cubic foot of solid matter, which is so
continuously unbroken as to allow within itself no intervals of
nothingness, might, apart from any loss of its own matter, shrink
to a cubic inch ; that this same cubic foot might, apart from
any gain of matter and apart from any admission of empty
space, swell out and occupy a cubic yard ; that these unimagin
able processes and results might be brought about by the in
fluence of external causes on the special quality of density or
rarity within the original cubic foot substance. And for the
purpose of emphasising the genuine trend of this theory, St.
Thomas and all its supporters distinguish explicitly between
instances of real expansion or contraction due to changes of
quality, and instances apparent expansion or contraction due to
the intrusion into, or extrusion from, the pores of subtler matter.
Three arguments are generally advanced in favour of the domi
nant theory. A first argument was based on the changes of
volume that occur in certain changes of substance : air, when
generated out of water, occupies a larger volume than did the
water, and water, when generated out of air, occupies a smaller
volume than did the air — and yet, in both instances, the quantity
of matter perseveres unchanged ; there must be, then, in these
and similar instances, real rarefaction and real condensation.
This first argument was confirmed by an appeal to those observ
able changes of volume which, apart from loss or gain of matter,
sometimes occur in bodies : heat expands, cold contracts, bodies.
Thirdly, these Schoolmen, denying as they did the existence
of empty space, could explain the possibility of local motion
only by admitting real rarefactions and real condensations :
unless such processes occurred, bodies could never move from one
point to another in a world that had no void ; they would remain
for ever in the same position crammed together like sardines in
a tin. Despite these arguments the dominant theory had always
its rivals. A few Schoolmen (45) admitted real expansion and
real contraction, yet denied the need of this distinct quality of
rarity or density. But for the supporters of the common view,
the assumption of density and rarity as distinct physical qualities
was essential. Density or rarity are not identical with less or
greater ubication : two bodies can have equal local extension,
and yet exhibit differences of density or rarity ; the various

222 COSMOLOGY

parts of Christ's Eucharistic Body have no ubication, and yet
bone, blood, and flesh preserve their respective density or rarity.
Hence, the dominant theory was, not merely that expansion and
contraction were real, but also that they were due to sensible
qualities which were perceived by the sense of touch and which
produced greater or less volume in bodies.

Scotus's (46) treatment of this question emphasises three
other dissentient views : and his non-committal statement of
two of these three has led to his being claimed as patron of both.
The third and most far-fetched theory (47) suggested that all
the old quantity was destroyed, both during rarefaction and
during condensation, and that a totally new quantity was gene
rated in its stead. Scotus, as well as St. Thomas, rejected this
fantastic theory : the destruction of quantity would involve
that of all the other accidents, and there was no proof of such
a holocaust ; the destruction of all these accidents would involve
the destruction of their substance, and there was not enough
either of efficiency or of finality in mere changes of volume to
produce this prodigious result. One (48) of the two theories,
which claim Scotus as patron, is obviously allied to this extreme
view, for it explains rarefaction as a generation of additional
quantity and condensation as a destruction of some of the pre
existing quantity. Most of the Schoolmen held this to be in
admissible : the additional quantity generated in rarefaction
must either be received into no substance or introduce double
quantification — and therewith compenetration — into the already
existing substance : the destruction of already existing quantity
in condensation must either leave some portion of the substance
without quantity, or result in the information of the whole
substance by a quantity which previously informed only part of
that substance. The last of these dissentient (49) views amounted
to a denial of real rarefaction or real condensation : rarefaction
was the intrusion into a body, condensation the extrusion from
it, of subtler matter. The common view had admitted instances
of apparent expansion or contraction, and explained them by the
presence of pores in continuous bodies : but, as we saw, it put
forward several arguments in favour of the thesis that apparent
expansion or contraction did not explain all the known facts.
Some of the confirmatory illustrations given by the supporters
of the dominant view were not happy : interstices cannot explain
the rarefaction of blood or of any human organ because the
human soul can inform only a continuous substance ; milk can
rarefy to twice or thrice its volume — yet no one seriously pro
fesses either to observe new corpuscles in it or to compare rarefied
milk to a mixture of wine and water ; under appropriate condi
tions, eggs or chestnuts can condense or rarefy but matter, how
ever subtle, cannot pass through the shell or the rind ; some
parts of the heavens are dense — for instance, the milky way —
other parts are rare, but there can be no pores in heavenly bodies
because aether is the most subtle matter that exists !

FORM AND FIGURE 223

ARTIFICIAL FORM AND FIGURE.

Artificial form and figure were put together by Aristotle and
the School (50) as a special kind of quality. They differ merely
accidentally : a figure is called a form, in this sense, because the
shape of any artistic product is that which determines the specific
nature of such products. The Schoolmen defined figure as that
quality by which the extension of a substance is definitely limited
in its three dimensions. No body can, however, assume different
shapes apart from other qualitative changes : liquids and gases
take the figure of their containing vessels ; soft solids such as
wax can also take on various figures ; and finally, hard bodies
can be broken up into parts of the most varied shapes. The
Schoolmen drew, from these facts, the conclusion that figure was
not identical with quantity but was a distinct accident, a sensible
quality. They held, however, that figure was a quality which
affected quantity directly. And from this, they concluded that,
since quantity was not an active accident, figure was not an
active quality. This last point seemed to them to need ex
planation owing to the changes wrought in bodies by the advent
of fresh shapes. When a body thins or thickens, it undergoes a
change of shape : but this change of shape is a secondary effect
of the alteration wrought by the process of expansion or con
traction. When a house receives the finishing touches of natural
perfection by being walled in or covered over, it undergoes some
kind of change. The School refused, however, to consider the
reception of a new shape as an alteration in the technical medi
eval sense of a change of quality : alteration does not occur in
substance when these substances are being produced, and the
reception of a definite natural shape is part of the process of
production of any substance. Two other points of medieval
doctrine refer to this quality of figure : a natural body cannot
be infinitely extended because every existing body must be
definite, and the quantitative infinite has no limits ; a natural
body cannot be infinitely divisible because a stage of quantitative
division is reached below which this body, be it element or mixture,
cannot exist. Meagre and vague as is the foregoing summary,
it embodies practically all that the medievals taught about
figure in the non-living world. It is only when dealing with
living bodies that the Schoolmen were able to make much of this
special quality. Figure was regarded in the living being as a
characteristic sign of species : probably, it was the importance
of this quality, in tree and plant and animal, that led the medievals
to interpret shape in non-living bodies as a distinct quality.

VIRTUAL OR OCCULT QUALITIES.

Medieval realism did not stop short at sensible qualities. The
intellect was, for the Schoolmen, veridical : and whenever an
observed effect could not be traced to the sensible qualities of

224 COSMOLOGY

matter, they postulated the existence of unperceived and im
perceptible qualities. These inferrible qualities have lived in
history as the virtual or occult qualities of matter. To try to
track down all qualities of this kind, that appear in medieval
treatises, is useless for, although the medievalists were willing
betimes to eke out the slender resources of Aristotelian physics
and chemistry by appealing to these qualities, they did so only
when at the end of their tether ; they did all the spade-work
in Cosmology with the four elements and the four primary
qualities. No one can deny that the guiding principle of the
Schoolmen on this topic was clear and defensible : they did but
seek a distinct qualitative cause for each specifically distinct
effect which they observed. But the a priori assumptions of
Aristotelian natural science, and their own lack of instinct for
spying out chances of reducing the apparently irreducible, left
them in this problem of occult qualities at the mercy of every
kind of fantasy. St. Thomas's (51) text warns us of pitfalls which
even his sober talent could not evade. He speaks of a quality
of attraction in magnets, a conclusion reasonable enough to com
mand the assent of many moderns : he speaks of heat-producing
qualities in pepper and wine, an explanation as good as any
ever since proposed of the effects of pepper on the palate and of
wine on the stomach ; he speaks also of a blood-stopping quality
in sapphires, a suggestion at which all modern readers begin
to take fright ; but when he speaks, in this connexion, of a quality
in gold which lifts one's heart, and seriously traces that quality
to the influence exerted by the heavens on the bowels of the
earth, every reader becomes vividly conscious of the absurdities
which lesser minds, in these ages, could read into natural facts
that did not easily tally with the theories of Aristotle. Many
of these occult qualities were referred to the heavenly bodies,
on the plea that various effects found in sublunary bodies could
not be traced either to the sensible qualities of terrestrial sub
stances or to the motion or light of the celestial bodies. One
kind of effect, which they were prone to refer to such occult
causes was, — in the non-living world — the production of metals
in the bowels of the earth : the four elements are less perfect
than gold or silver and, therefore, cannot produce either ; gold
does not produce gold, silver does not produce silver ; the motion
and the light of the heavenly bodies cannot immediately produce
these metals at such depths, for they cannot penetrate that far
into the soil ; neither can the motion and the light of these bodies
produce such metals mediately — not by causing heat for the
farther down you penetrate the colder the sub-soil, nor by causing
any other known quality at these depths, for if you are asked
what that quality is, you cannot say ; therefore, you are driven
logically to the admission of an occult quality of the heavenly
bodies as the cause of these metals. Again, the pole-star attracts
a magnet : it cannot do this by its light seeing that, even when
that light is shut of? by impenetrable clouds, the attraction

IMPETUS 225

occurs ; therefore, the only solution is the admission of an occult
quality. Similarly, the moon at all times affects the tides of the
sea and the four humours within the human body : since these
effects are caused, even when the moon is below our hemisphere,
they cannot be due to its light : therefore, once more, we must
admit an occult quality of the moon. Such was the general
purport of this medieval plea. There is no need, then, to pursue
further the discussion of these virtual or occult qualities. The
reader needs only to remember that, whenever the Schoolmen
speak of such qualities, they describe them and argue about
them after the analogy of these qualities that were for them
irrefragable : the proper sensibles. There is one virtual or occult
quality, however, which refers to sublunary bodies, and has a
particular interest, both because of its manner of development
and because of its importance : the quality of impetus.

IMPETUS.

The medieval history of this quality is an interesting illustra
tion of the desertion of Aristotle, St. Thomas, and Scotus, by
most of the School. (52) St. Thomas in his Commentary on
Aristotle's Physics follows the Stagyrite in teaching explicitly
that missiles owe their free flight to motion and motion alone — a
motion caused first in the surrounding air (or water) and, through
this, in the missile : and he refutes painstakingly the opposing
theory of the production within the missile of any motive quality
or impulse. The Commentary of Scotus on Aristotle's Physics
is lost, but his disciples attribute to him, on this topic, a view
similar to that of Aristotle and of St. Thomas. Most of the
disciples (53) of St. Thomas and of Scotus adopt the opposing
theory, and postulate this internal quality as an explanation of
the free flight of stones, spears, arrows, and cannon-balls. They
are apt, however, to gloss over the fact that their leaders taught
quite the contrary. Thomists sometimes deny that this theory
of impulse involves a desertion of St. Thomas. They parade
two texts (54) from his later writings which appear, at first sight,
to countenance the need of this internal quality. An attentive
reader can easily unmask the weakness of this plea. Even if
these two texts did imply the theory of internal impulse, they
are, in their context, the merest asides and cannot be accepted
as a definite rejection of St. Thomas's explicit refutation in the
Physics : at most, the reader would be face to face with another
of those inconsistencies that occur, both in Aristotle and in St.
Thomas, whenever these thinkers have not succeeded in reaching
a definite solution. The truth seems to be, however, that those
two texts of St. Thomas do not bear the later interpretation.
This interpretation is founded mainly on the iise of three words,
namely, virtue, impression, impulse : but on looking up the
lectures on Aristotle, the reader will find St. Thomas employing
the same words in sentences where he is confessedly denying the

15

226 COSMOLOGY

qualitative interpretation of such words. The Scotists are more
ingenious but, not a whit more ingenuous. Their method of
concealing disloyalty is to forget, for the nonce, the existence of
Scotus, and to make Aristotle the scapegoat of the older view :
some of these say that Aristotle's authority makes that older
view probable, but that reasoning makes the later view more
probable ; others say bluntly that Aristotle is their friend, truth
their divinity.

Setting aside these feeble evasions on the minor issue of dis
loyalty, the later Schoolmen make out a good case against the
older theory : a gale will sweep before it feathers and leaves,
the sails of ships, and the vanes of mills, but it has little, if any,
effect on heavy missiles ; hurricanes and tornadoes can influence
the motion of many heavy missiles, but they cannot prevent
these latter from being hurled in their teeth : moreover, the sup
position that stones and spears, arrows and cannon-balls, are
ever being borne on their paths by imperceptible hurricanes or
tornadoes, which are ceaselessly renewed at their tail-ends, during
their flight is utterly fantastic ; finally, no air intervenes between
hand and stone or spear, between powder and cannon-ball, at the
instant when these missiles are being hurled into space. On
grounds like these, most of the School rejected all attempts to
explain the free flight of projectiles merely by the motion of
successive layers of the surrounding air (or water). A motive
quality, an internal accident, an impetus, was, they said, essential.
Their difficulty was to locate this occult cause of the free flight.
Some of them located it in these successive layers of following
air : the projector impresses this qualitative impetus on the mass
of air immediately behind the projectile at the moment of expul
sion, and this mass, in turn, communicates a qualitative impetus
to its neighbour in turn, and so on. The strength of this view
was the obvious fact that, somehow or another, the surrounding
air is set in motion both when the projector releases the projectile
and where the projectile passes in its subsequent flight. Still,
that air motion seemed much too insignificant a cause for the
powerful flight of these missiles. Hence, most of the later School
men held that the free flight of projectiles could never be fully
explained by the forward push of travelling masses of air, and that
it required, at the moment of propulsion, the production within
the projectile of a motive quality — an impetus — by the projector.
This occult quality was, for them, the main cause of the visible
spatial motion of the projectile.

One great difficulty about this impetus was the explana
tion, on the presuppositions of the physics of these days, of its
disappearance. The later opponents I55) of this quality urged
that, once produced, it could never disappear : it cannot be de
stroyed by the introduction of its contrary, for it has none ; it
cannot be destroyed by the withdrawal of a created conserving
cause, because it persists, sometimes, without a created conserving
cause ; finally, it cannot be destroyed by the withdrawal of the

INTENSIFICATION AND REMISSION 227

divine concurrence, because God conserves a quality as long
as that quality has no contrary. Vasquez laid this spectre
by declaring that gravity or levity were sufficiently contrary
to impetus to weaken and destroy it. But most of these early
defenders of impetus preferred to answer that, as the impetus
was intended only for the definite purpose of carrying the pro
jectile a certain distance, the need of conserving the order of
the universe leads to a subtraction of the divine concurrence,
once that purpose is fulfilled : their main reason being, that,
otherwise, the projectile would never stop ; some of them picturing
this perpetual motion as going on in the sublunary world ; others
picturing it as an invasion of the heavenly bodies with all sorts
of possible consequences, especially, the creation of a void ;
finally, the question was seriously debated whether this impetus
wanes gradually, or, whether it was not as strong in its own
nature at the moment of God's withdrawal of His concurrence
as it was at the moment of its production.

THE INTENSIFICATION AND REMISSION OF MATERIAL QUALITIES.

Material qualities increase and decrease in intensity: the
gradual heating of water when put on the fire, its gradual cooling
when removed from the fire, the varying brightness from sunrise
to sunset and from starlight to moonlight, these, and countless
other observations, left no doubt on the minds of the Schoolmen
about the fact of the growth and decay of qualities. The effort
to give a philosophical explanation of this intensification and
this remission led, however, to much diversity of opinion. St.
Thomas (56) recalls four ancient opinions : Simplicius, Plotinus,
and other Platonists admitted increase or decrease of the quality
itself ; others, and perhaps Aristotle in the Categories, denied
the possibility of this kind of increase or decrease, and explained
intensification and remission as due to greater or lesser participa
tion in the substance ; the Stoics admitted the possibility of
increase or decrease in certain habits, such as the arts, but denied
it in other habits, such as the powers ; a fourth group of thinkers
admitted the possibility of increase or decrease in material
qualities, but denied that possibility in immaterial qualities.
His own view was that a quality is incapable of specific increase
or decrease, but is capable of greater or less participation by its
substrate : what is specific is indivisible, and, if present at all,
must be present as an indivisible — for instance, heat, and white
ness, and other qualities of the same kind, are specific indivisibles
of this type : but, he allows that such material qualities can be
more or less intense in substances owing to their greater or less
participation by these latter. Then, he reviews three contem
porary explanations of what exactly is meant by this greater or
less intensity : one explanation denied any essential increase
in the quality, but spoke of it as more deeply rooted in its sub
strate — a view rejected by St. Thomas as self-contradictory ;

15*

228 COSMOLOGY

another admitted essential increase in the quality, but spoke of
this increase as due to the addition of something new — a view
rejected by St. Thomas, firstly, because specific increase is im
possible and, secondly, because numerical increase both involves
a distinctly new substrate and puts qualitative increase on a
par with quantitative increase ; the third explanation accounted
for intensification, not by the addition of quality to quality, but
by the addition of quality to its substrate — and this view was
accepted by St. Thomas. Qualitative intensification is due, he
says, to the fact that the same quality in its specific indivisibility
is shared more and more by the substance, and exercises more
and more activity within that substance : primary qualities
grow stronger, because the agent in respect to anyone of them
reduces the patient 'from potency to actuality as well as that
agent can and, because the patient in the same respect is educed
more and more from potency to actuality as far as its disposition
permits ; secondary qualities grow stronger owing to the increasing
strength, within a substance, of those primaries whence they spring.
The Thomist text in turn led to lively controversy. The
Thomists,(57) rallying round the central thesis of the specific
indivisibility of the material qualities, taught that qualitative
intensification was due to greater participation of this quality
by its substrate. They failed (58) to agree, however, as to how
this greater participation was brought about : some explained
it by better union with the substrate ; others by a nobler kind
of existence ; others by the new f angled doctrine of " modes " ;
others by the expulsion of contrary dispositions. Durandus (59)
and others took a line of their own : the growth or decrease
of a quality involved for them a series of births and deaths ;
every new grade of quality, whether for better or worse, was
generated only by the destruction of its immediate predecessor.
This theory found few supporters : it was too big a paradox to
assert a fire could gradually heat the water in a kettle only by-
destroying, at every successive advance in temperature, all previ
ously existing heat ; besides, a natural agent does not destroy
but preserve and perfect its like ; it was too big a paradox to
assert that when a kettle of boiling water was removed from the
fire, the cooling water entered on a series of holocausts of its
higher temperatures ; besides, if you grant a first holocaust, no
adequate cause can be assigned for even its immediate successor,
in this alleged succession of newly born temperatures. Scotus
differed from both St. Thomas and Durandus and drew with him
almost all the greater minds outside the Dominican School. (60)
He explains intensification by the addition of new grades of quality,
remission by the subtraction of pre-existing grades of quality :
he admits, therefore, that a quality may be compounded of
distinct units or grades which unify as parts of a single accident.
The Scotistic line of criticism was that all the Thomistic attempts
at explanation of intensification or remission were so much
verbiage unless it be presupposed that, somehow or other, a

ACTIVE MATERIAL QUALITIES 229

single quality may have within itself many or few units as distinct
grades : no matter what you say, intensification means an in
crease of quality, remission a decrease of quality, and the Thomistic
denial of the existence of these units or grades, as distinct, seems
to destroy all intelligible explanation of the obvious presence of
the more or the less in the varying strength of the material quali
ties. Suarez and his disciples sided with the Scotists : Suarez
insisting that a certain amount of dissimilarity between those
various units or grades and, in consequence, a due subordination
of one to the other, was needful in order to render the Scotist
theory quite satisfactory.

THE FACT OF FINITE ACTIVITY.

Previous to the time of Albert the Great and St. Thomas,
some thinkers had denied all activity to creatures : these un
known occasionalists taught that fire does not warm but God
causes heat when fire is present, that a man does not move his
hand but that God causes this motion whenever the man wishes
it, and so on. St. Thomas (61) denounces this occasionalism as
sheer folly : it destroys the systematic order of the universe, the
genuine activity of bodies, and the scientific value of sense-
perception. Elsewhere, he expands these points into seven
arguments : our senses testify to differences of effects in nature,
and these could not arise, did God alone work in all actions ;
the wise do not act without purpose, and if God alone is active
the creature has no purpose of existence ; accessories ought to
accompany their principals, and, since God communicates to
creatures His likeness as regards being, He must also communi
cate to them His likeness as regards activity ; the denial to
creatures of this power of producing accidents is a denial of God's
power, for the communication to others of one's own perfections
marks an abundance of perfection ; the Sovereign Good does
everything for the best, and unless each creature can actively
communicate its perfections to others, this best is impossible ;
order is the best feature of creation, and if activity be denied to
creatures, that order is destroyed ; the nature of creatures can
never be judged from their effects, if these creatures cannot
produce effects, and, thus, this occasionalism saps the basis of
all scientific investigation. This refutation of occasionalism was
endorsed by Thomist, Scotist and Nominalist. Peter d'Ailly
and Gabriel allowed, indeed, the probability of occasionalism,
but did not adopt it ; and at the end of the sixteenth century,
Suarez, in summing up the history of a doctrine that never found
a defender in the School, can refer only to those nameless occasion
alists cited by Albert the Great and St. Thomas.

THE ACTIVE QUALITIES OF MATTER.

The only accidents that could act as efficient causes, according
to the School, were qualities : a doctrine, for which many subtle

230 COSMOLOGY

arguments were evolved, but the genuine basis of which was the
medieval interpretation of the facts of experience. Still, not all
the qualities were active : figure, for instance, was inactive.!62)
And not all the active qualities were active in the same way :
some were less perfect than others in their causality. Density
and rarity, for instance, produce merely changes of ubication.
Gravity, and levity, and impetus, produce merely changes of local
motion. The secondary qualities produce merely intentional
qualities, that is, representative copies of themselves in the
medium, and in the external sense-organ. Light and the four
primaries are the most active of all : they produce not merely
intentional qualities in sense-perception, but also physical qualities
of the same kind as themselves in non-living patients. That is
why, when the Schoolmen treat of the activity of material qualities,
they have uppermost in their thoughts the activity of the four
primary ones : the secondary qualities owe their activity, ulti
mately, to the primaries ; light, being a quality of the heavenly
bodies, was more or less ignored in discussing the changes of
terrestrial bodies ; density and rarity produced ubications, while
gravity, levity, and impulse produced local motions — but neither
ubications nor locations were, for medievalists, alterations or
changes of quality, and it is characteristic of medieval thought
to mean, chiefly, by the activity of a quality, its power of pro
ducing another quality either intentionally or physically. The
problem of the activity of qualities is, accordingly, the problem
of the activity of the four primary qualities. It is well to re
member that all these four are active : the hot heats, the cold
cools, the dry dries, the wet wets.(63) Aristotle had, indeed,
spoken of the hot and the cold as active, and of the dry and the
wet as passive ; but he explains away this distinction as purely
relative, and based merely on the greater or less activity exercised
by these qualities in the production of substantial change ; he
is explicit that all four are, in a genuine sense, active qualities.
And this teaching was endorsed by the School : it was, for medi
evalists, an obvious fact of observation.

TRANSEUNT CAUSALITY A MAKING, NOT A MIGRATION, or
BEAUTIES.

The key-note of the medieval view of material qualitative
activity, apart from the fundamental question of the divine
concurrence, lies in its insistence that there is one. and only one,
difference between God's creative power and the creature's
efficient causality : creation implies the production of something
out of nothing ; finite causality implies the production of some
thing out of a pre-existent substrate — and since this chapter
deals solely with the production of accidents, we mean here, by
pre-existent substrate, a substance. " There are," writes St.
Thomas,(64) " two notes, characteristic of creation. The first
is that nothing is presupposed, in any way, when something is

TRANSEUNT CAUSALITY 231

said to be created. This note marks off creation from all other
changes : generation, for instance, presupposes (primordial)
matter which is not generated but is made complete in generation
by the actuality of the (substantial) form ; and in the remaining
kinds of change, a complete being is presupposed as substrate.
Hence the causality, exercised by the source of generation or
alteration, does not extend to everything that is present in the
patient : this causality extends merely to the particular form
which is educed from potency to actuality. The causality that
is exercised in creation extends, however, to everything that is
present in the effect : that is why creation is defined as produc
tion out of nothingness — nothing increate, if one may say so,
being presupposed for the fact of creation." And in contra
distinction to creation, finite transeunt causality, in reference
to accidents, meant for the School the production in a pre-existing
substance, as patient, by some active quality in another substance,
as agent, of an accident that previously did not exist either in that
patient or in any other body : gravity, levity, impetus produce
de novo locations ; rarity and density produce de novo ubications ;
the secondary qualities produce de novo intentional accidents
in the medium and in the external sense-organ ; the primary
qualities produce de novo both intentional accidents and physical
accidents in already existent substances.

This robust theory of qualitative activity is explicitly em
phasised by St. Thomas in his refutation of the only opposing
theories known to him : the theory of Democritus and the theory
of certain Moorish Professors. Democritus tried to explain
transeunt causality by the suggestion that the atoms of the
agent penetrated the pores of the patient. St. Thomas repeats,
against this view, the arguments urged by Aristotle : even if
the alleged immigration were a fact, the resulting contact between
the atoms of the agent and these of the patient would not, of
itself and apart from the intervention of active principles, account
for the changes wrought in the patient ; moreover, this alleged
migration would affect only those parts of the patient in which
the immigrant atoms congregate, whereas transeunt causality
affects the patient as a whole ; finally, this alleged migration
cannot be a fact, because did it happen transeunt causality would
result obviously in a gradual decrease of size in the agent. " It
is clear, then," St. Thomas concludes,(65) " that action is not
brought about, as Democritus believed, by local motion, but by
the fact that something real is educed from potency to actuality."
And in meeting the objection, that transeunt causality does not
occur because an accident cannot exist outside its natural sub
strate, he recurs once more (66) to this theory of Democritus.
"It is not contrary to the nature of an accident to be active
outside its substrate . . . unless one imagines that this (kind of
activity) involves the flow of the same numerical accident from
agent to patient, as Democritus seems to have believed in his
explanation of activity as a migration of atoms."

232 COSMOLOGY

This reply of St. Thomas affords a natural transition to the
causal theory of these Moorish Professors. These Moors thought
the only possible explanation of transeunt causality was that of
a flow of accidents from agent to patient : and since they knew
this flow to be an utter impossibility, they denied the possibility
of transeunt causality. St. Thomas states and refutes this
theory in three of his treatises.!67) " Some doctors of the Moor
ish Law are said to bring an argument to show that accidents
are not traceable to the action of bodies, the ground of the argu
ment being this, that an accident does not pass from subject to
subject : hence, they count it an impossibility for heat to pass
from a hot body to another body heated by it, but they say that
all such accidents are created by God. Now, it is a ridiculous
proof, to assign of a body not acting, to point to the fact that
no accident passes from subject to subject. When it is stated
that a hot body heats another, no one means that the same
numerical heat which is in the heating body passes into the body
which becomes hot ; what is meant is that, by virtue of that
heat which exists in the heating body, a numerically distinct
heat which, until that moment was only in potency in the body
about to be heated, begins to exist actually in this latter. For,
a natural agent does not transfer its own form to another subject,
but, reduces that subject on which it acts from potency to act
uality." An equally explicit statement is found in the De
Polentia. In the latter treatise, St. Thomas makes this tart
reply. " This reasoning is utterly silly. For, when we say an
accident cannot pass from one subject to another, this is to be
understood of an accident which preserves its numerical identity :
it does not mean that an accident, of a similar kind, may not be
produced in a distinct subject by the power of one which resides
in its own natural subject. The truth is that this last fact is
what necessarily happens in every instance of natural action."
A third criticism of this Moorish view is found in the de Veritate.
" Rabbi Moyses says this is the view of certain exponents of the
law of the Moors : for they say, that fire does not heat, but, God
heats through the fire. But this is a foolish theory for it destroys
natural activities in all things : moreover, it is contrary to the
teachings of the philosophers and of the Saints." The teaching
of St. Thomas on transeunt causality in reference to accidents is,
therefore, clear and unmistakable : transeunt causality is neither
a migration of atoms or a flow of accidents ; it is the production
de novo of accidents in the patient by the agent.

This Thomistic theory of transeunt causality was reproduced
and defended by every member of the medieval School : Thomist,
Scotist, Nominalist and Suarezian present, on this problem, a
united front against Democritus and these nameless Moors ;
not a single text can be quoted, from any of them, in defence of
either of these opposing views of transeunt causality. All the
Schoolmen i68) held that the active qualities of a finite agent,
apart from all transference of accidents from itself to the patient,

THE HISTORY OF A PHRASE 233

can set up, in this latter, a process of change which involves the
passage from non-existence to existence within the patient of a
totally new accident : of course, the active quality of the agent
must be actually active ; some active qualities are always exer
cising their activity, and need merely the juxtaposition of a patient
in order to produce their effects ; other active qualities exist
normally, as regards causality, in a state of potency, and require
to be previously reduced to actuality, as causes, before they can
produce their effects on a juxtaposed patient. But once the
active qualities of any agent are in actuality, the exercise of
transeunt causality does not imply the slightest change in that
agent. As a matter of fact, a subsequent change always does
occur in the agent, but that change occurs only because of the
reaction of the patient upon the agent : it occurs in other words
only because the agent, in its turn, has become a patient (69)
The only change that ever occurs in transeunt causality, as such,
begins and ends in the patient ; this change consists in the
coming into existence of a new accident ; this change is called
" motion," because that was the technical medieval term for
gradual transition from potency to actuality. " Motion " falls,
then, wholly within the patient : and, except for the purpose of re
futing Democritus and the Moors, not a single line was written in
those far off days about the problem of the transference of any
kind of accident from one substance to another. The attempt to
explain transeunt causality as a flow of motion looms large for the
first time, in post-Greek philosophy, with the advent of Descartes.
The incipient convert to Cartesianism, who attempts to spy out
the medieval territory of transeunt causality from the heights
of Cartesianism, and, has sufficient self-control to prevent his
personal feelings from leading him to misrepresent facts of history,
must sum up his medieval researches on the flow-of-motion
theory of causality as briefly as did the author of the famous
chapter : " There are no snakes in Iceland."

THE HISTORY OF A PHRASE.

But though the Schoolmen rejected from first to last the flow-
of-motion theory of causality, they never achieved unanimity
concerning the fitness of the famous Aristotelian phrase that
action and passion are the same " motion." " Motion," accord
ing to Aristotle, is the gradual transition from non-existence to
existence of either location or quantity or quality : this physical
process, which occurs within the patient, is called action, when
viewed as caused by the agent, and is called passion, when viewed
as received by the patient ; and this action and passion, although
the same " motion," differ virtually. St. Thomas, in his Commen
taries, endorses all these statements. Both masters warn their
readers, however, against seeing in these technical phrases any
suggestion that transeunt causality consists in the flow of the
same numerical accident from agent to patient. This warning

234 COSMOLOGY

is implicit and explicit. It is implicitly conveyed in their illus
tration of these phrases by the art of teaching : the professor
teaches, the pupil is taught, and the resulting " motion " is the
gradual enlightenment of the pupil's mind : this gradual en
lightenment viewed as caused by the professor is action, viewed
as assimilated by the pupil is passion. No one would dream of
saying that the knowledge gained by the pupil is numerically
that living knowledge, which exists in the professor's mind, and,
which is exercised by him, when lecturing — in other words, of
saying that every bit of information acquired by the pupil in
volves a loss of that information to him who imparts it, the
professor : yet, that is the consequence involved in the flow-of-
motion theory of causality. But if anyone is prejudiced enough
to insist that this consequence, however incredible to us and to
the later Schoolmen, was really at the back of the minds both of
Aristotle and of St. Thomas, he may be brought to his senses by
actual study of their explicit warning on this very point. A few
lines farther on, when dealing with the same illustration, Aristotle
writes (70) : " Teaching is the actuality of the master : yet it is
in another (i.e. the pupil), but it is not in this latter as a something
that has been cut off." . . . And on these sentences, St. Thomas
makes the following comment. " This (i.e. Aristotle's doctrine
of the presence of the actuality of one substance in a distinct
substance) would be impossible if the actuality of this one
(substance) were, in that same way in which it is this sub
stance's actuality, in another (substance)." No words could
be clearer : Aristotle and St. Thomas were determined that
any interpreter, who would read into their phrases about the
identity of " motion " with action and passion any suggestion of
a flow-of-motion causal theory, should be disavowed by them
selves.

It cannot be denied, however, that the phrase, which says
that action is in the patient, startles every reader. St. Thomas (71)
recurs to it, again and again, giving it now one twist and now
another : yet, always excluding any suggestion of the migration
of an accident from the agent to the patient. And after St.
Thomas's day, this verbal controversy pitted Thomist against
Thomist, Scotist against Scotist, Suarezian against Suarezian.
Scotus (72) defined action as the relation of the agent to the effect,
and, consequently, declared action to be, not in the patient, but in
the agent. His view was that, prior to the production of the
effect, there was no intermediary between tlie agent and the
effect : that is, no intermediary distinct from the pre-existing
form, which is the source of action, and the newly produced form,
which is the result of action. Ockham (73) and a few freelances
improved on this Scotistic emasculation of the meaning of action
by denying the existence of action : things of themselves come
into existence just as things of themselves persevere in existence ;
if any intermediary be necessary between cause and effect, the
extrinsic Will of God suffices — that extrinsic Will changed David

THE HISTORY OF A PHRASE 235

from plebeian to king, and ought to suffice, therefore, for the
transition of an accident from potency to actuality ; if the cause
is sufficiently prepared to produce its effect, there is no necessity
for action, as intermediary, between the exercise of this causality
and the origin of the effect. The majority of the Schoolmen (74)
rejected these solutions of Scotus and Ockham : they admitted
the relationship of which the Scotists spoke, but they refused to
identify it with the Aristotelian category of action, on the grounds,
that this relation arose out of, and was consequent on, action ;
they denied the applicability of Ockham's razor to this same
category, on the grounds, that a particular cause and its effect
may co-exist in our world even though this latter has not been
produced by the former — in proof, whereof, they urged that cause
and effect exist simultaneously the moment after production,
and, yet, the effect no longer depends for its existence on its
causes.

But the opposition of the majority to the Scotists and to the
Nominalists did not secure unity of opinion among themselves.
Cajetan (75) acknowledged, as frankly as Scotus, the ambiguity of
the incriminated phrase, and pointed out other texts where St.
Thomas says, explicitly, that transeunt action is in the agent.
He suggests that transeunt action involves three factors : the
process of " motion," the reference of this " motion " to the agent
as source, and a third factor, the activity of the agent, which re
sides in the agent and is an essential feature of all action. He
interprets those Thomistic texts that proclaim action to be in
the patient as referring to the first two factors of " motion,"
the process and the reference of that process to its source. He
adds that St. Thomas does not, at any stage, exclude the third
factor of activity : St. Thomas seems to ignore this third factor,
in certain texts, simply because he had not separate names for
each of these three factors ; but, as a matter of fact, just as
St. Thomas's use of the preposition " in" in reference to passion,
emphasises the passive actualisation of the patient, similarly,
his use of the preposition " a&," in reference to action, is a per
petual reminder for the initiated of this third factor of action,
the activity of the agent. Cajetan's subtle solution of the
phrase-difficulty aroused but little enthusiasm. The majority of
the Dominicans stuck to the interpretation which puts transeunt
action in the patient and explains away all contrary Thomistic
texts as referrible only to immanent action. Of these, Capreolus
gives the fullest meaning to the category of action : action and
passion are physically identical with the process of " motion,"
and, from this point of view, are both in the same subject, the
patient ; but action and passion are, as formalities, opposed to
each other and, from this point of view, they exist in different
subjects. Action, then, has a double reference : it is produced by
the agent, is, in fact, the exercise of the activity of the agent ;
it results in an accidental form, an actuality that resides in the
patient. Action is the actuality both of the agent and of the

236 COSMOLOGY

patient : it is the actuality of the agent, because it completes
this agent by originating there ; it is the actuality of the patient,
because it completes the patient by enriching this latter with a
process that results in a new accident. Suarez approves of the
explanation given of St. Thomas by most of the Thomists : he
sets out, however, to establish a modal distinction between
action and its term, and ends by whittling down action proper
to nothing more than a special dependence of the effect on its
cause — a conclusion akin to the Scotistic theory of action as a
relation. Later still, John of St. Thomas and Goudin (76) suggest
a new way of reconciling the divergent texts of St. Thomas.
Action implies, at least, two formalities : a formality that con
sists in reducing the active quality of the agent from potency to
actuality, and must exist in the agent ; a formality that consists
in reducing the patient from potency to actuality and producing,
therein, a new accident, and must exist in the patient. And in
addition to these two formalities, action may be understood
as referring to the relation between the effect and its cause : in
this reference, action must be connected with the agent, not be
cause of inherence, but because of denomination or emanation.
Here we may close this long-drawn controversy about this phrase
of Aristotle : everything that has since been written by scholas
tics, about the subject of the category of action, is but a ringing
of the changes on one or other of these medieval views. But in
finishing, it is worth insisting that all the fog, there was, about
this question centred on the correct usage of a phrase : apart
from this verbal controversy, the Schoolmen propounded a definite
and intelligible theory of transeunt qualitative activity.

CONTACT AS A CONDITION OF ACTION.

The Schoolmen (77) held with Aristotle that there was no empty
space in universe : all space within the crystalline spheres was
filled with matter of one kind or other. This denial of the
possibility of empty space did not prevent, however, the occur
rence of controversy about action at a distance. St. Thomas (78)
and all the Thomists, Suarez and most of his disciples, taught
that transeunt qualitative activity took place under conditions
of contact : direct contact, when the agent and the patient
touched one another ; indirect contact, when the agent and the
patient did not touch but when the agent's activity affected the
intervening bodies and was propagated, through them, to the
patient. Ockham and the Nominalists, Scotus and many
Scotists admitted (79) that transeunt activity took place, in most
instances, under conditions of either direct or indirect contact :
but they insisted that transeunt activity took place, in some
instances, at a distance and without contact of any kind ; these
medievalists, also, rejected empty space, and meant by action at
a distance activity between an agent and a patient that are
separated by intervening bodies which are, in no way, affected by

CONTACT AND ACTION 237

this particular activity of the agent. For centuries, a priori
arguments were greatly in favour with the opponents of action
at a distance. Capreolus, Suarez, and others urged that the
agent is actuality, the patient potency, and that potency and
actuality must be somehow brought together : their opponents
allowed the need of this conjunction in reference to informative
actuality and its corresponding potency, but denied its need in
other instances. Soto and others urged that the limitations of
matter, as substance, prohibited it from influencing other sub
stances except under the condition of contact : their opponents re
plied that, if the limitations of matter did not prohibit a material
agent from influencing a patient two yards away through an
intervening body, no reason was assignable why that limitation
should prevent an agent from influencing a patient at the same
distance independently of any intervening body. John of St.
Thomas and others that urged the origin of the effect demanded
the spatial conjunction of agent and patient: their opponents
replied that this argument merely begs the question.

These replies seem to have convinced later defenders of the
traditional thesis that a priori arguments were futile ; and then,
a group of Scholastics appeared who based their case against
action at a distance on a posteriori arguments and asserted that
only arguments of that kind were employed by Aristotle and
St. Thomas. The strong point of these later Schoolmen was that
action by contact, whether direct or indirect, was a fact of obser
vation embodied in all our experience of natural transeunt
causality. With this appeal to experience, these writers were
wont to couple the following appeal to absurdity : if a finite
agent can act at a distance, then, it can act at all distances, and,
even, at an infinite distance ; both consequences — that of absolute
indeterminacy in distance and that of infinite distance — contra
dict the rigorous determinateness of all individual finite qualities
existing in our world. Ockham, Camerarius and their followers
rebutted, as best they knew how, both of these arguments.
They countered the appeal to absurdity by insisting that bodies,
which can act at a distance, have, in each instance, a determinate
sphere of activity within which their activity is effective. They
met the appeal to experience by allowing its validity, in the
majority of cases, and quoting a number of cases which cannot
be accounted for by contact action. This list of instances of
alleged action at a distance varies from author to author and
from century to century. In 1671, De Rhodes, (80) a convinced op
ponent of action at a distance, gives as objections to the traditional
thesis the following list : the power of a magnet over iron at a
distance ; the popular account of the cause of birth marks ;
the malign influence on children of a witch's eye ; the numbing
of a fisherman's hand by the torpedo-fish ; the stoppage of large
ships by the sucking-fish ; the bleeding of a corpse owing to the
presence of its murderer ; the playing of one cithara by another ;
the hatching power of the gaze of the ostrich ; the basilisk's

238 COSMOLOGY

killing of men by glances, and of serpents by odours ; a man's
loss of voice at the sight of a wolf ; the charming of serpents
by music or song ; the greater heating of the water at the top of
a kettle on the fire ; the enticement of serpents from their caverns
by the breath of hinds ; the toad's power of attracting reluctant
weasels into its mouth by merely opening its jaws ; the sun's
power of manufacturing gold, and other minerals, in the depths
of the earth ; the extraction of jaundice from a sufferer's body
by the stare of the wit- wall ; the frightening of dogs by the leaves
of a plane tree ; the silencing of dogs by the shadow of a hyena ;
the lighting of naphtha by a distant fire ; the cure of poisoning,
due to the bite of the Tarantual spider, by music when enforced
by the killing of the spider. Pe Khodes contests, only in a few
cases, these alleged facts : he denies that the ostrich hatches its
eggs by gazing at them ; he denies that the death of the Tarantula
helps in the cure of its victim ; and though he accepts Plutarch
and Pliny and other ancient worthies as authentic witnesses to
the existence and powers of the sucking-fish, he wonders why
no sailor on the high seas, in recent times, has observed this
extraordinary phenomenon of the stoppage of a huge vessel by
a tiny fish — should such things be, he would explain them by a
resisting quality that emanates from the sucking-fish. But, while
admitting all the remaining objections to be facts, he denies that
any of these facts can be proved to be a genuine instance of action
at a distance. All these facts are due to active qualities which
act both on intervening bodies and on the patients : the dif
ferences, observable between the effects produced by these quali
ties, on the intervening bodies, and on the patients, are due solely
to the fact that these intervening bodies have dispositions which
are different from those of the patients.

UNLIKENESS AS A CONDITION OF ACTION.

The agent can be like or unlike the patient in one or other of
three ways : first in a specific quality, for example, heat ; secondly
in the grade of that specific quality, for example, the same degree
of heat ; thirdly in concomitant accidents, for example, rarity,
density, figure, location, and whatever else is conducive to
activity. The main question was, whether action is possible
between one substance, as agent, and another, as patient, when
both substances are alike in all these three ways : in other words,
can an agent, with a heat quality of four degrees, act on a patient
which has both similar concomitant circumstances and a similar
grade of heat ? Aristotle denied that, in such instances, action
was possible, and urged three main arguments (81) : the purpose of
action is to produce likeness but, in this instance, likeness already
exists ; the stimulus to action is the production of likeness but, in
this instance, that stimulus is lacking ; the agent acts, because it is
in actuality, and the patient is acted on, because it is in potency,
but, in this instance, the exact likeness of these two prevents them

UNLIKENESS AND ACTION 239

from fulfilling these respective roles. St. Thomas (82) and the
School followed Aristotle's lead on this question : so deeply
rooted did this belief of dissimilarity — in the sense explained—
as an essential of transeunt action, become, in later days, that
Suarez speaks of it as almost a first principle of philosophy.
But when we pass from this hypothesis of complete likeness to
instances of incomplete likeness, medieval unanimity breaks up.
Practically all were agreed that an agent, with a quality of greater
intensity, could act on a patient with a similar quality of less
intensity. A few thought that an agent, with a quality of less
intensity, could act on a patient with a similar quality of greater
intensity : but the majority denied this for the reason that action
implies victory, and, in inorganic nature, the physically weak
never vanquish the strong ; and when this majority was con
fronted with the fact that air, which from the standpoint of
medieval science is less cold than water, causes water to freeze
in winter, they replied that this freezing was due mostly to the
influence of the cold stars. There was difference of opinion, (83)
also, on the possibility of action between substances, alike both in
specific quality and in grade of that quality, but, unlike in the
accompanying accidents : some denied, others admitted, the
possibility of action in such instances ; a number suggested that,
although these concomitant dissimilarities did not enter directly
into the principle of activity, still, one set of them might somehow
aid the active principle in their substance, and, thus, bring about
as much dissimilarity in the two principles of activity as would
permit action.

CHAPTER IX.

THE ARISTOTELIAN SCHOOLMEN ON THE MEANING AND
CONDITIONS OP MOTION IN MATTER.

WORDS have their day : from age to age they wax and wane, they
wither and burgeon. This wear and tear of words is vividly
illustrated by the philosophical history of the term, motion : in
the halcyon days of Scholasticism, motion was, for every thinker
in Europe, the synonym of several distinct kinds of material
change : since the time of Descartes, that ancient richness of
content has dwindled away, and nowadays, outside the Scholastic
School, the sole connotation of motion both in philosophy and
in natural science is the meagre, if all important, one of local
movement. The older meaning is essential, however, to an intel
ligible grasp of medieval philosophy : the shaft that is drawn to
the head flies farthest. The modern scholastic will never catch
up with his forbears unless his mind, in reading their writings, is
ever alert to the Aristotelian technical connotation of this word ;
and, for lack of a similar attention, much anti-scholastic criticism
is a mere tilting at windmills.

THE AMBIGUITY or THE MEDIEVAL TERM, MOTION.

The Schoolmen included under this all-embracing term of
motion various changes which were for them, in ultimate analysis,
different in kind. These differences in motion seemed to Aristotle^1)
at one stage, as manifold as the differences in being : but, on
further thought, he and the School marked off four distinct varieties
of motion : generation or corruption, alteration, augmentation or
diminution, local motion. St. Thomas saw clearly the confusion
that was bound to arise from the inclusion of these distinct kinds
of change under a term that, naturally, suggests only one kind
of change, namely, local motion. His apology (2) is that the
human mind must start from the obvious in its invention of
names : " and as local motion is naturally the first of all motions
... we employ words that arise out of it for alteration and for
every other kind of change." A fair defence of the inventor —
someone will say — but surely his successors ought to have selected
less ambiguous terms. The probability is that these successors,
trained as they were from their youth to the peculiar Aristotelian
terminology, did not feel this ambiguity as keenly as we do who
are initiated, from our youth, into a wholly non- Aristotelian ter
minology : however that may be, the Aristotelian terminology
stuck in the Schools for centuries, and must be grappled with, on

240

POTENCY AND ACTUALITY 241

its own merits, by anyone who seeks to understand medieval
philosophy. Another point (3) worth noting, here at the beginning
of our study of motion, is that neither Aristotle nor the Schoolmen
professed to define motion. A definition is an attempt to explain
its object by something that is more simple and better known.
Ultimate facts are, however, irreducible ; and as the four varieties
of motion are ultimates in their own order, motion cannot be
strictly defined. Hence, Aristotle and the Schoolmen are content
with an accurate description of the metaphysical characteristics
common to all four varieties of motion : a description that is
possible only with the aid of concepts more general than those
found in the categories — the concepts of potency and actuality.

THE TRANSCENDENTAL MEANING OF POTENCY AND OF
ACTUALITY.

The correlatives, potency and actuality, occur hundreds of
times in the writings of Aristotle and of the Schoolmen. The
former devoted, to their explanation, the twelfth chapter of the
fourth book of his Metaphysics and all the ninth book of his
Metaphysics. The Schoolmen, in their Aristotelian commen
taries and elsewhere, are equally painstaking in their elucidation
of these terms : expounding and discussing at great length every
line written on this topic by Aristotle. Now, Aristotle and the
Schoolmen (4) believed that the analysis of the facts of causality
reveals two kinds of potency : active potency which is a force or
a faculty ; passive potency which is a mere capacity for being
acted on by an active potency. Each of these kinds of potency
has its corresponding kind of actuality : the actuality, that
corresponds to active potency, is activity ; the actuality, that
corresponds to passive potency, is that complete form or perfection
which its nature permits it to acquire owing to the activity of
some active potency. But in the course of these researches into
the mystery of causality, Aristotle analysed, as we saw, in a new
and fruitful way the implications of passive potency : at the root
of all passive potency, lies a reality which does not exist here and
now but is coming into existence immediately, because all the
active and passive presuppositions of its production are not only
actually in one another's presence, but are also entering on those
interactions that will result in the transition of something real from
non-existence to existence. Accordingly, he and the Schoolmen
called this kind of reality, potency, and, made it one of the foun
dation-stones of their metaphysics : potency was, for them in this
fundamental sense, a transcendental, that is, a reality which cannot
be subsumed under any one of the categories of being because it
is equally applicable to all categories. Moreover, since physical
motion is another of those realities which could not in their eyes,
for a somewhat similar reason, be subsumed under any special
category of being, it was this transcendental sense of potency
and a corresponding transcendental sense of actuality as its

16

242 COSMOLOGY

correlative that were employed in the attempt to define motion.
A reality is in potency in this transcendental sense, then, when,
although it does not de facto exist, it is a non-existent that is on
the point of crossing the chasm between existence and non-
existence : a not-yet-existent reality which is clearly distinct not
only from what already exists, and from what can never exist, but
also, from what will exist at some far distant date. Actuality in
its corresponding transcendental meaning (5) is a reality of any
kind that does here and now exist. " In the course of our
analysis," writes Aristotle,(6) " it will also become clear, with
regard to the potential, that we not only ascribe potency to that
whose nature it is to move something else, or to be moved by
something else, either without qualification or in some particular
way, but also use the word in another sense in the pursuit of
which we have discussed these previous senses. Actuality means
the existence of a reality not in the way which we express by
(saying it is) in potency : we say, for instance, that a statue of
Hermes is potentially in the block of wood and that the half -line
is potentially in the whole because each of these might be separ
ated out ; and we even call the man who is not studying a man
of science, if he be capable of studying a particular problem. Our
meaning can be seen in the particular cases by induction, and we
must not seek a definition of everything but be content to grasp
the analogy : that as that which is building is to that which is
capable of building so is the waking to the sleeping, and that which
is seeing to that which has its eyes shut but has sight, and that
which has been wrought up to the unwrought. Let actuality
be defined by one member of this antithesis and potency by
the other." " For," comments St. Thomas,(7) " prior to the
chiselling of the wood, we speak of the image of Mercury as exist
ing not actually but potentially in the block : but when the block
has been chiselled, then, the image of Mercury is said to be as an
actuality in the wood. The same is true of the part and the
whole : a part, for instance the half, is in potency inasmuch as
it is possible by dividing the whole to cut off that much from the
whole : but when the division of the whole is already accom
plished, that part exists in actuality. The same is true of the
man who has brains and does not use them and of the man who
is capable of meditating but does not meditate : but if such a
one does think or does meditate — that involves the existence of
an actuality." These texts are clear and pat. And in their
further explanation,!8) Aristotle and St. Thomas distinguish
explicitly between this transcendental meaning of potency and
that mere logical possibility which implies only the absence of
contradiction between the notes of any concept. Both of them,
also, stress the condition that potency can be strictly predicated
only of a reality that is almost immediately coming into existence :
potency is an anticipation, a promise of new realities, and when
ever this promise is not seriously and proximately grounded in
reality, there is not potency but sheer non-being.

MEDIEVAL DEFINITION OF MOTION 243

THE MEDIEVAL DEFINITION OF PHYSICAL MOTION.

Motion is a peculiar mixture of potency and actuality ; it is a
process by which material realities pass either from non-existence
to existence or from existence to non-existence. " You must
understand," writes St. Thomas,!9) " that while something may
be in actuality only, and another something may be in potency
only, a third something may be a mean of some kind between
mere potency and complete actuality. Whatever is in potency
only, is not yet in motion ; whatever is already in a state of
finished actuality is not in motion, its motion is over. But
whatever is a mean of some kind between mere potency and
finished actuality, whatever is partly in potency and partly in
actuality, that reality is in motion." " The reason," writes
Aristotle, (10) " why motion seems incapable of definition is that
it cannot be reduced either to mere potency or to finished actual
ity. . . . Motion seems to be an actuality but it is an imperfect
kind of actuality because it is the actuality of a being in
potency. ..." The same authority has left us four descrip
tions of motion (u) : motion is the actuality of potential being
as such ; motion is the actuality of the movable as such ; motion
is the actuality of the active and passive as such ; motion is the
actuality of a being in potency in so far as this being is in potency.
" Accordingly," comments St. Thomas,(12) " any unfinished
actuality has the (two) characteristics of motion : the first,
because it is in potency in reference to further actuality ; the
second, because it is an actuality in reference to whatever is less
finished than itself. Motion, then, is neither the potency of what
exists potentially nor the actuality of what exists actually but
the actuality of what exists in potency : the word, actuality,
pointing out its relation to the previous potency ; and the word,
potency, pointing out its relation to the subsequent actuality.
Hence, Aristotle's definition of motion as the actuality of the
potential as such, is excellent." St. Thomas proceeds to illustrate
these abstractions by the familiar process of heating water on a
fire : before the water is brought near the fire, it is merely hot in
potency and it is not yet in heat-motion ; when the heating has
been carried to boiling point, the heat-motion is over and the
finished actuality of heat exists in the water ; but, in the interval
that elapses between the time that the kettle is put on the fire
and that the water is fully boiled, the water is gaining heat little
by little, and it is this gradual acquisition of heat from start to
finish which constitutes heat-motion. That gradual acquisition
of heat is motion because, at every stage of it, an unfinished heat-
actuality exists ; every stage of the heating is an actuality because
some heat is present ; every stage of the heating is an unfinished
actuality because more heat is being continually produced. No
particular degree of heat before or during the process of heating
is motion, simply because it is such and such a degree of heat :
the degree of heat which the water had, before coming under the

16*

244 COSMOLOGY

influence of the fire, is not part of the heat-motion, it is simply a
starting-point of motion and, as such, a complete actuality, not
part of the making of an actuality ; each degree of heat gained
during the boiling is a heat-motion only because it is an actuality
in the making which tends to pass beyond itself into a further
actuality ; were any degree of heat to cease to pass beyond
itself, because, for instance, the kettle was removed from the fire
at some particular moment before the water wras fully boiled, that
degree would be a finished state of heat and not a motion of heat ;
similarly, if, after some time away from the fire, the kettle were
put back and thereby the heating begun again, that particular
grade of heat, from which ex hypothesi the heating starts afresh,
would not be part of the subsequent heat-motion but would be
its starting point. Heat-motion — and the same is true of every
other motion — exists only as long as any grade of heat is being
produced and is passing, unbrokenly, into another grade. This
illustration puts flesh and bones on the bloodless abstractions of
potency and actuality as descriptions of motion : of course, it
must be interpreted in the light of the medieval theory of heat as
a qualitative accident distinct from local motion and from quan
tity. Motion, then, was the name given by the Schoolmen to
every continuous process in matter which tends to pass beyond
itself into something else : this process has a starting point
whence motion begins and a finishing point where motion ends ;
there is no motion at the starting-point, there is no motion at the
finishing point, all the motion lies in the unbroken process that
links the one with the other.

THE MOTION OF GENERATION OR CORRUPTION.

All the Schoolmen agreed (13) that physical motion, in the
strict sense, was verified only in those gradual changes of quantity
or quality or location that occur in substances. They held, also,
that strict physical motion implied certain conditions. It is a
process between extremes that are contrary : one positive term
is lost and another gained. It is successive : the transition from
one extreme to the other is effected by traversing the intervening
phases. It is continuous and unbroken in its succession : a few
Schoolmen denied the need of this continuity in local motion, and
a large number denied its need in alteration, augmentation,
diminution ; but, the majority affirmed its need in all three
kinds of physical motion on the grounds that any interruption of
motion was rest.

But motion had been used, also, by Aristotle, in a wide sense,
and from this point of view, a controversy arose as to whether
generation and corruption could be set down as forms of motion.
Aristotle seems to have held that they could, for he cites generation
and corruption and local motion as examples at the close of his
definition. St. Thomas (14) and most of the Schoolmen agreed
with him. Soto and others urged, against this view, that genera-

AUGMENTATION AND DIMINUTION 245

tion and corruption are not actualities of potential being as such
because their occurrence takes place instantaneously, and does
not leave the subject of these changes in potency towards any
subsequent actuality. Their opponents replied that even in
generation and corruption the process of change can be distin
guished from its result, namely, the gain or loss of a substantial
or accidental form : and that prior to this change the subject is
in potency to two actualities, the unfinished one of change and
the finished one of the end-state ; and that, therefore, even in
generation or corruption there exists an actuality which is
incomplete and tends to something further. This reply covers
both kinds of generation or corruption : the gain or loss of atmos
pheric brightness, the gain or loss of the substantial forms of the
elements. Some Schoolmen added a special plea for substantial
generation or corruption on the grounds that, even if it were not
of itself continuous and successive, it presupposes alteration and
falls on that account within the Aristotelian definition of motion.

THE MOTION OF AUGMENTATION OR DIMINUTION.

The motion of augmentation or diminution never occurs in
those bodies to which we have limited the scope of Cosmology :
non-living bodies. By motion of augmentation or diminution, the
Schoolmen (15) meant only that growth or decline in size which
results in living bodies as a consequence of the balance they
maintain between the intake of food and the output of work.
Normal human development was the common example of this
kind of motion : up to the age of twenty or twenty-five, the human
body is, medievalists believed, gradually increasing in size ; from
twenty-five to about thirty-five, it is merely holding its own in
size ; from thirty-five onwards, it is gradually shrinking in size.
Good nutrition is the basis of growth : when food is absorbed by
a thriving organism, all the organs increase in size. Malnutrition,
whatever be its cause, is the basis of shrinkage : when the food
absorbed is less than the amount of wastage, all the organs
decrease in size. These facts of living growth and of living
decline include all that the medievals meant by motion in quan
tity. They steadily refused to reckon as motion in quantity any
of the increases or decreases in size which occur in non-living
bodies. Not that they were particularly consistent in their usage
of words : " augmentation " is often used for all sorts of increase
in size in non-living bodies ; increase either in extension or in
intensity ; increase in quantity whether continuous or discrete ;
increase in bulk either owing to rarefaction or owing to the juxta
position of new parts. Still, when treating explicitly of motion
in quantity as one of the kinds of physical motion, they emphati
cally lay down that this kind of motion is verified only in the growth
and decline of living bodies. And, at the same time, they insisted
with equal emphasis that all apparently similar happenings in
non-living bodies were totally distinct in nature : that these

246 COSMOLOGY

non-living increases in size, sometimes, did not involve an addi
tion of quantity ; that even when non-living increases in size do
involve an addition of quantity, this addition is sometimes an
addition of discrete quantity ; that even when these non-living
increases in size involves an addition of continuous quantity, this
addition is the mere resultant of local motion.

THE MOTION OF ALTERATION.

Alteration is another medieval word with many meanings : in
its widest sense, it implies simply a difference of accidents and
was used to signify any kind of accidental change — whether of
quality or quantity or location ; in a less wide sense, it was
restricted to those changes that are changes of quality. But even
this restricted meaning is not the technical meaning of this word
as one of distinct kinds of physical motion. There are changes of
quality which do not imply the loss of a preceding quality, either
because the incoming quality has no contraries or because the
incoming quality is the natural sequel of quantitative change :
atmospheric brightness is an example of the former, shape an
example of the latter change. Now, both Aristotle (16) and
Schoolmen excluded these changes of quality from alteration in
the strict sense. For them, alteration or motion in quality
occurs only when a body loses one sensible quality and gains
another by gradual transition through all the intervening phases
which separate these two contraries : the cooling of hot water
and the heating of cold water are the favourite illustrations.
They distinguished three sub-varieties of this alteration : ordinary
alteration whereby a body gains some sensible quality which it
previously lacked ; intensification whereby a quality already
existing in a body becomes more intense ; remission whereby a
quality already existing in a body becomes more feeble. They
were careful, also, to point out that alteration, as a distinct kind of
physical motion, refers primarily and directly to the sensible
qualities of matter — those qualities that come third in Aristotle's
fourfold division of the category of quality : qualities of the first
and fourth division either do not imply the loss of a contrary
quality or arise as natural resultants of some other change :
some qualities of the second division, power and powerlessness,
have no contraries and are properties which originate by dimana-
tion ; other qualities of the second division, the rough and the
smooth, the hard and the soft, etc., are at times properties which
originate by dimanation, but at other times they are present as
adventitious accidents and, then, they fall under the third division
and exemplify motion in quality.

LOCAL MOTION.

Local motion consists in successive and unbroken transition
from one point in space to another : this implies, first, that the

LOCAL MOTION 247

position in space of the moving body is, at each successive instant,
immediately outside but still in contact with the position occupied
the instant before ; it implies, moreover, that each position
between the starting point and the finishing point is incomplete
in itself and tends to pass beyond itself into its successor. The
analysis of the ever recurring and apparently simple fact has been
the torment of philosophers of all ages. It is little wonder, then,
that, on the crude presuppositions of Aristotelian physics, the
problem arising out of local motion played havoc with the solid
phalanx of medievalism. Two controversies concerning local
motion have already been discussed : Thomist was pitted against
Scotist on the explanation of the natural motion of the elements ;
Thomist and Scotist deserted Aristotle, St. Thomas, and Scotus,
on the explanation of the free flight of projectiles. An even
more bewildering variety of opinion prevailed as to what exactly
happens or does not happen in local movement, apart from the
question of the efficient cause of that motion.

Nine different theories were advocated about the middle of
the seventeenth century. (17) The pith of this problem lay in
the theory of ubication : local motion is confessedly an unbroken
series of locations ; and location was commonly said to be due
to ubication. But what is ubication ? Aristotle, St. Thomas,
Scotus and many Schoolmen seemed to have explained ubication
as some sort of extrinsic relation. (18) Even thus early, there
was little agreement concerning the source of this extrinsic
relation : some held ubication to be the result of a divine decree ;
others, the result of the agency that produced the located body ;
others, the result of the nearest surrounding bodies ; and so on.
This earlier theory of ubication continued to find defenders at all
times, but most of the later Schoolmen rejected it, and taught
that ubication was something intrinsic added to the body for the
purpose of keeping it in this rather than that location. Molina (19)
is credited with being one of the first advocates of this later view :
Suarez became its patron ; and his teaching seems to have been
accepted not only by most of his brethren but also by the later
Dominicans. The main concern of Suarez and his successors is
the nature and the number of these intrinsic ubications. Was
this intrinsic ubication a mode or an accident ? Most of them
taught it was a mode, but a minority insisted that it was an
accident. Was there in each body one or more of these intrinsic
ubications ? A minority taught that one intrinsic ubication
sufficed for each distinct location of a whole body : some of these
putting that ubication in the substance, others putting it in the
quantity. Others — and they seem to have been at one time in
a majority — taught that a distinct ubication was needed for each
distinct reality in the body, that is, for each of the substantial
constituents, for each of the distinct accidents, for each of the
intrinsic modes, in short, for every distinct reality in the body,
except the ubications themselves ; and some of these writers
gravely explain this exception on the grounds that if the

248 COSMOLOGY

ubications themselves needed other distinct ubications, the result
would be an infinite regress of entities. The root-cause of this
amazing development has been already treated in another refer
ence, but is worth repeating briefly here. Those who maintained
that ubication is either an intrinsic mode or an intrinsic accident
did so on the plea that location is not a nothing : it is not the
same thing to be in Dublin as to be in Cork, it is not the same
thing to be fixed at one position in space as to be traversing
successively and continuously several positions in space ; there
fore, location implies in each located reality — substance and
accident and mode or all three combined — an internal something,
whether accident or mode. Those who denied that ubication is
either an intrinsic mode or an intrinsic accident did so on the plea
that entities are not to be needlessly invented : it is not the same
thing to be in Dublin as to be in Cork, it is not the same thing to
be fixed at one position in space as to be traversing successively
and continuously several positions in space, but, the difference
lies solely in the extrinsic relationships of the located body ;
immediate contact, whether permanent or fleeting, with different
surroundings is something real, just as being clothed is something
real ; and as clothes add nothing intrinsic to the person covered
by them, so location adds nothing to the located body.

It is obvious that the adoption of one or other of these theories
of ubication involved important consequences for the concept of
what, apart from efficient causality, is meant by local motion. All
the Schoolmen admitted that local motion was an unbroken and
successive series of locations : consequently, what was for Aris
totle, St. Thomas, and Scotus, an unbroken series of extrinsic
relations that added nothing internal to the moving body, became
for Molina and his successors an unbroken series of generations
and destructions of either intrinsic modes or intrinsic accidents ;
a series of generations and destructions of single successive modes
or accidents for those who held that one intrinsic ubication
sufficed for each location of the whole body ; a series of generation
and destruction of several simultaneous modes or accidents for
those who postulated distinct ubications for every distinct
reality in the moving body. Even this last appalling birth-rate
and death-rate during local motion does not seem to have satisfied
everyone. A modern (20) scholastic suggests a subtle extension
of this doctrine of intrinsic ubication which I have been unable to
track to its medieval source. It appears that some author, by
reflecting on these intrinsic ubications, convinced himself that,
useful and necessary as they are, they were after all only formal
causes of location. What, then, is the formal cause of motion ?
Impulse or impressed force ? No, it is an efficient cause which,
at most, starts and keeps up the motion. Accordingly this
Schoolman invented other entities, distinct both from impulse
and from intrinsic ubications, that function as formal causes of
local motion.

Another interesting point in reference to the medieval account

THE MOVER AND THE MOVED 249

of local motion is the nature of the superiority claimed for it,
over quantitative and qualitative motion, by the Schoolmen.
" Local motion (21) is superior to other kinds of motion from the
point of view of time because it alone can be eternal ... it is
also superior to them in nature because it is a necessary pre
liminary of all of them : growth is impossible unless preceded by
an alteration by which what is unlike is changed and made like ;
and in its turn, alteration is impossible without previous local
motion because alteration begins only when that which causes
change of quality in another is nearer to that other than it hitherto
was. It is also superior in perfection to these other kinds of
motion, because local motion does not cause any intrinsic change
in the moving body but merely changes this body in an extrinsic
way ; and that is why it may be present in a body already
perfect." So far St. Thomas : the only difficult allusion in his
text being a " body already perfect " : by that, he meant simply
the incorruptible heavenly bodies. This teaching of St. Thomas
about the superiority of local motion was accepted by all the
Schoolmen : of course, those Schoolmen who interpreted ubica-
tion as an internal mode or accident did not admit that local
motion implied no intrinsic change. These supported this thesis
of St. Thomas, however, on the grounds that local motion caused
much less change within a body than did growth, diminution,
alteration, generation, corruption.

THE DISTINCTION BETWEEN THE MOVER AND THE MOVED.

The principle on which Aristotle and St. Thomas based this
distinction is familiar, in its Latin dress, to every student of
Scholasticism : quidquid movetur, movetur ab olio. The ordinary
English translation — whatever is in motion is moved by something
else — lends itself to two misconceptions. Minds that are familiar
with no physics except the physics of Newton are apt to interpret
this medieval principle as referring merely to the need of an
initial push or stir. That is not so. The genuine medieval sense
of the principle is that motion, of its very nature, needs not only
starting but also continual keeping up by some continually
acting cause ; hence the better translation is — whatever is in
motion is put in motion and kept in motion by something else.
A second common misconception is that the suggested distinction
between mover and moved must be always a distinction between
supposit and supposit. Neither is that so. Aristotle (22) has
two formulations of this principle : everything in motion must be
put and kept in motion by something ; everything in local motion
is moved either by itself or by another. And both he and the
Schoolmen taught that things which had souls were moved by
themselves, but in these instances they insisted that one part of
the substance was the mover and that another part of it was the
moved. St. Thomas (23) and his disciples admitted no exceptions
to this law of physical motion : Scotus and his disciples did

250 COSMOLOGY

admit exceptions. The Scotists (24) carefully stressed the point
of their objection : they allowed that bodies are immediately
influenced by God in their motions and, in this sense, did not
impugn the principle ; they allowed, also, that bodies are extrin-
sically stimulated to motion by their surroundings and, in this
sense, they did not impugn the principle. What they did main
tain was that, presupposing the divine concurrence, some bodies
act as total secondary causes : that is, that these bodies act
independently of the effective, immediate concurrence of any
other secondary causes in the production of their effects ; and
that, therefore, such bodies move themselves. The controversy
ranged over all kinds of motions, psychical and physical, vital
and non- vital. I shall avoid altogether the question of psychical
motions and shall refer to vital motions, only as far as is necessary
to illustrate the points at issue concerning physical motion.

The first argument in favour of the universality of the principle
was based on the nature of physical motion. Physical motion is
the transition from non-existence to existence of some reality
out of some substrate. This transition is sometimes instan
taneous : generation of substance consists in the instantaneous
emergence of a substantial form from primordial matter ; simi
larly, the generation of an accident like brightness is instantaneous.
But, as we have already remarked, these instantaneous births of
realities were included under the concept of motion, only by
majority vote and, even then, with subtle explanations. Strict
physical motion is a gradual transition from non-existence to
existence, and was verified only in augmentation or diminution,
alteration, and local motion. Now it is obvious, the Thomists
argued, that any of these kinds of motion can happen only in a
substrate which is previously lacking in that particular reality
that is its goal of the motion : primordial matter cannot undergo
the process of acquiring a substantial form which it already
possesses ; a substance cannot undergo the process of acquiring
either a quantity or a quality or a location which it already
possesses ; in technical language, no being can be reduced from
potency to actuality in any reference except it was previously in
potency in that reference. But whatever is lacking in any par
ticular reality cannot, out of its own unaided resources, enter on
the process of supplying itself with that reality : no being can
give itself what it has not got to give. Therefore, whenever a
being or part of a being that lacks any reality undergoes the
process, be it instantaneous or gradual, of acquiring that reality,
it must during that process be drawing on resources external to
itself : in other words, whatever is in motion is put and kept in
motion by something else ; otherwise, the reality that is acquired
by the process of motion would have no cause. " The mover,"
says St. Thomas,!25) " works change continually until the body
moved attains the term of its motion " : if it did not, the motion,
either in whole or in part, would be a beginning without a cause.
To deny this principle of motion, then, is to deny the principle of

THE MOVER AND THE MOVED 251

causality. St. Thomas goes on to show that a denial of the
principle of motion involves a denial of the principle of contra
diction. It follows from the argument already given that the
new reality acquired by motion must come from a source
distinct from the substrate which is in motion towards that
reality. St. Thomas draws from this the obvious inference, that
the cause of motion must possess in some way that reality which
it produces in the patient : no being can be reduced from potency
to actuality except by some being that is already in actuality ;
fire which has the actuality of heat moves wood, by making it
pass from the potency to the actuality of heat. This actuality
may exist in one or other of two ways in the cause of motion :
formally, when it exists in the cause of motion in a manner
similar to its subsequent existence as an effect in the patient,
and this occurs in all instances of univocal causality ; eminently,
when it exists in the cause of motion in a higher and better way
than it exists subsequently as effect in the patient, and this occurs
in all instances of equivocal causality. But whatever be this
manner of pre-existence of the actuality in the cause of motion,
that pre-existence marks off the cause of motion from the patient :
the agent has this actuality, the patient has merely the potency
of that actuality. Now, the same being or part of a being cannot
be simultaneously in potency and in actuality with reference to
the same perfection : the principle of contradiction affirms that
the same reality cannot be simultaneously hot and not-hot,
white and not-white. Therefore, to deny the principle of motion
is to deny the principle of contradiction.

The second argument in favour of the universality of this
principle was based on induction. From the point of view of
origin, motion was distinguished by the School as three-fold :
incidental, violent, natural. Incidental motion occurs in any
reality, simply because that reality is affected concomitantly by
the motion of another reality : a rider is incidentally moved when
his horse moves ; whiteness is incidentally moved when a white
body moves ; a man's hand is incidentally moved when someone
shakes it ; a musician is incidentally moved, as being healed, when
the convalescent is a musician ; and so on. Violent motion
occurs when a body is moved by an external cause after a fashion
in which it, as recipient, cannot co-operate : this motion is not
identical, then, with every kind of motion produced by an external
cause ; it is verified only in motions that are contrary to, or
stronger than, the natural powers of their recipient. These
violent motions occur in quantity, in quality, in location : violent
quantitative motions are exemplified by premature puberty due
to overfeeding or by abnormal size in grain due to unseasonable
rains ; violent qualitative motions are exemplified by fevers that
reach their various crises on other than the generally accepted
critical days, or by those qualitative changes that immediately
precede change of substance ; violent local motions are exempli
fied by the hurling upwards of stones, the hurling downwards of

252 COSMOLOGY

fire, and by the free flight through the air of heavy projectiles.
Natural motion is that which proceeds from any internal prin
ciple of a body in accordance with its specific nature : all those
motions that are neither incidental nor violent are natural ; but
these motions are usually exemplified by -the vital motions of
living beings, and by the ]ocal motions of the four elements to
their proper places. These being the presuppositions of the
Thomists, they had no difficulty about this inductive proof as
regards motion that was either incidental or violent : in all such
instances, whatever was in motion was put and kept in motion
by something else. They were also confident about the veri
fication of the law in all vital motions : their general thesis
being that vital motions are caused by the soul in faculties which
are distinct from itself — locomotive, vegetative, sentient. The
natural local motions of the elements seem to have been their
greatest difficulty. An easy wav-out would have been to hold
that gravity and levity are the principal causes of these motions :
accidental qualities resident in the elements and distinct from the
locations they produce, somewhat after the analogy of the impulse
of the later Schoolmen. But St. Thomas and the earlier School
men reject that kind of solution for several reasons : it would
imply that the elements are living ; that the elements could
stop themselves at any stage of their natural motion — a supposi
tion contrary to all experience ; that a self-moving being might
have only one direction in its motion — an unreasonable supposition,
for if the self-mover can move upwards, why cannot it move
downwards ? ; that the elements had a collection of parts like
the limbs of an animal — an irrealisable supposition in a homo
geneous continuum. Consequently, these writers insist that the
natural motions of the elements is due to two external causes :
the generating cause which gave them a nature that seeks a
particular place in the universe, and gave them, for that purpose,
gravity and levity as instrumental causes of motion ; the external
cause that, at the moment preceding their motion, removed any
external obstacles which prevented them from seeking their
natural places. And thus, even the natural motions of the
elements verify the general principle of motion.

Scotus and his disciples challenged both of the Thomistic
arguments. They granted the impossibility of formal potency
and formal actuality in regard to the same perfection at the same
time. They urged, however, that formal potency and virtual
actuality were simultaneously compatible, and that a being in
this state could move itself : such a being can be a cause of
motion for it has the power of producing perfection ; such
a being can be a recipient of motion for it has the capacity
of acquiring perfection. Thomists retorted that, since virtual
actuality implied the power of producing a perfection, the being
which possessed it could not be lacking in that perfection : and
that, consequently, the alleged simultaneous compatibility of
formal potency and virtual actuality was impossible. Scotists

THE MOVER AND THE MOVED 253

met this retort by a distinction. Virtual actuality may mean
the presence of a perfection in a higher and better way than is
implied by its formal presence : thus, the sun possesses heat
virtually, and not formally as fire possesses it ; and when virtual
actuality means presence of a perfection in this higher way, it is
contradictory to speak of the possibility of self-motion towards
a formal actuality of the same kind. Formal heat would be of
no use to the sun except to produce heat in other bodies, but the
sun can do that apart from formal heat : hence, the sun would
not be made more perfect by the formal actuality of heat ; on
the contrary, the formal possession of heat by the sun would be
an imperfection for two reasons — this formal heat would be a
superfluity, and would involve corruptibility or some other imper
fection in that heavenly body. There is, however, another and
totally distinct meaning for virtual actuality. A perfection may
exist in virtual actuality in a body in the sense that this body,
although it can produce this perfection, cannot accomplish without
that perfection what it can accomplish by means of its formal
possession. Now, to contain a perfection in this kind of virtual
actuality is obviously not to contain it more perfectly than is
implied by formal actuality. Therefore, it would not be contra
dictory to assert of any being the simultaneous presence in it of
this second kind of virtual actuality and of formal potency in
regard to a perfection. And this is the only kind of virtual
actuality, Scotists contended, that we claim for those bodies that
are self-moving. Thomists rebutted this argument by pointing
out that the power of producing a perfection is something distinct
both from the exercise of that power and from the perfection
afterwards produced by that power : hence, the increment of
reality which separates the virtual possession of any perfection
from the later formal possession of the same perfection is certainly
not in the virtual actuality ; now, no being can give itself that
by which its own sum of reality is enriched ; further, the transition
from virtual to formal actuality is not, according to the Scotists,
aided from outside ; therefore this transition must be, on their
hypothesis, an event without a cause, a causeless beginning of
being. The Thomists added that Aristotle was able to prove the
existence of a motionless Prime Mover only because he insisted
on their interpretation of this principle of motion. Scotists
replied that the existence of a motionless Prime Mover can be
proved from the fact that no secondary cause can move itself
independently of two factors extrinsic to itself : the stimulation
of other secondary causes as a condition determining action here
rather than there, now rather than then ; the immediate con
currence of God as a concomitant higher cause. But neither of
these extrinsic factors contradicts, they asserted, the thesis of
self-motion as defended by Scotists. And they added that
Aristotle proved the existence of a motionless Prime Mover, not
by showing that self-motion was an utter impossibility, but by
pointing out that even self-moving beings owe their powers of

254 COSMOLOGY

self-motion to their respective generating causes and, thus,
compel us ultimately to admit a motionless Prime Mover : a
Being who does not depend on anything outside Himself for His
perfections, and who is the ultimate source of every perfection
that is found in all extrinsically conditioned beings.

The Scotists urged against the second Thomistic argument,
that based on induction, a number of typical medieval facts : the
local motion of the elements to their proper places ; certain
qualitative motions involved in the restoration of bodies to their
natural state after violent alteration ; the heating of slaked lime
and of pressed grapes ; the greater heat, in winter, of the stomach
and of well-water. The brunt of the controversy was borne by
the first pair of alleged facts. Scotists argued that no secondary
causes of such motions can be assigned except the bodies in which
these motions occur. The only other available secondary causes
in the circumstances are those that remove the obstacles to
motion : the cause that removes whatever prevents a stone from
falling or a fire from ascending ; the cause that removes whatever
prevents hot water when taken off the fire from recovering the
natural coldness of water. Now, no one dreams of explaining
the motions in question by these latter causes : they are ob
viously incidental ; their destruction does not put an end to the
motions. Nor can it be maintained, for instance, that the recovery
of its natural coldness by water is due to the presence of some
residual coldness in the water at the moment it is taken off the
fire : sometimes, there is apparently none of this residual cold
ness ; at any time, there is not sufficient residual coldness to
account for all the coldness subsequently produced ; moreover,
other bodies, that are capable indeed of being made cold but do
not postulate connaturally the coldness of water, never develop,
when removed from the influence of heat, that degree of cold
which is characteristic of water. Therefore, there is no explanation
of any of these facts except the admission of self-motion in those
bodies within which these motions occur. Thomists met the
objection from the natural motion of the elements by assigning
those motions to the generator of these elements as a principal
cause, and to gravity and levity as its instrumental causes : for
the reasons already given in the explanation of their inductive
argument. And those Thomists who admitted impetus as
qualitative cause of the free flight of projectiles pointed out that
this qualitative cause, being but an accident borrowed for an
emergency and not a true property, did not involve vitality in
non-living bodies : but that gravity and levity, if admitted as
principal causes of natural motion, would imply vital motion in
the elements. Thomists, also, answered that the alleged instances
of restoration are due to the generating causes of the water or
other substance, in which this restoration occur. They con
cluded, then, that neither of these objections affect the universality
of the principle of motion. The force of these Thomist replies
is bound up with that theory of theirs which refuses to see in

THE MOVER AND THE MOVED 255

resultance an instance of efficient causality. The dimanation
of properties is a natural resultance of the generation of a specific
essence, and the only efficient cause in question is that which
generates the specific essence. As for the heating of slaked
lime and of pressed grapes, Thomists were wont to account
for the former by the presence in lime of latent fiery particles, and
for the latter by the presence in grapes of spirituous parts. They
explained the alleged higher temperature, in winter, of the stomach
by the suggestion that winter cold closes the pores of the skin
and prevents the vital spirits from leaving the body : and they
explained the alleged higher temperature of well-water by the
suggestion that, in winter, the subterranean fiery spirits of the
bowels of the earth cannot escape through the pores of the earths'
crust, and are concentrated in wells.

After centuries of controversy on this question between
Thomism and Scotism, Suarez (26) went over the whole ground
again and wound up his survey by compromise : a compromise
accepted by most of his disciples. He sided with the Thomists
in reference to the motions of non-living bodies ; he sided with
them, also, in reference to alteration and growth in living bodies.
He sided with the Scotists in reference to the alleged compati
bility of formal potency and virtual actuality. He sided with
the Scotists, also, in reference to the local motion of living beings :
and it is for the purpose of illustrating this application of the
law, that I follow at some length here the exposition of Suarez.
He remarks pertinently that you cannot go on talking for ever
of one part moving another within an animal. You must stop
somewhere at a part which apparently moves itself. The usual
reply is that the soul is the continually acting cause of this local
motion, that it puts and keeps in motion the muscles, and through
them the limbs. Suarez admits the probability of this reply but
urges its difficulty in reference to animals for a consistent hyle-
morphist. He draws attention to those texts in St. Thomas
that speak of the heart as the source of this local motion :
the nerves and vital spirits seem to be under the control of the
heart — at any rate under control either of it or of the brain.
Hence, the real issue centres on the motion of either of these :
and in conformity with the earlier view, Suarez discusses this
issue from the standpoint of the heart as the source of living
local motion. Heart-beats, owing to the alternation of expansion
and contraction were a tremendous puzzle to the Schoolmen :
some held that the heart was put and kept in motion by an
external being — a solution scouted by St. Thomas as irreconcilable
with vital action ; others suggested that the heart was put and
kept in motion by innate heat — a solution rejected as implying
heat to be an immediate cause of local motion ; others suggested
that one part of the heart puts and keeps in motion the other parts —
a solution set aside as pushing back and not solving the problem ;
others — among them St. Thomas — suggested that the heart is
moved by the soul as natural form of the body, but that this

256 COSMOLOGY

motion of the heart must be attributed to the generating cause
since it results, as a property, from the soul as form. Suarez
objects to this solution of St. Thomas, mainly, for the reason that
it puts the motion of the heart on the same plane as non-living
motions : he adds that if you attribute the pulsations of the
heart to the generating cause, you are logically bound to attribute
to the same cause the motions of respiration and nutrition. He
concludes, accordingly, that somehow or other the whole heart
moves itself. " Hence,(27) I see no difficulty in attributing this
motion to the animal itself, and in saying that an animal, in
reference to the same integral part, may be mover, and moved ; and
that, it is sufficient (in motion which is vital and partial) to have
a distinction merely between the aspects of acting and of being
acted on ; for it is only when speaking of the motion of an animal
as a whole, that Aristotle talks of the motion of one part being
brought about by another part." John of St. Thomas, in reaffirm
ing at a later date the Thomistic view, grants that the motion
of the heart, since it is vital, cannot be readily attributed to the
generating cause. " Still, since (28) even life in creatures is received
and derived from another, the living creature in that first motion
with which its life begins does not move itself in a sense that
excludes being moved by another : as St. Thomas teaches (I, q.
13, a. 3, also I, q. 105, a. 4, ad 2). Hence the vitality of that (first)
motion consists in a beginning of life that is received from another,
but that (first) motion is not the completion and perfection of
life. For, this latter is the activity of the living being which
moves itself inasmuch as it causes motion in some parts by means
of one part that has been already moved and actualised : that is
why the motion of the heart has as its goal not quiescence in any
particular form, but existence as an actuality for the motion of
other parts (of the body) ; and this, its peculiar make, must
come from the generating cause for it is the first motion. There
is, as St. Thomas teaches, in the thirty-fifth Opuscule, a likeness
in this way between the motion of the heart and the motion
of the heavens : for the heaven is moved not with a view to
quiescence in any particular form, but with a view to its duty
as mover and first alterative of other bodies." Goudin,(29) also a
post-Suarezian Thomist, puts the same point more briefly. " I
reply that the motion of the heart is from the generator as cause.
For, as St. Thomas lays down, Op. 35, the motion of the heart
follows the form of the heart since it is a property of this
latter : hence, this motion comes from the cause by which the
heart is produced : for that which gives being gives also the
(necessary) consequences of being."

PHYSICAL TERRESTRIAL MOTION AND THE HEAVENLY BODIES.

The material heaven of the Schoolmen was, in essentials,
that of Aristotle. They were not quite so confident, as he was, of
these subsidiary hypotheses which Eudoxus and Calippus and he

MOTION AND THE HEAVENS 257

had invented to explain away the apparent deviation from per
fect circular motion of the planets : as we have seen, Ptolemy's
theory of epicycles and eccentrics was dominant in medieval
astronomy. But this hesitancy, about the exact manner in which
certain anomalous appearances in the movements of the planets
were to be accounted, for did not prevent the Schoolmen (30) from
accepting as absolutely certain the fundamental doctrines of
pre-Copernican astronomy : the existence of solid crystal spheres
as bearers of the stars and planets ; the perfect circular motion
of each of these crystal spheres ; the linkage of each lower sphere
to its immediate outer sphere, and its consequent participation
in the motion of all outer spheres. When introducing this theory
into their metaphysics, they attended mainly to the principal
spheres. Aristotle had spoken of eight principal spheres and
had called the outermost one, that which bore the fixed stars,
the first moved. Later discoveries added to this Aristotelian
number. Hipparchus (c. 155 B.C.) discovered that the sun no
longer crossed the equator at the first point of Aries, but some
little way back westwards in the constellation, Pisces : and as the
eighth heaven could not be subject to two simultaneous revolu
tions in contrary directions and in different planes, another
principal sphere, distinct from and outside the eighth, was postu
lated for this precession of the equinoxes. Alphonso X of Castile,
a contemporary of St. Thomas, discovered in the firmament a
new motion which was called trepidation, because it caused an
inclination now to one pole and now to the opposite pole : and
for the reason given above, a third principal sphere, distinct from
and outside the eighth, was postulated for this alleged phenomenon,
Accordingly, the Schoolmen admitted ten principal star-bearing
crystal spheres : one each — in order — for the Moon, Mercury,
Venus, Mars, Sun, Jupiter, Saturn ; an eighth outside these for
the fixed stars ; a ninth outside the eighth to account for trepida
tion ; a tenth outside the ninth to account for precession. Apart
from the Empyrean, then, the heavens were thought to resemble
a set of those curiously carved Indian balls which consist of
several hollow spherical shells one within the other. The tenth
and outermost sphere is the first moved, the primum mobile
of medieval philosophy : a sphere which, by its diurnal motion
from east to west, controls the motion of all inferior material
things. Within this tenth sphere are set the other nine as wheels
within wheels : each of these is affected by a proper motion of
its own about the earth — a motion which is slower than that of
diurnal rotation, and proceeds in an opposite direction from west
to east ; yet each sphere is linked up with all spheres outside
itself, and is, in consequence, influenced by the circular motion
of these enclosing spheres. Moreover, the Schoolmen differed
from Aristotle on the question of the movers of these spheres.
Aristotle attributed the motion of the primum mobile to God,
and the proper motion of each of the other spheres to an un
changing immaterial form. The Schoolmen attributed the motion

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258 COSMOLOGY

of the primum mobile to God — or an angel — and the proper
motion of the others to angels.

The Schoolmen followed Aristotle in contrasting the uniform
motions and incorruptible nature of the heavenly bodies with the
irregular motions and corruptible nature of all sublunary bodies.
They insisted, as he did, on the commanding influence of those
heavenly bodies over all terrestrial bodies. The heavenly bodies
are " perfect without blend of contraries, being neither light nor
heavy, neither hot nor cold." They control all the movements
on our earth. When the sun is mounting the zenith, earth and
water are drawn up and changed into air and fire : heat is
increased. When the sun is descending and, finally, sets below
the horizon, this temperature falls, and air and fire are changed
into earth and water. All meteorological facts in the sublunary
world are regulated by the stars : if astronomers knew accurately
the complex interactions of heavenly bodies, they could foretell
with certainty the coming of showers, of temperatures, of storms.
The diversity of the four seasons and the resulting birth, growth,
decay, and death among living beings is due to the motion and
light of the heavenly bodies and, particularly, of the sun. In
the absence of the sun, the moon controls the tides, and also
exercises countless effects on plants and animals. There is
practically no limit to the influences exercised on the human body
by the stars — in conception, gestation, birth, health, sickness :
hence, a knowledge of astronomy is absolutely essential to doctors.
But although everything physical on earth was directly affected
by the activities of the heavenly bodies, the course of these
terrestrial motions was not solely determined by them : the results
attained depend also on the conditions and capacity of the ter
restrial patients. Moreover the heavenly bodies are not arbiters
of human will and conduct, except remotely : the rational soul
is never directly affected by the action of these heavenly bodies ;
it is affected, however, indirectly owing to its union with a body
—but, in normal humanity, this indirect influence does not destroy
the fact of free-will. The chief agencies, to which the Schoolmen
assigned this commanding influence of the heavens, were local
motion and light. And when this manner of refunding sub
lunary facts to heavenly influences failed them, they had recourse
to the occult powers of the heavens. This appeal to the occult
was a necessary sequel of their false notions about the higher
perfection of heavenly bodies, and of their false theories in physics
and biology : whenever a fact or an alleged fact cropped up that
could not be explained either by the motions or light of the
heavenly bodies, or by the theory of the four elements and its
crude concomitant in physiology, the theory of the four humours,
it was attributed to the occult influence of some heavenly body ;
the most frequently cited examples of these occult influences
being the alleged spontaneous generation of living beings, and
the alleged heavenly generation of metals and gems in the re
cesses of the earth. So far, the Schoolmen were genuine Aristo-

MOTION AND THE HEAVENS 259

telians. They outstrip Aristotle, however, in a certain sympathy
for astrology : succumbing, therein, to the doctrines of the Neo-
Platonists and of the Arabians. Their theory was Aristotelian :
astrologers could predict with certainty the future motions of the
heavenly bodies, and could predict with probability the future
influences of heavenly upon terrestrial bodies. Their practice was
tinged with Neo-Platonism : occasionally, their writings are dis
figured by the baubles of astrology.

Thomist and Scotist disagreed as to the means by which this
heavenly control was brought about. St. Thomas (31) and his
disciples held that Aristotelianism involved the essential causal
subordination of all physical sublunary motions to the local
motion of the heavenly bodies, and ultimately to the local motion
of the first moved, the prime minister of corporeal creation.
For the Thomist, terrestrial agents are applied to action by the
motion of the heavenly bodies just as tools are applied to action
by the hands of the workman ; the action of all sublunary bodies
proceeds from themselves, not only through their own power
but also through that of the celestial bodies ; and, therefore,
the influence by motion of heavenly bodies on all terrestrial effects
is as immediate as that of their respective terrestrial causes.
St. Thomas supported this interpretation of the influence of
heavenly motion by a profusion of arguments. Were there no
intermediate heavenly causes to carry into execution in sublunary
affairs the decrees of Divine providence, there would be in the
corporeal world no order of causes : that would be a defect.
The higher the natural position of any body, the nobler its form
and the more extensive its activity : hence the heavenly bodies
must act on terrestrial bodies. The more powerful agents neces
sarily control the less powerful : but heavenly bodies are more
Eerfect and, therefore, more powerful than terrestrial bodies,
ntelligent creatures are the intermediaries by which the rest
of the terrestrial creation is governed : but the heavenly bodies
are like intelligences because incorruptible, and near them because
immediately moved by them. All motion implies a motionless
prime mover as source ; therefore, the closer a body approximates
in nature to this motionlessness, the greater must be its power
of moving inferior bodies. The motionless prime mover is the
source of all motion, and therefore some relatively motionless
being must be the source of such and such motions : hence, the
qualitatively changeless heavenly bodies must be the source
of all alteration in alterable bodies, alteration in its turn the
source of growth or diminution and generation, generation in
its turn the principal cause of the local motion of heavy and
light bodies. These are the main points of all the arguments
but one in a chapter on this topic from the Contra Gentes (III, c. 82).
That one is worth transcribing in full for it seems to be the foun
dation-stone of this particular Thomistic thesis. :' Whatever
is primary in any genus is the cause of those that come after it.
But the motion of the heavens is primary among all other motions.

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260 COSMOLOGY

The first reason for this primacy is that local motion is the first
of all motions : it is the first from the point of view of time,
because, as proved in the Physics (b. 8, tt. 54 sqq.), it, and it only,
can be perpetual : it is the first from the point of view of nature,
because no other motion can take place without it — for augmenta
tion follows on a preceding alteration by which the unlike is
changed into the like, and this preceding alteration is impossible
without a preceding local motion, because alteration can take
place only when the alterative agent is nearer than it was to the
alterable patient ; it is first from the point of view of perfection,
also, because local motion does not cause any internal changes
in a thing but causes merely an extrinsic change, and, on that
account, can occur in an already perfect being. The second
reason (for the primacy of heavenly motion) is that circular
motion is first amongst even local motions ; it is first in time,
because, as proved in the Physics (8, text. comm. 64), it, and it
only, can be perpetual ; it is first in nature, because it is more
simple and more one since there is no distinction in it between
the beginning, the middle and the end — the whole of it being in
some sense a middle ; it is first even in perfection, because it
bends back on its beginning. The third reason (for the primacy
of heavenly motion) is that the motion of heaven is the only
motion that is always regular and uniform : for, there may be
an increase of velocity in the natural motions of heavy and
light bodies. (For these three reasons), therefore, it follows that
the motion of the heavens is the cause of all other motions."
This single chapter of the Contra Gentes embodies all the prin
ciples and all the arguments that St. Thomas and his disciples
bring forward, whenever they are defending this theory of heavenly
causality. The theory is a kind of metaphysical feudalism.
Feudalism was dominant in government in those days, and St.
Thomas propounded an order of nature and of divine providence
in accordance with this dominant idea. " The order of causes,"
he writes,(32) " must answer to the order of effects because effects
are proportioned to their causes. It follows, then, that special
effects must be traced to special causes, and the common feature
of these special effects to some common cause. For instance,
over and above the particular causes of this or that generation,
the sun is the universal cause of all generation : and the king
is the universal cause of government in his kingdom above the
officials of the kingdom, and also above the officials of individual
cities." As a consequence of this theory of heavenly influences,
the Thomists taught that if the movements of the heavenly
bodies were to stop, all terrestrial physical motions — substantial,
quantitative, qualitative, local — would cease simultaneously : and
when challenged with the scriptural account of the stoppage of
the sun and moon at the request of Josue, they declared that
the persistence of terrestrial motions on that occasion was a
distinct miracle.

Scotus,(33) Suarez and their disciples allowed that the heavenly

MOTION AND THE HEAVENS 261

bodies may be truly called universal causes, but refused to inter
pret the universal causality as due to the essential causal subor
dination of terrestrial to heavenly bodies. No secondary cause is,
they argued, essentially dependent in its causality on any created
being : essential subordination in causality is the sequel of
essential subordination in existence, and can occur, therefore,
only between the creature and the Creator. They argued, also,
that essential causal subordination would imply immediacy of
supposit or immediacy of power : immediacy of supposit is
impossible, because of the distances that separate heavenly and
earthly bodies ; immediacy of power is thinkable only as diffused
power, and that diffusion is either not proven or where proven
is interpretable as supplementary co-ordinate causality. Scotist
and Suarezian get rid of the Thomist interpretation simply by
denying that all physical motion requires a preceding local motion.
The gist of their own theory is that heavenly causality is some
times necessary and sometimes unnecessary for terrestrial bodies ;
but that, even when necessary, it never implies essential subor
dinate causality. Some terrestrial causes are imperfect in their
own order and insufficient for certain effects : hence, these require
the help of the heavenly bodies. Well-known instances of this
type are the generation of metals and gems, of perfect mixtures
and of living bodies ; metals and gems are generated by the
heavenly bodies ; the four elements do not contain, either for
mally or eminently, the substantial form of a perfect mixture ;
perfect mixtures themselves are confessedly very weak in the
power of generating their like ; plants depend, in growth and in
reproduction, on the heavenly bodies ; animals, also, depend a
good deal on the heavenly bodies in procreation — sun and man
are commonly said to generate man, because human seed is of
itself weak and can fulfil its function only by aid of the heat of
the sun. To maintain, despite these facts of the imperfect
powers of certain bodies and of the opposition to the activity
by other bodies arising out of unfavourable environment, that
continuity which is essential to the order and progress of the
universe, Providence has set on high the heavenly bodies : each
with a wide range of activities, and each with a never-failing
motion. There are terrestrial agents, however, which, so far as
observation or reasoning can enlighten us, produce their effects
independently of the local motion of the heavens : fire can
generate heat whatever be the positions or motions of the heavenly
bodies. And in that, and all similar instances where the terres
trial agent is sufficient either of itself or with the aid of other
terrestrial agents to produce its effects, it does produce them with
out essential subordination to the local motion of the first moved
or any of its supralunary sub-agents. And even in those instances
where a terrestrial cause is insufficient either of itself or with the
aid of other terrestrial causes to produce certain effects, and where
owing to some incidental circumstance it is deprived of the
needed co-operation of the heavenly bodies, perhaps even resisted

262 COSMOLOGY

by these latter, still, it produces, in virtue of whatever power it
can muster, some kind of effect.

PHYSICAL MOTION AND THE INFINITE.

" He announces," writes St. Thomas, (34) commenting on Aris
totle, " the presuppositions of motion. To begin with, a first
mover which is the source of motion. Secondly, a mobile that
is put in motion. Thirdly, time during which the motion takes
place. And in addition to these three, two terms are necessary :
one from which the motion begins and another to which it pro
ceeds, for all motion is from something to something." St.
Thomas proceeds to illustrate these conditions in the simplest
way : fire as first mover heats wood ; wood as mobile is made
hot by fire ; this process of heating takes time ; the term from
which the process starts is the quality of cold in the wood ; the
term towards which the process proceeds is the quality of heat
in the wood. The same five conditions and the same simple
illustration figure also in the Commentary of Scotus on Aristotle.
Yet, as we have seen, Aristotle and the Schoolmen found them
selves compelled to raise question after question on this problem
of causality : the fact and the meaning of causality ; the nature
and seat of action, passion and motion ; the proximate principle
of causality in the agent ; contact, unlikeness, and, the distinction
between mover and moved, as conditions of causality ; the in
fluence of the heavens on terrestrial motions. The more impor
tant aspects of medieval speculation on these and cognate topics
have been discussed as far as space permitted. But in addition
to all these questions, there is another fundamental presupposition
which must never be forgotten by the student who wishes to
grasp the medieval theory of physical motion : that of an im
mediate divine concurrence. The explanation of that pre
supposition belongs to the treatise on Natural Theology. Here
it must suffice to state that, during the middle ages, practically
the whole School (35) held there was irrefragable philosophical proof
of the necessity of an immediate divine concurence in all physical
motions : somehow or other, finite causality abuts on the Infinite.
Despite this unanimity of opinion about the fact itself and about
the existence of its philosophical proof, Thomist and Scotist and
Molinist were never able to agree about the inner details of this
fact. All three Schools postulated a simultaneous concurrence :
Thomists postulated in addition an intrinsic physical promotion
which consists in some kind of premoving physical quality ;
Scotists rejected this intrinsic premotion but postulated an ex
trinsic premotion which consists in an absolute and efficacious
divine decree; Molinists rejected any kind of premotion whether
intrinsic or extrinsic. Non nostrum inter vos tantos componere
lites.

CHAPTER X.
THE ECLIPSE OF ARISTOTELIAN COSMOLOGY.

" THERE are two ways of behaving towards St. Thomas's writings,
analogous to two several treatments of a church still standing,
in which the saint might have worshipped. One way," proceeds
Fr. Rickaby, S.J., in a preface to his translation of the Summa
contra Gentes, " is to hand the edifice over to some Society for
the Preservation of Ancient Monuments : they will keep it
locked to the vulgar, while admitting some occasional connoisseur :
they will do their utmost to preserve every stone identically the
same that the medieval builder laid. And the Opera Omnia of
St. Thomas, handsomely bound, may fill a library shelf, whence
a volume is occasionally taken down for the sole purpose of
knowing what St. Thomas said and no more. Another thirteenth-
century church may stand, a parish church still, in daily use ;
an ancient monument, and something besides ; a present-day
house of prayer, meeting the needs of a twentieth-century con
gregation ; and for that purpose refitted, repainted, restored,
repaired and modernised ; having that done to it which its
medieval architects would have done, had they lived in our time.
Nothing was more remarkable in our old English churches than
the sturdy self-confidence, and the good taste also lasting for
centuries, with which each successive age has superimposed its
own style upon the architecture of its predecessors. If St.
Thomas's works are to serve modern uses, they must pass from
their old Latinity into modern speech : their conclusions must
be tested by all the subtlety of present-day science, physical,
psychological, historical : maintained, wherever maintainable,
but altered where tenable no longer. Thus only can St. Thomas
keep his place as a living teacher of mankind." This quotation
expresses admirably the aim of this Cosmology. The volume
which has been completed purports to give the Cosmology of
Aristotle and the School exactly as these ancient architects
built it. The second volume is intended to test that Cosmology
by all the subtley of modern science and of modern philosophy.
And this present chapter is written to explain the causes of the
eclipse of Scholastic Cosmology from the seventeenth to the
middle of the nineteenth century. That Cosmology sprang
from certain intellectual conditions. That is whv when ex
pounded in reference to the science of the times when it originated
and developed, many a phase that seems abnormal shows a

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reasonable meaning. So natural a growth was this Cosmology
in the eyes of Aristotle and of the School that they never dreamt
it could disappear from the universities of the West : for them,
it was like Tennyson's " tower of strength, that stood four
square to all the winds that blew." A day came, however,
when all the fury of an alien civilisation was directed against
the Cosmology of the School, and as a continual dropping wears
away the stone, so blow after blow sufficed first to render un
popular in, and at last to banish from, the universities of Europe,
Aristotle's Philosophy of Matter. First came the Humanists,
then Copernicus, Kepler, Galileo, then Descartes and Newton,
then Lavoisier and Cavendish.

THE GIBES OF THE HUMANISTS.

The first revolt against the philosophy of the School was
launched by the men of the Renaissance. That movement
held full sway in Western Europe between 1400 and 1600. Its
strength lay in its disinterested championship of scholarship
and its rehabilitation of the joy of life : a return to the springs
of creative Hellenism. Its religious defect lay in an unbridled
liberty of mind and heart that degenerated into eccentric and
even sinister emotionalism : the religion of Greece was set up
as a rival of the religion of Christ. Its educational defect lay
in a tendency to regard the classics of Greek and Rome as the
sole standard of learning and the sole instrument of mental
training. It was from this last point of view that the Humanists
started their campaign of ridicule against the philosophy of the
School. Rabelais makes himself the mouthpiece of all their
grievances in the following description of a visit made to the
Queendom of Whims or Entelechy. " We met on the Key a great
number of Guards. . . . The Captain told us : — Aristotle, that
first of Men and peerless Pattern of all Philosophy, was our
Sovereign Lady's Godfather ; and wisely and properly gave her
the Name of Entelechy. Her true name then is Entelechy. . . .
The Captain afterwards took us to the Queen's Palace, leading
us silently with great Formality. . . . She looked young, though
she was at least Eighteen hundred years old ; and was handsome,
slender and as fine as a Queen, that is, as hands could make
her. . . . The officers desired us not to take it amiss if the
Queen did not invite us to dine with her ; for she never ate any
thing at Dinner but some Categories, Abstractions . . . Second
Intentions . . . Antitheses, Metempsychoses, Transcendent Pro-
lepsies and such other Light food. ... I then, saw a great
number of the Queen's officers who made Niggers white as fast
as hops. . . . Others with three couples of Foxes in one yoke
plowed a sandy Shore and did not lose the seed. . . . Others
sheered Asses and thus got Long-fleece wool. . . . Others
gathered Barberries and Figs off Thistles. . . . Others taught
Cows to dance and did not lose their fidling. . . . Others built

HUMANISTIC GIBES 265

Churches to jump over the Steeples. . . . Others set Carts before
the Horses. . . . Others out of nothing made great things, and
made great things to return to nothing. . . . Others cut Fire
into stakes with a knife and drew Water with a Fish-net. . . .
Others made a Virtue of Necessity and the best of a bad Market,
which seemed to me a very good piece of Work. I saw two by
themselves, keeping Watch on the top of a Tower ; and we
were told, they guarded the moon from the Wolves. In a blind
Corner, I met four very hot at it, and ready to go to Logger-heads.
I asked what was the cause of the stir and ado, the mighty coil
and pother they made ? And I heard that for four live-long
days, those over-wise Roisters had been at it ding-dong, disputing
on three deep, more than Metaphysical Propositions, promising
themselves Mountains of Gold by solving them. The first was
concerning a He-Asse's shadow : the second, of the Smoke
of a Lanthorn ; and third of a Goat's Hair, whether it were
Wool or no ? We heard that they did not think it a bit strange
that two Contradictions in Mode, Form, Figure and Time should
be true. Though I will warrant the Sophists of Paris had rather
be unchristened than own so much. While we were admiring
all those Men's wonderful doings, the Queen . . . appeared,
attended with her Court, and again amazed and dazzled us.
She perceived it and said to us. ' What occasions the Aberrations
of humane Cogitations through the perplexing Labyrinths and
Abysses of Admiration, is not the Source of the Effects, which
sagacious Mortals visibly experience to be the consequential
Result of Natural Causes ; 'Tis the Novelty of the Experiment,
which makes Impressions on their conceptive cogitative Faculties
that do not previse the facility of the Operation adequately,
with a subact and sedate Intellection, associated with diligent
and congruous Study. Consequently, let all manner of Per
turbation abdicate the Ventricles of your Brains, if anyone had
invaded them while you were contemplating what is transacted
by my Domestic Ministers. Be Spectators and Auditors of every
particular Phenomenon and every individual Proposition within
the extent of my Mansion, satiate yourselves with all that can
fall here under the Consideration of your visual or auscultating
Powers, and thus emancipate yourselves from the Servitude of
Crassous Ignorance. And that you may be induced to apprehend
how sincerely I desire this, in consideration of the studious
Cupidity, that so demonstratively emicates at your external
Organs, from this present Particle of Time, I retain you as my
Abstractors. Geber, my principal Talachin, shall Register and
Initiate you at your departing. We humbly thanked her Queen-
ship without saying a word, accepting of the Noble Office she
conferred on us." All this, and there is much more of it, is ex
cellent fooling, when it is not worse. But if one remembers that
these are the gibes of men who believed as firmly as did the
Schoolmen in the empirical science of Plato or Aristotle, this first
assault on the School is seen to be sheer pedantic sentimentality :

266 COSMOLOGY

and as such, it was met fully and fairly by Vasquez in the open
ing pages of his Commentary on the Summa. His defence was
meant for the theology of the School : as against the gibes of the
Humanists, it applies equally well to the philosophy of the School.

THE RETORT OF VASQUEZ.

" First of all we cannot deny that there have been very
many ... in the School who have treated . . . questions in
a frivolous manner. . . . But that is not the fault of the science
... it was the misfortune of the times in which minds were
not cultivated, nor arts so elaborated, nor books so abundant.
Now that there is a better supply of books and much greater
exercise of intellect, our scholastic theology ... is daily en
riched and treated in a more deserving manner. . . . Secondly,
many even Catholics inveigh against scholastic theology in the
following way. There are very many doctors seemingly born
for disputation, contentious party men, who are less anxious
about the investigation of truth than about the defence of their
own School and of that Master to whom they have sworn allegiance.
And by this kind of action no small injury is done to theology
and to truth. . . . But that, so far as it is a fault, is not a fault
of Scholastic theology, but a fault of personal character. . . .
Francis Victoria, a disciple and keen defender of St. Thomas,
used to say (and he is followed by Melchior Canus . . .) that the
authority of St. Thomas ought so far to prevail as to suffice for
us, if a better reason be not forthcoming : still, that the words
and reasons of so great a Doctor were not to be accepted without
discrimination and examination. Moreover, if St. Thomas laid
down anything not altogether probable, that we ought to imitate
the Saint's own modesty and industry, in neither disparaging
the credit of ancient Doctors nor adopting their opinion if reason
urged to the contrary. Wherefore he wishes us not to be so
attached to the doctrine of St. Thomas as to think it a crime to
depart a hair's breadth from any reason, ground, opinion or con
clusion of his. . . . For we see that some famous authors of the
Thomistic School, nay, the keenest defenders of the teaching of
St. Thomas — men like Cajetan, Francis Victoria, Dominicus
Sotus, Melchior Canus, Bartholemeus Torrensis who have written
wonderful commentaries on his text — do not believe they are
guilty of any offence towards this holy Doctor when they, occa
sionally, and as a result of deep thought, modestly dissent from
one or other of his views. For these men did not believe that
the Angelic Doctor wished his views to be embraced under any
other conditions than those which Augustine laid down about
his own when ... he writes : ' I should wish no one so to embrace
my opinions as to follow me except on points in which he sees that
I am not mistaken. For that reason I am now writing my Retracta
tions to show that I have not in all things followed myself.' . . .
But you see some people who purposely set out to refute the teach-

A SCHOLASTIC RETORT 267

ing of St. Thomas, and then fancy they have done something
glorious when they have uttered a pronouncement against an
opinion of his. . . . These deserve no light blame : and they are
undoubtedly creating obstacles for their own pursuit of truth.
The above-mentioned Thomists, then, teach that such disinter
estedness and sincere desire of truth should rule our treatment
of questions, which are not dogmas of faith but are doubtful
and probable matters, that despite our respect for the authority
of the Blessed Thomas, reason, maturely pondered, should hold
the first place, whenever such reason can be discovered. ... If ,
therefore, many theologians go astray in their treatment of theo
logical disputes, that is their own fault. . . . And the science
of Theology ought not to be despised on their account. . . .
Thirdly, some are offended at scholastic theology for its style :
its uncultured mode of speech, its mean and vulgar phraseology,
its barbarisms and solecisms. These are the votaries of Rhe
toric and Eloquence : men who delight in words rather than
facts ; men who neglect to investigate the natures and pro
perties of things or to examine the difficulties of things ; men who
hate the very name of Scholasticism. Herein they are far from
following that oracle of theirs, Cicero. . . . For he, when men
tioning Epicurus in his book, de Finibus, writes : ' The style
of this philosopher does not offend me : for he puts into words
what he means and speaks so plainly that I understand him ; and
though if a philosopher brings eloquence, I do not despise it,
yet if he has it not, I do not demand it.' . . . This barbarism
and unskilful language of the Schoolmen is to be attributed
rather to the fault and misfortune of the age than to the doctrine
itself. That doctrine would not lose its force and instructiveness
by being treated in a purer style. Moreover, that doctrine does
not require for its treatment and its exposition an extended
vocabulary, much eloquence, and oratorical style ; only a few
words to unite the knot of any difficulty and a plain brief style
which will not be a source of obscurity but a help in disputation.
. . . Fourthly . . . while it may be true that several questions
treated by the older and recent Schoolmen are not of much im
portance to theology . . . Still, there are other questions which
are common to theology and to philosophy. ... I grant that
some of these common questions are of little use from the pious
point of view : but that does not show their uselessness in theo
logy. Neither does that multiplication of questions and articles,
which some are always crying down, make theology useless.
This fault, if it be a fault, arises solely from the extensive curiosity
of the Doctors. Further, subtle questions of that kind are
excellent for sharpening people's wits. . . . Hence a theology
which examines sincerely only theological problems — or even
philosophical problems that are pertinent to theology — is not
to be scoffed at and ridiculed. Vale, then, to these Rhetoricians,
who think nothing worth studying except Liter ce Humaniores."
This plea of Vasquez has more good sense to the line than

268 COSMOLOGY

almost any other subsequent apologia. Time vindicated him and
the School. That type of Humanist, who in the sixteenth century
denounced the School, showed himself in his true colours in the
eighteenth century by denouncing the " Philanthropists," that
is, the students of mathematics, of modern sciences, of modern
languages and of history : with the result that the term, Human
ist, became a byword of contempt denoting one who delights
more in words than in facts. And when the historical criticism
of the nineteenth century set to work on the philosophy of the
middle ages, students discovered and exposed the flimsy basis
of the gibes of the Humanists : to-day, every competent critic
admits the seriousness of the attempt made by the abler Aris
totelian Schoolmen to explore all sources of knowledge, available
in their day, for the purpose of discovering a rational solution
of the riddle of the universe.

ANTI- ARISTOTELIAN DISCOVERIES IN EMPIRICAL SCIENCE.

The genuine assault on the Cosmology of Aristotle and the
School began with those scientific discoveries that ushered in
modern astronomy, physics, and chemistry. Astronomy was the
first to enter the lists. Copernicus (De Revolutionibus, 1543)
taught that the sun is at rest in the centre of our universe and that
the earth and planets move round it as centre : he admitted,
however, uniform circular motion for all heavenly bodies and the
existence of crystalline spheres. Tycho-Brahe by measuring the
parallax of the comet of 1557 showed that comets were stars ex
traneous to our atmosphere, and not sublunary will-o'-the-wisps ;
in 1572, he discovered in the constellation of Cassiopeia a new
star, that at first shone more brightly than all the fixed stars but
later waned and finally disappeared in March, 1574. Kepler
(The Motions of Mars, 1609) taught that the planets move in
ellipses. Galileo (1564-1642) discovered by means of the tele
scope new stars in several of the constellations : he also dis
covered movable spots on the disc of the sun, and the valleys
and mountains of the moon. Thus, within one half century,
all that Aristotelians believed about the superior perfections
and the nobler motions of the heavenly bodies was proven untrue.
Physics, then, entered the lists. Otto von Guericke's discovery
of the air pump (1650) enabled physicists to prove experimentally
the weight of air : thereby confirming Galileo's conclusion drawn
from weighing flagons of compressed air. Newton's discovery
of gravitation (Principia, 1687) was taken as proof of the weight
of all four elements. But the great seventeenth century anta
gonist of Aristotelian natural science was Descartes (1596-1650).
Descartes revived the physics of that ancient enemy of Aristotle,
Democritus : led thereto, far more than he was wont to admit,
by the scientific successes of his contemporaries. The revival
of this ancient quarrel between Democritus and Aristotle broke
up the serried ranks of seventeenth-century Scholasticism :

A BEEAK WITH TKADITION 269

pitting Catholic against Catholic, Protestant against Protestant,
University against University, Order against Order. It created
immense excitement in France and Belgium and Holland : princes
and bishops took sides ; churches and parliaments issued edicts ;
salons lionised the more famous protagonists ; lampoons and
libels were bandied about. After a fierce controversy, Cartes-
ianism triumphed in the worlds of science and of letters. Its
triumph, there, was short-lived. Voltaire and Maupertius intro
duced into France Newton's theory of gravitation : and after
an equally fierce but much shorter struggle, the vortices of Des
cartes became in France as unpopular as had been the substantial
and accidental forms of the Schoolmen. But whether Newton
or Descartes won, Aristotle lost. Henceforth, every material
event was explained by physicists as a group of particles — with
or without inherent motive forces — moving in accordance with
the laws of mechanics. And when the Physicists had thus
scotched the theory of the four elements, the Chemists stepped
in to give it the death-blow. The fundamental point of this
theory was that air, water, earth, fire, were four unanalysable
ultimates out of which all other bodies are made. Boyle (1627-
91) tried to discredit that teaching by chemical analysis.
His successors succeeded in disproving it experimentally : Lav
oisier (1743-94) and Cavendish (1731-1810) succeeded in analysing
air and water; Davy (1778-1829) and Berzelius (1779-1818)
decomposed various earths. The first chemists blundered over
fire. Already in the sixteenth and seventeenth centuries, many
physicists had made up their mind that fire was not a substance
but an intense grade of heat : Cardan (1550), Descartes and New
ton advocated this view. Chemists held, however, that fire
was a substance : Stahl propounded in 1697 the theory of phlo
giston ; Lavoisier, who destroyed that chimera, bequeathed the
theory of caloric. But the experiments of Davy and Kumford
(1753-1814), showing that a definite quantity of heat could be
produced by a definite amount of mechanical work, convinced
chemists as well as physicists that heat was some form of motion.
At that stage, not a trace was left of all those theories of empirical
science on which Aristotle, St. Thomas, and Scotus had built their
Cosmology.

A BREAK WITH THE TRADITION OF ARISTOTELIAN SCHOLASTICISM.

No one, who has developed the historic sense, scoffs at Coperni
cus because he did not know of Kepler's Laws or at Newton because
he did not know of Einstein's Theory of Eelativity. The same
reason should prevent anyone from scoffing at the Aristotelian
Schoolmen who wrote before the seventeenth century because
they did not write as Keplerians, Cartesians, Newtonians. In
those earlier centuries, a Keplerian, a Cartesian, a Newtonian
was as impossible as an Einsteinian. But the Aristotelian
Schoolmen I1) of the thirteenth century did make a fight for

270 COSMOLOGY

truth which ought to have been a guiding light to those successors
of theirs that had to face the disproof by the scientific world of
the empirical science of Aristotle. It was the glory of the first
Aristotelians among the Dominicans and Franciscans to have
broken, in the interests of science, with that earlier Scholasticism
which was founded mainly on the Neo-Platonism of St. Augus
tine. Arabians and Jews had at that time begun to handsel
the Aristotelian writings for the purpose of destroying the
Catholicism of Europe. And these Catholic pioneers averted
the danger by personal study of Aristotle : proving, text in hand,
that his encyclopaedic erudition and rationalistic metaphysics
was either necessary to or compatible with the dogmas of faith.
" Our intention," declares Albert the Great,(2) " is to make all
the parts of Aristotle, physics, metaphysics and mathematics,
intelligible to the Latins." Nor did this loyalty to Aristotle
imply any unreasonable servility. " He who thinks that Aris
totle was a god," declares Albert,(3) " is bound to hold that he
has never made a mistake. But those who believe he was a man
are bound to admit that he can go astray just as we do." St.
Thomas and Duns Scotus worked, also, along those lines with
the result that Aristotle was firmly enthroned as the guide in
Philosophy of the School. In this reform of Philosophy, Albert,
St. Thomas, and Scotus, are but types of that thinker in every
crisis of human progress who wins for mankind a new kingdom
of truth not opposed to but only beyond and independent of the
truth already discovered. Such pioneers have always to en
counter a fierce and angry opposition from the defenders of what,
at that moment, has to be shown up as out- worn human learning.
The adherents of a poorer, narrower outlook have no sympathy
with, because no understanding of, a culture more ample than
their own : after the discovery of wheat, they would continue
to live on acorns. Thus it happened that Oxford and Paris,
the famous universities of the age, condemned again and again
this nascent Aristotelianism of the School : for the authorities
of these universities, Aristotelianism was inseparable from that
curse of the thirteenth century, Averroism. This ineffectual
opposition to St. Thomas and to Scotus did but give colour to
their personalities, and prove them to be of the same calibre as
the truth-seekers of every other age : not intransigeant partisans
of the past ; not special pleaders pro domo. Both of them knew
that the mind of man, driven by an irresistible urge towards the
pursuit of truth, will not brook for long worthless man-made
traditions. " An appeal to any merely human authority is,"
writes St. Thomas, (4) " the feeblest of all arguments." This clear
duty of the Aristotelian Schoolman to accept truth from what
soever source it comes was unfortunately neglected by those
Schoolmen who, from the seventeenth to the middle of the nine
teenth century, had to grapple with the task of reconciling Aris
totle's Cosmology with the new discoveries of modern science.
They refused to try to accommodate Aristotle's Cosmology tq

A BREAK WITH TRADITION 271

these truths either by mending or ending it : thereby, breaking
with the foundation-stone on which Aristotelian Scholasticism
was built in the thirteenth century.

This scientific intransigeance of the School (5) began with the
controversy on Copernicanism. At first the Schoolmen affected
to ignore the existence of any such doctrine : writers of the calibre
of Suarez and of John of St. Thomas make no mention of helio-
centrism. And when the march of events compelled them(6)
to take notice, the majority during the seventeenth and eighteenth
centuries rejected this theory root and branch : the only con
cession, they made to the new astronomy, consisting in various
ineffectual emendations of Ptolemy. Three extenuating pleas
may be mentioned : Aristarchus of Samos had three centuries
before Christ defended a form of Copernicanism, and Ptolemy
had declared this theory absolutely ridiculous ; many astrono
mers followed Tycho-Brahe in rejecting the views of Copernicus ;
for a long time, the Copernicans themselves taught their theory
merely as a mathematical hypothesis useful for explaining
appearances. Of course these decadent Schoolmen mooted all
sorts of doubts about the new astronomy : may not one admit
spheres that revolve within one another ? may not one admit
heavenly canals through which the stars move ? are comets
always natural facts ? are the observations of the astronomers
so very certain ? But despite the obstinacy of the Ptolemaists,
Copernicanism marched from conquest to conquest. In 1728,
the actual state of this controversy was described, as follows,
by Jerome of Montefortino. " The opinion of philosophers
regarding the nature of the heavenly bodies is banished long since
from the schools (of astronomy) by absolutely certain observa
tions which show that the sun and moon and other stars are made
of the same kind of stuff as our earth : the result is a strong
confirmation of the doctrine of the saints that God made all
things. We think it useless to enter here on a discussion of the
fables of the philosophers — Aristotle and his commentators.
St. Thomas and Dun Scotus would, no doubt, have thought
the same, had God deigned to reveal in their day all that He has
made known to their successors concerning the heavenly bodies."

The new discoveries in physics and chemistry were treated
by these Schoolmen in much the same way. Some of them (7)
admitted in the seventeenth century the gravity of air : others (8)
continued to assert its levity. But, in that century, hardly any
Schoolman admitted the gravity of fire although some,(9) at a later
date, attributed to fire only a relative levity, that is, a less weight
than the other three elements. And all through the seventeenth
century, the School (10) continued to teach that cold and wet
are positive qualities and not merely the absence of heat and
dryness. So much for the four qualities. The Schoolmen of
the seventeenth and eighteenth centuries were even more stub
born concerning the existence of four elements : encouraged,
thereto, by the fact that, outside the School, some non- Aristotelian

272 COSMOLOGY

philosophers and scientists continued to teach the existence of
four elements. One group of Schoolmen (n) continued to defend
this theory by the traditional arguments : these were very
numerous in the seventeenth century, less numerous in the
eighteenth, a remnant in the first half of the nineteenth century.
All these laid great stress on the argument from authority. " I
implore you, young people, by the Almighty and by all the Saints
that Spain has sent to heaven," writes Puigserver, in a preface,
" not to allow yourself to be led astray by these men whose boast
it is to despise all the ancients." Another group of School
men (12) took a different line : they stuck to the theory in its
general outlines, but they compromised about matters of detail,
and they expressed doubts about the value of the traditional
proofs. From about 1830 to 1850 another group of School
men!13) got out of this embarrassing choice between the old
science and the new, simply by omitting from their philosophical
treatises either all Cosmology or, at least, the problem of the
ultimate constituents of matter. Finally, from the middle of
the eighteenth century onwards, a number of Scholastics (14)
accepted the theory of Boscovich : thereby proclaiming their
conviction of the impossibility of reconciling the hylemorphism of
the ancients with the science of the moderns.

The Boscovichians may have made a hasty choice : they
cannot be accused, however, of disloyalty to that guiding prin
ciple of the thirteenth century — hear all sides. But if it be,
in the words of the Aeterni Patris, " a calumny on that (scholastic)
philosophy to say that it is opposed to the advance of the physical
sciences," no one can deny the break with the Aristotelian tradi
tion during these centuries. That decay arose, mainly, out of the
exaggeration of two characteristics of later Scholasticism. " It
was legalist and it was a priorist. Law, even more than phil
osophy, was the favourite pursuit of the medieval scholar. A
knowledge of the canon and civil law was the surest avenue to
preferment and wealth. Hence arose a tendency to treat phil
osophy like law. Aristotle was cut up into texts, which were
quoted like texts from the Pandects. A like use was made of
the Fathers and Holy Scripture, and, as time went on, of the
great Schoolmen who had gone before. The danger of this
practice was a neglect of context and spirit, and a losing sight
of the intrinsic grounds of the argument. Scholasticism was
also a priorist, making out what must be in the nature of things.
Now it is easy to make out what must be, to our minds, so far
as our knowledge goes and our hypothesis extends. The dim-
culty is in testing our hypothesis by experiment and observation,
and widening our knowledge by research into actual facts,
unfavourable as well as favourable to our preconceived theory.
This rough and tumble a posteriori work was not much to the
taste of some of the Schoolmen and their speculations suffered
accordingly." (15)

THE LEONINE REVIVAL 273

THE LEONINE REVIVAL OF ARISTOTELIAN SCHOLASTICISM.

The experiment of welding together the science of the moderns
and the philosophy of the Aristotelian Schoolmen was begun
in the Catholic Schools in the second half of the nineteenth
century. Leo XIII crowned that experiment by insisting that
it should be a nineteenth century revival of the spirit of the
thirteenth century Aristotelian reform. This Pope in the
Aeterni Patris (1879) urged Catholic philosophers to follow a
living not a dead Scholasticism : to reject everything that St.
Thomas and Scotus, were they now alive, would reject ; to
carry forward through seven centuries the teaching of these Masters
and yet be, in every innovation, Scholastics. " St. Thomas,
Blessed Albert the Great, and other leaders of the Schoolmen,
for all their study of philosophy spent much of their energies
in seeking to acquire knowledge of the facts of physics. . . .
While, then, We pronounce that every wise saying, no matter
who said it, every useful invention or contrivance, no matter
who discovered it, is to be willingly and gratefully taken up,
We earnestly exhort you all ... for the defence and adornment
of the Catholic Faith, for the good of society, for the advance
ment of all sciences, to restore the golden wisdom of St. Thomas,
and propagate it far and wide to the best of your power. The
wisdom of St. Thomas, We say : for if there be in the Scholastic
Doctors any excessive subtlety of inquiry, any inconsiderate
teaching, anything less consistent with the ascertained conclusions
of a later generation, in a word, anything in any way improbable,
We have no mind to hold that up for the imitation of our age."
The starting-point of this reform in Cosmology is the rejection
of the out-worn learning of the Schoolmen : their obsolete
astronomy ; their mistaken physics ; their total ignorance of
chemistry ; their a priori aversion to any form of atomism or
of kineticism ; their reliance on the Aristotelian method of
scientific proof rather than on observation and experiment and
a posteriori methods generally. The next step in this reforma
tion is to extract, from the Cosmology of the medieval School,
whatever is of perennial value. There is, naturally, some diver
gence of opinion amongst contemporary Schoolmen regarding
details. But, apart from these open issues, most contemporary
Schoolmen are agreed that the Cosmology of the Aristotelian
Schoolmen, when vindicated from the ravages of time and from
the still worse ravages of injudicious handling, contains a Phil
osophy of Matter which is more in accordance with the teachings
of modern science and the principles of sound metaphysics than
any of its present-day rivals. An account of the line of argument
that leads up to this optimistic estimate of modern Scholastic
Cosmology will be found in the second volume.

18

NOTES.
INTRODUCTION.

THE mottoes of this volume are taken from Albertus Magnus, Phys., viii, tr. 1,
c. 14, and from St. Thomas, Ethic. Nicom. i, lect. 6.

The Creation of Rational Science : — (1) Cf. Bury, History of Greece
(1920), cc. 1, 2. (2) Cf. Grote, History of Greece, i, c. xvi ; Gilbert Murray,

Four Stages of Greek Religion, cc. 1, 2 ; Miss Harrison, Prolegomena to Greek
Religion ; Miss Harrison, Themis ; Dr. L. Farnell, Cults of the Greek States ;
G. Murray, Euripides and His Age ; Whibley, A Companion to Greek Studies
(1906), cc. 3, 5. (3) Burnet, Early Greek Philosophy (1920), p. 25. (4)

Burnet, Greek Philosophy (1914), pp. 10-11.

The Originality of Greek Rationalism : — (5) Burnet, E.G. Philosophy,
pp. 15-24.

The Religion of Rationalism :— (6) Burnet, Greek Philosophy, pp. 11-13.

Rationalism in Revealed Religion : — (7) Cf. Fr. Joseph Rickaby, S.J.,
Oxford and Cambridge Conferences (1900), pp. 61-66; Rev. P. Finlay, S.J.,
Divine Faith (1917), pp. 200-218. (8) De Revelatione, can. i. There can

be no doubt, then, about the official attitude of the Catholic Church concerning
the possibility and necessity of a philosophy of theism. The unofficial mind of
our ablest apologists is voiced by Cardinal Billot in his contention that the
" five ways " of the Summa Theologica of St. Thomas are the only valid proofs
of the existence of God. It is almost impossible, however, to bring all this
home to the minds of authors who have got little or no training in the Meta
physics of the School. They continue to propound non-Thomistic proofs which
are as worthless as they are facile : aids to atheism rather than proofs of theism.
At times, they are capable of reverting to a position closely allied to Tradi
tionalism and of maintaining that the miracles of our Lord — for instance, His
Resurrection — establish the existence of God quite independently of the philo
sophy of theism. This attempt to put history on a level with philosophy as
an ultimate basis of theism would have been scouted by St. Augustine, St.
Thomas, Scotus, Suarez. These masters of Catholic Apologetics would have
warned the public that an important part of Catholic Theology must never
have been known or must conveniently have been forgotten by such semi-
traditionalists. They would have pointed out that the Bible from Genesis to
the Book of Revelation is full of the records of the intervention in our world of
spirits good and bad ; that century after century there has been an ever-growing
accumulation of excellent evidence for this intervention in the lives both of
saints and of sinners ; that, in fact, the intervention of disembodied spirits in
the happenings of this world may be said to be an essential part of the dogmatic
teaching both of Judaism and of 'Christianity from the beginning. Other ditches
in this new path, along which popularisers would have their readers find an
easy way to the proof of the existence of God, will occur to the mind of every
alert student of modern Apologetics. But eschewing these modern difficulties
and putting ourselves at the standpoint of the Schoolmen, the question at once
arises concerning the historical miracles of our Lord : How can we be sure that
these miracles were the work, not of a superhuman spirit but of the Second
Person of the Blessed Trinity ? To raise that grave question is to blow sky-
high the frail card-houses of men who are indolent enough or thoughtless enough
to wish to fling on the scrap-heap the rational theism of St. Thomas. For, the
only possible way of meeting that question is to reinstate the philosophical
proofs of God's existence in that ultimate position which they have always held

275 18 *

276 NOTES

in the works of trained apologists. If philosophy can prove that the Maker of
man and of man's environment is an infinitely perfect personal God, it follows
at once that such a God will not allow the human race to be led astray by
preternatural events on the gravest questions of Revealed Religion. But unless
philosophy can and does take this first step, preternatural facts cannot bridge
the chasm that separates the Superhuman from the Infinite. Thus, the
argument from the miracles of our Lord in favour of His Divinity presupposes
in ultimate analysis an independent philosophical proof of the existence of God.

(9) Fr. Rickaby, S.J., Oxford and Cambridge Conferences (1900), pp. 54-61.

(10) Idem., pp. 66-67. (11) Idem., pp. 68-69. The Tertullian sentences are
quoted out of their order. (12) Fr. Jos. Rickaby, S.J., Scholasticism (1908),
pp. 118-121. This topic of Rationalism in Revealed Religion must not be
confounded with such totally distinct topics as, the divine motive and the
supernatural basis of Faith, the proper attitude of born Catholics towards the
motives of credibility, the obligations of all Catholics regarding intellectual
arguments against Faith, etc. Cf. Fr. Rickaby, S.J., Oxford and Cambridge
Conferences (1900), pp. 54-62, 70-87 ; do., In an Indian Abbey (1919), pp. 47-67 ;
Fr. P. Finlay, S.J., Divine Faith (1917), passim.

Aristotle's Division of Speculative Philosophy or Science : —
(13) Taylor, Aristotle on His Predecessors (1907), pp. 17-28 ; Joachim, Aristotle
on Coming-to-be and Passing-away (1922), pp. xiii-xxx ; Zeller, Aristotle and
the Earlier Peripatetics, i, pp. 171-190.

The Physics of Aristotle : — (14) Mansion, Introduction a la Physique
Aristotelicienne, cc. 1, 4, 5, 8 ; Joseph, Introduction to Logic, p. 350 sqq. ;
Joachim, Aristotle on Coming-to-be and Passing-away, pp. xxxi-xxxviii ; cf.
Chapter iii. (15) Joachim, Aristotle, etc., p. xxix.

The Revolt against Aristotelianism :— (16) Cf. Chapter x. (17) Des
cartes (Cousin's edition), vol. x, p. 255 and pp. 294-296.

Physical Science and Modern Philosophy : — A detailed account of the
physical and mechanical theories provisionally sketched in this and the next
two sections (The Evolution of Modern Physics, Theoretical Physics and
Abstract Mechanics) will be part of the second volume on Modern Cosmology.
For that reason, no authorities are quoted at this stage. A wide-ranging defence
of the view taken in this provisional sketch can be found in the following books :
Merz, History of European Thought in the Nineteenth Century, vols. i and ii ;
Lucien Poincare, The New Physics ; Mach, The Science of Mechanics ; Danne-
mann, Die, Naturwissenschaften in Ihrer Entwicklung und in Ihrem Zusammen-
hange, 4 vols. ; Siegmund Gunther, Geschichte der Anorganischen Naturwissens
chaften in Neunzehnten Jahrhundert ; Picard, La Science Hoderne ; Henri
Poincare, La Science et I 'Hypothese ; do., La Valeur de la Science ; do., Science
et Methode ; Whetham, The Eecent Developments of Physical Science ; Bohr,
The Theory of Spectra and Atomic Constitution ; Eddington, Space, Time and
Gravitation ; Loring, Atomic, Theories ; Planck, The Origin and Development of
the Quantum Theory ; Reiche, The Quantum Theory. (18) Joachim, Theory of
Truth, pp. 69-73.

The Evolution of Modern Physics : — (19) Kundt, Die neuere Entwicklung
der Electricitatslehre (1891), p. 35.

The Practical Interest of Physical Science : — (20) Merz, History of
European Thought, etc., i, pp. 326-329. (21) Merz, History, etc., i, p. 330, n. 1.

(22) Merz, History, etc., ii, pp. 207-208. (23) Merz, History, etc.. ii, pp. 201-

202. (24) Riicker, Presidential Address to the British Association, Report

(1901), p. 5. Cf. Poynting, Address to the Mathematical and Physical Section
of the British Association (1899), Report, pp. 1-10. (25) Hicks, Nature,

vol. Iii, p. 472. (26) Riicker's Presidential Address, etc., p. 23.

The Manufacture and Diffusion of Irrational Science : — (27) Silvanus
P. Thompson, Life of Lord Kelvin ( 1910), vol. ii, pp. 1 121-1 124. (28) Brewster,
Memoirs of Sir Isaac Newton (1855), p. 313. (29) Observations upon the

Prophecies of Daniel and the Apocalypse of St. John (London, 1732), pp. 75-79,
85-86, 113-114, 191-200, 256-272, 279, 282-283, 305, 314-322. (30) Life of

Kelvin, ii, p. 1087, note. (31) Life of Kelvin, ii, p. 1091. (32) Newton,

Observations, etc., pp. 191-192.

NOTES 277

The Purpose of Modern Cosmology :— (33) Taylor, Elements of Meta
physics, pp. 48-49. (34) Maxwell, Matter and Motion, p. 40. (35) Tait,
Force, Nature, vol. xvii, p. 459. (36) Aston, The Atoms of Matter, Nature,
Nov. 25, 1922, p. 702 sqq.

The Utility of Cosmology :— (37) St. Thomas, Meteor, iv, lect. 1. The
far-reaching consequences of Cosmology in what St. Thomas calls " speculation
about divine truth " are strikingly illustrated in many chapters of the late
Dr. McDonald's Motion : Its Origin and Conservation (1898).

Method in Cosmology :— (38) Pater, Plato and Platonism (1907), pp. 8-10.
(39) Arist., de Ccelo, 279b 7-12 ; do., Met., 983b 1-6 ; do., Met., 995a 25-995b 5 ;
St. Thomas, de Ccelo, i, lect, 22 ; do., Met., i, lect. 4 ; do., Met., iii, lect. 1 ;
Scotus, Met., i, s. 2, c. 1 ; do., Met., iii, s. 1. c 1. (40) Arist., Ethic. Nicom.,

1096a 14-18. (41) St. Thomas, Ethic., i, lect. 6. (42) St. Thomas,

de Ccelo, i, lect. 22.

CHAPTER I.

(1) The works of the Pre-Socratics have not come down to us in their entirety.
All that we possess of their writings are either fragments or the accounts of
disciples, collectors, commentators. A critical edition of these sources is to he
found in the volumes of H. Diels : Doxographi Greed, Berlin, 1879 ; Fragmente
der Vorsokratiker, Berlin, 1906 (2nd ed.). All fragments, except those of
Heracleitus, are quoted from Diels.

The Milesians :— (2) Met., i, 3, 983b 22. (3) Zeller, Pre-Socratics, i,

232 sqq. ; Burnet, Early Greek Philosophy, 53 sqq. (4) Aet. i, 3, 4.

(5) In Arist. de Ccelo, 273b 45 ; Schol, in Arist., 514* 33.

The Pythagoreans :— (6) Met., i, 5, 986a 1 ; xiv, 3, 1090a 22 ; xiii, 6, 1080b
2 and 16 ; xiii, 8, 1083b 11 ; xiv, 3, 1090a 32 ; i, 5, 986a 1 ; i, 8, 990a 21 ; xiii,
6, 1080h 18 ; xiv, 3, 1091a 18 ; xiii, 6, 1080b 16 ; xiv, 3, 1090a 20 ; i, 5, 987a
15 ; de Ccelo, iv, 1, 300a 15. (7) Phys., iii, 4, 203a 4 ; iii, 5, 204a 20 ; Met.^i,

5, 987a 15 ; iii, 1, 996a 6 ; iii, 4, 1001a 9 ; x, 2, 1053b 12. (8) Phys., iv, 6,

213b 22 sqq. ; Met., xiv, 3, 1091a 13 ; de Part. An., ii, 10, 656b 15 ; deAn., ii, 10,
419b 34 ; Met., i, 3, 984a 7 ; i, 5, 9S6a 25. (9) Arist., Phys., v, 3, 227a 27 ;

Met., xiii, 6, 1080b 18 sqq. ; 1083b 8 ; de Ccelo, iii, 1, 300a 16. (10) Burnet,

E.G.P., p. 276 sqq. ; Zeller, Pre-Socratic Philosophy, vol. i, p. 407 sqq.
(11) Gomperz, Greek Thinkers, vol. i, p. 105. (12) Burnet, Greek Philo

sophy, p. 90 ; E.G.P., p. 99. (13) Burnet, E.G.P., p. 307.

Heracleitus :— (14) Plato, Tht, 152e 1 ; Crat., 401<* 5 ; 402a 8 ; Arist., Top.,
i, 11, 104b 22 ; de Ccelo, iii, 1, 298b 30 ; Phys., viii, 3, 253b 2. (15) Bywater,

Herad. Eph. Eeliguicp., frag. 77. (16) Frag. 78. (11) Frag. 81.

(18) Frag. 32. (19) Frag. 25. (20) Frag. 41-42. (21) Frags. 20

and 28. (22) Frag. 22. (23) Frags. 21, 23, 25. (24) Diogenes,

ix, 7. (25) Frags". 21 and 23. (26) Arist., de An., i, 2, 405a 25.

(27) Frags. 74-76. (28) Frags. 73 and 68. (29) Frag. 45. (30)

Frag. 46. (31) Frag. 44. (32) Frag. 43. (33) Frag. 69.

(34) Burnet, E.G.P., 166-167. (35) Frag. 20. (36) Frag. 29.

(37) Frag. 103. (38) Frag. 101. ' (39) Frag. 67. (40) Cf. Burnet,

E.G.P., 156. (41) Baeumker, Das Problem der Materie, p. 23 sqq. ; Zeller,

Pre-Socratic Phil, vol. ii, p. 30 sqq. ; Burnet, E.G.P., p. 165. (42) Met.,

iv, 3, 1005b 23 ; iv, 7, 1012a 25 ; xi, 5, 1062a 31 ; xi, 6, 1063b 24 ; Top., viii, 5,
155b 30 ; Phys., i, 2, 185b 19. (43) Vorlesungen iiber d. Gesch. d. Phil, i,

305 ; Logik, \, 80.

The Eleatics :— (44) Frag. 6. (45) Frag. 5. (46) Frag. 8.

(47) It is customary to throw this argument into the following form : what-is
must come either from what-is or from what-is-not. The existence of the first
horn of this dilemma in the original text is doubtful. Cf. Diels, Vors., frag. 8,
line 12. (48) Parmenides gives an account also of the " opinions of mortals "

regarding the origin of the world of experience : but he says before beginning
this account — " at this point I cease trustworthy discourse and the thought
about truth," frag. 8, line 50. Cf. Burnet, E.G. P., p. 182. (49) Simplicius,

Phys., i, p. 139, 7 sqq., and p. 141, 1 sqq. (50) Simpl., Phys., i, p. 140,

278 NOTES

28 sqq. (51) Simpl., Phys., iv, p. 562, 3 sqq. ; Arist., Phys., iv, 1, 209a 23,

and iv, 3, 210b 22. (52) Simpl., Phys., vii, p. 255. (53) Arist., Top.,

viii, 8, 160b 8 ; Phys., vi, 9, 239b 5-33 ; Phys., vi, 2, 233a 11 and 21. (54)

Diels, Vors., frags. 3, 5, 6. (55) Frag. 8.

Empedocles :— (56) Frags. 11, 12. (57) Frag. 14. (58) Frag. 6.

(59) Empedocles meant by air atmospheric air as distinct from empty space
on the one hand and from ratified mist or vapour on the other : a new point
of view at this date ; cf. Burnet, E.G.P., p. 229. (60) Earth was al

ways in popular thought one of the primary bodies : Arist., Met., i, 8, 989a 5.
(61) Frag. 9. (62) Frag. 17. (63) Frag. 89. (64) Frag. 17.

(65) Frag. 23. (66) Arist., de Gen. Con., i, 8, 324b 34. (67) Frag. 91-

Anaxagoras :— (68) Frag. 17. (69) Arist., Phys., iv, 6, 213a 22.

(70) Frag. 10 ; Dox., p. 279. (71) Frags. 1, 4. (72) Frag. 6. (73)

Arist., Met., i, 3, 984b 15. (74) Frags. 11-14. (75) Arist., Met., i, 4,

985a 18; Plato, Phd., 97b 8. (76) Frags. 11, 8. (77) Frag. 12.
(78) Frag. 6. (79) Frag. 3.

The Atomists :— (80) Burnet, E.G.P., p. 330 sqq. ; Baeumker, Das Problem
d. M.,p.lQ. (81) de Gen. Corr., i, 8, 324b 35 ; Phys., i, 3, 187a 1 ; de Ccelo,

iii, 4, 303a 8. (82) Arist., de Ccelo, i, 7, 275b 32 ; Phys., Hi, 4, 203a 34.

(83) Arist,, Met., i, 4, 985b 13 sqq. ; viii, 2, 1042b 12 sqq. ; "Phys., i, 5 ; iii, 4,
203a 19 ; de Gen. Corr., i, 1, 314a 21 ; 2, 315b 33 ; 9, 327a 18 ; 2, 315b 9 ; 8,
325b 27 ; 8, 325a 30 ; de Ccelo, iii, 4, 303a 5 sqq. ; Phys., iii, 4, 203a 33 ; de
Ccelo, iv, 2, 308b 35. (84) Democritus, frag. 125. (85) The point at

issue is whether the atomists held weight to be an original quality of the atoms :
cf. Zeller, Pre-Socratic Phil, vol. ii, pp. 226-241 ; Burnet, E.G.P., p. 340 sqq.
(86) Aet., i, 25, 4 (Dox., p. 321).

Plato:— (87) Tim., 29. (88) Tim., 31-32. (89) Tim., 48-49.

(90) Tim., 49-50. (91) Arist., Phys., iii, 4, 203a 15 ; iii, 6, 306b 27 ; iv, 2,

209b 33; i, 9, 192* 11 ; Met., i, 6, 987b 20; i, 7, 988a 25; iii, 3, 998b 10.
(92) Phys., iii, 4, 203a 3 ; i, 9 ; iv., 2, 209b ; Met., i, 7, 988a 25. (93) Zeller,

Plato, p. 293 sqq. ; Burnet, Greek Philosophy, p. 343 sqq. ; Baeumker, Das
Problem d. Mat., p. 151 sqq. (94) Tim., 48-52. (95) Tim., 53-57.

(96) Tim., 52, 56, 57, 62. (97) Cf. Zeller, Plato, p. 320 sqq. ; Burnet, Greek

Philosophy, p. 312 sqq. ; Baeumker, Das Problem, etc., p. 189 sqq.

CHAPTER II.

t.,i, I,981b28; iii, 1, 1003a 26; i, 3,984a25; i,3,984bll; i, 3,984a16;
vi, 1, 1025b 3 ; vii, 3, 1029a 1 ; de Gen. Corr., ii, 9, 335a 29 ; ii, 9, 335b 29 ;
ii, 9, 336a 1 ; 335a 33 ; 335b 1 ; 335a 30 ; 333b 7 ; Phys., ii, 8, 198b 36 ; 199a 1 ;
199, 18; 199b 7.

Aristotle on the Milesians :— (2) Met., i, 8, 988b 23 ; iv, 5, 1009a 36 ;
i, 7, 988a 34 ; i, 8, 988b 28 ; i, 8, 988b 26 ; de Gen. Corr., ii, 9, 335b 32 ; 335b 24 ;
ii, 1, 329a 8 ; de Ccelo, iii, 5, 304b 11 : i, 3, 270a 14 ; de Gen. An., v, 1, 778b 7 ;
Phys., i, 7, 190a 13 ; iii, 5, 205a 4. (3) Met., xii, 2, 1069b 20 ; i, 7, 988a 30 ;
i, 8, 989a 14 ; Phys., i, 4, 203a 16 ; 205a 25 ; i, 4, 187a 12 ; iii, 5, 204b, 22 ;
de Ccelo, iii, 3, 302a 15 ; 303b 10 ; de Gen. Corr., ii, 5, 332a 20 ; ii, 1, 328b 35.

Aristotle on the Pythagoreans :— (4) Met., i, 8, 989b 29 sqq. ; xiii, 8,
1083b 8 ; i, 8, 990a 12 ; iii, 4, 1001b 17 ; xiv, 3, 1090a 30 ; 1092b 15 : 1080b
16; 1091* 13. (5) Met., 1092b 24. (6) 1092b 18-30. (7) 1093a 251.
(8) 987a 23. (9) 990a 18. (10) 986a 5.

Aristotle on Heracleitus :—(!!) Met., 984a 7; 987a 23. (12) Met., iv,
5, 1010a 15; Phys., viii, 3, 253b 9. (13) Met., 1005b 25. (14) Met.,
1062a 31. (15) Met., 1012a 24 ; cf. Chapter i, note (42).

Aristotle on the Eleatics :— (16) Phys., i, 2, 185a 20; 187a 3; Met.,
iii, 4, 1001b 7. (17) Phys., i, 8 ; Met., xiv, 2, 1089a 26. (18) Phys., i, 3,
187a 1 ; iv, 3, 210b22 ; vii, 5, 250a 19 ; vi, 9 ; vi, 2, 233a 21. (19) Phys.,
i, 2, 185b 19. (20) Phys., i, 3, 186a 5 ; i, 2, 184b 25 ; Met., i, 5, 986b 10 ; de
Ccelo, iii, 1, 298b 14 ; de Gen. Corr., i, 8, 325a 17,

NOTES 279

Aristotle on Empedocles :— (21) Met., i, 8, 989a 22; deGen. Corr., ii, 1,
329b; 7, 334a 18 ; i, 1, 314b 10 ; i, 1, 315a 3 ; i, 8, 325b 16 ; de Ccelo, Hi, 7, 420.

(22) de Gen. Corr., i, 2, 329a 3 ; 325b 1 sqq. ; 314a 10 ; 315* 3 ; de Ccelo, 390a 9.

(23) Met., i, 4, 985a 25 ; iii, 4, 1000b 12 ; Phys., viii, 1, 252a 4 ; 251b 28 ; de
Gen. Corr., ii, 6, 333b 2 ; de Ccelo, i, 10, 280a 11 ; de Part. An., i, 1, 640a 19.

Aristotle on Anaxagoras :— (24) Phys., i, 4, 187b 7 ; iii, 4, 203a 19; iii, 5,
205b 1 ; iv, 6, 213a 22 ; de Ccelo, iii, 4 ; 302b 14 ; iv, 2, 309a 19 ; de Gen. Corr.,
i, 1 ; i, 10, 327b 19 ; Met., i, 8, 989a 30 ; Phys., viii, 252a 10. (25) Met., i, 8,
989a 30 ; Phys., viii, 5, 256b 24 ; de An., i, 2, 405a 13 ; 405b 19 ; iii, 4, 429"1 18 ;
Met., i, 3, 984b 20 ; xii, 10, 1075b 8 ; xiv, 4, 1091b 10 ; i, 4, 985a 18 ; iii, 7, 988b 6.

Aristotle on the Atomists :— (26) de Gen. Corr., i, 2, 315b 1. (27) Phys.,
iv, 7, 214a 26-216a 27 ; Phys., iv, c. 6-10 ; de Ccelo, iv, 2 ; Phys., iv, 8, 214b
28 ; de Ccelo, i, 7, 275b 29 ; 277a 33 ; 294b 30 ; 300b 8 ; 279a 11. (28) Aristotle
was mistaken in denying that all bodies fall with equal rapidity in the void : it
must be remembered, however, that his opponents had no proof of this fact — its
experimental verification being altogether bevond the reach of Greek science.
(29) Phys., 216a 27. (30) de Gen. Corr.,"i, 2, 317a 1 ; 325b 27 ; 315b 9 ;

314a 21'; Phys., vi, 1, 231a 20 ; i, 4, 187b 22 ; viii, 6, 259a 8 ; iii, 4, 203a 19 ;
iii, 5, 204a ; iii, 6 ; de Ccelo, iii, 4, 303a 20 ; 303a 17 ; 303a 29 ; 303b 4 ; 306b 9 ;
de Gen. Corr., i, 8, 326a l-326b 2. (31) de Ccelo, iv, 2. 310a 7 ; 312b 20 ;

308a 21 ; 309b 27 ; 308b 35 ; 306b 29 ; 308a 34 ; 274b 8 ; 276b 6 ; Phys., iv, 8,
214b 28 ; 216a 13 ; de Gen. Corr., i, 8, 326a 3. (32) de Ccelo, iii, 7 ; 305b 28 ;

306a 30 ; 305b 1 ; 305a 16 ; 305b 20 ; 303a 24 ; de Gen. Corr., i, 1, 314b 10 ;
327a 14 ; 327a 22 ; 334a 18 ; 326b 6 ; 327a 7 ; Met,., i, 8, 989a 22 ; i, 9, 99 la 14 ;
viii, 2, 1042b 16 ; de Gen. Corr., i. 10 ; 327b 13 ; 328a 18 ; 327b 10 ; 328a 23 ;
328a 10 ; 328a 5 ; 327b 22. (33) Aristotle often couples Empedocles with

the Atomists here. It is worth noting that Aristotle admits this theory about
rain : his objection is to its incompleteness. Meteor., i, 11, 347b 18 ; de Somno,
3, 457b 31 ; de Part. An., ii, 7, 653* 2. (34) de An. Gen., 789b 1. (35)

Phys., 198b 34-199a 7 ; 199a 8-15 ; de Part. An., i, 1, 641b 12 ; Phys., 199a
15-20 ; 199a 20-30 ; Meteor., iv, 2, 379b 25 ; de Part. An., 641a 25 ; 641b 32 ;
Polit., i, 2, 1252b 32 ; de Gen. An., ii, 6, 742a 28 ; de Gen. Corr., ii, 9, 335b 6 ;
de Ccelo, ii, 8, 289b 26 ; 290a 31 ; 29 lb 13 ; de Vita et M., 469a 28 ; Eth. N.,
1173a 4. (36) Meteor., iv, 2; de Ccelo, 311a 1 ; de An., ii, 4, 415a 26;

Phys., ii, 8, 199a 20 ; de Part. An., i, 5, 645b 14 ; de An., iii, 12 and 13 ; Met.,
vii, 8, 1033b 29 ; 1034a 22 ; xii, 3, 1070a 4 ; de An., ii, 1, 735a 3. (37) de

Vita et M., 469a 28 ; de Part. An., ii, 14, 658a 23 ; iv, 10, 687a 15 ; de Incess.
An., ii, 704b 16 ; de Gen. An., i, 5, 717a 15 ; Met., v, 16, 1021b 12 ; 1055a 11 ;
Phys., iii, 6, 207a 8 ; Met., v, 16, 1021b 15 ; xii, 7, 1072b 30 ; Phys., vii, 3, 246a
13 ; de Gen. Corr., ii, 10, 336b 27 ; Met., xii, 10, 1075a 11 ; 1075b 33 ; 1078a 31 ;
1072£ 32 ; 984b 11 ; de Ccelo, ii, 14, 296a 33 ; de Part. An., i, 5, 645a 23 ; 639b 19.
(38) It is of fundamental importance for the study of Aristotelianism to grasp
the implication that primordial matter prevents final causes from obtaining
complete mastery in the world of change.

Aristotle on Plato :— (39) de Ccelo, iii, 1, 299a 6 ; 300a 7 ; 306* 23 ; 305b 31 ;
306b 5 ; 306b 9 ; 306b 22 ; de Gen. Corr., ii, 1, 329a 21. (40) de Ccelo, iii, 1, 299a
25; 299b 31 ; 308b 3; 312b 20; 306a 1; 306a 20; 299b 23. (41) de Ccelo,
306b 29 sqq. (42) Plato's view of the scientific worthlessness of Cosmology,

arising out of his theory of knowledge, is dealt with in that portion of the fourth
chapter which expounds Aristotle's criticism of the Theory of Ideas.

CHAPTER III.

Theory of Scientific Proof : — (1) For a textual defence of this view as
outlined consult Joseph, Introduction to Logic, p. 350 sqq. ; of. Notes to Intro
duction, no. (14). (2) Zeller, Aristotle, pp. 243-245. (3) de Gen. An.,
iii, 10, 760b 27 ; Eth. Nic., vi, 2, 1143b 13 ; de Gen. Corr., i, 8, 325a ; de Ccelo, ii,
12, 292a 15 ; ii, 5, 287-288 ; ii, 12, 291b 25. (4) Darwin, Life and Letters,
iii 252 • also, despite an obvious anti- Aristotelian bias, Lewes, Aristotle, pp. 154,
155. (5) Hist. An., vi, 10, 565b ; Hist. An., ii, 3, 501b 19 ; Hist. An., v,
5 541a 26 • de Gen. An., iii, 1, 751a 13 ; Hist. An., iii. 12, 519a 3 ; de Insomniis,
2, 459b 27. (6) Burnet, E.G.P., p. 296 sqq. ; Zeller, Plato, 379-381 ; Taylor,
Plato, p. 145. (7) Met., xiv., 3, 1090b 39* :

280 NOTES

The Terrestrial and Celestial Universe :— (8) de Ccelo, i, 3, 270b 5 ;
Meteor., i, 3, 339b 21. (9) de Ccdo, i, 2, 268b 14 ; i, 9, 279b 2 ; ii, 6, 288a 34 :

i, 3, 269b 18 ; i, 3, 270a 13 ; ii, 12, 292b 17. (10) Meteor., i, 3, 339b 13 ; 340a 18.

(11) de Ccdo, i, 3 ; and practically all book iv. (12) de Gen. Corr., ii, 2,

329b 7-34 ; 330a 24 ; Meteor., iv,' 1 ; Meteor., iv, 5, 382a 27 ; 10, 388a 21 ;
11, 389a 29 ; de Gen. Corr., ii, 3, 331a. (13) de Gen. Corr., ii, 7 and 8.

The Structure of the Heavens :— (14) Cf. Zeller, Aristotle, vol. i, p. 492.
(15) de Ccdo, ii, 8, 289b 1-34 ; 291a 7-22 : 290a 25 ; 291b 14. (16) de Ccelo,

ii, 12, 292b 31 ; Met., xii, 8, 1073a 28 ; 1073b 17. (17) Met., xii, 8, 1074a 1.

(18) Met., xii, 8, 1073a 26 ; de Ccdo, ii, 1, 284a 27 ; Met., xii, 8, 1074a 14. (19)

Meteor., i, 3, 340b 10 and 341a 2 ; de Ccelo, ii, 4, 287a 15. (20) The view

that Eudoxus and Calippus propounded the sphere-theory simply as a mathe
matical hypothesis and that Aristotle converted this mathematical hypothesis
into a physical fact, and thereby grossly misunderstood it, is doubtful. Cf.
Gomperz, "Greek Thinkers, vol. iv, 'p. 230-233. (21) de Ccdo, ii, 12 ; iii, 5 ;

ii, 1 ; i, 9, 279a 10. (22) de Ccelo, 288a 14 ; 289a 4. (23) Phys., ii, 4,

196a 33 ; Met., xii, 8, 1074a 17 ; de Ccelo, ii, 12, 292b 32 ; 3, 286a 11.

Interaction of Terrestrial and Celestial Bodies :— (24) Meteor., i, 2, 339a
21 ; i, 3, 340a 14. (25) Meteor., iv, 1 ; iv, 4 ; iv, 5 ; iv, 10 ; iv, 11. (26) de

Ccelo, ii, 7, 289a 14 ; Meteor., i, 3, 340b 6. (27) de Gen. Corr., ii, 10, 336a

23 ; Meteor., i, 9, 346b 20 ; ii, 2, 354b 26 ; de Gen. Corr., 336b 1 ; Met., xii. 8,
1073b 17. (28) de Gen. An., iv, 10, 777b 16. (29) de Gen. Corr., ii, 10,

337a 7. (30) de Gen. Corr.y ii, 10, 336b 9 and 26 ; 337a 1 ; 338b 3 ; Meteor.,

first three books passim.

The Shape of the Universe :— (31) de Ccelo, ii, 14, 297a 6 ; 293b 34; 297b
23 ; 296a 27 ; 296b 25 ; 297a 21 ; 296a 34. (32) de Ccelo, ii, 4, 287b 1 ;

Meteor., ii, 2, 355a 35; 355b 15; 356a 33. (33) Meteor., i, 3, 340b 19;

34la 2 ; 4, 34lb 6 ; 7, 344b 8 ; 8, 345b 3 ; ii, 2, 354b 4 ; de Ccelo, ii, 4, 287a 30.
(34) de Ccelo, ii, 4, 287a 30 ; 287a 11 ; 287b 14 ; 278a 25 ; 279a 7.

The Universe as aWhole :— (35) de Ccelo, i, 9, 278a 25 ; 279a 7 ; i, 8, 276a
18 ; 276a 30 ; 277a 3 ; 277b 9. (36) de Ccelo, i, 8 ; i, 9, 278b 21 ; 279a 11.

(37) de Ccelo, i, 8, 277b 9 ; Met., xii, 8, 1074a 31. (38) de Ccelo, i, 9. (39)

de Ccelo, i, 3, 270a 11 ; i, 9, 279a 25 ; ii, 12, 292b 17 ; i, 4, 271a 20 ; i, 9, 277b ;
Met., i, 12, 1074a 35. (40) de Ccelo, i, 3, 269b 29. (41) de Ccelo, i, 3,

270a 12 ; ii, 6, 288a 22-34 ; 288b 1 ; ii, 1, 284a 13. (42) de Ccelo, i, 10,

279b 20 ; 280a 21 ; de Gen. Corr., ii, 10, 336a 15 ; 336b 27.

CHAPTER IV.

Proof of the Possibility of Change :— (1) Met., ii, 4, 999b 6 ; x, 6, 1062b
25 ; Phys., i, 4, 187a 28, 34 ; de Gen, Corr., i, 3, 317b 30. (2) Phys., i, 5, 188a

19-26 ; 188a 31b 26 ; 188b 27-30 ; 188b 33-35 ; iii, 5, 205a 6 ; Met., iv, 2, 1004b
31-33; xii, i, 1069b 3; xii, 10, 1075a 28; xiv, 1, 1087a 29; de Ccelo, iv, 3,
3104 25; de Gen. An., iv, 1, 766* 13. (3) Phys., i, 6, 189a 21-27; i, 7,

190b 33 ; i, 5, 188a 30 ; v, 1, 224b 4 ; de Gen. Corr., i, 1, 314b 23 ; i, 6, 322b 16 ;
ii, 1, 329b 2 ; Met., xii, 1, 1069b 6 ; xii, 10, 1075a 30. (4) Phys., i, 7, 189b

32 sqq. ; Met., xii, 2, 1069b 7 : vii, 7, 1033a 5 ; de Gen. Corr., i, 1, 324a 15 ;
de Gen. An., i, 18, 724b 2 ; Cat., 10, 13a 18. (5) Phys., i, 7, 189b 30 ; 190b

13 ; 190b 10-1 91a 15 ; i, 8, 191b 15 ; i, 9, 191b 35 ; i, 9, 192a 1 sqq. ; i, 3, 187a
5 ; i, 7, 190b 23 ; 190b 27 ; de Gen. Corr., i, 7, 324a 15 ; Met., xii, 2, 1069b 33 ;
xii, 4, 1070b 18 ; xii, 5, 1071a 9. (6) Phys., i, 7, 190a 31 sqq. ; 190b 17.

(7) Phys., i, 7, 191a 10. (8) Phys., i, 8, 191b 27 ; 191a 23 ; de Gen. Corr.,

i, 3, 317b 23 ; ii, 9, 335b 29 ; Met., v, 12, 1019b 22 ; ix, 1, 1046a 69 ; v, 12, 1019a
15 sqq. ; 1046a 9-13 ; 1017b 1 ; 1045b 33 ; 1089a 28 ; 1045a 23 ; 1050b 2 sqq. ;
1071a 8-10 ; 1069b 15 sqq. ; 1009a 32 ; de An., ii, 1, 412a 9 ; 402a 26 ; 414a 16.
(9) Phys., i, 8, 191 a 23 sqq. ; i, 8, 191b 27. (10) The Aristotelian doctrine

of potential being has often been caricatured : partly owing to the malice of
enemies, partly owing to the folly of friends. But Aristotle's explicit teaching
on the strict meaning of potential being forecloses all attempts at satire. Poten
tial being exists for him only when there exists in nature an active cause capable
here and now, all things considered, of producing some new reality. A sick
man is potentially healthy only if either the doctor or nature or both can cure

NOTES 281

him and are on the point of beginning the process of healing : if, for any reason
whatsoever, these efficient causes of healing are not on the point of starting a
genuine cure, the invalid ceases to be potentially healthy. Another example
of Aristotle's is based on earth, brass and statue : earth became brass and
brass became a statue. Is earth potentially a statue ? No, for it must first
change to brass. His third example is the most striking. Earth, he argues,
can become male sperm. Is earth, then, potentially a man ? Not at all. Is
even male sperm potentially a man ? Again, certainly not. The potential
being of man does not arise until this sperm has undergone " a change in a
foreign medium " : in other words the fertilised ovum, and it alone, is potentially
a man. In short, what is never to be actual cannot be called potential ; and
even what is to be actual cannot be called potential until it is on the brink of
becoming actualised. Met., ix, 7.

Facts and Factors of Accidental Change :— (11) Met., xii, 2, 1069b 9-13 ;
viii, 1, 1042* 32 ; vii, 9, 1034b 2 ; xi, 11, 1067*) 12 ; 1067b 25 ; 1067b 36 ; 1068a
11 ; 1068* 15 ; xii, 2, 1069b 9 ; xiv, 1, 1088b 31 ; 1088b 1 ; Phys., v, 1, 225a 3 ;
v, 1, 225a 25 : 225b 32 ; 225b 1 ; 200b 32 ; 225b 13 ; 226a 23 ; 226a 26 ; i, 7.
190* 31 ; de Gen. Corr., i, 1, 319b 30 ; i, 4, 320a 2 ; etc., etc. (12) Phys.,

i, 2, 185a 15 ; ii, 1, 193a 3 ; viii, 3, 253a 24 ; Met., i, 5, 986b 31. (13) This

part of the Aristotelian teaching is the main topic of Chapter viii. (14)

Met., i, 4, 985b 10 ; iii, 5, 1002a 22 ; v, 7, 1017b 7 ; v, 2, 1013a 25 ; v, 4, 1014b
29 ; vii, 10, 1035a 13 ; ix, 7, 1049a 18 ; ix, 7, 1049a 23 ; v, 2, 101 3a 25 ; 4,
1014b 29 : vii, 3, 1029a 4 ; 10, 1035a 6 ; viii, 2, 1043a 8 ; Phys., i, 7, 190b 6 ;
191a 9 ; ii, 3, 194b 25 ; 195a 6 ; 195b 8 ; iii, 6, 207a 28 ; i, 4, 188a 15 ; 7, 190b 8 ;
ii, 9, 200a 26 ; i, 7, 191a 9 ; ii, 1, 193a 14 ; i, 7, 190b 17 ; ii, 3, 194b 25 ; de
Part. An., i, 5, 645a 34 ; ii, 1, 646a 27 ; i, 1, 640b 23 ; de Gen. An., i, 21, 729b 17 ;
ii, 6, 743a 25. (15) Phys., v, 1, 225a 20; Met., xi, 11, 1067b 31 ; Phys.,

ii, 1, 192b 14 ; v, 1, 225b 7 ; v, 2, 226a 24 ; vii, 2, 243a 6 ; viii, 7, 260a 26 ;
de Ccelo, iv, 3, 310a 23 ; de An., i, 3, 406a 12 ; Met., xi, 12, 1068* 9 ; Aristotle
is not always consistent in this verbal usage : — Phys., iv, 10, 218b 19 ; iii, 1,
200b 32 ; 201a 11 ; viii, 7, 261a 33 ; de Ccelo, i, 2, 315a 26 ; etc. (16) Met.,

vii, 13, 1038b 5 ; ix, 7, 1049a 28 ; de Gen. Corr., 324a 15-19.

Facts and Factors of Substantial Change :— (17) de Gen. Corr., i, 2, 315b
15 ; i, 3, 319a 10 ; ii, 4, 331a 12 ; i, 3, 318a 13. (18) de Gen. Corr., i, 10,

327b 31 sqq. ; ii, 7, 334a 26 ; i, 10, 328a 3 sqq. ; ii, 7, 334b 28 ; ii, 7, 334b 2 ;
334b 8 ; i, 10, 327b 22 ; de Hist. An., i, 1, 486a 5 ; de Part. An., ii, 1, 647a 2 ;
ii, 10, 655b 37 ; de Ann., ii, 1, 412a 27. (19) De Gen. Corr., i, 9, 327b 10 ;

1, 13, 328» 23 sqq. (20) Cf. the references in Notes to Chapter ii., no. (32).
(21) This medieval usage of the term " primordial matter " is not found in
Aristotle's text. So far as I know, there are but two passages that seem to
countenance it : Met, viii, 4, 1044a 15 ; de Gen. Corr., ii, 1, 329* 25. Ordinarily
Aristotle uses this term, Trpwr?? v\r/, in a totally different meaning. Primordial
matter, in his usage, means that elementary body — or bodies — which is farthest
distant in reference to any compound body : the four elements are the " pri
mordial matter " of a statue. In contrast with this meaning of primordial
matter, he speaks of a proximate matter, eVxarTj v\-r) : this proximate matter
is matter that unites itself immediately and without requiring further change
with a special form ; stone or brass is the proximate matter of a statue.
(Cf. Met., viii, 4, 1044b 2 ; 6, 1045b 18 ; ix, 7, 1049a 25 ; xii, 3, 1070a 20 ;
Meteor., iv, 2, 379b 20 ; de An., ii, 2, 414a 26.) But Aristotle is not consistent
in this usage : either phrase is sometimes employed in the opposite meaning.
(Cf. Met., v, 5, 1015a 7 ; xii, 2, 1069b 35.) These verbal inconsistencies do but
illustrate, in regard to one pair of terms, the verbal confusion that reigns in our
present Aristotelian text regarding many important words. Happily, the
meaning is rarely obscured by such inconsistencies. (22) de Gen. Corr.,
ii, 9, 335a 24 sqq. ; i, 5, 320a 13 ; Met., ix, 8, 1050b 12 ; xii, 6, 1071b 18 ; xiv,

2, 1088b 19 ; vii, 7, 1032* 20 ; 17, 1041b 7 ; 15 ; 1039b 29.

Primordial Matter :— (23) Met., vii, 3, 1029a 20 ; Phys., i, 9, 192a 31 ;
i, 7, 191a 10. (24) Met., xiv, 1 ; xiv, 4, 1091b 30 ; xii, 10, 1075a 22 ; ix, 6,

1048a 30 ; 8, 1050a 21 ; vii, 3, 1029a 20 ; 11, 1037a 27 ; ix, 7, 1049a 24 ; iv, 4,
1007b 28 ; Phys.. i, 6, 189a 20 ; 9, 192a 16 ; iv, 9, 217a 22 ; i, 9, 192a 28 ; i, 7,
191a 7 ; iii, 1, 201a 29 : iv, 2, 209b 9 ; de Gen. Corr., i, 10, 328b 10 ; ii, 9, 335a
32 ; de An.'n,\, 412a 6 ; 2, 414a 9 ; de Ccelo, iii, 8, 306b 17. (25) Baeumker,

282 NOTES

Das Problem, etc., p. 247 sqq. ; Hertling, Materie und Form und die Definition
der Seele bei Aristoteles, Bonn (1871), p. 87 sqq. (26) Met., viii, 2, 1042a

23 ; i, 4, 985b 10 ; 9, 992b 1 ; viii, 1, 1042* 13 ; vii, 3, I029a 23 ; viii, 4, 1044*
15 ; ix, 7, 1049a 35 ; 8, 1050b 27 ; xiii, 2, 1077a 35 ; viii, 1, 1042a 26 ; 2, 1042b
9 ; de Gen. Corr., i, 5, 321b 19 ; i, 3, 317b 23 ; Phys., ii, 2, 194a 12 ; 8. 199a 30 ;
i, 7, 191a 8 ; de Gen. Corr., i, 6, 322b 19 ; Met., v, 4, 1015a 13. (27) de Ccelo,

iii, 6, 305a 22 ; de Gen. Corr., i, 5, 320b 23 ; ii, 1, 329a 33 ; ii, 1, 329a 8 ; 2,
329b 17 sqq. ; de An., ii, 11, 423b 28 ; da Part. An., ii, 1, 646a 16 ; 647a 18 ;
de Ccelo, iii, 6, 305a 22 sqq. (28) de Gen. Corr., i, 3, 318a 23 ; i, 3, 319a

5 sqq. ; i, 5, 320b 16 ; ii, 1, 329a 10 sqq. ; Phys., iii, 8, 208a 8 ; iv, 2, 209b 22 ;
4, 212a 1 ; 7, 214a 14 ; ii, 1, 193b 3 ; Met., vii, 3, 1029a 27 ; 10, 1035a 8 ; 11,
1036b 23 ; 12, 1038a 5. (29) de Gen. Corr., i, 7, 324b 18 ; ii, 9, 335b 29 ;

i, 7, 324b 5 ; 324a 34 ; i, 10, 328a 19 ; ii, 9, 335b 24 ; Met., i, 3, 984* 21 ; ii, 6,
1071b 29 ; de Gen. An., ii, 6, 743a 26. A number of texts seem at first sight to
deny the passivity of primordial matter. The solution of this difficulty is that
these texts do not refer to primordial matter. " Matter " as a physical reality
has for Aristotle at least three meanings : (a) primordial matter or the " matter "
of substantial change ; (6) an existing substance or the " matter " of accidental
change ; (c) the patient as opposed to the agent — a slight variant of (6) for the
purpose of treating causal problems. Whenever there is question of active
power of force in " matter," the reference is to either (b) or (c). Cf. Baeumker,
Das Problem, etc., p. 266 sqq. ; Mansion, Introduction a la Physique Aristoteli-
cienne, pp. 123 sqq. ; Werner, Aristotle et Vldealisme Platonicien, pp. 91 sqq. ;
Piat, Aristote, pp. 35 sqq. (30) de Gen. Corr., i, 3, 319a 33 ; 5, 320b 12 ;

ii, 4, 33 la 12 sqq. ; i, 3, 318a 13 ; Met., viii, 4. 1044a 15 ; Phys., iv, 9, 217a 25 ;
de CcKlo, iii, 1, 298b 9. (31) Phys.. iii, 6, 206b 14 ; iii, 4, 203b 18 ; 8, 208a 8 ;

de Gen. Corr., ii, 10, 337s1 5 : Anal Post., ii, 12, 95b 38. (32) Phys., i, 9,

192a 25 sqq. ; Met., xii, 3, 1069b 35 ; vii, 8, 1033a 28 ; viii, 1, 1042a 26. (33)

de Gen. Corr., ii, 5, 332a 35 ; Phys., iii, 6, 207a 25 ; i, 7, 191a 7 ; Met., vii, 10,
1036a 8 ; 1035a 8 ; 15, 1039b 27. (34) Phys., i, 9, 192a 17 ; ii, 1, 192b 18 ;

Met., xii, 7, 1072b 3 ; v, 23, 1023a 8 ; v, 5, 1015a 26 ; v, 23, 1023a 17 ; xii, 7,
1072b 12. (35) Met., vii, 8, 1034a 5-8 (the first quotation) ; vii, 10, 1035b

33 ; 1036a 6 ; 1036a 28 ; 15, 1039b 23 ; viii, 1, 1042a 28 ; i, 6, 988a 3 ; xii, 5,
107 la 27 (the second quotation) ; x, 9, 1058a 34 sqq. Hertling's contention
that the substantial form in Aristotle must be in itself an individualised reality
is ablv discussed by Zeller, Aristotle and the Earlier Peripatetics, vol. i, pp. 369
sqq. " (36) Met., xii, 3, 1070a 21 ; vii, 8, 1033a 28 ; de An., ii, 4, 415a 25 sqq. ;
de Gen. An., ii, 1, 731b 31.

Substantial Form :— (37) de An, iii, 3, 427a 17 ; 428a 17 ; ii, 5, 417b 22 ;
Top., v, 2, 130b 15 : 3, 131a 23 ; 4, 133b 29 ; 5, 134b 16 ; vi, 8, 146b 1 ; An.
post., i, 8, 75b 24 ; i, 2, 7lb 15 ; 4, 73a 21 ; 6, 74b 6 ; 31, 87b 28 ; 18, 81b 6 ;
i, 24, 86a 29 ; 31, 87b 37 ; 31, 87b 32; ii, 12, 96a 8 ; i, 8 ; 24, 85b 15 ; 24, 86a 4 ;
Met., iii, 4, 999b 4 ; vii, 15, 1039b 30 ; xii, 1, 1069b 3 ; vii, 10, 1036a 6 ; 15,
1040a 2 ; 1039b 27 ; xiii, 10, 1086b 33 ; 9, 1086° 5 ; i, 2, 982a ; iii, 4, 999a 28 ;
6, 1003a 14 ; xi, 1, 1095b 25 ; 2, 1060b 20. (38) Met., i, 9, 990b 10-30.

(39) Met., i, 9, 991a 9-991b 7. (40) Met., i, 9, 990b 1. (41) Met.,

xiii, 9, 1086b 2 ; 4, 1078b 30 ; vii, 13, 1038b 11 ; iii, 4, 999b 34 ; v, 9, 1017b 35 ;
8, 1017b 13 ; vii, 3, 1028b 36 ; de Interpret.. 7, 17a 39 ; Anal. Post., i, 4, 73b
26 ; 31, 87b 32 ; Anal. Post., i, 11 ; i, 27, 43a 35 ; de Part. An., i, 4, 644a 27 ;
Cat., c. 5. (42) Met., vii, 6, 1031b 6 ; viii, 1, 1042* 29 ; iv, 4, 1007a 23 ;

x, 9, 1058b 1 ; vii, 8, 1033b 14 ; 9, 1034b 8 ; viii, 3, 1043b 17 ; 5, 1044b 22 ;
xii, 3, 1069b 35 ; 1070a 15 ; vii, 8, 1033a 34 ; xii, 3, 1070a 2 ; vii, 15, 1039b
20; vii, 9, 1034b 13 ; xii, 11, 1067b 9 ; de Ccelo, i, 9, 277b 30 sqq. ; de Gen.
Corr., ii, 9, 335b 7 ; 335b 35 ; Phys., v, 1, 224b 4. (43) de An., ii, 4, 415b

10 sqq. ; de Part. An., i, 1, 641a 27 ; i, 5, 645b 14; Phys., ii, 1, 193b 8 ; 2,
194b 13 ; 7, 198a 26 ; iii, 2, 202a 11 ; de Gen. Corr., i, 5, 320b 20 ; ii, 6, 333b 7 ;
de Part. An., i, 1, 640a 25 ; ii, 1, 646a 33 ; de Gen. An., ii, 1, 735a 21 ; Met.,
vii, 7, 1032a 25 ; 8, 1033b 32 ; 9, 1034b 2 , xii, 3, 1070a 8 ; 4, 1070b 31 ; xiv,

5, 1092a 16 ; Phys., i, 7, 190b 6 ; 191a 9 ; ii, 3, 194b 25 ; 195a 6 ; 195b 8 ; iii,

6, 207a 28 ; Met., v, 2, 1013a 25 ; 1013b 27 ; 4, 1014b 29 ; vii, 3, 1029a 4 ; 10,
1035a 6 ; ix, 7, 1049a 18 ; and in numerous other texts of the Phys., the Met.,
the de Part. An. and the de Gen. An. (44) de An., ii, 1, 412b 4. (45)
Phys., ii, 7, 198a 24 ; i, 7, 190b 17 ; ii, 8, 199a 30 ; ii, 9, 200a 14 ; de An., ii,

NOTES 283

4, 415b 7 ; i, 1, 403b 6 ; Met., xii, 5, 1071* 18 ; viii, 4, 1044b 1 ; vi, 2, 1026b
13 ; 1032b 11 ; de Gen. An., i, 1 ; ii, 1, 732* 3 ; 6, 742* 28 ; ii, 4 740b 28 • de
Part. An., i, 1, 639b 14 ; i, 1, 641* 25 ; i, 1, 640a 31 ; de Gen. Con., ii, 9, 335b
5 ; 335b 33 ; 35 ; i, 7, 324a 34 ; i, 7, 324b 15. (46) Met., vii, 3 1029* 5 •

1029* 27 ; v, 4, 1015* 13 ; Phys., i, 9, 192* 5 ; 192b 20 ; ii, 1, 193* 36 • ii 2
194* 28 ; i, 9, 192* 16 ; de Ccelo, i, 2, 268b 16 ; iii, 5, 304b 13 ; de Part An '
i, 1, 640b 28 ; 642* 17 ; de Gen. Corr., ii, 9, 335b 34 ; de Gen. An., ii, 1, 732* 3.
(47) Met., vii, passim ; v, 8, 1017b 21 ; vii, 4, 1030* 6 ; 1030b 26 ; v, 13, 1020*
18 ; vii, 6, 1031* 18 ; 1031b 2 ; 7, 1032b 2 ; 1032b 14 ; viii, 1, 1042* 18 ; viii,

3, 1043b 1 ; i, 3, 983a 27 ; viii, 4, 1044* 36 ; i, 10, 993* 17 ; iii, 2, 996b 8 ; vii 7
1034* 30 ; vii, 7, 1032* 15 ; de Gen. Corr., ii, 9, 335b 6 ; Phys., ii, 3, 194b 26 ;

7, 198* 16 ; ii, 1, 193* 31 ; 2, 194* 20 ; 194b 10 ; 194b 26 ; 200* 14 ; 200* 34 •
200* 22 ; ii, 7, 198b 3 ; ii, 7, 189* 16 ; de Ccelo, i, 9, 277b 30 ; ii, 8, 289b 21 ;
de An., i, 1, 403b 2 ; ii, 2, 414* 9 ; de Part. An., i, 1, 642* 17 ; 641* 25 ; 640b
28 ; iii, 2, 663b 23 ; iv, 5, 678* 34 ; i, 1, 642* 25 ; i, 1, 639b 26-640* 6 ; 640*
31 ; ii, 1, 646* 35-b28 ; Post. Anal., ii, 11. 94* 21 ; de Gen. An., i, 1, 715* 5 ;
iv, 2, 767* 16 ; Meteor., iv, 2, 379b 25 ; 379b 35 ; de Somno, 2, 455b 16 ; Post.
Anal., ii, 3, 90b 30 : Top., vii, 5, 154* 31 ; 4, 101b 21 ; 7, 103* 25 ; i, 5, etc.,
etc. Cf. Bonitz, Index Arist., under these titles. (48) Phys., iii, 7, 207*
35 ; i, 1, 193b 6 ; iv, 2, 209b 1 ; 4, 21 lb 10 ; de An., ii, 1, 412* 9 ; ii, 2, 414* 9 ;
de Gen. Corr., i, 4, 320* 2 ; 10, 328b 11 ; de Ccelo, iv, 4, 312* 12 ; Met., x, 4,
1055* 29 ; viii, 2, 1042b 9. (49) Phys., iv, 2, 209b 23 ; de Gen. Corr., i, 7,
324b 18-22. (50) Met., iv, 4, 1007* 23 ; x, 9, 1058b 1. (51) Phys.,
ii, 7, 198* 24 ; i, 7, 190b 17 ; de An., ii, 4, 415b 7 : Met., xii, 5, 1071* 18 ; viii,

4, 1044b 1 ; De Gen. An., ii, 1, 732* 3 ; ii, 6, 742* 28 ; Met., ix, 6, 1048* 30 ;

8, 1050a 21 ; Phys., i, 7, 191* 7 ; iii, 1, 201* 29 ; ii, 3, 195* 8 ; Met., ix, 8, 1049b ;
vii, 9, 1034b 16. (52) Phys., ii, 7, 198a 25 ; viii, 2, 252b 24 ; 8, 199* 30 ;
de An., ii, 4, 415b 7 ; ii, 1, 412* 15 ; de Part. An., i, 1, 640b 22 sqq. ; 5, 645b
14 ; de Gen. An., i, 1, 715* 4 ; ii, 4, 738b 26 ; Met., vii, 8, 1033b 29 ; viii, 4,
1044a 36 ; 1044b 1 ; ix, 8, 1050* 8 ; de Gen. Corr., ii, 9. (53) Met., xii, 5,
1071* 27. (54) Met., xii, 3, 1070* 23. (55) Met., vii, 8, I033b 14;

9, 1034b 8 ; viii, 3, 1043b 17 ; 5, 1044b 22 ; xii, 3, 1069b 35 ; 1070* 15 ; vii, 8,
1034* 8 ; xi, 9, 1058b 9 ; iii, 3, 998b 28 ; x, 8, 1058* 18 ; 9, 1058b 8 ; vii, 8,
1034* 5 ; ix, 7, 1049* 23 ; i, 6, 988* 1 ; de Ccelo, i, 9, 278* 18. (56) Met.,
xii, 5, 1071* 27 ; 3, 1070* 21 ; de An., ii, 4, 415* 25 ; de Gen. Corr., ii, 1, 731b
31 ; Met., vii, 8, 1033* 28 ; de Gen. An., ii, 1, 731b 31. (57) Met., vii,
cc. 7, 8, 9 ; xii, cc. 3, 4 ; Phys., i, c. 4. (58) Cf. Chapter ii, notes (37) and (38).

Substance and Attribute :— (59) Phys., i, 9, 192* 13-25. (60) Met.,

viii, 6, 1045b 17-20 ; de An., ii, 1. (61) Met., viii, 3, 1043b 4-23 ; cf. Bonitz,

Aristotelis Metaphysica, pp. 367-368. (62) Aristotle extends the application

of these concepts, matter and form — and their synonyms, potency and actuality
— beyond the sphere of physical change. " Aristotle goes on to speak of
(intelligible) matter which he finds, for example, in conceptions and in mathe
matical figures. To this belongs whatever, without being itself corporeal,
stands to something else in the same relation as corporeal Matter (i.e. the
Matter of bodies) stands to Form. Hence we see that not only does each of
these notions denote a single existence or definite class of things, but they
are used, though undoubtedly obtained in the first instance by abstraction
from corporeal things, wheresoever a relation subsists analogous to that which
they originally express. Thus in analysing conceptions into their two elements,
Aristotle attributes to the genus the same significance as Matter while he
identifies the specific difference with the Form. Similarly in the scheme of
the universe, in physiology, in zoology, in psychology, the upper and the lower
spheres and elements, the soul and body, the male and female, the Active and
Passive Reason, stand to one another in the same relation as the Form and
the Matter. The same is true, it need hardly be remarked, of Potency and
Actuality. These also express a definite relation which may subsist between
all possible kinds of objects, and which can best be explained by analogy.
Aristotle applies them in precisely the same way as Matter and Form. He
uses them, for instance, to elucidate the connexion between the genus and the
specific differences, and in general to show the possibility of several properties
belonging to one and the same thing. By them he explains the relation between
the passive and the active understanding. It follows that one and the same

284 NOTES

thing may be viewed in one aspect as Matter, in another as Form ; as Potency
in the first, as Actuality in the second. The elements, for instance, which
contain the material of all other bodies, are Forms of the primitive Matter ;
the brass which supplies the material for a statue has its own peculiar Form as
a specific metal. While the soul in general is viewed as the Form of the body,
yet even in its own highest and most immaterial part a distinction is made
between two elements which are related to one another as Form and Matter.
Indeed, we shall find that everything except the ' eternal immaterial substances '
contains some element of Matter, while on the other hand, as we already know,
Matter never actually presents itself to us except as endowed with Form. We
may therefore distinguish several stages in the development of Matter into
Form. The first purely formless Matter lies at the foundation of all things :
but it is also true that everything has its own peculiar and intimate Matter.
Between these two lie all the material foundations through which the original
Matter has to pass before it becomes the particular Matter with which the
Form of the thing immediately unites itself. The same holds true of SiW^uis.
We ascribe potential knowledge not only to the man of learning when he is
conceived as not actually engaged in scientific activity, but also to the learner,
and even to man in general. But the sense in each case varies, and we have to
distinguish between the degrees of proximity to ivepyfia. Nothing attains
the realisation of that which it had at first the mere capacity to be, except by
degrees : and in the universe at large there are an infinite number of inter
mediate stages between mere Potency or the first Matter, and complete Actuality,
which is pure Form or God." Zeller, Aristotle, and the .Earlier Peripatetics, i,
pp. 352-355, where all references are given. (63) Met., v, 30, 1025a 30 ;

7, 1017a 12 ; iii, 1, 995b 18 ; 2, 997a 25 ; iv, 2, 1004b 5 ; vi, I, 1025b 12 ; vii, 4,
1029b 13 ; Anal. Post., i, 22, 83b 11 ; i. 4, 73b 5 ; i, 6, 75a 18 ; i, 7, 75a 42 ;
Phys., i, 3, 186b 18 ; ii, 2, 193b 26 ; 3, 195b 13 ; iii, 4, 203b 33 ; de An., i, 1,
402b 16 ; cf. Joseph, Introduction, etc., pp. 61 sqq. ; Zeller, Aristotle, etc.,
vol. i, pp. 223 sqq. (64) Met., vi, 2, 1027a 13 ; vi, 3, 1027b 15 ; x, 9, 1058a

34 ; viii, 4, 1044b 12 ; de Gen. An., v, 1, 778a 32 sqq. ; 8, 789b 20 ; i, 18, 725a 4 ;
Phys., ii, 8, 198b 18 ; de Part. An., iv, 2, 677a 15 ; iii, 2, 663a 6 sqq. (65) de

Gen. Corr., i, 5, 320b 16 ; 320b 22 ; 320b 32 ; de An., ii, 11, 423a 21 ; Phys.,
iv, 9, 217a 26. (66) de Gen. Corr., i, 5, 322a 10-28 ; 321a 2-20 ; 321b 22-34 ;

iv, 2, 335a 15 ; Phys., iv, 2, 209b 8 ; de An., ii, 4, 416b 11. (67) Phys.,

iv, 9, 217a 31 sqq'. ; cf. Chapter viii— Density and Rarity. (68) Met.,

viii, 6, 1045a 8-12 ; v, 6 passim ; Phys., v, 3, 227a 10 sqq. ; vi, 1, 231a 20 sqq. ;
de Gen. Corr., i, ix, 327a 18.

Post-Aristotelian Greek Theories of Matter : — For a detailed account
of Aristotle's Greek successors in Cosmology consult : Baeumker, Das Problem,
etc., p. 303 sqq. ; Zeller, Stoics, Epicureans and Sceptics ; Whittaker, The
Neo-Platonists.

Palmieri (Institutions Philosophicce, vol. ii, pp. 128 sqq.) contrasts two
theories of hylemorphism : the " vague " and the " explicit." " Explicit "
hylemorphism teaches that neither primordial matter nor substantial form is a
complete substance and that material substance in the genuine sense arises
only from the union of these distinct positive principles : and as a result of
this false starting-point, it teaches all sorts of reprehensible doctrines about the
nature and properties of primordial matter and substantial form. " Vague "
hylemorphism teaches that " matter " and " form " are simply different aspects
of actually existing bodies : that " matter " is a complete substance or a group
of them and " form " the disposition and arrangement of them ; and as a result
of this valuable starting-point, it teaches conclusions which differ only verbally
from those of modern dynamism and atomism. Having invented this distinc
tion between " vague " and " explicit " hylemorphism, Palmieri proceeds to
prove that, while the later Schoolmen certainly advocated " explicit " hyle
morphism, Aristotle propounded nothing but " vague " hylemorphism. This
is sheer mythology. At this stage of our inquiry, there can be no need of
pointing out the chasm between this thesis and the text of Aristotle. The
reader who wants a documented criticism of details may consult Fr. de San
S.J. Cosmologia (pp. 164 sqq.). Palmieri makes his myth plausible by equivo
cation concerning a few texts, and by wholesale suppression of the majority of
pertinent texts. He tells his readers that Aristotle speaks of primordial matter

NOTES 285

as substance : he does not tell them that Aristotle makes perfectly clear the
special meaning in this reference of substance, that he contrasts this meaning
with the proper meaning of substance, and that he denies primordial matter
to be substance in the proper sense. He tells his readers that Aristotle speaks
only of " sensible subjects " as ceasing to persist during substantial change ;
he does not tell them that Aristotle denies the existence of material substances
other than " sensible subjects," and proves the incorporeality of primordial
matter. He tells his readers that Aristotle sometimes speaks of one and the
same substance as " matter," as " form," and as a composite whole : he does
not tell them that Aristotle acknowledges in the use of these terms " matter "
and " form " a wide relativity based on the analogy of their respective roles as
factors of change. He tells his readers that Aristotle teaches there can be no
generation of " form " ; he does not tell them that Aristotle insists on the
coming into existence of a new substantial form whenever generation of sub
stance occurs, and on the passing out of existence of an already existing substan
tial form whenever corruption of substance occurs. In view of this manipulation
of the Aristotelian text, it is clear that the only readers who can accept this
thesis of Palmieri are those who never consult the text of Aristotle. The his
torical facts are : Aristotle fought " vague " hylemorphism tooth and nail —
read his criticism of Empedocles and of Democritus ; Aristotle exulted in
" explicit " hylemorphism as the last word in Cosmology — read the positively
indecent psean of self-praise (Met., xii, c. 10) which he chants over his discovery
of primordial matter and substantial form. These historical facts are proclaimed
by every authoritative commentator : ancient or modern, pro- Aristotelian or
an ti- Aristotelian. Aristotle's philosophy of matter may be true or false but
there is no shirking the issue that part of his fame as a cosmologist stands or
falls by his advocacy of what Palmieri styles " explicit " hylemorphism and his
rejection of what Palmieri styles " vague " hylemorphism.

CHAPTER V.

THE noteworthy Realist writers among the Schoolmen from the thirteenth
century onwards were : Alexander of Hales (+ 1245), St. Bonaventure (1221-
1274), Roger Bacon (1214-1294), Albert the Great (1193-1280), St. Thomas
(1225-1274), Giles of Rome (Aegidius) (1243-1316), Herve (Hervaeus) of Nedellec
( + 1323), Henry of Ghent (+ 1293), Scotus (1266/74-1308), Francis of Mayron
( + 1327), Antony Andreas ( + 1320), John Canonicus (fl. 1320), John Bassolius
(fl. 1320), Peter de Palude (+ 1342), Durandellus (+ 1380), Walter Burleigh
( + 1337), John Capreolus (1380-1444), Dominic of Flanders (+ 1500), John
Gerson (1364-1429). Thomas of Strasburg (+ 1357), Denis the Carthusian
(1402-1471), Soncinas ( + 1494), Cajetan (1469-1534), Francis a Sylvestris
(Ferrariensis) (1474-1528), Javellus (1488-1550), Soto (1494-1528), John of
St. Thomas (1589-1644), Vasquez (1551-1604), Toletus (1532-1596), Fonseca
(1528-1599), Suarez (1548-1617), Cosmo Alemanni (1559-1634), Sylvester Maurus
(1618-1687), Goudin( 1639-1695), Claudius Frassen (1620-1711), Soares (fl. 1650),
Aquirre (fl. 1670), Mastrius de Meldula (fl. 1698). Besides these individual
authors, there were famous group-writers like the Complutenses, the Conimbri-
censes, the Salmanticenses, the Salisburgenses. Nor can an Irishman forget
the Franciscan Commentators of the Lyons edition (1639) of Scotus: Lucas
Waddingus, Waterfordiensis ; Mauritius a Portu (an O'Fihilly, Archbishop
of Tuam) ; Hugo Cavellus (a Caughwell, Archbishop of Armagh) ; Joannes
Poncius, Corcagiensis ; Antonius Hiquaeus, Tuomoniensis ; Franciscus Lychetus,
Brixiensis ; Franciscus Pitigianus Arretinus.

The great medieval nominalist philosophers were : the Dominican Durandus
of St. Pourcain, a Bishop ( + 1322) ; the Franciscan Peter d'Auriol, a Cardinal
(+ 1321) ; William of Ockham (+ 1347) ; Gregory of Rimini (+ 1358) ; Peter
d'Ailly, a Cardinal (+ 1420); Marsilius of Inghen (+ 1396), John Buridan
(+ 1360) ; Albert of Saxony (+ 1390) ; Gabriel Biel (1430-1495).

Aristotle is generally quoted in these medieval chapters after the fashion
of the School : in such quotations, 1. stands for book, c. for chapter, t. for text.

The Commentaries of the Schoolmen on the Four Books of the Sentences of
Peter Lombard (+ 1160) are also quoted after a medieval usage : thus, Scotus>

286 NOTES

4, dist. (or d.) 12, q. 2 stands for, Scotus on the fourth Book of the Sentences, twelfth
distinction, second question.

As the chapters on Medieval Cosmology in this volume are mainly an
exposition of Thomistic Cosmology and the controversies consequent thereon,
I wish to draw the reader's attention here to the value of the various works of
St. Thomas that are quoted. Setting aside all the Commentaries on Scripture
as extraneous to my purpose, the authentic treatises of St. Thomas are given in
the official catalogue (1319) as follows: Quatuor libri super Sententias ; Tres
partes Summae ; De quaestionibus disputatis, partes tres ; Undecim quodlibet
disputata ; Opus contra Gentiles — quatuor libri ; Super Dionysium De divinis
nominibus ; Super Boethium De hebdomadibus ; Super Boethium De Trinitate ;
De fide et spe ; Super primum Perihermenias ; Super librum Posteriorum ; Super
librum Physicorum ; Super libros De Caelo tres ; Super librum De Generations ;
Super duos libros Metheororum ; Super secundum et tertium De Anima ; Super
librum De Sensu et Sensato ; Super librum de Memoria et fteminiscentia ; Super
librum De Causis ; Super Metaphysicam ; Super librum Ethicorum ; Super
Politicam, libri quatuor. The authentic opuscules of St. Thomas are given in the
official catalogue as follows : Contra impugnantes Dei cultum et religionem ; De
operationibus occultis ; Item — in quibus potest homo licite uti judicio astrorum ;
De principiis naturae ; De substantiis separatis ; De. rationibus fidei ; De per-
fectione vitae spiritualis ; Contra doctrinam retrahentium a religione ; De sortibus ;
De forma poenitentiae absolutions sacramentalis ; Contra errores Graecorum ;
Declaratio triginta sex quaestionum ; De regimine ludaeorum ; Declaratio triginta
trium quaestionum ; Declaratio sex quaestionum ; De ente et essentia ; De mix-
tione elementorum ; De motu cordis ; De, unitate intellectus ; De aeternitate
mundi ; Expositio circa Primam decretalem De Fide catholica et Summa Trini
tate ; Expositio circa secundam Damnamus ; De articulis fidei et sacramentis
Ecclesiae ; Brevis compilatio theologiae. All these treatises and opuscules were
written by St. Thomas. His Lectura Super primum de Anima has come to us
in notes taken down by Raynaldus de Piperna from St. Thomas's oral lectures
on that book. The other works generally ascribed to St. Thomas are of more or
less doubtful authenticity. Some of these doubtfully authentic works are
quoted in the notes to this volume, but it will be found that no view is attributed
to St. Thomas except when found in one, or more, of the certainly authentic
writings of the Saint. Cf. Mandonnet, Des ecrits authentiques de Saint Thomas
d'Aquin, Revue Thomiste, 1909, March- April, sqq. ; De Wulf, Histoire de la
Philosophic Medievale, 1912, pp. 401-402.

The Proofs of Hylemorphism :— (1) St. Thos. 2, d. 30, q. 2, a. 2 ; de Verit.,

?. 13, a. 3, lm. (2) Aristotelian texts quoted in favour of this composition :

de Ccelo, c. 9. tt. 93, 94, 95 ; 12 Met., t. 22 ; 2 de Gen., c. 9, t. 51 ; 8 Met.,
t. 10. Texts quoted against it : 8 Met., tt. 4, 12, 14 ; 9 Met., t. 17 ; 12 Met.,
t. 10. (3) St. Thomas, S. Th., 1, q. 66, a. 2 ; 1 de Ccelo, lect. 6 ; 8 Phys.,

lect. 20 ; Capreolus, 2, dist. 12, q. 1 ; Socin., 12 Met., q. 7 ; Javel, 1. 8, q. 12 ;
Soto, Phys., q. 1 ; Scotus, 2, dist. 14, q. 1 (on theological grounds) ; Aegidius,
2, dist. 2 ; do., 1 part., Hexam., c. 4 ; Ockham, in 2, q. 22 ; St. Bonaventure,
2, dist. a. 2, q. 1 ; Avicenna, 1. 1 Suffic, c. 6 ; Conimbr., de Ccelo, 1, c. 2, q. 4,
a. 2 ; Aquirre, de Ccelo, d. 63, s. 1. The remark of the Nominalist, Marsilius
of Ingen (in iv, 1. 2, q. 8) that the contrary opinion was common in his time,
late fourteenth century, is difficult to reconcile with extant sources. Of the
thirteen great writers of that century only four, three of whom including
Marsilius himself are Nominalists, advocate that opinion. And in the seven
teenth century, Pontius, whilst denying that reason supports the hylemorphic
composition of the heavenly bodies,* allows that the number and authority of
the " Doctor es " make it the more probable theory. Cursus Phil, disp. 51, q. 1.
(4) de Ccelo, 1, lect. 6 ; S. Th., 1, q. 66, a. 2 ; Phys., 1, 8, lect. 21 ; de Angelis,
c. 8. At an earlier period of his life, St. Thomas was not so convinced of this
opinion : cf. Spirit. Great., a. 6, ad. 2 ; 2, d. 12, q. 1, a. 1, ad. 5. (5) Sent.,

2, d. 13, a. 2, q. 1. (6) Sent., 2, d. 12, q. 3, a. 3. (7) Disp. Met., d. 13,

s. 10, n. 8.

Primordial Matter— What it is not :— (8) St. Thos., 1 Met., lect. 12 ; 2 de
Gen., lect. 4 ; Suarez, D. M ., d. 13, ss. 2, 3 ; Pontius, Curs. Phil, d. 32, n. 6 ;
Scotus (?), Phys., 1, qq. 17, 18, 19, 20 ; Fr. Pitigianus in Scot. Phys., 1, qq. 17-20 ;
Scotus, Met., 1, s. 3 ; Cavellus, in Scot. Met., 1, s. 3. (9) De Gen., ii,

NOTES 287

tr. i. c. 4. (10) St. Thos., 1 Met., lect. 4 ; 1 Phys., lect. 9 ; 1 Met., lect. 7 ;

1 de Gen., lect. 1 ; 1 de Gen., lect. 22 ; Suarez, D.M., d. 13, s. 2. (11) St.

Thos., 7 Jfe«. lect. 12 ; S. Th., 1, q. 76, aa. 3, 4 ; contra Gentes, ii, c. 58 ; Capreo-
lus, in 2, dist. 15, q. 1 ; Cajetan on Summa as quoted ; do., 2 de ,4tt., c. 1 —
and all the Thomists ; Suarez, D.M., d. 13, sec. 3, n. 13, etc. ; in reference to
non-living bodies, Scotus in 4, dist. 11, q. 3, a. 2 ; Henricus, Quodlibet, i, qq. 2,
3 ; do., Quodlibet, 3, qq. 13, 14 — and all their followers. (12) In 4, dist.

12, q. 1, a. 2 ; de Nat. Mat., cc. 1, 4, 5, 6, 7 ; S. Th., i, q. 76, a. 6, ad. 1 and 2 ;
de Spir. Great., a. 3, ad. 19 and 20; de Gen., 1, lect. 10; S. Th., i, 2, q. 113,
a. 8 ; do., Quodl, i, a. 6, ad. 2 ; Scotus in 4, dist. 12, q. 2 ; Cavellus in Scot.,

4, dist. 12, q. 2 ; Suarez, D.M., d. 40, s. 2, n. 7.

Primordial Matter— What it is :— (13) Met. 7, lects. 2, 6 ; 1 Phys., lects.
11, 12, 15 ; 12 Met., lect. 2 ; 10 Met., lect. 5 ; 1 de Gen., lect. 20 ; etc. (14)

5. Th., i, q. 66, a. 1, ad. 3 ; 8. Th., i, q. 77, a. 1, ad. 2 ; i, q. 15, a. 3, ad. 3 ;
1 Phys., lect. 15 ; 2, contra Gentes, c. 55 ; S. Th., i, q. 66, a. 1 ; 8. Th., i, q. 84,
a. 3, 'ad. 2 ; 8. Th., iii, q. 75, a. 3 ; 4, d. 12, q. 1, a. 1 ; 4, d. 12, q. 3, ad. 1 ;
de Spir. Great., a. 2 ; de Princ. Nat. (about the middle) ; de Princ. Nat. (a few
lines from the beginning) ; de Verit., q. 3, a. 5, 3™ ; 3, d. 14, a. 4 ; S. Th., i, 4,
q., a. 1 ; de Spir Great., a. 1 ; de Verit., q. 3, a. 5, ad. 1 ; S. Th., i, q. 115, a. 1,
ad. 2 ; 1, d. 3, q. 4, a. 2, ad. 4 ; Quodl., ix, a. 6, ad. 3 ; de Princ. Nat. (the begin
ning) ; de Princ. Nat. (the middle) ; de Ente et Ess., c. 7 ; 7 Met., lect. 2 ; de
Verit., q. 3, a. 5, ad. ult. ; 1 Phys., lect. 13 ; de Malo, q. 2. (15) Raphael
Ripa, Comm. de Ente et Essentia, c. 2, q. 2. (16) de Gen., i, c. 3.

Origin and Unity of Primordial Matter:— (17) St. Thos., 1 de Gen.,
lect. 9 ; 2, dist. 2, q. 1, a. 2 ; 8. Th., 1, q. 16, a. 7, ad. 2 ; etc. (18) St. Thos.,

contra Gentes, 3, c. 22.

A War of Words :— (19) St. Thos., 8. Th., i, q. 44, a. 2, ad. 3 ; do., 8. Th.,
i, q. 45, a. 4 ; do., 8. Th., i, q. 46, a. 1 ; do., Quodl., 4, a. 1 ; do., Quodl., 3, q. 1 ;
Cajetan, de Ente, etc., c. 5, q. 8 ; do., i, q. 76, a. 1 ; Ferr., contra Gentes, 2,

c. 68 ; Soncin, Met., 7, q. 17 ; Javellus, q. 5 ; Durandus, 2, dist. 12, q. 2 ;
do., 4, dist. 44, q. 1 ; Complutenses, d. 3, q. 5 ; Aquirre, Phys., d. 5, s. 4.
(20) Scotus 2, dist. 12, qq. 1, 2 ; do., Met., 9, q. 1 ; do., de Rer. Princ., q. 7,
nn. 1, 3, 6, 7, 8 ; do. (?), Phys., 2, q. 7 ; do., Met., 8, q. 5, n. 3 ; do. (?), Phys.,
1, qq. 19, 20, 24 ; Suarez, D. M., d. 13, sec. 4. (21) Phys., i, d. 1, q. 2, a. 2.

The Distinct Existence of Primordial Matter :— (22) Suarez, D. M.,

d. 31, sec. 1 sqq. ; Aegidius, de Ente et Essentia, q. 9 sqq. ; Scotus, 3, dist. 6, q. 1.
(23) Henricus, Quodl, i, q. 10 ; do., Quodl, 4, q. 16 ; Scotus, 2, dist. 12, qq., 1, 2 ;
Gregory, 2, dist. 12, q. 1 ; Mastrius, Phys., disp. 2, q. 2, a. 2 ; Pontius, Phys.,
disp. 32, q. 4 ; Frassen, Phys., d. 1, sec. 1, q. 2 ; Suarez, D.M., d. 13, sees. 4, 5 ;
Fonseca, Mel, 8, c. 1, q. 1 ; Toletus, Phys., 1, q. 13 ; Conimbr., Phys., i, c. 9,
q. 6, a. 2. (24) For references see above, note (19). (25) Contra
Gentes, 2, c. 54. (26) D.M., d. 13, sec. 4, n. 14. (27) St. Thos., 8. Th.,
i, q. 66, a. 1 ; do., Quodl, 3, a. 1. (28) Scotus 2, dist. 12, q. 2 ; Suarez,
D.M., d. 15, sec. 9. (29) Phys., i, q. 6.

Possibility of Accidents in Primordial Matter :— (30) St. Thos., 7 Mel,
lect. 1 ; do., 8 Mel, lect. 5 ; do., 4, dist. 12, q. 1, a. 1, sol. 3 ; do., S. Th., i,
q. 76, a. 6 ; do., de Spir. Creal, a. 3, ad. 12 and 18 ; do., Q. d. de An., a. 9 ;
do., Ops., 31, 32 ; do., de Gen., 1, lects. 9, 10 ; do., Phys., 5, lect. 7 ; do., Quodl,
i, a. 6 ; do., de Gen., 2, lect. 4 ; do., Opus., 41 ; do., c. Gentes, 2, c. 71 ; do.,
4, dist. 10, q. 1, a. 2 ; do., Op., 30, cc. 5, 7 ; do., de Gen., i, lect. 7 ; do., S. Th.,
iii, q. 77, a. 2 ; do., i, dist. 8, q. 5, a. 2 ; do., 4, dist. 12, q. 1, a. 3 ; Cajetan,
de Ente, c. 7, q. 16 ; Durand, 1, dist. 8, 2 p., q. 4 ; Capreol, 2, dist. 13, q. 1,
concl. 2, 3 ; do., dist. 18, q. 1, concl. 6 ; Soncin, 8 Mel, qq. 7, 15, 17, 18 ;
Ferr., c. Gentes, 4, c. 81, qq. 2, 3 ; Soto, Phys., i, q. 7 ; Aquirre, Phys., disp. 49 ;
Fonseca, Mel, 8, c. 1, q. 1, sec. 5 ; Scotus, 2, dist. 3, q. 4, nn. 5, 17 ; Scotus, 4,
dist. 11, q. 2 ; Pontius, Phys., i, disp. 35, qq. 4, 5 ; Frassen, Phys., 2, disp. 1,
sec. 3, a. 1 ; Mastrius, de Gen., disp. 5, q. 3. (31) St. Thos., S. Th., iii,

q. 77, a. 1 ; do., S. Th., i, q. 76, a. 6 ; do., de Spir. Creal, a. 3, ad. 19 ; do.,
c. Gentes, 4, c. 81 ; do., de Gen., i, lect. 10. (32) St. Thos., S. Th., i, q. 45,

a. 4 ; do., i, dist. 8, q. 4, a. 3 ; do., de Princ. Nat. (33) de Gen., i, tt. 23,

24 ; Phys., i, tt, 81, 82 ; de Gen., i, t. 24 ; de Gen., 5, t. 8 ; Mel, 7, t. 8 ; Met.,
7, t. 4 ; 12 Mel, t. 43 ; in Prcedic., c. de Substantia. (34) St. Thos., 8. Th.,

288 NOTES

i, q. 76, a. 6. (35) de Gen., i, lect. 24 ; S. Th., i, q. 76, a. 4, ad. 4 ; c. Gentes,

4, c. 35 ; S. Th., iii, q. 2, a. 1. (36) Scotus, 2, dist. 15, q. u. (37)
Cajetan, S. Th., i, q. 76, a. 4 ; Durandus, 4, dist. 12, q. 3, ad. 2 ; Ferrarensis,
c. Gentes, 2, c. 45 ; do., 4, c. 81 ; Sonc, Met., i, q. 27 ; Javellus, Met. 8, q. 4 ;
Capreolus, 2, dist. 15 ; Bannes, de Gen., i, c. 10, q. 3. (38) Gregory, 2,
dist. 12, q. 2, a. 2 ; Marsilius, de Gen., i, q. 7 ; Aegidius, Met., 7, q. 4 ; Suarez,
M.D., d. 14, s. 3 ; Toletus, de Gen., i, q. 6. (39) John of St. Thomas,
Cursus Phil. Thorn., de Gen., q. 1, aa. 6, 7, also q. 9 ; Aguirre, Phil. Rat., disp.
49, 50, 51. The Scotists held that there was in living beings a bodyform (forma
corporeitatis), and in these cases denied the destruction at death of all the acci
dents : cf. Mastrius, Pontius, Frassen as quoted above in note (30). (40) St.
Thos., 3, d. 3, q. a. 2. (41) St. Thos., de Verit., q. 28, a. 8, ad. 7. (42)
St. Thos., de Verit., q. 28, a. 7, ad. 11. (43) St. Thos., de Verit., q. 28, a. 8 ;
do., 3, d. 13, q. 3, a. 1. (44) St. Thos., de Verit., q, 28, a. 9, ad. 5. (45)
John of St. Thos., C. P. Th. de Gen., q. 1. (46) St. Thos., de Verit., q. 29,
a. 1, ad. 10. (47) St. Thos., 8. Th., i, q. 76, a. 6, ad. 1. (48) St. Thos.,
Q. de An., a. 9. (49) St. Thos., de Spir. Great., a. 2. (50) St. Thos.,
de Spir. Great., a. 3. (51) S. Th., i, q. 77, a. 8. (52) St. Thos., Q. de
An., a. 19, ad. 2. (53) Cajetan in i, q. 77, a. 1 ; Capreolus, 1, dist. 3, a. 2 ;
John of St. Thos., Log., q. 15, a. 5 ; Complut., Log., d. 12, q. 5 ; Mastrius,
Log., d. 7, q. 1 ; Pontius, Log., d. 12, q. 3 ; Suarez, D.M., d. 14, sec. 4. (54)

5. Th., iii, q. 77, a. 2.

The Nature of Substantial Form :— (55) Comm., deEnte etEss., c. 5, q. 9.
(56) St. Thos., S. Th., i, q. 54, aa. 2, 3 ; do., de Spir. Great., a. 11 ; do., 8. Th.,
i, q. 67, a. 3, ad. 3 ; do., 2, dist. 13, a. 3, ad. 7 ; do., de Ccelo, 2, lect. 10 ; do.,
Phys., 7, lects. 3, 4 ; do., de Gen., i, lect. 18 ; etc., etc. ; Suarez, D.M., d. 15,
sec. 1.

The Unicity of Substantial Form in Non-living Bodies :— (57) deGen., i,
t. 84 ; de Gen., 2, t. 48 ; de Codo, 3, t. 32 ; de Gen., i, c. 10. (58) Avicenna,

1, Sufficient, c. 10 ; Averroes, de Gen., c. de Mixtione ; do., de Ccelo, 3, t. 87 ;
Albertus Magnus, de Ccelo, 3, tr. 2, cc. 1, 8 ; do., de Gen., i, tr. 6, cc. 2, 5, 6, 7,
11, 8 ; do., de Gen., i, tr. 5, c. 6; do., de Gen., 2, tr. 2, c. 15. Cf. de Barberis,
Cursus Philosophicus ad mentem S. Bonaventurae, iii, tr. 4, q. 6, no. 133. (59)
St. Bonaventure, 4, d. 49, p. 2, sect. 2, a. 1, q. 1 ; Aureolus, Quodl., 14; do.,

2, dist. 15, aa. 1, 2 ; Niphus, de Gen., i, text 118 ; do., Met., 8, d. 4. (60)
8. Th., i, q. 76, a. 4, ad. 4 ; do., de Gen., 1, lects. 24, 25 ; do., Quodl. , i, q. 4,
a. 6, ad. 3m ; do., Q. de An., a. 9, ad. 10 ; do., de Mixt. Elementorum ; do., de.
Gen., 2, lect. 8 ; do., de Ccelo, 3, lect. 8 ; do., de Plur. Form. ; do., c. Gentes,
4, c. 35 ; do., c. Gentes, 2, c. 56 ; do., 2, dist. 18, q. 1, a. 2. (61) De Mixt.
Elem. ; de Gen., i, lect. 8. (62) De Mixt. Elem. (63) de Potentia,
q. 5, a. 8. (64) S. Th., i, q. 96, a. 4, ad. 4. (65) 2, dist. 30, q. 2, a. 2.

(66) Henricus, Quodl., 1, qq. 2, 3 ; do., Quodl, 3, qq. 13, 14 ; Scotus, 2, d. 15,
q. 1 ; Lychet., in Scot., 2, d. 15, q. 1 ; Suarez, D.M., d. 15, sec. 10 ; Hervaeus,
de Plur. Form., q. 15 ; Aegidius, Quodl., 4, q. 11 ; Pontius, de Gen., d. 5, q. 2 ;
Conimbric., de Gen., i, c. 10, q. 3 ; Aguirre, de Gen., d. 62.

The Simplicity of the Substantial Form of Non-living Bodies : —

(67) St. Thos., 4, d. 10. a. 3, q. 3. (68) St. Thos., de Nat. Mat., c. 5.
(69) St. Thos., de Nat. Mat., c. 5 ; do., de Nat. Mat., c. 9 ; do., de Spir. Great.,
a. 4.

Origin of Substantial Form :— (70) Met., 7, cc. 8, 9. (71) 2, d. i,

q. 1, a. 4, ad. 4 ; 8. Th., i, q. 45, aa. 4, 8 ; 8. Th., i, q. 110, a. 2, ad. 3 ; de Pot.,
q. 3, aa. 8, 11 ; de Virt., q. 1, a. 8 ; de Verit., q. 11, a. 1 ; Met., 7, lect. 7, 8 ;

2, d. 18, q. 2, a. 1 ; de Pot., q. 5, a. 1. (72) 8. Th., i, q. 110, a. 2. (73)

3, d. 33, q. 1, a. 2, s. 2 ; cf. c. Gentes, 3, c. 69, n. 9. (74) 2, d. 1, q. 1, a. 4,
ad. 4. (75) de Pot., q. 3, a. 8 ; cf. S. Th., i, q. 118, a. 1 ; i, q. 65, a. 4 ;
i, q. 90, a. 3 ; de Sensu et S., lect. 7. (76) Soto, Phys., 1, q. 7 ; Sonc.,
Met., 7, q. 28 ; Durandus, 2, d. 18, q. 2 ; Aureolus, 2, d. 18. (77) B. Pere-
rius, S. J., de Comm. omnium rer. nat. principiis etc., 1. 4, c. 22. (78) Suarez,
D.M., d. 15, sec. 2 sqq. ; Scotus, 2, d. 18, q. 1. (79) St. Thos., S. Th., i,
q. 77, a. 6. (80) de Spir. Great., q. 1, a. 11. (81) St. Thos., S. Th.,
iii, q. 77, a. 3, ad. 3 ; i, q. 57, a. 1, ad. 4 ; i, i, q. 115, a. 1, ad. 5 ; i, q. 45, a. 8,
ad. 2 ; i, q. 115, a. 1, ad. 5 ; iii, q. 77, a. 3, ad. 2 ; i, q. 77, a. 1, ad. 4 ; 4, dist.

NOTES 289

12, q. 1, a. 2, q. 2 ; 4, dist. 1, q. 1, a. 4, q. 1 ; de Verit., q. 27, a. 4. (82) St

Thos., 8. Th., i, q.77, a. 1. Cf. i, q. 54, a. 1, 2, 3 ; de An., q 1, a. 12 ; c. Gentes.,
3, c. 69 ; Cajetan, in 8. Th., i, q. 54, a. 3, and other texts ; Capreol., 3, dist. 3,
q. 3, a. 2 ; do., 4, dist. 12, q. 1, a. 3 ; Goudin, Phys., 1 Part, Thesis II. (83)

Scotus, 1, dist. 37 ; Lychet., in Scot., 1, dist. 37 ; Scotus, 4, dist. 12, q. 3 ;
Hiquaeus, in Scot., 4, dist. 12, q. 3 ; Durandus, 2, dist. 1, q. 4 ; Pontius, Phys.,
2, disp. 38, q. 2 ; Mastrius, Phys., disp. 7, q. 6, a. 2 ; Frassen, Phys., disp. 2,
sec. 1, a. 2 ; Ockham, 2, q. 23 ; Dandinus, de An., i, q. 8 ; Suarez, D. M ., d. 18,
sec. 2. (84) St. Thos., de Pot., q. 3, a. 4, ad. 7. (85) St. Thos., 5. T£.,

i, q. 66, a. 2 ; do., de Pot., q. 5, a. 4, ad. 9.

At the end of the notes to Chapter IV., attention was drawn to Palmier!' s
suggestion that Aristotle did not defend " explicit " hylemorphism. He makes
a somewhat similar suggestion about St. Thomas : he is doubtful whether
St. Thomas taught a real distinction between primordial matter and sub
stantial form — the genuine issue, as he rightly says, in peripatetic hylemorphism.
(Instit. Phil., Cosmologia, c. 2, th. xxi.) This doubt of his is as unfounded as
his Aristotelian myth. Every text of St. Thomas that we have quoted through
out our present chapter about primordial matter in the paragraphs dealing with
its potency, its distinctive existence, its capability of supporting accidents
implies clearly a real distinction between primordial matter and substantial
form. But St. Thomas's texts about the disappearance of the form during
substantial change and the persistence of the primordial matter remove all
possibility of doubt on this question : realities that are separable from each
other are obviously really distinct. Numerous and decisive as are the texts
we have given from St. Thomas, they might be reinforced by others equally-
decisive and more numerous. (Cf. Almannus, Sumwa Philosophic?, tome i,
sec. 2, qq. 3, 4, 6, 8, 9 ; tome ii, sec. 3, qq. 27, 35, 46 ; tome iii, sec. 6, qq. 34 ;
appendix, qq., 1, 2, 6.) Palmieri ignores all these texts. Nor can he quote a
single text that denies this real distinction. His defence consists in quoting
four Thomistic principles and in inferring from them this doubt of his. The
four principles are : the whole, not the "form, is made ; the form is educed
from the potency of matter ; matter cannot exist apart from form ; the form
is induced by physical motion and is the term of alteration. Palmieri's attempt
to infer from these principles a denial of the real distinction between primordial
matter and substantial form needs no special discussion here : St. Thomas's
personal explanation of their genuine meaning occurs again and again in this
chapter and in the next. Zigliari, as contemporary of Palmieri at Rome,
found it advisable to give a detailed refutation of this attempt to falsify the
teaching of St. Thomas (Cosm., ii, c. 2, a. 3 : also vol. iii, appendix). Five years
later Fr. T. Pesch, S.J. (Phil. Nat., vol. i, p. 203) could write : " That St. Thomas
is a loyal Aristotelian on this question (the real distinction between primordial
matter and substantial form) can be doubted only by one who either never
read the text of the Angelical or barely glanced at it." And Fr. de San, S.J.,
refuses to discuss the question : " We' need not waste time over this author's
assertion that it is doubtful whether St. Thomas taught this point on which
depends the whole strength of the Peripatetic theory. That assertion is too
paradoxical. Only a man incapable of distinguishing" between what is evident
and what is doubtful would set about refuting it." (Cosm., p. 1C6.)

CHAPTER VI.

Primordial Matter and the Essence :— (1) Averroes, 7 Met., comm. 21 and
34 ; Jandunus, 7 Met., q. 12 ; Durandus, 4, dist. 44, q. 1 ; Alexander of Hales,

2, dist. 30 ; do., 4, dist. 44, q. 1 ; Albertinus, 2 Phys., text 28 ; Zimara, 2 Phys.,
text, 28 ; Pereira, 1. 6, c. 7 ; Arist,, 2 Phys., text, 28 ; do., Prced., c. 6 ; do.,
7 Met., c. II; do., 5 Met., c. 2 ; do., 1 Met., c. 7, t. 52 ; do., 2 de An., c. 2.
(2) St. Thos., 7 Met., lects. 5, 9 ; do., Op., 30, c. 2 ; do., 8 Met., lect. 3 ; do.,
Quodl, 2, a. 4 ; do., 4, dist. 44, q. 1, a. 1, sol. 2, ad. 2 ; do., 8. Th., i, q. 29,
a. 2, ad. 3 ; do., 8. Th., i, q. 75, a. 4 ; do., de Pot., q. 9, a. 1, ad. 6 ; do., 3,
dist. 6 ; do., 3, dist. 5, q. 3, a. 2 ; do., 1, dist. 23, q. 1, a. 1 ; Cajetan, de Ente
et Essent., c. 2, q. 4 ; Capreol., 4 dist., q. 1, a. 1 ; Aegidus, 7 Met., q. 2 ; Scotus,

3, dist. 22, q. u. ; do., 7 Met., q. 16 ; Suarez, D.M., d. 36, sec. 2 ; Aversa,

19

290 NOTES

q. 19. sec. 4 ; Amicus, Phys., i, tr. 6, q. 6 ; Pontius, Phys., i, disp. 35, q. 3 :
Ockham, in 4, q. 11 ; Conimbr., Phys., i, c. 9. q. 5 ; Scares, Phys., i, disp. 4,
sec. 2.

The Problem of Union :-— (3) Scotus, 2, dist. 3, q. 4 ; do., 4, dist. 12 ;
do., 3, dist. 1, q. 1 ; do., 2, dist. 1, q. 5 ; Suarez, D.M., disp. 13, sec. 9 ; do.,
de Incarn., disp. 8, sec. 3 ; Bannes, i, q. 76, a. 1, dub. 3 ; Cabrera, iii, q. 2,
a. 4, disp. 8, n. 27 ; Complut., Phys., disp. 6, q. 2 ; Pontius, Phys., i, d. 34,
qq. 2, 3 ; Aguirre, Phys., d. 34 ; Rubius, Phys., i, tr. 2, q. u. ; Scares, Phys.,
i, disp. 5. (4) St. Thos., S. Th., iii, q. 2, a. 1 ; do., S. Th., i, q. 76, a. 7 :

do., Met., 8, lect. 5 ; do., 3, dist. 2, q. 2, a. 2 ; do., de Spir. Great., a. 3 ; do.,
Q. de An., a. 9, ad. 18 ; cf. also, C. Alemanni, appendix (de F.), q. 6, a. 2 :
Cajetan, in iii, q. 2, aa. 7, 10 ; Goudin, Phys., i, disp. 1, q. 4, a. 2 ; John of
St. Thomas, Phys., q. 6, a. 3 ; Kondig et Hueber, Harm. Phil., Phys., theor. 5,
sec. 2. (5) St. Thos., 8 Met., lect. 5 ; do., 8. Th., i, q. 76, a. 7 ; do..

3, dist. 2, q. 2, a. 3 ; do., c. Gentes, 2.

The Problem of Totality : — (6) Scotus, 3, dist. 2, q. 2 ; do., 8 Met., q. 4 ;
Mairon, d. 1, q. 10 ; Mastrius, Phys., d. 5, q. 13, n. 151 ; Pontius, d. 35, q. 1 ;
Frassen, Phys.. d. 3, q. 1 ; Hervaeus, Quodl., 2, q. 15 ; Capreolus, 3, dist. 2,
a. 1 ; Cajetan, iii, q. 6, a. 5 ; Ferrar, c. Gentes, 4, c. 81 ; Javellus, 7 Met., q. ult.
(7) St. Thos., 4, c. Gentes, c. 81, ad. 2 ; do., 4, dist. 4, q. 1, a. 1 ; do., .9. Th.,
iii (supp.), q. 79, a. 2, ad. 2 ; do., 5 Met., lect, 2 ; Suarez, D.M., d. 36, sec. 3 ;
Durandus, 3, dist. 2, q. 2 ; Gregory, 1. dist. 24, q. 1, a. 1 ; Soto, Phys., q. 3 ;
Complut., d. 6, q. 4 ; John of St. Thos., Phys., q. 6, a. 2 ; Aguirre, Phys., d. 7 ;
Scares, Phys., i, d. 7, sec. 2.

Essence and Existence :— (8) St. Thos., S. Th., i, q. 3, a. 4; do., 8. Th.,

1, q. 75, a. 5, ad. 4 ; do., c. Gentes, 2, cc. 62, 53 ; do., de Ente et Ess., c. 5 ; do..
Quodl., 2, a. 3 ; do., Quodl., 9. a. 6 ; do., de Pot., q. 7, a. 2 ; do., de Pot., q. 3,
a. 13, ad. 4 ; do., c. Gentes, i, c. 22, n. 2 ; do., Op., 30, c. 5 ; do., Op., 69, c. 2 ;
do., 8. Th., i, q. 54, a. 1 ; do., de Verit., q. 2, a. 11 ; do., 1, dist. 18, q. 1, a. 2 ;
do., 2, dist. 3, q. 1, a. 1 ; etc. ; Capreol., 1, dist. 8, a. 1, q. 1 ; Cajetan, in i,
q. 3, a. 4 ; do., de Ente et Ess., c. 5, q. 11 ; Ferrar, c. Gentes, 2, c. 52 ; Soncin.,
Met., 4, q. 12. (9) Alexander, Met., 7, ad. text, 22 ; Durandus, i, d. 8,
q. 2 ; Gabriel, 3, dist. 6 ; Hervaeus, Quodl, 7, q. 9 ; Suarez, D.M., d. 31, ss. 1,

2, 3 ; Vasquez, i, d. 179, n. 6 ; do., iii. q. 17, a. 2 ; do., iii. d. 72, c. 2. (10)
Scotus, 3, dist. 6, q. 1 ; do., 1, dist. 36 ; Henricus, Quodl, i, qq. 9, 10 ; Pontius,
d. 69, q. 4 ; Mastrius, Met., d. 8, q. 2, n. 77. (11) St. Thos., Comm. in Beet,
de Hebdomad, lect. 2; do., de Verit., q. 21, a. 1, ad. 8. (12) Capreol., 1,
dist. 8, q. 1. (13) Capr., 2, dist. 16, q. 1 ; Goudin, Phys., i, d. 1, q. 2, a. 2.
(14) Lib. Prced, de Subst., q. 1. (15) Bannes, Comm. in S. Th., \, q. 3, a. 4 ;
Blasius a Cone., Met., disp. 7, qq. 1, 2 ; Dominic, a Flandr., Met., 4, q. 3, a. 6.
(16) St. Thos., S. Th., i, q. 3, a. 4 ; do., 8. Th., 1, q. 8, a. 1 ; do., S. Th., 1, q. 45,
a. 5 ; do., c. Gentes, 2, c. 21 ; do., c. Gentes, 3, c. 66 ; do., de Verit., a. 9, ad. 7 ;
do., de Pot., q. 3, a. 1 ; do., de Pot., q. 7, a. 2 ; do., S. Th., 1, q. 104, a. 1 ; Cajetan,
in locis cit. 8. Th. ; Ferrar., in c. Gentes, 2, c. 21 ; do., in c. Gentes, 3, c. 66 ;
Scotus, 4, dist. 1, q. 1 ; Suarez, D.M., d. 31, sec. 9 ; Mastrius, Met., d. 8, q. 3,
n. 156.

The Principle of Individuation in Material Substance : — (17) St. Thos.,
de Nat. Mat., c. 3. (18) Scotus, 2, dist. 3, qq. 1, 2, 3, 4, 5, 6 ; Frassen,

Phil. Acad., Log., d. 2, s. 3 ; Pontius, Curs. Phil, d. 6, qq. 1-7 ; Mastrius,
Met., d. 10, q. 9, n. 126. (19) Suarez, D.M., d. 5, sees. 1-6; Toletus, in

i, q. 50, a. 4 ; Valentia, in i, d. 4, q. 1 ; Vasquez, in i, d. 181, c. 3 ; Scares,
Met., i, d. 4, sec. 6 ; Fonseca, Met., 5, c. 6, q. 5. (20) St. Thos., S. Th.,

i, q. 3, a. 3 ; do., S. Th., i, q. 39, a. 1, ad. 3 ; do., S. Th,, i, q. 50, a. 4 ; do.,
8. Th., i, q. 56, a. 1, ad. 2 ; do., S. Th,, i, q. 75, aa. 4? 5 ; do., S. Th., i, 2, q. 63,
a. 1 ; do., 8. Th., iii, q. 77, a. 2 ; do., c. Gentes, i, c. 21 ; do., c. Gentes, 3, c. 65 ;
do., de Pot., q. 9, a. 1 ; do., de Spir. Great., a. 5, ad. 8 ; do., Quodl, 7, a. 3 ;
do., Quodl, 8, a. 2 ; do., de Ente et Ess., cc. 2, 6 ; do., Op. de. Princ. Indiv. ;
do., Met., 7, lect. 15 ; etc., etc. (21) Capreol., 2, dist. q. 1, a. 1 ; Ferrar,

in c. Gentes, i, c. 21 ; Sonc., Met., 7, qq. 33, 34. (22) Cf. Suarez, D.M.,

d. 5, s. 3, n. 22. (23) Cajetan, in de Ente et Ess., c. 2, q. 5 ; Javellus, Met.,

5, q. 15 ; Aegidus, Quodl, 1, q. 5, a. 1 ; John of St. Thos., C. Phil, part ii,
q. 9, aa. 3, 4. (24) In i, q. 29, a. 1. (25) Salmanticenses, de Princ.

Indiv., i, disp. 1, dub. 5, n. 132.

q.

de

NOTES 291

Essence and Subsistence : — (26) Henricus, Quodl, 4, q. 4; Durandus, 1,
dist. 34, q. 1 ; St. Thos., 3, dist. 5, q. 1, a. 3, ad. 3 ; do., 3, dist. 5, q. 3, a. 3,
ad. 3 ; do., Op. contra Grcecos, etc., c. 6, ; do., Met., 7, lect. 5 ; do., S. Th., iii,
q. 2, a. 2 ; Scotus, 3, dist. 1, q. 1 ; do., 3, dist. 6, q. 1 ; do., 1, dist. 13 ; do.,
Quodl, 19, a. 3 ; Mairon, 3, dist. 1, q. 11 ; Mastrius, Met., d. 11, q. 4 ; Pontius,
C.P., d. 69, q. 4. (27) St. Thos., S. Th., i, q. 3, a. 3 ; do., S. Th., iii, q. 4,

a. 2 ; do., de Unione Verbi Incarn., a. 1 ; do., Met., 7, lect. 11 ; do., de Pot.,
q. 7, a. 4 ; do., Op., 37, c. 4 ; do., c. Gentes, 4, c. 35 ; Cajetan, in iii, q. 4, a. 2 ;
Ferrar, c. Gentes, c. 43 ; Capreolus, 3, dist. 6, q. 6, a. 3 ; Javellus, Met., 7,
. 17 ; Suarez, D.M., d. 35, ss. 1, 2, 3, 4 ; Vasquez, in iii, q. 4, a. 2, d. 31 ; Lugo,
e Incarn., disp. 12, sec. 2 ; Scares, Met., tr. 2, d. 2 ; John of St. Thomas,
Phys., q. 7, a. 1 ; Aguirre, Phil. Rat., Met., d. 6.

The Distinction between Substance and Material Accident : — (28)
de Pot., a. 7 ; Quodl, 9, a. 5, ad. 2. (29) St. Thos., S. Th., iii, q. 77, a. 2 ;

do., 4, dist. 12, q. 1, a. 1 ; do., S. Th., i, q. 45, a. 1, ad. 2 ; do., S. Th., i, q. 45,
a. 3 ; do., S. Th., i, q. 77, a. 2, ad. 3 ; do., de Gen., i, lect. 19 ; do., de Sensu et S.,
i, lect. 10 ; do., 1, dist. 3, q. 4, a. 2 ; do., de Spir. Great., a. 11 ; do., Q. de An.,
a. 1.2 ; do., Quodl., 10, a. 5 ; do., c. Gentes, 4, c. 65 ; do., Op. contra Grcecos,
A. et S., c. 8 ; Cajetan, in S. Th. (loc. cit.) ; Capreol., 2, dist. 18, a. 2 ; Hervaeus,
Quodl., i, q. 15 ; Soncin., Met., 5, q. 19 ; Scotus, 4, dist. 12, qq. 2, 3 ; do., 2,
diat. 2, q. 9 ; Pontius, C. Phil, d. 13, q. 3 ; Suarez, D.M., d. 40, sec. 2 ; do.,
D.M., d. 18, sec. 3 ; Sylv. Maurus, Qucest. Phil, ii, q. 36 ; Soto, 4, dist. 10,
q. 2, a. 2 ; Conimbric, de Gen., i, c. 4, q. 6 ; Fonseca, Met., 5, c. 13, q. 2 ; John
of St.Thos., Phil Nat., ii, q. 9, a. 2 ; Toletus in iii, q.75, a. 5 ; etc., etc. (30)

Ockhain, 4, q. 4 ; do., Quodl, 4, qq. 29-30 ; do., de Corpore Christi, c. 17 sqq. ;
do., Logica, c. de Quantit. ; Gabriel, 2, dist. 10 ; Major, 2, dist. 12, q. 2 ; Adam,
in 4, q. 5 ; Albert, de Sax., Phys., i, q. 7 ; Marsilius, q. 9, a. 2 ; and with these,
Arriarra, Curs. Phil, Phys., d. 5, s. 1, subs. 6. (31) Suarez, D.M., d. 18,

sec. 3, nn. 17, 18. (32) Scotus, 1, dist. 37 ; do., 4, dist. 12, q. 3 , do., 2,

dist. 16 ; do., 2, dist. 9, q. 2 ; do., 4, dist, 22, q. 3; Pontius, C. Phil., ii, d. 38,
qq. 2, 3 ; Mastrius, disp. 7, a. 3 ; Arriaga, disp. 11, sec. 2 ; Frassen, PhiL
Acad., Phys., disp. 2, sec. 1, a. 2, q. 2. (33) Suarez, D.M., d. 40, sec. 2,

n. 22.

The Origin of Accidents : — (34) Cajetan in i, q. 54, a. 3 ; Ferrar, c. Gentes,

4, c. 65 ; Conrad, i, 2, q. 110, a. 3 ; Soto, in Logica, c. de Proprio ; John of St.
Thomas, Phil Nat., i, q. 12, appendix ; Complutenses, Phys., d. 10, q. 7 :
Fonseca, Met., 5, c. 2, q. 6, s. 5 ; Toletus, de An., 2. q. 9, concl. 4. (35)
Scotus, 2, dist. 16 ; do., 4, dist. 12, q. 3 ; Pontius, C. Phil, d. 38, q. 3, concl. 1 ;
Frassen, Phil. Acad., Phys., i, d. 2, s. 1, a. 2, q. 2 ; Suarez, D.M., d. 18, s. 3 ;
Hurtado, Phys., d. 9; Arriaga, d. 11, s. 2; Sylv. Maurus, Quasi. Phil, 4,
q. 30, ad. 4. (36) (a) Texts that seem not to imply causality : — 1, dist. 3,
q. 4, a. 2 ; 1, dist. 3, q. 4, a. 2, ad. 2 ; Op., i, cc. 87, 89"; de VeriL, q. 14, a. 5 ;

5. Th., i, q. 77, a. 6, ad. 1, 2 ; S. Th., i, q. 77, a. 7 ; S. Th., i, q. 77, a. 1, ad. 1 ;
8. Th., i, q. 18, a. 1, ad. 2 ; de Pot., q. 3, a. 7. Texts that seem to imply
causality -.—8. Th., i, q. 77, aa. 6, 8 ; 8. Th., i, q. 77, a. 5, ad. 1, 2; Q. de An.,
a. 19, ad. 2 ; de Spir. Great., a. 11, ad. 5. (37) In i, q. 77, ad. 2 and 3.

The Existence of the Accident :— (38) Capreol., 3, dist. 6, q. 1 ; do., 3,
dist. 16, q. 1 ; do., 1, dist. 18, q. 1. (39) Scotus, 4, dist. 12, q. 1 ; Suarez,

D.M., d. 31, s. 11, n. 23 sqq. ; Molina, in i, q. 3, d. 2. (40) St. Thos., de

Ente et Ess., cc. 2, 7 ; do., de Spir. Great., a. 3 ; do., 4, dist. 12, q. 1 ; do.,
c. Gentes, 4, c. 14 ; do., S. Th., i, q. 77, a. 2 ; do., 1, dist. 9, q. 1, a. 2 ; do.,
Phys., 5, lect. 9 ; do., de Un. Verbi., a. 1, ad. 10 ; Cajetan, de Ente et Ess.,
q. 16 ; do., in i, q. 28, a. 2 ; Soncin., Met., 7, q. 5. (41) St. Thos., de Ent,

et Ess., c. 7 ; do., 8. Th., iii, q. 17, a. 2. ' (42) St. Thos., Comp. Theol,
«. 211.

The Individuation of the Accident :— (43) St. Thos., 8. Th., i, q. 29, a. 1 ;
do., 2, d. 2, q. 1, a. 2 ; do., 8. Th., 1, q. 39, a. 3 ; do., Op. de Prin. Individ. ;
do., Quodl, 1, a. 19 ; do., 8. Th., ii, 2, q. 24, a. 5 ; do., de Verit., q. 1, a. 11 ;
do., S. Th., iii, q. 35, a. 5 ; do., S. Th., ii, q. 77, a. 2 ; do., Met., 1, lect. 15 ;
Cajetan, in S. Th., loc. cit. ; Capreolus, i, dist. 54, a. 2 ; John of St. Thos.
€. Phil, Phys., 2, q. 9, a. 5. (44) St. Thos., S. Th., i, q. 29, a. 1 ; do.

19*

292 NOTES

8. Th., 1, q. 29, a. 3 ; do., Op. de Princ. Ind. (45) Scotus, 4, dist. 12 ;

Suarez, D.M., d. 5, sec. 7 ; Lossada, Met., d. 1, c. 6, n. 144 ; Pontius, C. Phil,
d. 6, q. 8 ; Frassen, Phil Acad., Log., d. 2, sec. 3, q. 2.

The Introduction of Physical Intrinsic Modes : — (46) Mastrius, Met.,
d. 2, q. 6, a. 1 ; Pontius, d. 69, q. 3, Addit. de modis intrinsecis ; Suarez, D.M.,
d. 7, sec. 1 ; do., D.M., d. 13, sec. 9 ; do., D.M., d. 39, sees. ], 2 ; Vasquez,
in i, d. 126 ; do., in iii, d. 31, c. 6 ; Fonseca, Met,, 5, o. 6, q. 6 ; Rubius, Phys.,
q. 6 ; Lessius, de Div. Per/., 1. 12, n. 29 sqq. (47) Babenstuber, Philos.,

Phys., I, d. 6, a. 2, q. 2. (48) In iii, d. 41, c. 4 ; in iii, d. 32, c. 4. (49)

Kondig et Hueber, Harm. Phil., ii, th. 5 ; Babenstuber, Phil., Phys., i, d. 6 ;
Cardinal Ptolemaeus, Phil. Mentis et 8., Phys. -Met., dist. 5, see. 3; V. Gufl,
Met., iii, tr. 3, a. 2 ; J. Martinon, de Incarnat., d. 5 ; C. Tiphanus, de Hypostasi,
cc. 40-60, and all Nominalists, teste Hurtad., Phys., d. 11, s. 2, n. 5. (50)

de Div. Per/., 1. 12, n. 29. (51) Kondig et Hueber, loc. cit., n. 221. (52)

Babenstuber, loc. cit., a, 2, ad. finem. (53) Gufl, O.S.B., Met., P. 3, tr. 3,

a. 2.

CHAPTER VII.

Medieval Presuppositions : — (1) Arist., Met., 5, c. 13 ; do., Phys., 6, c. 1 ;
do., Phys., 5, c. 3 ; do., Categ., c. 4 ; St. Thos., Met., 5, lect. 15 ; do., Phys., 5,
lect. 5 ; Scotus, i, dist. 44, q. 1 ; Suarez, D.M., d. 40, sec. 1. (2) St. Thos.,

S. Th., iii, q. 75, a. 5 ; do., c. Oentes, 4, c. 65 ; do., 4, dist. 1, q. 1, a. 1 ; do., 4,
dist. 12, q. 1, a. 1, ad. 2 ; Scotus, 4, dist. 10, q. 2 ; Suarez, de Euch., d. 56,
s. 1 ; do., de Euch., d. 51, s. 2. (3) Cf. Chapter VI.— The Distinction between

Substance and Material Accidents. (4) Suarez, de Euch., d. 51. s. 2.

(5) St. Thos., S. Th., iii, q. 76, a. 4. (6) St. Thos., S. Th., iii, q. 76, a. 4 ;

do., S. Th., q. 76, a. 4, ad. 1.

The Essence of Quantity : — (7) Simplicius who advocated measurableness
as the essence of quantitj^ appeals to St. Thos., de Nat. Loci. An appeal in
favour of this view was made also to Aristotle, in Prced., c. 6 ; do., Met., 5,
c. 13 ; to Albert. M., tr. 8, c. 1 ; to Capreolus, 2, dist. 3, q. 1, ad. 11. Soncinas,
Met., 5, q. 21, and Javellus, q. 20, advocated divisibility : they appealed to
Aristotle, Met., 5, tt. 12, 18, Phys., i, t. 16, Phys., 3, t. 2, Phys., 6, t. 3, de Ccelo,
i, t 2 ; also to St. Thorn., 2, dist. 3, q. 1, a. 4, 8. Th., i, q. 50, a. 2, i, dist. 19,
q. 1, a. 1, ad. 1 — and several other texts collected by C. Alemanni, Summa Phil.,
i, q. 9, a. 1. An appeal in favour of this view was made also to Scotus, in Prced.,
q. 17, and Met., 5, q. 9. Arriaga, Met., d. 5, sec. 2, and Oviedo, Met., Controv.,
7, n. 27, advocated impenetrability. Durandus, 4, dist. 10, q. 2, advocated
actual local extension : so did the Nominalists as regards the quantity of
substance — cf. above, note (3). (8) Capreol., 2, dist. 19, q. 1, a. 3, ad. 2 ;

do., 2, dist. 18, q. 1, a. 3, ad. 2 and 4 ; Cajetan, in i, q 52, a. 1 ; Ferrar, c. Oentes,
4, c. 87 ; Complutenses, Logic., q. 3, n. 30 ; John of St. Thos., Logic., q. 16,
a. 1 ; Vasquez, in iii, d. 187, c. 2, n. 11 ; do., in iii, d. 190, c. 3, n. 20 ; do., in
iii, d. 194, c. 3, nn. 26, 27 ; Goudin, Phys., 4, q. 2, a. 3 ; St. Thos., S. Th., i,
q. 50, a. 2 ; do., 8. Th., iii, q. 76, a. 3 ; do., c. Gentes, 4, c. 65 ; do., Op., 42,
c. 16 ; do., Op., 48, c. 14 ; do., Phys., 4, lect. 7 ; do., 4, dist. 10, q. 1, a. 3, ad. 2 ;
do., Op., 70, q. 3, a. 3, ad. 3 ; do., Quodl, 9, a. 6. A few of these Thomists— for
instance, the Complutenses — insist that material substance, even when quanti
fied, has no actual integral parts which are entitatively substantial ; for them,
therefore, material substance, even when quantified, is wholly indivisible and
exists whole in the whole continuum and whole in each part thereof. Cf . Goudin,
loc. cit. (9) Sotus, de Prced., c. 6, q. 2, ad. 1 ; Scotus, 2, dist. 12, q. 2 ;

do., 4, dist. 10, q. 1 ; Mastrius, Phys., d. 9, q. 1, a. 1 ; Frassen, Phil. Acad.,
Log., tr. 3, d.s. 2 ; Pontius, Phys., d. 14, q. 2, concl. 4 ; Suarez, D. M., d. 40,
s. 4, n. 7 seqq. ; Fonseca, Met., 5, c. 13, q. 1 ; Aguirre, Met., d. 8, s. 3.

The Secondary Effects of Quantity :—( 10) Op. in Lib. Bait, de Trinitate,
q. 4, a. 3. (11) St. Thos., loc. cit. (12) St. Thos., Quodl, i, a. 21.

(13) 4, dist. 11, q. 1, a. 3, qla. 3, ad. 2. (14) D.M., d. 43, sec. 1, n. 8 sqq.

The Endless Divisibility of Continua : — (15) Phys., 6, c. 1 ; Phys., 5, c. 3.
(16) St. Thos., Phys., 6, lects. 1, 3 ; do., de Gen., lect. 5 ; do., Met., 9, lect. 5 ;
do., 2, dist, 30, q. 2, a. 2 ; do., 8. Th., i, q. 48, a. 4 ; do., 8. Th., i, 2, q. 85,

NOTES 293

a. 2 ; do., c. Gentes, i, c. 12 ; Scotus, 2, dist. 2, q. 9 ; Suarez, D.M., d. 40, s. 5 j
Sotus, Phys., 6, q. 1 ; John of St. Thos., Phys., q. 20 ; Complut., Phys., d. 25 •
Goudin, Phys., i, d. 3, q. 5, a. 1 ; Mastrius, Phys., d. 9, q. 2, a. 2 ; Pontius,
(hesitantly) Phys., 6, d. 47, q. 2 ; Lynceus, Phys., 3, tr. 6 and 7 ; Frassen]
Phil. Acad., Phys., 2, d. 2, sec. 1, q. 2 ; Toletus, P%s., 6, q. 1 ; Conimbric.,
Phys., 6, c. 2. " (17) Arist., Phys., 6, c. 1. (18) St. Thos., Phys., 6,

lect. 1. (19) St. Augustine, de Immort. An., c. 7. (20) St. Thos.,

Phys., 1, lect. 9. (21) St. Thos., de Sensu et Sensato, lect. 15. (22)

Scotus, Met., 5, q 2 ; do., 2, dist. 1, q. 9 ; Ockham, 2, dist. 28 ; Valles., Phys.,
contr. 5. (23) J. Major, 2, dist. 2, q. 1, concl. 1 ; Gregory, 1, dist. 36,

q. 1 ; do., 2, dist. 2, q. 2 ; Tartaretus, Phys., 6, q. 1 ; Lugo, de Incarn., d. 26,
s. 8, n. 3 ; do., de Sacram., d. 4, s. 6 ; do., de Penit., d. 16, s. 1 ; Tellez, Phys.,

2, 1. 6, d. 35, s. 1 ; Arriaga, d. 16 ; Oviedo, Phys., contr. 7. (24) Hurtado,
Phys., d. 15, s. 5, sub. 4.

The Manner of Existence of Parts within a Continuum : — (25) St.
Thomas, Phys., 8, lect. 21. (26) Op. de Nat. Mat. (27) St. Thos., Met.,

3, lect. 13. " (28) 4, dist. 44, q. 1. (29) 2, dist. 17, a. 1, q. 4. (30)
St. Thos., Phys., 1, lect. 3 ; do., Met., 5, lect. 2 ; do., Phys., 1, lect, 9 ; do.,
de Ccelo, i, lect. 2 ; do., Met., 1, lect. 13 ; do., 4, dist. 10, q. 1, a. 3, ad. 1 ; do.,
de Sensu et n Sensato, lect. 13 ; Aegid., Phys., 8, lect. 11 ; do., Phys., 6, lect. 16 ;
Capreol., 1, dist. 43, a. 3, q. 1, ad. 3 ; Henric., Quodl, 4, q. 15 ; do., QuodL,
9, q. 4 ; Albertin., in Prced. Quant., d. 3, q. 6, n. 19 ; Amicus, de Angelis, d. 9,
n. 180 ; Fonseca, Met., 5, c. 13, q. 6, ss. 4, 5 ; Sylv. Maur., Qucest. Phil, ii, q. 40,
p. 382 ; Scares, Phys., iv, d. 1, sec. 1. (31) Scotus, 2, dist. 1, q. 3 ; do.,

4, dist. 12, q. 4 ; Soncinas, Met., 5, q. 19 ; Soto, lib. Prcedic. de Quant., q. 2 ;
Suarez, D.M., d. 7, s. 1, nn. 22, 23 ; do., D.M., d. 40, s. 1, n. 7 ; Toletus, Phys.,
6, q. 1, concl. 3 ; Conimbric., Phys., 6, cc. 1, 2 ; Complu tenses, Phys., d. 25,
q. 3 ; Aguirre, Phys., d. 32, sec. 2 ; Mastrius, Phys., d. 9, q. 2, a. 3 ; Pontius
(hesitantly), Phys., 6, d. 47, q. 1 ; Hurtado, Phys., d. 15, sec. 1 ; Arriaga,
Phys., d. 6, n. 14 sqq.

Indivisibles as Links and Limits in a Continuum :— (32) Scotus, 2, dist.

2, q. 9 ; do., 2, dist. 1, q. 3 ; Suarez, D.M., d. 40, sec. 5 ; Pontius, Phys., 6, d. 47,
qq. 3, 4 ; Frassen, Phil. Acad., Phys., 2, d. 2, s. 1, q. 3 ; Mastrius, Phys., d. 9,
q. 2, a. 2 ; Conimbric., Phys., 6, q. 29, a. 2 ; Arriaga, Phys., d. 16, sec. 7 ; Oviedo,
Phys., contr. 17, punct. 1 ; Complut., Phys., d. 25, q. 1. (33) Albert. M.,
de Indivisibilibus, c. 7 ; St. Thos., de Gen., 1, lects. 4, 5 ; do., Phys., 6, lects.
8, 9 ; do., 3, dist. 21, q. 1, a. 1, ad. 5 ; do., Phys., 5, lect. 5 ; do., Phys., 7, lect. 3 ;
do., de Ccelo, 1, lect. 2 ; do., de Tot. Log. Arist. Summa., tr. 3, c. 3 ; do., Met.,

3, lect. 13 ; do., de Pot., q. 3, a. 17, ad. 5 ; do., de Instantibus, c. 2 ; Durandus,
2, dist. 2, q. 4 ; Ockham, Log., c. de Quantitate ; do., de Euchar., cc. 1, 2 ;
Gregory, 2, dist, 2, q. 2, a. 1 ; De Rhodes, Phil. Peripat., 2, d. 3, q. 2, s. 3 ;
Pereira, Phys., 1. 10, c. 5 ; Albertinus, de Quant., d. 3, q. 7 ; Dandinus, de An.,
Comm., Ill ; Rubius, Phys., 6, tr. de. comp. Cont., q. 1, d. 2 ; Tanner, t. 1,
d. 2, q. 4, n. 23 ; Scares, Phys., tr. 4, d. 1, s. 3, p. 2.

CHAPTER VIII.

(1) Categ., c. 6-8 ; do., Met., 5, c. 14. (2) St. Thos., S. Th., i, q. 28,

a. 2 ; do., ,9. Th., i, 2, q. 49, aa. 1, 2 ; do., Met., 5, lect. 16 : do., Met., 5, lect. 9 ;
do., Phys., 3, lect, 5 ; do., S. Th., i, 2, q. 50, a. 2, ad 3 ; do., 4, dist. 4, q. 1, a. 1 ;
do., Tot. Log. Summa., tr. 4 ; Scotus, 4, dist. 12, qq. 2, 4, 10 ; Suarez, D.M.,
d. 42. (3) Albert M., Sup. Prcedic., c. 1. (4) Goudin, Logica, q. 5,

a. 1. (5) Suarez, D.M., d. 42, sec. 1, nn. 5, 6.

Astronomy and Alchemy : — (6) Alfraganus, Elementa Astronomica (1669) ;
Aguirre, de Ccelo, d. 67. (7) St. Thos., Meteor., 3, lect. 9 ; Albert. M.,

de Alchimia, par. 2.

The Medieval Distinction between Primary and Secondary Quali
ties :— (8) St. Thos., de Gen., 2, lects. 2, 3 ; do., de An., 2, lect. 13 ; do., de
Ccelo, lect. 10 ; do., de Sensu et Sens., lect. 10 ; do., Met., 10, lects. 4, 6 ; Pontius,
C.P., d. 56, q. 3 ; Conimbrio., de Gen,, 2, c. 3, qq. 2, 3 ; Scares, de Gen., d. 4,
sec. 2. (9) Arist., de An., 2, c. 2 ; do., de An., 3, cc. 1, 4 ; do., de Sensu et

294 NOTES

Sens., cc. 1, 4 ; do., de An., 2, c. 6 ; St. Thoc., de An., 2, lect. 13 ; do., 4, dist. 49,
q. 2, a. 2 ; do., de Sensu et Sens., lect. 11 ; do., de An., 3, lect. 1 ; do., de Sensu et
Sens., lect, 2 ; do., 8. Th., i, q. 78, a. 3.

The Medieval Theory of Sense-Perception :-— (10) Frags. 125, 9, 117,
11— cited in this order. (11) St. Thos., de An., 3, lect, 1 ; do., de An., 2, lects.

15, 16, 17, 19, 20, 21, 22, 23 ; do., de Sensu et Sens., lects. 12, 13, 14, 5 ; do., 8. Th.,
i, q. 78, a. 3, ad. 3 ; Complut., d. 11, n. 43. Scotists postulated a medium only
for sight : — Scotus, de An., q. 4 ; Cavellus, de An., q. 4 ; Pontius, d. 59, q. 3.
Suarez, de An., cc. 17, 21, 24, etc. (12) St. Thos., de An., 2, lects. 10, 11, 12 ;

do., c. Gentes, 2, c. 66 ; do., de Sensu et Sens., lect. 3 ; do., 3, dist. 19, q. 1,
a. 1. (13) St. Thos., de An., 2, lect. 20 ; do., 2, dist. 2, q. 2, a. 2, ad. 5 ;

Suarez, de An., 3, c. 21, n. 1 ; Conimbric., de An., 2, c. 9, q. 3 ; do., de An., 2,
e. 8, q. 2, a. 2 ; Complut,, de An., d. 12, q. 2 ; do., de An., 2, d. 12, q. 5 ; John
of St. Thos., de An., q. 5, a, 4; do., de An., q. 7, a, 3. (14) St. Thos.,

8. Th,, i, q. 17, aa. 2, 3 ; do., 8. Th., i, q. 85. a. 2 ; do., de Verit., q. 2, aa, 2, 6 ;
do., 8. Th., i, q. 78, a, 3 ; do., i, dist. 35, q. 1, a. 1, ad. 3 ; do., Quodl., 8, a. 4 ;
do., Phys., 1, lect. 4 ; do., de An., 2, lects. 6, 16 ; do., de An., 3, lect. 17 ; do.,
de Verit., q. 10, a. 8, ad. 1 ; do., de Ccdo, 2, lect. 12 ; do., 4, dist, 44, q. 1, a. 3,
sol. 4 ; do., 4, dist. 44, q. 2, a. 1, sol. 3, 4 ; Suarez, de An., 3, cc. 1, 2 ; Soares,
de An., tr. 7, d. 1. The Nominalists denied the existence of this impressed
form : the Scotists admitted its need for some senses, but not for all ; cf. Pontius,
d. 59, q. 6. (15) Arist., de Somno., 2, 454a 7. Cf. St. Thos., i, dist. 40,

q. 1, a. 1 ; do., i, dist, 15, q. 5, a, 3, ad. 4 ; do., de Verit., q. 8, a. 6 ; do., de
Pot., q. 10, a. 1 ; do., de Sensu et Sens., lect. 4 ; do., de An., 3, lect. 12 ; do.,
de Somno, lect. 1. (16) St. Thos., S. Th., i, q. 17, aa. 2, 3 ; do., 8. Th.,

q. 85, a. 6 ; do., de Verit., q. 1, a. 11 ; do., de An., 3, lects. 11, 13 ; Suarez,
de An., 3, c. 10 ; Scotus, 1, dist. 3, q. 4 ; Aguirre, de An., d. 85, n. 39 ; Conim
bric., de An., 2, c. 6, q. 6 ; Pontius, C. P., d. 59, q. 2 ; Frassen, Ph. Ac., Phys.,
3, d. 3, s. 3, a, 1.

The Democritean Theory of the Proper Sensibles :— (17) Theophr.,
de Sens., pars. 49, 50 ; Arist., 405b 12-16 ; Sext. Emp., adv. Math., 7, par. 116 ;
Mullach, Dem., pp. 206, 401 ; Arist., 442a 29; Stob. Eel., 1, 16 (Diels, Dox.f
p. 314) ; Theophr., de Sens., par. 57 ; Arist., de Sens., iv, 442a 29. (18)

Theophr., de Sens., par. 76-78; Arist., 303a 14; do., 329b 26; Theophr., de
Sens., par. 18. (19) Theophr., de Sens., par. 69 ; do., de Sens., pars.

64-67 ; Mullach, Democ., p. 219 ; Theophr., de Causis, PI. VI., 1, 6. (20)

Arist., de Kens., iv, 442* 29 ; Mullach, Democ., p. 405 ; Theophr., de Odor.,
pars. 64, 57, 63, 82. (21) Theophr., de Sens., pars. 55-56 ; Diels, Dox.,

515 ; Mullach, Democ., pp. 212-213, 342-344. (22) St. Thos., de Gen., 2,

lect. 2. (23) St. Thos., de. Gen., 1, lect. 22. (24) St. Thos., de Gen.,

1, lect. 3 ; do., de Sensu, lect. 6 ; do., de Sens., lect. 8 ; do., de Sens., lect. 12.

(25) St. Thos., de Sens., lect. 11 ; do., de Sens., lect. 9 ; do., de Sens., lect. 10.

(26) St. Thos., de Sens., lect. 12 ; do., de Sens., lect. 11. (27) St. Thos.,
de An., 2, lects. 16, 17, 18 ; do., de Sens., lect, 16. (28) St. Thos., de Sens.,
lect. 9. (29) St. Thos., de An., 3, lect, 2. (30) St. Thos., de An., 2,
lect. 16. (31) St. Thos., de An., 3, lect. 2. Cf. St. Thos., de An., 2, lects.
6, 8, 12, 13, 24 ; do., de Sen*., lects. 6, 15, 16. (32) St. Thos., de An., 3,
lect. 2. (33) This Aristotelico-Thomistic teaching on the extra-mental
existence of the proper sensibles as formal accidents distinct from quantity and
motion was followed by the whole School. Two minor controversies arose
concerning sound : one over the question whether sound was a permanent or
successive quality ; another on the question whether sound as a formal quality
resided in the vibrating body or in the medium. St. Thomas held that sound
was a successive quality residing in the medium and most of the Schoolmen
endorsed this view. There were, however, dissenters on both points : and on
the second question, compromisers who combined the two views. A more
important controversy about the nature of colour will be referred to when
discussing the quality of light. Cf. Conimbric., de An,, cc. 8, 9. 10, 1 1 ; Pontius,
C.P., d. 60 ; Frassen, Phil Ac., Phys., 3, d. 3, sec. 3, a. 2 ; John of St. Thos.,
de An., qq. 4, 5, 6, 7 ; Goudin, Phys., 4, q. 3, aa. 1, 2 ; Suarez, de An., 1. 3 ;
Soares, de An., tr. 2, d. 2.

Light and Brightness :— (34) St. Thos., de An., 2, lects. 14, 15; do., 2,
dist. 13, q. 1, a. 3 ; do., 8. Th., i, q. 67, a. 3 ; Scotus, 2, dist. 13 ; Suarez, de

NOTES 295

An., 3, c. 14. (35) St. Thos., de Sens., lect, 6 ; do., de An., 2, lect. 14 ;

do., de An., 2, lect. 15. (36) See note (34) ; also, St. Thos., de Sen*., lect. 11.

(37) Albert M., de Sens., tr. 2, c. 1 ; do., de An., 2, tr. 3, c. 7 ; do., Summa. de
Creaturis, ii, q. 21, a. 3, part 1 ; Aegidius, de An., 2, c. 7 ; Cajetan, de An., 2,
c. 7 ; Javellus, de An., 2, q. 33 ; Soncinas, Met., 10, q. 2 ; Ferrar., de An.,
q. 13. These appealed to Arist., de An., 2, t. 67, and de Sens., c. 3, and to St.
Thos., i, dist, 17, q. 1, a. 1. (38) St. Thos., de An., 2, lects. 14, 15, 16 ;

do., de An., 3, lect. 2 ; do., de Sens., lects. 2, 6, 7 ; do., Qucest. de An., a. 4,
ad. 4 ; do., Quodl., 7, a. 1 ; Conimbric., de An., 2, c. 7, q. 2 ; John of St. Thos.,
de An., q. 7, a. 2 ; Suarez, de An., 3, c. 15 ; Scares, de An., tr. 2, sec. 2, 7.

(39) Si. Thos., S. Th., i, q. 67, a. 3 ; do., 2, dist. 13, q. 1, a. 3 ; do., de An., 2,
lect. 14 ; St. Bonaventure, 2, dist. 13, q. 2 ; Richard of Middletown, 2, dist. 13,
q. 2 ; Durandus, 2, dist. 13, q. 2 ; Hervgeus, Quodl, 3, q. 18 ; Suarez, de An.,

c. 14 ; Soares, de An., tr. 2, d. 2, s. 2, a. 6 ; John of St. Thos., de An., q. 7, a. 2.

(40) Scotus, 2, dist. 13 ; Aegidius, de An., 2, t, 76, dd. 2, 3 ; Alex. Thiens., de
An., 2, t. 71 ; Buridan, q. 17 ; Cabeus, Meteor, 3, t. 6, q. 2 ; Pomius, C.P.,

d. 60, q. 1, concl. 5.

Gravity and Levity :— (41) St. Thos., de Ccelo, i, lects. 3, 5 ; do., de Coelo,
3, lects. 5, 7 ; do., de Ccelo, 4. lects. 2, 3 ; do., de Gen,, 2, lect. 3 ; do., 8. Th.,

1, q. 46, a. 7 ; do., de Gen., 2, lect. 1 ; do., de An., 2, lect. 13 ; do., de Ccelo,

2, lect. 10 ; do., Phys., 8, lect. 14 ; do., Op. de Nat. Mat., c. 1 ; Conimbric.,
de Ccelo, A, c. 4 sqq. ; Rubius, de Ccela, 3, c. 8, q. 2 ; do., de Ccelo, 4, qq. 1, 2 ;
Aguirre, Phys., d. 58, sec. 2 ; de Rhodes, Phil. Perip., 1. 2, d. 9 ; Soares, de Gen.,
d. 4, s. 4. (42) Scotus, 2, dist, 2, q. 1.0 ; Gregory, dist. 6, q. 1, a. 3 ;
Mairon., dist. 14, q. 6 ; Placa, Phys., 2, d. 5, q. 7 ; Pereri'us, 1. 6, c. 16 ; Cabero,
Phys., 1, d. 1, dub. 5 ; Pontius, Phys., d. 48, q. 1 ; Aversa, q. 14, s. 5 ; Arriaga,
de Gen., d. 3, s. 10 ; Mastrius, de Ccelo, d. 3, q. 2, n. 20 seqq. (43) St. Thos.,
S. Th., i, q. 18, a. 2 ; do., S. Th., q. 105, a. 2 ; do., c. Gentes, 2, c. 46 ; do.,
c. Gentes, 3, c. 28 ; do., Phys., 8, lect. 8 ; do., de Ccelo, 2, lect, 2 ; do., 2, dist. 14,
q. 1, a. 3 ; Capreol., 2, dist. 6, a. 3 ; Cajetan in i, q. 18, a. 1 ; Ferrar., c. Gentes,

1, c. 97 ; do., Phys., 8, q. 9 ; Soncin., Met. 9, q. 7 ; Sotus, Phys., 8, q. 3 ; John
of St. Thos., Phil Nat., 1, q. 23, a. 1 ; Complut., Phys., d. 28, q. 2 ; Suarez,
D.M., d. 18, sec. 7 ; Fonseca, Met., 5, c. 4, q. 2, sec. 7 ; Conimbric., Phys., 8,

c. 4, q. 1, a. 2. Cf. Chapter IX— Distinction between the Mover and the
Moved.

Density and Rarity :— (44) St. Thos., Phys., 4, lect. 14 ; do., de Meteor.,
lect. 16 ; do., Phys., 7, lects. 4, 5 ; do., de Gen., 1 lect, 14 ; do., Phys., 8, lect, 14 ;
do.,de Ccelo, 3, lect, 3 ; do., de Ccelo, 2, lect. 22 ; do., 1, dist. 17, q. 2, a. 1 ;
do., 4, dist. 12, q. 1, sol. 3, ad. 6 ; do., 8. Th., iii, q. 77, a. 2, ad. 3 ; do., 8. Th.,
iii, q. 77, a. 7, ad. 1 and 2 ; Capreol., 2, dist. 19, q. 1, a. 3 ; Soncin., Met., S,
q. 27 ; Conimbric., de Gen., 1, c. 5, q. 17 ; Durandus, 1, dist, 17, q. 7 ; do., 2,
dist. 18, q. 1 ; John of St. Thos., Phys., q. 7, a. 1 ; Compluten., de Gen., d. 7,
q. 2 ; Aguirre, de Gen., d. 55. (45) Cf. Aguirre, de Gen., d. 55, s. 2, n. 26.

(46) Scotus, 4, dist. 12, q. 4. (47) Marsilius, 4, dist, 12, q, 9, a. 2 ; Goti-

fredus, Quodl, 11, q. 3 ; Pomponatius, de Augmenta.t, 2, c. 10. (48) Phil.

Faber. in 4, d. 40 ; Bassil., q. 3, a. 2 ; Cajetan, in iii, q. 77, a. 5 ; Hispalensis,

2, dist. 18, q. 1; Toletus, Phys., 4, q. 11. (49) Ockham, de Euchar. ,
Gabriel, in Canon., lect. 45 ; Vallesius, Phys., 4, text 84 ; do., Contr., q. 27 ;
Oviedo, de Gen., contr. 7, punct. 5 ; Arriaga, Phys., d. 16, s. 6 ; Soares, de Gen.:

d. 3, s. 7, par. 3 ; Pontius, C. P., d. 50, q. ult., concl. 5.

Artificial Form and Figure :— (50) St. Thos., 3, dist. 16, q. 2, a. 1 ; do.,
S. Th., iii, q. 45, a. 1, ad. 2 ; do., 4, dist. 1, q. 1, q. 1, a 3, ad. 2 ; do., S. Th., i,
q. 7, a. 1, ad. 2 ; do., 8. Th., i, q. 7, a. 3 ; do., Phys., 7, lect. 5 ; do., Met. 5.,
lect, 8 ; do., 8. Th., ii, 2, q. 96, a. 2, ad. 2 ; do., c. Gentes, 2, c. 76 ; do., c. Gentes,

3, c. 105 ; Cajetan and Ferrar., — his locis ; Scotus, 4, dist. 1, q. 4 ; Suarez, D.M.,
d. 18, s. 4, nn. 8, 9 ; do., D. M., d. 42, s. 6, n. 5 ; Conimbric., Log., q. 1, de
QuaL, a. 3.

Virtual or Occult Qualities :— (51) St. Thos., de OccuUis Operibus Natures ;
do., Q. de An., a. 1 ; do., 2, dist. 15, q. 1 ; do., de Ccelo, 2, lect. 10 : Albert. M.,
2, dist. 15, q. 1 ; Suarez, D.M., d. 22, sec. 5, n. 15 ; Scotus, 2, dist. 14, q. 3 ;
Conimbric., Meteor., tr. 13, c. 2 ; Rubius, de Ccrlo, 2, q. 2; Pontius, C.P., d. 53,
q. ult., concl. 2 ; Aguirre, de Ccelo, d. 73, n. 59 ; Soares, de Casio, d. 5, s. 2,
subsec. 8 ; Tolet., de Gen., 2, c. 3, q. 3.

296 NOTES

Impetus :— (52) Arist., de Codo, 3, c. 2, t. 28 ; do., Phys., 8, c. 10, t. 82;
do., de Insomniis, c. 2 ; do., de Divinatione, etc., c. 1 ; do., Problem., sec. 11,
probl. 6 ; do., in Mech., q. 33 ; St. Thos., de Ccelo, 3, lect. 7 ; do., de Ccelo, 2,
lect. 8 ; do., Phys., 8, lect. 22 ; do., 8. Th., i, 2, q. 23, a. 4 ; do., 8. Th., i, 2,
q. 26, a. 2 ; do., Quasi, disp. de Spe, a. 3 ; Scotus (?), Phys., 8, q. 3. (53)

Capreolus, 4, dist. 1, q. 1 ; Sotus, Phys., 8, q. 3 ; John of St. Thos., Phil Nat.,
i, q. 23, a. 2 ; Roselli, Suimma Phil, 2, q. 25, a. 4 ; Vasquez, in i, d. 91, c. 2 ;
Suarez, D.M., d. 35, s. 6, n. 24 ; Conimbric., Phys., 7, c. 2, q. 1, a. 8 ; Pontius,
O.P., d. 49, q. 1 ; Aversa, q. 40, s. 6 ; Frassen, Phil. Ac., Phys., 2, d. 1, s. 3,
q. 1 ; Soares, Phys., tr. 3, d. 3, sec. 1 ; Oviedo, Phys., contr. 20, punct. 2.
(54) St. Thos., de Pot., q. 3, a. 11, ad. 5 ; do., Q. de An., a. 11, ad. 2. (55)

Maior, 2, dist. 13, q. 7 ; Burlaeus, Phys., 8, t. 70 ; Mairon, 1, dist. 22, q. 7 ;
Pererius, Phys., 1. 14, c. 5.

The Intensification and Remission of Material Qualities : — (56) St.
Thos., S. Th., i, 2, q. 52, a. 1 ; do., de Virt. in comm., q.l, a. 11 ; do., Phys., 4, lect.
14 ; do., 1, dist. 17, q. 2, a. 2 ; do., 8. Th., ii, 2, q. 24, a. 5 ; do., Tot. Log. S., tr. 2,
c. 4. (57) Cajetan, in i, 2, q. 52, a. 1 ; do., in ii, 2, q. 24, a. 5 ; do., i, 2,

q. 54, a. 4 ; Capreol., 1, dist. 27, q. 2 ; Hervseus, 1, dist. 27, q. 5 ; do., Quodl.

S? « t: . J^ /~I«.~J7 £* ™ 1 1 . O ~Z 1/f—i O _. C\t /••< 1 j 7 _ y"f _l J

qualitate ; do., Phys., 4, t, 84. (58) John of St. Thos., de Gen., q. 4, a. 2 ;

Babenst., de Gen., d. 3, a. 2, sec. 2 ; Suarez, D.M., d. 46, sec. 1. (59) 1,

dist. 17, q. 7 ; Gofred., Quodl, 11, q. 3 ; Albert, a Mpho, Met., 8, d. 11, c. 3.
(60) Scotus, 1, dist. 17, qq. 3, 4 ; Pontius, C. Phil, d. 51, qq. 3, 4, 5 ; Frassen,
Phil Acad., Phys., 2, d. 1, a. 3, q. 2 ; St. Bonav., 1, dist. 17, p. 2, a. 1, q. 2 ;
Ockham, 1, dist. 17, q. 6 ; Tolet., de Gen., 1, c. 3, q. 4 ; Suarez, D.M., d. 46,
sec. 1 ; Vasquez, in i, 2, d. 82, c. 3 ; Fonseca, Met., 8, c. 3, q. 2, sec. 3 ; Soares,
Met., tr. 4, d. 2, sec. 2.

The Fact of Finite Activity :— (61) St. Thos., 2, dist. 1, q. 1, a. 4; do.,
c. Gentes., 3, c. 69 ; do., de Verit., q. 5, a. 9, ad. 4 ; do., S. Th., i, q. 105, a. 5 ;
do., de Pot., q. 3, a. 7 ; Albert. M., Phys., 2, tr. 2, c. 5 ; Durandus, Hervseus,
Aegidius. etc., 2, dist. 18 ; Capreol., 1, dist. 42, a. 3 ; Rubius, Phys., 2, c. 3 ;
Amicus, Phys., tr. 11, q. 6, dub. 2, a. 3 ; Suarez, D.M., d. 18, sec. 1 ; Soares,
Phys., tr. 2, d. 4, sec. 1 ; Conimbric., Phys., 2, c. 7, q. 11 ; Peter d'Ailly, 4,
disit. 1, q. 10 ; do., 4, dist. 2, q. 1 ; Oviedo, Phys., controv. 9, punct. 2.

The Active Qualities of Matter :— (62) St. Thorn., S. Th., ii, 2, q. 96, a. 2,
ad. 2 : do., c. Gentes, 2, c. 76 ; do., c. Gentes, 3, c. 105 ; Cajetan and Ferrar.,
his locis ; Scotus, 4, dist. 1, q. 4 ; Suarez, D.M., d. 18, sec. 5. (63) St.

Thos., de Gen., 2, lects. 2, 3, 4, 6 ; do., de Sens., lect. 10 ; do., Meteor., 4, lects.
1, 2, 7, 8 ; do., de An., 2. lect. 13 ; do., de Ccelo, 2, lect. 10 ; do., Phys., i, lect.
10 ; John of St. Thos., Phil Nat., 2, q. 10, aa. 1, 2 ; Conimbric., de Gen., 2,
c. 3, qq. 2, 3 ; Pontius, C.P., d. 56, q. 3 ; Soares, de Gen., d. 4, sec. 2 ; Oviedo,
de Gen., controv. 8, punct. 5 ; Aguirre, P.R., d. 59.

Transeunt Causality a Making not a Migration of Realities : — (64) St.
Thos., 2, dist. 1, q. 1, a. 2, sol. ; cf. also, c. Gentes, 2, cc. 17, 18, 19, 21. (65)

St. Thos., S. Th., i, q. 115, a. 1, ad. 3. (66) 8. Th., i, q. 115, a. 1, ad. 5.

(67) c. Gentes, 3, c. 69 ; de Pol, q. 3, a. 8 ; de Verit., q. 5, a. 9, ad. 4. (68)

St. Thos., Met., 5, lects. 1, 3 ; do., Phys., 1, lect. 1 ; do., de Verit., q. 23, a. 5,
ad. 1 ; do., 1, dist. 29, q. 1, a. 1 ; do., de Pot., q. 10, a. 1, ad. 8 ; do., Phys., 2,
lects. 1, 5 ; do., Op. de Princ. Nat. ; do., S. Th., i, q. 105, a. 5 ; do., S. Th., i,

?. 44, a. 2 ; do., c. Gentes, 2, c. 16 ; do., Phys., 3, lects. 1, 2 ; Scotus, 4, dist.
2, q. 3 ; Aegidius, Quodl, 3, q. 1 ; do., Theor., 43 ; Pontius, Phys., 2, d. 38 ;
Suarez, D.M., d. 18 ; Rubius, Phys., 2, tr. 4, q. 2 ; Hurtado, Phys., d. 9, sec. 2 ;
Toletus, Phys., 2, c. 3 ; Arriaga, Phys., d. 11, s. 2, subsec. 4 ; cf., also, references
in note (61). (69) St. Thos., Phys., 3, lect. 4 ; do., de Gen., i, lects. 17, 20,

25 ; do., S. Th., i, q. 51, a. 2, ad. 1.

The History of a Phrase :— (70) Arist., Phys., 202" 6-7 ; do., Phys.,
3, c. 3 ; St. Thos., Phys., 3, lect. 5. (71) St. Thos., Phys., 3, lects. 1, 3, 4, 5 ;

do., Met., 9, lect. 8 ; do.. 8. Th., i, q. 41, a. 1, ad. 2 and 3 ; do., c. Gent., 2,
c. 73, n. 4 ; do., 8. Th., i, q. 45, a. 2, ad. 2 ; do., 1, dist. 40, q. 1, a. 1 ; do.,
de Pot., q. 3, a. 2 ; do., 1, dist. 32, q. 1, a. 1 ; do., 3, dist. 8, q. 1, a. 5 ; do.,

NOTES 297

de Pot., q. 7, aa. 8, 9 ; do., S. Th., i, q. 28, a. 3 ; do., S. Th., i, q. 45, a. 3 -
do., 4, dist. 46, q. 2, a. 2, sol. 3 ; do., 4, dist. 1, q. 1, a. 4, sol. a, ad. 1 • do
S. Th., i, q. 23, a. 2, ad. 1 ; do., de An., 3, lect. 2 ; do., Met., 11, lect. 9 ; do.,
Phys., 7, lect. 4 ; do., c. Oentes, 2, c. 23 ; do., de Pot., q. 10, a. 1 ; do., de Pot.,
q. 8, a. 3 ; do., de Verit., q. 4, a. 2, ad. 7 ; do., 2, dist. 40, q. 1, a. 4, ad. 1.
(72) Scotus, 4, dist. 13, q. 1 ; do., Quodl, 13 ; Ant. Andreas, de Sex Princip.,

c. de Actione ; P. Venet., Summa, Phys., c. 18 ; Pontius, C.P., d. 17, q. 3 ;
Mastrius, Phys., d. 7, q. 3, a. 2. (73) Ockham, 1, dist. 3, q. 2 ; Gabriel,

I, dist. 30 ; Gregory, 1, dist. 28, q. 2 ; Aliaco, in 1, q. 7 ; Wadding, de Incarn.,

d. 1, dub. 3 ; Martinon, de Deo, d. 22, sec. 2 ; Toletus, Phys., 3, q. 3, a. 2 ;
Sotus, Phys., q. 2. (74) Capreolus, 2, dist. 1, q. 2, a. 3 ; do., 4, dist. 49,
q. 1, a. 3 ; Hervseus, Quodl. , 4 ; Soncinas, Met., 5, q. 37 ; Javellus, Met., 9,
q. 15 ; Complut., Phys., d. 17, q. 4 ; Conimbric., Phys., 3, c. 3, q. 1 ; Suarez,
D.M., d. 48 ; Scares, Met., tr. 6, d. 1. (75) in i, q. 25 ; Hispalen., 1,
dist. 27, q. 1, n. 3 ; Flandr., Met., 5, q. 22. (76) John of St. Thos., Phys.,
q. 14, a. 4 ; Goudin, Phys., i, d. 3, q. 1, a. 2.

Contact as a Condition of Action :— (77) St. Thos., Phys., 4, lects. 10,

II, 14; do., de Ccelo, i, lects. 20, 21 ; do., 2, dist. 1, q. 1, a. 5 ; Conimbric.,
Phys., 4, c. 9, q. 1, a. 4 ; Soares, Phys., 5, d. 2, sec. 1. (78) St. Thos.,
Phys., 7, lect. 3 ; do., de Gen., i, lects. 18, 23 ; do., c. Gentes, 3, c. 68, n. 4 ;
do., de Pot., q. 3, a. 9 ; do., 4, dist. 49, q. 2, a. 3, ad. 6 ; do., 2, dist. 15, q. 1,
a. 2, ad. 6 ; do., S. Th., i, q. 105, a. 2, ad. 1 ; do., 3 c. Gentes, 2, c. 56 ; do.,
de Ccelo, 3, lect. 7 ; do., de An., 2, lect. 15 ; do., de Gen., lect. 16 ; Cajetan
andFerrar., locis citatis, S. Th., et c. Gentes ; Capreolus, 1, dist. 37 ; Durandus,

1, dist. 37, q. 1 ; Suarez, D.M., d. 18, sec. 8 ; Complut., Phys., d. 18, a. 3;
Aguirre, Phys., 7, d. 39 ; Conimbric., Phys., 7, c. 2, q. 1 ; Sotus, Phys., 1,
q. 1 ; Soares, Phys., 2, d. 4, sec. 4 ; John of St. Thos., Phys., q. 22, a. 2 ;
Compton, Phil. Univ., d. 36. (79) Ockham, 1, dist. 37 ; Scotus, 1, dist, 37 ;
Gabriel, Bassol., Mairon. Lichet., ibidem ; Camerarius, p. 2, q. 2 ; Mastrius,
Phys., d. 7, q. 4, a. 3 ; Pontius, Phys., 7, d. 48, q. 2 ; Cabeus, Meteor., 4, fol.
129. Some authors contest the attribution of this opinion to Scotus — cf.
Compton and Aguirre, loc. cit. : wrongly, I think. Pontius and others made
a distinction between total causality and partial causality that does not affect
the main issue. (80) Phil. Peripat., 2, d. 10, q. 1, sec. 5.

Unlikeness as a Condition of Action : — (81) Arist,, de Gen., i, cc. 7,
8, 9 ; do., Phys., 1. 1 ; do., Phys., 3, t. 15 ; do., Met., 5, c. 12, t. 17. (82)

St. Thos., de Gen., 1. lects. 19, 22 ; do., Phys., 8, lect. 21 ; do., Meteor., i, lects.
14, 16 ; do., Phys., 3, lect. 5 ; do., Met. 11, lect. 9 ; do., Met., 9, lect. 1 ; do.,
8. Th., i, q. 84, aa. 1, 2, 3 ; do., 8. Th., i, 2, q. 85, a. 1, ad. 4 ; do., S. Th., ii,

2, q. 59, a. 3 ; Bannes, de Gen., c. 9, q. 2 ; John of St. Thos., Phys., 2, q. 5,
a. 2 ; Goudin, Phys., 1, d. 3, q. 6, a. 1 ; Conimbric, de Gen., 1, c. 9, q. 2 ; Com
plut., Phys., d. 8, q. 1 ; Suarez, D.M., d. 18, sec. 9 ; Soares, Phys., tr. 2, d. 4,
sec. 5 ; Pontius, C.P., d. 54, q. 1 ; Arriaga, de Gen., d. 3, sec. 7 ; Hurtado,
Phys., d. 9, sec. 9 ; Aguirre, de Gen., d. 56. (83) Tolet., de Gen., i, c. 7,
q. 13 : Marsilius, de Gen., 1, q. 18 ; Niphus, de Gen., c. 2, q. 2 ; Soto, Phys.,
2, q. 4.

One of the chief ambitions of Descartes was to introduce the Democriteaii
theory of material quality and of transeunt causality into the Catholic Schools.
Kineticism in matter seemed to him the best basis for Physics and for Cos
mology. He admitted, however, that Democritean kineticism could be made
philosophically consistent only when connected up with Occasionalism. What
Descartes proposed to do in Physics and in Cosmology, his followers carried
out everywhere in Philosophy and in Theology. This propagandism of the
Cartesians made kineticism the storm-centre of Catholic speculation during the
seventeenth and eighteenth centuries in France and the Netherlands and — to
a. less extent — in Germany and Italy (cf. Bouillier, Histoire de la Philosophie
Cartewenne, 1854). But by the close of the eighteenth century, kineticism had
been definitely set aside in Philosophy and Theology by the overwhelming
majority of Catholic thinkers. Those who are conversant with the details of
these long and bitter controversies on the continent will find little new in
the late Dr. McDonald's Motion, Its Origin and Conservation (1898). Of these
controversies, those that concern Cosmology are the two dealing with the
kinetic explanation of the qualities of matter and the kinetic explanation of

298 NOTES

transeunt causalitj^ : and in the subsequent volume on Modern Cosmology,
the revival in this connexion of Democritus by the Cartesians and by Dr.
McDonald will engage our attention for the purpose of examining whether
these moderns have added anything to the arguments for those Democritean
theories which were set aside, centuries ago, as unconvincing by Aristotle and by
St. Thomas.

One original thesis in Motion is the author's contention (cc. 2, 3, 4) that
Aristotle and St. Thomas were, in Cosmology, kineticists. The student who
goes to the trouble of verifying the Aristotelian and Thomistic texts quoted
in the eighth and ninth chapters of the present volume will be convinced, I
trust, of the utter inaccuracy of this contention.

The general reader to whom this patient collation of texts is caviare can,
if he has at hand the writings of Aristotle and of St. Thomas, satisfy himself
in an hour or two as to the value of the evidence adduced by our author in
favour of this amazing myth. One of Dr. McDonald's strong points is that
neither Aristotle nor St. Thomas has left us in the Physics any statement or any
dissertation on force as distinct from local motion. This is as convincing an argu
ment against the existence of such a statement or dissertation in Aristotle and
St. Thomas, as would be an argument against the existence of London on the
map based on the fact that this city is not marked on a map of South America.
The Physics, to which Dr. McDonald refers, is but one of a dozen Aristotelian
treatises dealing with bodies and their activities. Now, several of these other
treatises contain lengthy and exhaustive dissertations against the kineticism of
Democritus, and in favour of the existence of indwelling forces distinct from
local motion : Aristotle, de Generatione et Corruption^ de Anima (2nd book),
Parva Naturalia (de Sensu et Sensili), and, also, to some extent, de Ccelo, de
Mundo ; St. Thomas, de Generatione et Corruptione, de Anima (2nd book),
de Sensu et Sensato, de Ccdo et Mundo. When the general reader has verified
these facts for himself, he will naturally grow suspicious about the statement
(p. 27) that Aristotle " rarely if ever " uses the word, Svva/uus, in the sense
of foroe as distinct from local motion : let him open the Index of the Berlin
edition (1830-1870) of Aristotle, and he will learn that this word generally
means in Aristotle either force or passive potency, and that it is employed more
than 150 times for force but less than 80 times for passive potency. All these
discoveries will prepare the reader to see through the ruse of discussing St.
Thomas's use of the word, force, solely from the standpoint of the word, virtus,
and its two meanings : St. Thomas, in the series of Commentaries mentioned
above, speaks bluntly of qualitates activce, and insists everywhere on the existence
of active qualities distinct from local motion — in other words, 'of that kind of
force which is such a metaphysical scandal to all kineticists.

So much for the written testimony of Aristotle and of St. Thomas on the
first plank of the kinetic platform in Cosmology. The second plank of that
platform is that transeunt causality between bodies consists in a flow of local
motion from the agent to the patient. Dr. McDonald is not quite so confident
that Aristotle and St. Thomas accepted this plank of the kinetic platform.
He urges, however, that only men of straw refuse this particular plank : " But
it is altogether too manifest that agents are in some way the subjects of their
transient actions — while these motions are in the agents and before they have
been transferred (p. 207) ". And as no Catholic reader would think of Aristotle
and St. Thomas as men of straw, the unwary are led to believe that Aristotle
and St. Thomas interpreted transeunt causality as a flow of motion. However
manifest such a view may have been to the author of Motion, it was rejected
in the most formal manner both by Aristotle and by St. Thomas. But
Dr. McDonald takes good care not to put before his readers these explicit
denials of the flow of motion theory of causality. He fights shy of the three
famous texts in which St. Thomas scoffs at those who interpret transeunt
causality as a flow of anything from agent to patient : c. Gentes, 3, c. 69 ; de
Pot., q. 3, a. 8 ; de Verit., q. 5, a. 9, ad. 4. And his attitude to Aristotle on this
topic takes one's breath away. So lengthy are his quotations from, and his
discussions on, the three opening chapters of the third Book of the Physics
that he feels it necessary to apologise (p. 25) : and yet, despite these lengthy
quotations and exhaustive discussions, he has the nerve to omit to quote from
the third chapter the particular sentence in which Aristotle explicitly disavows

NOTES 299

the kinetic interpretation, advocated by Dr. McDonald himself, of the troublesome
phrase — action and passion are one and the same " motion " : CCTTI yap f) 8i'5a|is
fvepyeia rov 5 SaffKaXiKov, ev TIVI yueWot, KaL OVK a.TTOT€Tfj.ri/j.fvr), a\\a roCSe tV r^Se
(202b 7-8). Then, notwithstanding a grave omission of this kind, our author
speaks of these chapters as "the basis of the whole Aristotelic system of Physics,"
uses the opening sentence of that third chapter as the first motto on his title-
page, employs the much-discussed phrase about action and passion as a Thomistic
quotation for his second motto, declares this phrase " axiomatic in the Catholic
Schools " : thereby, attributing, to Aristotle and to St. Thomas, with a wealth of
emphasis on a fundamental and far-reaching problem, a view which both of
them reject explicitly and formally again and again.

CHAPTER IX.

The Ambiguity of the Medieval Term, Motion:— (1) Phys., 3, cc. 1,
2 ; do., Phys., 5, c. 2 ; St. Thos., Phys., 3, lects. 1,2; do., Phys., 5, lects. 2, 3, 4 ;
Scotus (?), Phys., 3, Expos. Text., 5 ; do., Phys., 5, qq. 1, 2, 3, 4. (2) S. Th.,

i, q. 67, a. 2, ad. 3 ; cf. S. Th., i, 2, q. 7, a. 1. (3) St. Thos., Phys., 3, lect. 2.

The Transcendental Meaning of Potency and Actuality : — (4) Arist.,
Met., 5, c. 12 ; do., Met., 9, passim ; do., de An., 2, c. 5 ; do., Met., 5, c. 7 ;
do., Met., 12, c. 5 ; St. Thos., de An., 2, lect. 11 ; do., Met., 5, lects. 9, 14 ;
do., Met., 9, lects. 1, 9 ; do., Met., 12, lect. 4 ; do., Phys., 1, lect. 15 ; do., 4,
dist. 4, q. 1, a. 1 ; do., Summa T. Log., tr. 4, c. 3 ; do., de Pot., q. 3, a. 1 ; Scotus,
Met., 9, Summse, i, ii ; do., Qucest. Met., 9, qq. 1-10 ; Suarez, D. M ., d. 20, s. 1 ;
do., d. 18, sec. 3 ; do., d. 43, sec. 2 ; do., d. 31, sec. 3 ; do., dd. 43, 13, 15.

(5) The problem of applying this definition to primordial matter led to a contro
versy between the Thomists and the Scotists : cf . Chapter v— A War of Words,

(6) Met., 9, 1048a 27-1048b 5. (7) St. Thos., Met., 9, lect. 5. (8) Arist.,
Met., 5, c. 12 ; do., Met., 9, c. 7 ; St. Thos., Met., 5, lect. 14 ; do., Met., 9,
lect. 6.

The Medieval Definition of Physical Motion :— (9) Phys., 3, lect. 2,
(10) Phys., 3, c. 2. (11) Arist., Phys., 3, 201b 4 ; do., Met., 10, 1065b 16 ;

do., Phys., 3, 202a 7 ; do., Phys., S, 251a 9 ; do., Phys., 3, 202b 26 ; do., Phys.,
3, 201a 9. (12) St. Thos., Phys., 3, lect. 2. Cf. also S. Thos., Met., 11.

lect. 9 ; do., Phys., 3, lect. 3 ; Scotus, Met., 11, s. 4, c. 1 ; do., 2, dist. 12, q. 1 ;
Suarez, D.M., d. 49, sec. 2 ; Pontius, d. 52, q. 1 ; Conimbric., Phys., 3, c. 2,
q. 1 ; Fonseca, Met., 5, c. 13, q. 9, s. 2 ; Cabeus, Meteor., 2, t. 56, q. 2 ; Tolet.,
Phys., 3, c. 2, t. 6 ; Hurtado, Phys., d. 11, s. 1 ; Oviedo, Controv., 12, p. 6,
n. 5 ; Scares, Phys., tr. 3, d. 1, sec. 1 ; John of St. Thos., Phys., q. 14. a. 1 ;
Aguirre, Phys., 3, d. 19, sec. 1.

The Motion of Generation or Corruption : — (13) Arist., Phys., 5'
cc. 2, 5 ; do., Met., 11, c. 10 ; do., Phys., 4, cc. 11, 12 ; do., Phys., 6, cc. 2, 4, 5 ;
do., Phys., 3, cc. 1, 2 ; St. Thos., Met., 12, lect. 5 ; do., Phys., 4, lect. 17 ;
do., Met., 11, lect. 9 ; do., de Gen., 1, lect. 24 ; do., Phys., 6, lects. 3, 8 ; do.,
Phys., 5, lects. 2, 3, 8 ; do., Phys., 3, lect. 1 ; do., 2, dist. 5, q. 2, a. 1 ; do.,
de Gen., 1, lect. 10 ; do., de, Sens., lect. 16 ; do., S. Th., i, q. 67, a. 2 ; do.,
S. Th., i, q. 46, a. 3 ; do., i, dist. 8, q. 3, a. 3 ; Scotus, 2, dist. 2, q. 2 ; Mastrius,
de Gen., d. 3, q. 5 ; Aegidius, de Gen., 1, q. 16 ; Conimbric., Phys., 5, c. 1, q. 1,
a. 3 ; do., Phys., 3, c. 2, q. 2, a. 1 ; Fonseca, Met., 5, c. 15, q. 9, s. 4 ; Scares,
Phys., 3, d. 1, sec. 1 ; Pontius, d. 53, q. 2 ; Toletus, de Gen., 1, q. 6 ; Sotus,
Phys., 3, q. 1 ; Javellus, Phys., 8, q. 8 ; Pereira, de Communibus, 13, cc. 58
and 14, c. 6 ; John of St. Thos., Phys., 1, q. 14, a. 1 ; do., Phys., 2, q. 3, a. 3 ;
Acniirre, de Gen., d. 54, sec. 2 ; Suarez, D.M., d. 46, sec. 3 ; Complut., de Gen.,
d. 2, q. 10 ; Babenstuber, de Gen., d. 3, a. 1. (14) Arist., Phys., 3, cc. 1, 2 ;

St. Thos., Phys., 3, lecta. 2, 3 ; do., Phys., 5, lects. I, 2 ; Scotus, 2, dist. 12,
q. 1 ; Suarez, D.M., d. 49. sec. 2 ; Complut., Phys., d. 49, q. 2, n. 16 ; John of
St. Thos., Phys., q. 14, a. 1 ; Mastrius, Phys., d. 15, q. 5 ; Pontius, Phys.,
d. 42, q. 1 ; Aguirre, Phys., 3, d. 19, sec. 1 ; Soares, Phys., 3, d. 1, sec. 2.

The Motion of Augmentation or Diminution : — (15) Arist., de Gen.,
1, cc. 4, 5 ; do., Phys., 5, cc. 1, 2, 3, 4 ; do., Phys., 4, cc. 4, 14 ; do., de An.,
2 c. 4 ; do., de Gen., 2, c. 2 ; do., Phys., 7, c. 2 ; do., Phys., 6, c. 5 ; St. Thos.,

300 NOTES

de Gen., 1, lects. 10, 11, 13, 14, 15, 16, 17 ; do., Phys., 5, lects. 2, 3, 4 ; do., Phys.,
3, lect. 2 ; do., Phys., 4, lect. 5 ; do., de An., 2, lects. 3, 8, 9 ; do., de Ccelo, 1.
lect. 7 ; do., Phys., 6, lect. 8 ; do., Phys., 7, lect. 4 ; do., Phys., 8, lect. 14 ;
do., & TA., i, q. 118, a. 2, ad. 2 ; do., & Th., i, q. 113, a. 1, ad. 2 ; do., c.

c. 89 ; do., 2, dist. 30, q. 2, a. 1 ; do., Quodl, 8, a. 5 ; Scotus, 1, dist. 47, q. 1 ;
Scotus, 4, dist. 44, qq. 1, 2; Pontius, C.P., d. 45, qq. 1-5; Conimbric., Phys.,
5, c. 2, q. 1, aa. 1, 4 ; Complut,, Phys., d. 22, a. 2 ; Aguirre, P%s., d. 32, sees.

1, 2 ; do., de Gen., d. 35 ; Suarez, de An., 2, c. 6 ; John of St. Thos.. Phys.,

2, q. 7 ; Soares, de Gen., d. 2.

The Motion of Alteration: — (16) Arist., de Gen., 1, cc. 4, 5, 8; do.,
?., 7, cc. 2, 3 ; do., Phys., 5, cc. 2, 4, 5 ; do., Phys., 4, c. 9 ; do., Phys., 8,

c. 3 ; do., Phys., 6, cc. 3, 5, 10, 11 ; do., Phys., 3, c. 1 ; do., de Ccelo, 3, c. 1 ; do.,
de Sens., c. 6 ; St. Thos., de Gen., 1, lects. 10, 14 ; do., Phys., 7, lects. 4, 5, 6 ;
do., de Ccelo, 1, lect. 7 ; do., Phys., 3, lect. 1 ; do., Phys., 5, lects. 4, 6, 7, 8 ;
do., Phys., 6, lects. 5, 7, 8, 9 ; do., de Sens., lect. 16 ; do., Quodl. , 9, a. 9 ; do.,
2, dist. 5, q. 2, a. 1 ; do., 2, dist. 13, q. 1, a. 3, ad. 9 ; do., 4, dist. 17, q. 1, a. 2,
sol. 1 ; do., Phys., 8, lects. 14, 17 ; do., de Verit., q. 28, a. 1 ; do., Phys., 4,
lect. 14 ; do., deCcelo, 3, lect. 3 ; do., Met., 5, lect. 15 ; Scotus, 2, dist. 2, qq. 2, 9 ;
do., 1, dist. 17, q. 4 ; do., 3, dist. 13 ; do., 1, dist. 19, q. 4 ; Pontius, C.P.,

d. 43, qq. 1-7 ; John of St. Thos., Phys., 2, q. 3, aa. 1, 2, 3 ; Conimbric., de
Gen., 1, c. 4, qq. 1, 2, 3, 4 ; do., Phys., 7, c. 3, q. 1 ; Aguirre, Phys., d. 32, sec. 3 ;
do., de Gen., d. 54, sees. 1-4 ; Soares, de Gen., d. 2.

Local Motion :— (17) Soares, Met., 7, d. 1, sec. 1. (18) Arist, Phys.,

4, cc. 1, 3, 7 ; do., Phys., 4, cc. 1, 4, 5 ; do., Phys., 3, c. 1 ; do., Phys., 5, c. 1 ;
do., Phys., S.c.l ; do., Phys., 4, cc. 1, 5, 6, 7, 8 ; do., Met., 11, c. 7 ; St. Thos.,
Phys., 3, lects. 1, 2 ; do., Phys., 7, lect. 3 ; do., Phys., 5, lects. 2, 5 ; do., Phys.,
8, lect. 14 ; do., Met., 12, lect. 7 ; do., Phys., 1, lect. 13 ; do., de Ccelo, 4, lect. 2 ;
do., de Gen., 1, lect. 18 ; do., de Ccelo, 1, lect. 20 ; do., de Gen,, 2, lect. 2 ; do.,

5. Th., i, q. 110, a. 3 ; do., de Pot., q. 6, a. 3 ; do., de Malo, q. 16, a. 10 ; do.,
2, dist. 12, q. 1, a. 1, ad. 5 ; do., de Verit., q. 26, a. 1 ; do., 4, dist. 47, q. 2, a. 2,
sol. 1 ; do., 4, dist. 11, q. 1, a. 3, sol. 1, et ad. 3 ; do., 4, dist. 44, q. 2, a. 3,
sol. 2, ad. 1 ; do., 3, dist. 22, q. 3, a. 1, ad. 1 ; do., Quodl., 6, a. 3 ; do., de Nat.
Loci ; do., de T. Logicce S., tr. 5, cc. de Ubi ; do., c. Gentes, 3, c. 82 ; Scotus,
Quodl., 11 ; Scotus (?), Phys., 3, c. 3, q. 2 ; Scotus, 4, dist. 49, q. 16 ; Pontius,
C.P., d. 17, q. 6 ; do., Phys., 4, d. 45, q. 1 ; Wadding, de Incarn., d. 4, n. 49 ;
Fasol., i, q. 10, a. 1, n. 24 ; Aegidius, de Sacram., q. 75, a. 4, dub. 1 ; Gilbert
Porret., de Sex Princ. ; Soto, Prcedic., c. 9 ; Fonseca, Met., 5, c. 15, q. 7, s. 3 ;
Amicus, de Angelis, d. 5, s. 2, n. 46 ; Babenstuber, Phys., 4, d. 1, a. 3 ; Bellar-
mine, de Euch., 3, c. 3 ; do., de Euch., 4, c. 15 ; Salas, in i, 2, t. 1, tr. 1, d. 3,
sec. 2 ; Tolet., Logica, c. de Ubi ; do., Phys., 3, c. 3, q. 3 ; Martinon, de Deo.,
d. 5, n. 45 ; Valent., i, d. 4, q. 3, punct. 2 ; Gregor., 2, dist. 1, q. 4, a. 1 ; Soncin,
Met., 5, q. 40 ; Hervseus, Quodl., 1, q. 9 ; Durandus, 2, dist. 15, q. 2 ; Jandunus>
Met., 4, q. 4 ; Maior, 2, dist. 2, q. 2 ; Ockham, 2, dist. 2, q. 9 ; de Rhodes,
Phil. Perip., 2, d. 4, s. 3 ; Tiphanus, de Hypostasi, c. 54. (19) Molina,
i, q. 52, a. 1 ; Vasquez, i, d. 188, c. 7 ; Suarez, D.M., d. 51, sees. 1, 2 ; do.,
de Angelis, 4, c. 2 ; Conimbric., Log., c. 9, q. 2, a. 1 ; do., Phys., 3, c. 3, q. 2,
a. 2 ; Arriaga, Phys., d. 14, s. 2, n. 49 ; Compton, Phil. Univ., d. 34, s. 3, n. 3 ;
Hurtado, Phys., d. 14, s. 2, n. 9 ; Lossada, Curs. Phil, 2, tr. 3, d. 2, n. 12 ;
Oviedo, Phys., contr. 15, p. 4, n. 3 ; Soares, Met., tr. 7, d. 1, sees. 1, 2 ; John
of St. Thos., Phys., 2, q. 16, aa. 2, 3 ; Goudin, Logic. Major, d. 2, q. 6, a. 2 ;
etc., etc. (20) Lahousse, Cosmol, c. 3, a. 2, n. 320. (21) St. Thos.,
c. Gentes., 3, c. 82. Cf. St. Thos., c. Gentes, 2, c. 43; do., Phys., 3, lect. 14;
Suarez, D.M., d. 35, s. 6, n. 16 ; Scotus, 1, dist. 3, q. 7 ; Conimbric., Phys., 8,
c. 7 ; do., de Gen., q. 3, a. 1 ; Ferrar., c. Gentes, c. 43 ; do., c. Gentes, 3, c. 82.

The Distinction between the Mover and the Moved : — (22) Phys., 1,
cc. 1, 2. (23) Arist., Met., 12, t. 35; do., Phys., 7, c. 1 ; do., Phys., 8,

cc. 4, 5 ; St. Thos., Phys., 7, lects. 1, 3 ; do., Phys., 8, lects. 7, 8, 9, 10, 22 ;
do., 8. Th., i, q. 2, a. 3 ; do., S. Th., i, 2, q. 36, a. 2 ; do., c. Gentes, 1, c. 13 ;
do., c. Gentes, 3, c. 23 ; do., de Ccelo, 3, lect/7 ; do., 1, dist. 8, q. 3, a. 1, ad. 3 ;
do., de Verit., q. 22, a. 3 ; do., Met., 12, lect. 6 ; do., Op. de Mot. Cordis ; Cajetan,
in i, q. 2, a. 3 ; Bannes, in i, q. 2, a. 3 ; Capreol., 1, dist. 3, q. 3 ; do., 2, dist. 6,
q. 1, a. 3 ; Aegid., Quodl., 3, q. 16 ; do., Quodl., 2, qq. 16, 17 ; do., Quodl, 5,,

NOTES 301

q. 15 ; Ferrar., c. Gentes, 1, c. 13 ; do., c. Gentes, 1, c. 97 ; do., c. Gentes, 3, c. 23 ;
Henrio., QuodL, 11, q. 6 ; Albert., Phys., 8, tr. 2, c. 4 ; Maior, de £ew., 2, q. 1 ;
do., 1, dist. 17, q. 12 ; Soncin., Met., 9, q. 7 ; Conimbric., Phys., 7, c. 1, q. 1 ;
Complut., Phys., 8, d. 28, q. 2 ; Maurus, Qucest. Phil, P-M., q. 8 ; Roselli,
Philos., 2, q. 23, a. 2. (24) Scotus, 2, dist. 2, qq. 9, 10 ; do., 1, dist. 3,'

q. 7, n. 28 sqq. ; Lychet., Comment, in Scotum h. 1. ; Scotus (?), Phys., 6,
qq. 1, 2, 3 ; do., Phys., 4, q. 8 ; do., Met., 2, qq. 4, 5 ; do., Met., 8, q. 3 ; do.,
Met., 9, q. 14 ; Comm. in Met. Scoti, h. 1. ; Mastrius, Phys., d. 15, q. 8, a. 2 ;
Pontius, Phys., 7, d. 48, q. 1 ; Mairon, 2, dist. 14, q. 6 ; Frassen, Phil. Acad..,
Phys., 2, d. 1, s. 1, q. 4 ; do., Phys., 2, d. 1, s. 3, q. 2 ; Jandun., Phys., 8, q. 12 ;
Ant. And., Met., 9, q. 1 ; Gregor., 2, dist. 6, q. 1, a. 3 j Buridan, Niphus, Saxon,
etc., Phys., 8. (25) c. Gentes, 3, c. 150 (151). (26) Suarez, D.M.,

d. 18, sec. 7, n. 35. (27) Suarez, D.M., d. 18, sec. 7, n. 35. (28) John

of St. Thos., Phys., \, q. 22, a. 1, ad primum. (29) Goudin, Phys., q. 6,

a. 1, ad obj.

Physical Terrestrial Motion and the Heavenly Bodies : — (30) Baben-
stuber, de Ccdo, d. 2, a. 1, s. 5 ; Aguirre, d. 67, sects. 1,4; Conimbric., de Ccelo, 2,
c. 5, q. 1 ; Scares, de Ccdo, d. 2, s. 1 ; Arist., de Ccdo, 2, passim ; St. Thos., de Ccdo,
2, passim ; do., 2, dist. 14, a. 1 ; Scotus, 2. dist. 14, q. 2 ; Lychet., Comm. in
Scot., 2, dist. 14, q. 2 ; Pontius, Suppl. Scoti, 2, dist. 14, q. 2 ; "of. Chapter viii —
Astronomy and Alchemy. (31) Arist., Meteor., i, cc. 2, 3 ; do., de Ccdo,

2, cc. 7, 9; do., Phys., 8, c. 9 ; do., de Gen., 2, cc. 9, 10; do., Met., 2, c. 1 ; do.,
de Gen. An., 4, c. 10 ; St. Thos., de Pot., q. 5, aa. 8, 9, 10 ; do., S. Th., i, q. 115,
aa. 3, 4 ; do., S. Th,, i, 2, q. 9, a. 5 ; do., S. Th., ii, 2, q. 115, aa. 1-8 ; do.,
S. Th., i, q. 104, a. 1 ; do., de Verit., q. 5, aa. 9, 10 ; do., c. Gentes., 3, cc. 22,
23, 70, 77, 78, 82-88, 91, 104, 105 ; do., c. Gentes., 2, c. 15 ; do. c. Gentes, 1,
c. 20 ; do., 2, dist. 2, q. 2, a. 3 ; do., 2, dist. 15, q. 1, aa. 2, 3 ; do., Phys., 8,
lects. 13, 14 ; do., de Ccdo, 2, lects. 4, 18, 19 ; do., de Gen., 2, lect. 10 ; do.,
Meteor., 1, lect. 2 ; do., Met., 12, lects. 5, 6 ; do., de Motu Cordis ; do., de Causis,
lect. 3 ; Cajetan in 8. Th., loc. cit. ; Ferrar., in c. Gentes, loc. cit. ; Bannes,
in S. Th., i, q. 115, aa. 1-6; Capreol., 2, dist. 14, q. 1 ; Javellus, Met., 12,
q. 13 ; Soncinas, Phys., 2, q. 4 ; do., 4, dist. 48, q. a. 2 ; T. Hurdaton, P.C.M.,
Prcecursus Phil, de Sens., Int., d. 2, c. 13, digressio ; Roselli, Philos., 3, q. 15,
aa. 1, 2, 3 ; Aguirre, de Ccdo, d. 73, sec. 6 ; Philipp. a. Trin., de Ccelo, q. 6, a. 6 ;
Joannes ab Annunc., de Ccelo, d. 4, qq. 3, 4. (32) c. Gentes, 2, c. 15.

(33) Scotus, 2, dist. 14, q. 3 ; do., 4, dist. 48, q. 2 ; Scotus (?), Phys., S, qq. 2, 7 ;
Pontius, Suppl. in Scot., 2, dist. 14, q. 3 ; Hiqueeus, Comm. in Scot., 4, dist. 48,
q. 2 ; Pitt. Aret., in Scot. Phys., 8, qq. 2, 7 ; Richard, 2, dist. 14, q. 6, a. 2 ;
Durandus, 2, dist. 14, q. 3 ; Henricus, QuodL, 11, q. 15 ; do., QuodL, 14, q. 1 ;
Suarez, D.M., d. 22, sec. 5 ; Conimbric., de Ccelo., 2, c. 3, q. 4, a. 2 ; Hurtado,
de Ccel. Propr., d. 2, s. 4 : Rubius, de Ccelo, 2, c. 3, q. 4 ; Scares, de Ccelo, d. 5,
s. 2, par. 7 ; Pontius, de Ccelo, d. 51, qq. 9, 10 ; Frassen, Phys., 3, d. 1, s. 1,
pars. 15-21 ; Arriaga, de Ccelo, d. un., n. 65 ; De Rhodes, Phil Perip., 2, d. 8,
q. 3.

Physical Motion and the Infinite :— (34) Phys., 5, lect. 1. (35) St.

Thos., 2, dist. 37, q. 2, a. 2 ; do., S. Th., i, q. 105, a. 5 ; do., S. Th., i, 2, q. 109 ;
do., c. Gentes, 3, c. 70 ; Albert. M., 2, dist. 35, a. 7 ; Scotus, 1, dist. 8, q. 5 ;
do., 2, dist. 1, q. 1 ; do., 2, dist. 37, q. 2 ; do., 4, dist. 43 ; St. Bonaventure, 2,
dist. 37, a. 1, q. 1 ; Suarez.. D.M., d. 22. In the twelfth century a number of
Schoolmen denied the existence of this immediate concurrence. In the four
teenth and fifteenth centuries another group of dissenters arose : Durandus
denied it : Ockham denied that it could be proved philosophically ; Gabriel
thought the view of Durandus probable ; Gregory subscribed to the opposite
view merely as more probable. There were dissenters also in the seventeenth
century : Lalemandet agreed with Durandus and claimed for that view Prse-
positivus (a distinguished contemporary of St. Thomas), Varo, Peter d'Auriol,
and Peter d'Ailly : Arriaga and Hurtado were inclined to agree with Ockham ;
Ludovicus a Dola, O.S.F.C., admitted immediate concurrence in non-free
actions, but denied it in free actions. Cf. Aguirre, Phys., d. 16, s. 1 ; Compton,
Phys., d. 28, s. 1-3 : Babenstuber, Phys., 2, d. 5, s. 1 ; Lalemandet, Cursus
Philosophicus (1656, 2nd ed.), pp. 392-408.

302 NOTES

CHAPTER X.

Philosophy (1901), pp. 310-346 ; Erdmann, History of Philosophy, vol. i (1898),
pp. 356-542 ; Fr. J. Rickaby, S.J., Scholasticism, cc. 4, 5, 6 ; De Wulf, Intro
duction d la Philosophic Neo-Scolastique, i, c. 3. (2) Phys., 1, tr. 1, c. 1.
(3) Phys., 8, tr. 1, c. 14. (4) S. Th., i, q. 1, a. 8, ad. 2. (5) On this
controversy between the Schoolmen and the Scientists, cf. Laminne, Les Quatre
Elements. (6) Sylvester Maurus, Qucest. Phil., 1. 3, q. 5 ; Aguirre, de Cadof
dd. 64-70 ; Schnell, Curs. Phil., iii, p. 16 ; Franciscus B. Spei, Comment. Un.
Arist. Phil., iii, p. 13 ; Laurentius, Curs. Phil., ii, p. 274 : Van Sichen, Int.
Curs. Phil, ii, p. 142 ; J. Duhamel, Phil. Univ., v, p. 26 ; Froidmont, Meteor.,

ii, d. 1, q. 2, a. I ; Mailhat, Summa Phil., ii, p. 34 ; Mastrius, de Gen., p. 539 ;
Roselli, iii, pp. 112-207 ; J. B. Duhamel, Phil Vetus et Nova, ii, pp. 356 sqq. ;.
Jerome de Montefortino, Summa Scoti, ii, p. 249 ; Wenzl, Phil Ang. -Thorn.,
de Olo, q. 1 ; Amort, Phil. Poll, pp. 745-856 ; Krisper, Phil Sch. Scot., p. 321.
(7) Sylv. Maurus, Qucest. Phil, iii, q. 48. (8) Goudin, Phil, ii, d. 1, q. 3.

a. 1. (9) Ferrari, Phil Perip., Phys., i, q. 5. (10) Sylv. Maurus, ii,

q. 36 ; Boyvin, Philos. Scoti, iii, p. 542 ; Baro, Scotus Defensus, ii, p. 223 :
Goudin, Phil, ii, q. 3, a. 2 ; Ferrari, Phil Perip., ii, p. 229. (11) John of

St. Thomas, C.P. Th., iii; Sylv. Maurus, Qucest. Phil, iii; Goudin, Phil. Thorn.*
Phys., iii ; Ruvius, Comm. in Arist. de Gen. Corr. ; Eustachius de St. Paul,
Summa Philos. ; Philip a S. Trinit., Summa Phil ; Boyvin, Phil Scoti, iii ;
A. Laurentius, de Triplici Ente ; C. Melchoir, Philosophia ; C. Carleton, Curs.
Phil ; Complutenses, Disput. in Arist. Log. et Phil. Nat. ; Mailhat, Philos. ;
Aguirre, Phil Rat. ; Hurtado de Mendoza, Disput. in Un. Phil All these
belong to the seventeenth century. In the eighteenth century the following
support this view : J. Duhamel, Phil Univer., v ; Babenstuber, Phil Thorn.,
iii ; Billuart, de Opere Sex Dierum, ii, a. 2 ; Krisper, Phil. Schol Scot., Phys.,
p. 341 ; Schnell, Curs. Phil Arist.-Thom., iii, p. 37 ; Roselli, Summa Phil, 4,
q. 17 ; Buecher, Prima Phil Experim. Principia, etc. In the nineteenth cen
tury, the following support this view : P. Puigserver, Phil S. Thomas ; A. Sendil,
de Vera . . . Philosophia; V. Mareddu, Annotator of Goudin. (12)

Arriaga, C. Phil, p. 406 ; Pontius, Int. Phil Curs., p. 687 ; Baro, Scotus
Defense, p. 224 ; N. Arnu, Dil Philos. Synt. ; J. B. Duhamel, Phil. Vetus et'
Nova, ii, p. 67. All these are of the seventeenth century. Eighteenth century
supporters are : Frassen, Phil A cad., iii, pp. 85 sqq. ; Ferrari, Phil Thorn. ;
Mastrius, Disput. de Gen. et Corr. ; Agnani, Phil Neo-Palcea ; Mangold, Phil
Rat. et Experim. ; Wenzl, Phil Ang.-Thom. ; Amort, Philos. Polling. (13)

Bouvier, Instit. Phil ; Galuppi, Elementi di Filosofia ; Delalle, Cours de Phil
Chret. ; Buezinski, Instil Philos. ; Blatairon, Instil Philos. ; De Decker,
Cours. Elem. de Phil ; Rattien, Cours Complet de Phil. ; Brunon, Elementa
Phil ; Noget, Instil Phil ; Balmes, Curso de Filosofia Elemental ; Gibon,
Cours de Philos. ; Dameron, Cours de Phil ; Rothenflue, Instil Phil Theor. ;
Deutinger, Grundlinien einer posit. Phil ; Ubaghs, Elementa Lor/, et Meta. ;
Dmowski, Instil Philos. ; Doney, Nouveuux Elements de Phil ; H. de Ferrari,
Phil Thorn. (14) Boscovich, Theor ia Phil. Nat. ; Contzen, Prod. Met. ;

Storchenau, Instit. Met. ; Horvath, Instit. Log et Met. ; Bech, Instil Met. ;•
Genovesi, Elementa Met. ; Ernesti, Initia Doct. Solidioris ; Palmieri, Instil*.
Philos. (15) Rickaby, S.J., Scholasticism, pp. 49, 50.

INDEX.

Accidents, material, Aristotle on, 115-
117 ; accidents and primordial mat
ter, 131-140; distinction between
accidents and substance, 168-173 ;
origin of accidents, 173-175 ; exist
ence of accidents, 175-177 ; indi-
viduation of accidents, 177.

Action, at a distance, 236-238.

Activity of matter, 229-239.

Actuality, 100, 206-217, 241-243.

Aether, of Aristotle, 90.

Air. See Elements.

Albert, the Great, 123, 142-143, 148,
219.

Alchemy, 204.

Alphonso, of Castile, 203, 257.

Alteration, 246.

Anaxagoras, 61-63, 77, 123.

Anaxamander, 47, 71-72.

Anaximenes, 48, 71-72.

Annihilation, 47.

Appollonius of Perga, 203.

A priori, character of later Scholas
ticism, 272.

Aristarchus, of Samos, 271.

Aristotle, on the division of philosophy,
15-16 ; his Physics, 16-18 ; on the
Milesians, 71-72 ; on the Pytha
goreans, 72-73 ; on Heracleitus,
73-74 ; on the Eleatics, 76 ; on
Anaxagoras, 77 ; on the Atomists,
77-83 ; on Plato, 83-84 ; his theory of
scientific proof, 85-89 ; on the terres
trial and celestial universe, 89-91 ;
on the structure of the heavens,
91-94 ; on the interaction of terres
trial and celestial bodies, 94 ; on the
shape of the universe, 95 ; on the
universe as a whole, 95-97 ; on the
possibility of change, 98-103 ; on
accidental change, 103-104 ; on sub
stantial change, 104-106 ; on pri
mordial matter, 106-109 ; on sub
stantial form, 109-115 ; on substance
and attribute, 115-117; medieval
controversy concerning his view of
primordial matter, 123 ; on the
possibility of accidents in primordial
matter, 132 ; medieval dispute con
cerning his view of the permanence

or non-permanence of the elements
in a true mixture, 142 ; on the origin
of substantial form, 146 ; medieval
dispute concerning his view of the
relation between primordial matter
and the essence, 154-157 ; on the
problem of union, 158-159 ; on quan
tity, 183-184 ; on the endless divisi
bility of continua, 193-194 ; on sense
perception, 206-211 ; on the Demo-
critean theory of the proper sensibles,
211-217 ; on 'gravity and levity, 220 ;
on density and rarity, 220-222 ; on
artificial form and figure, 223 ; on
impetus, 225 ; on the intensification
and remission of material qualities,
227 ; on the active qualities of
matter. 230 ; on the distinction
between action, passion and motion,
233-234 ; on contact between agent
and patient, 236 ; on unlikeness
between agent and patient, 238-239 ;
on the word " motion," 240 ; on
potency and actuality as employed
in defining motion, 241-242 ; on the
definition of physical motion, 243-
244 ; on generation and corruption,
244-245 ; on alteration, 246 ; on
local motion, 247 ; on the distinc
tion between the mover and the
moved, 249 ; on physical terrestrial
motion and the heavenly bodies,
257-258 ; on the presuppositions of
motion, 262 ; the overthrow of his
empirical science, 268-269 ; on the
strict meaning of potency, 280, note
(10); his usage of the name, TT^TTJ V\TJ,
281, note (21) ; on the passivity of
primordial matter, 282, note (29) ;
on the analogous usage of matter and
form, potencv and actuality, 283,
note (62) ; his rejection of cosmo-
logical kineticism, 298-299.

Arithmetic, Egyptian, 8.

Artificial, form and figure, 223.

Astrology, 10, 259.

Astronomy, Babylonian, 9 ; Aristo
telian, 91-94 ; medieval, 203-204,
256-258.

Athenians, 5.

Atomism, dynamic, 118 ; Greek, 63-
66, 77-83."

303

304

COSMOLOGY

Augmentation, 245.
Averroes, 123-124, 142, 154.
Avicenna, 123, 142, 154.

Babylonian, astronomy, 9
Berzelius, 269.
Bohr, 241.
Boscovitch, 272.
Boyle, 269.
Brightness, 217-220.
Bushmen, 5.

C

Caloric, 269.

Cardan, 269.

Causality, 21, 71, 85-86, 229-239.

Change, its possibility, 98-103 ; acci
dental, 103-104; substantial, 104-
06 ; generation or corruption, 244-
245 ; augmentation or diminution
245-246; alteration, 246; local

motion, 246-249; conditions of

change, 236-239, 249-262.
Chemistry, 23, 269, 271.
Cicero, 267.
Coldness, 91, 230.
Colour, 205-206, 209, 212-213, 217-

Combination, of the elements, 76 79-81

83, 104-106, 121, 131-140.
Compenetration, 191.
Contact, and action, 236.
Continua, 193-201.
Copernicus, 88, 268, 271.
Corruption. See Change.
Cosmogony, 4.
Cosmology, its purpose, 35-39; its

utility, 39-41 ; its method, 41-45 ;

decadence of Scholastic Cosmology

269-272 ; Leonine revival, 273.
Creation, 47.

Dispositions, previous and ultimate,

136-138.
Distinction, between the mover and the

moved, 249-256.
Divination, 3.
Divisibility, 193-196.
Durandus, 129, 148, 155-156, 178, 184-

186, 228, 301, note (35).
Dryness, 91, 230.

R

Earth. See Elements.
Eduction, of form, 146-154.
Effect. See Causality.
Egyptian, philosophy, 7-8; mathe
matics, 8-9.
Einstein, 24.
Sleatics, 56-59, 74-76.
Elements, the four, 59, 67, 76, 83, 90-91
104-106, 121, 123, 142-145, 204, 268-

Emanation, 173-174.

Impedocles, 59-61, 76.
Empirical science, 19-29, 87-89, 268-
269, 273.
Inergy, 24.

Inlightenment, the Greek, 5-7.
, Epicurus, 6, 123.
Essence, 71, 73, 85-86, 113, 155-157,

159-162, 166-168.
Eudemus, 70.
Euler, 23.
Eurytos, 50.

Experiment, 7, 18, 88, 268-269.
Explanation, 25, 85.

D

Dalton, 23.
Davy, 269.
Democritus, 63, 77, 81, 123, 206-207,

^Li-2i7, 231.
Density, 220-223.
Descartes, 19, 21, 268-269, 297.
Dialectic, 86.

Diaphanous. See Transparency.
Dickens, 35.
Diels, H., 277.
Dimanation, 173-174.
Dimensions, and primordial matter >

123, 164-166.

Faith, 276, note (12).

Faraday, 23.

Figurate numbers, 50.

Figure, and artificial form, 223.

Final Cause, 81-83.

Fire. See Elements.

Flow-of-motion, theory of causality

230-233, 298-299.
Force, 205-233, 297-298.
Form, substantial, 106, 109-115, 141-

154; accidental, 103-104, 168-178,

217-229, 269.

Four elements. See Elements.
Fracastorius, 203.
Fresnel, 23.

G

Galileo, 21, 22, 24, 25, 268.
Generation, 56-57, 59-60, 61-63, 64,

67-69, 76, 79-81, 83, 91, 104-106,

121, 131-141, 244-245.

INDEX

305

Geocentrism, 22, 91-97, 203-204, 268,
273.

God, 6, 262, 275, note (8).

Gods, Greek, 2-6.

Greeks, the, conquests and colonisa
tions, 2 ; myths and rites, 3-5 ; their
creation of science, 5-7 ; originality,
7-10; rational theology, 6, 10-11;
pre- Aristotelian cosmologists, 46-84 ;
Aristotelian natural science, 85-97 ;
Aristotle's hylemorphism, 98-117 ;
post-Aristotelian Greek cosmolo
gists, 117-118.

Guericke, Otto von, 268.

II

Heart-beats, 255-256.

Heavens, 89-97, 203-204, 268, 273.
See Astronomy.

Hegel, 22, 29, 34.

Heliocentrism. See Geocentrism.

Helmholtz, 24, 25.

Heracleitus, 51-56, 73-74.

Hermodorus, 70.

Hesiod, 4.

Hipparchus, 257.

Homer, 4.

Hotness, 91, 230.

Hume, 21.

Huygens, 21, 24.

Hylemorphism, the possibility of
change, 98-103 ; substantial change,
104-106 ; Aristotle on primordial
matter, 106-109 ; Aristotle on sub
stantial form, 109-115 ; Aristotle on
substance and attribute, 115-117 ;
medieval proofs, 121-123 ; medie
valists on primordial matter, 123-
141 ; medievalists on substantial
form, 141-154 ; medievalists on pri
mordial matter and the essence, 155-

157 ; medievalists on union, 157-

158 ; medievalists on totality, 158-

159 ; medievalists on the individua-
tion of material substance, 162-166 ;
medievalists on the relations between
material substance and accidents,
168-178 ; myth concerning the hyle
morphism of Aristotle, 284-285;
myth concerning the hylemorphism
of St. Thomas, 289.

Hypothesis, 7.

Impenetrability, 192-193.
Impetus, 225-227.
Indian philosophy, 8
Indivisibles, and continua, 193-19O,
199-201.

Intensification, of material qualities,

227-229.
lonians, 5.
Irrational science, 29-35.

K

Kant, 22.

Kelvin, Lord, 23, 24, 29-35.

Kepler, 22, 268.

Kineticism, cosmological, Descartes,
19, 21, 23, 25 ; the Greek Atomists,
64-66, 77-83, 211-217, 231 ; Aris-
totelico-Thomistic refutation of cos
mological kineticism, 205-211, 229-
236 ; a modern myth attributing
kineticism, in Cosmology, to Aris
totle and St. Thomas, 297-299.

Laplace, 22.

Lavoisier, 269.

Laws of nature, 3.

Legalistic, character of later Scholasti
cisms, 272.

Leibniz, 19.

Leo XIII., 273.

Leucippus, 63.

Likeness, and action, 238-239.

Light, 217-220.

Local motion, 246-262.

Love, and strife, Empedocles, 59-61
76.

M

Marsilius, of Inghen, a strange saying
of, 286, note (3).

Master of the Sentences, 156.

Materialism, 66.

Matter. See- Primordial matter, Sub
stantial form, Change.

Maxwell, 23.

McDonald, Dr., 277, note (37), 297-299.

Mechanics, modern, 24-26.

Media, of sensation, 206-211.

Melissus, 58, 76.

Method, Aristotelian scientific, 85-89.

Milesians, 46-48, 71-72.

Mixture, perfect and imperfect. aee
Combination of the elements.

Modes, physical intrinsic, 178-182.

Moist, the,' 9 1,230.

Motion, ambiguity of the medieval
word, 240-241 ; "definition, 243-244 ;
generation or corruption, 244-245 ;
augmentation or diminution, 245-
246 ; alteration, 246 ; local motion,
246-249 ; conditions of physical
motion, 249-262.

306

COSMOLOGY

Mysteries, 11.

Myths, 2-6, 284-285, 289, 298-299.

N

Nature, laws of, 3.

Newton, Sir Isaac, 21, 22, 25, 31-32, 34

268, 269.
Nominalism, 168, 171-173, 184, 200

201, 234-235, 236-238.
Nous, 62-63, 77.

0

Observation, Aristotle's gift of, 87-89.
Occasionalism, 229, 276 note (17), 297.
Odour, 205, 212, 214.
Opposites, union of. See Heracleitus.
Orbits, planetary. See Heavens.
Oriental, influences on Greek thought,
8-10.

Palmieri, 284-285, 289.
Pantheism, 6.
Parmenides, 56-57, 74-76.
Parts, in a continuum, 196-199.
Passion, in reference to action and

motion, 233-236.
Pater, W., 41-42.
Penetration, 191.
Perception, sense, 206-217.
Philosophy, and science, 10-11, 19-22 ;

and Catholicism, 11-15, 39-41, 275

notes (8)-(12), 277 note (37), 297.
Phlogiston, 269.
Physical qualities, of Democritean

atoms, 64, 78-81.
Physics, modern, 18-29, 268-269.
Planck, 22.

Planets. See Heavens, Astronomy.
Plato, 11, 66-70, 83-84, 109-111, 147-

148, 155-157.
Plotinus, 118.
Points, distended, 195-196.
Post- Aristotelian, Greek theories of

matter, 117-118.
Potency, Aristotle's discovery of, 98-

103 ; eduction of substantial form

from potency, 146-154 ; Aristotle's

strict conditions for potency, 280,

note (10) ; Aristotle's analogous use

of this term, 283, note (62).
Primary, qualities of matter, 205-217.
Primordial Matter. Aristotle's view of,

104-109; the medieval view, 121-

129 ; its distinct existence, 129-131 ;

its relation to accidents, 131-141 ;

Aristotle's usage of this name, 281,

note (21).

Privation, 98-103.

Projectiles, free flight of, 225-227.

Property, in the cosmological sense

17-18, 85-86, 115-116, 173-175
Ptolemy, 203-204, 271.
Pythagoreans, 48-51, 72-73.

Qualities of matter, the four primary,
91 ; the distinction between primarv
and secondary qualities, 205-206";
the existence, as distinct formal
accidents, of the proper sensibles,
206-211 ; other important medieval
qualities, 211-227; intensification
and remission, 227-229 ; active
qualities of matter, 229-230 ; medie
val rejection of kineticism and occa
sionalism, 230-236 ; conditions of
qualitative activity, 236-239.

Quantity, Aristotle on, 116-117; the
medieval outlook, 145, 184-186 ; its
essence, 186-191 ; its secondary
effects, 191-193 ; endless divisibility,
193-196 ; the manner of the exist
ence of parts in a continuum, 196-
199 ; indivisibles in a continuum,
199-201.

Quidquid movetur, etc., 249-256.

R

Rabelais, on the Aristotelian School
men, 264-265.

Rarity, 220-223.

Rationalism, 2-15, 275, notes (7)-(12).

Remission, of material qualities, 227-
229.

Renaissance, 264.

Resistance. Sec Impenetrability.

Resultance, 173-174.

Revelation, and rationalism, 11-15, 40,
275, notes (7)-(12).

Rhind, papyrus, 8.

Rickaby, Fr. Jos. S.J., 119-120, 263,
272.

Rumford, 23, 269.

Rutherford, 24.

S

Savour, 205-206, 212, 213.

Schoolmen, list of medieval, 285-286.

Science, its creation, 2-10 ; modern
natural science, 18-28, 268-269;
Aristotelian natural science, 15-18,
85-97, 268-269 ; manufacture and
diffusion of irrational science, 29-35.

Scientific proof, Aristotelian, 85-89.

INDEX

307

•Scotus, and Aristotle, 1 1 ; on the appli
cation of the term actuality, to
primordial matter, 128-129 ; on the
distinct existence of primordial
matter, 129-131 ; on the possibility
of accidents in primordial matter,
131-134 ; on the ultimate subject of
inhesion for accidents, 140 ; on the
unicity of substantial form in non
living bodies, 145 ; on the efficient
cause of the substantial form, 152 ;
on the nature of union, 157 ; on the
nature of totality, 158 ; on the dis
tinction between essence and exist
ence, 159 ; on the principle of
individuation in material substances,
163 ; on subsistence, 167 ; on the
distinction between substance and
material accidents, 170-171 ; on the |
origin of accidents, 174 ; on the
existence of the accident, 175 ; on
the individuation of the accident,
177 ; on modes, 179 ; on the essence
of quantity, 187 ; on endless divisi- j
bility, 195 ; on parts within a con- i
tinuum, 197 ; on indivisibles within
•a continuum, 199 ; on brightness,
219 ; on the natural motion of the
elements, 220 ; on density and
rarity, 222 ; on impetus, 225 ; on
intensification and remission, 228- j
229 ; on the meaning and location of
action, 234-235 ; on action at a
distance, 236-238 ; on ubication,
247 ; on the distinction between the
mover and the moved, 252-255 ; on
the universal causality of the
heavenly bodies, 260-261 ; on the
divine concurrence, 262 ; his part
in making Aristotle the Philosopher
of medieval Catholicism, 270.

'Secondary qualities of matter, 205-206.

Sensation, medieval view, 205-217.

Sensibles, proper and common, 205-206,
211-217.

Soto, 131, 148, 161, 244.

Sound, 205-206, 212, 214.

Species, sensibilis, 208-211.

Suarez, and Aristotle, 11 ; on the hyle-
morphic composition of the heavenly
bodies, 122 ; on the application of
the term, actuality, to primordial
matter, 128 ; on the distinct exist
ence of primordial matter, 129-131 ;
on the destruction of accidents during
substantial change, 134-140 ; on the
nature of substantial form, 141-142 ;
on the unicity of substantial form,
145 ; on the efficient cause of sub
stantial form, 152-153 ; on union,
157 ; on totality, 158 ; on essence
and existence, 159 ; on the principle
of individuation in material sub

stances, 163-164 ; on subsistence,
167 ; on the distinction between
substance and material accidents,
169 ; on the doctrine of Durandus
and the Nominalists concerning
quantity, 171-173, 185-186 ; on the
origin of accidents, 174 ; on the
existence of the accident, 175 ; on
the individuation of accidents, 177 ;
on modes, 178-182 ; on the essence
of quantity, 187-191 ; on impenetra
bility, 192^-193 ; on the parts within
a continuum, 197 ; on the indi
visibles of a continuum, 199 ; on
brightness, 219 ; on gravity and
levity, 220 ; on occasionalism, 229 ;
on action at a distance, 236 ; on
ubication, 247 ; on Quidquid move-
tnr, movetur ab alio, 255-256 ; on
the universal causality of the
heavens, 260-261 ; on the divine
concurrence, 262 ; his silence con
cerning heliocentrism, 271.

Substance, in matter, 104, 115, 121-122,
168.

Substantial form, Aristotelian view,
109-115 ; medieval view, 141, 155-
157 ; its unicity, 142 ; its simplicity,
145 ; its origin, 145-153 ; its dis
appearance, 153-154.

Tangibles, 91, 205, 212-213.

Tasmanians, 5.

Taylor, Prof. A. E., 36.

Teleology, of Aristotle, 81-83.

Tertullian, 13.

Thales, 47, 71-72.

Theism, rational, 6, 12, 41, 275, note (8).

Thomas, Saint, the writings of, 286 :
his appreciation of the rational
theism of Aristotle, 11-12; on the
greater merit of faith in the learned,
15 ; on Cosmology as a necessary
basis of rational theism, 41 ; on the
historic method in metaphysics, 43-
44 ; on the eclectic and critical
methods of studying philosophy,
44-45 ; on the proofs of hylemor-
phism, 121-122; on the nature of
primordial matter, 123-127 ; on the
origin and unity of primordial mat
ter, 127-128 ; on primordial matter
as pure potency, 128-129 ; on the
distinct existence of primordial
matter, 129-131 ; on the destruction
of all the accidents in changes of
substance, 131-140 ; on substantial
form, 141 ; on the unicity of sub
stantial form in non-living bodies,
142-145 ; on the simplicity of sub-

308

COSMOLOGY

stantial form in non-living bodies,
145-146 ; on the origin of substantial
forms, 145-148 ; on the efficient
cause of substantial forms, 150-152 ;
on the disappearance of substantial
forms, 153-154 ; on primordial mat
ter and the essence, 155-157 ; on
union, 157-158 ; on totality, 158-
159 ; on essence and existence, 159-
162 ; on the individuation of
material substance, 163-166 ; on
subsistence, 166-168 ; on the dis
tinction between substance and
material accidents, 168-170 ; on the
origin of accidents, 173-175 ; on the
existence of the accident, 175-177 ;
on the individuation of the accident,
177-178 ; on modes, 179 ; on the
essence of quantity, 187, 292, note
(7) ; on impenetrability, 192 ; on
the endless divisibility of continua,
193-194 ; on parts within a con
tinuum, 196-199 ; on indivisibles of j
a continuum, 199-201 ; on medieval
astronomy, 203-204 ; on alchemy,
204 ; on primary and secondary
qualities, 205-206 ; on sense-percep- i
tion, 206-211; on Democritean j
kineticism concerning colours, |
sounds, savours, odours, and, apart j
from extension, tangibles, 211-217 ; j
on light and brightness, 217-219 ; I
on gravity and levity, 220 ; on den- j
sity and rarity, 221 ; on artificial j
form and figure, 223 ; on virtual or j
occult qualities, 223-225 ; his denial j
of impetus, 225 ; on the intensifica- j
tion and remission of material quali
ties, 227-228 ; on occasionalism,
229 ; on the active qualities of
matter, 229-230 ; on the flow-of-
motion theory of causality, 230-233,
298-299 ; on action, passion and
motion, 233-234 ; on action at a
distance, 236-237 ; on unlikeness as
a condition of action, 238-239 ; on
the ambiguity of the term, motion,
240-241 ; on potency and actuality,
241-242 ; his definition of physical
motion, 243-244 ; on generation or
corruption, 244-245 ; on augmenta
tion or diminution, 245 ; on altera
tion, 246 ; on local motion, 246-249 ;

on Quidquid movetur, movetur ab alio*
249-252 ; on physical terrestrial
motion and the heavens, 256-260 ;
on the divine concurrence, 262 ; the
overthrow of the empirical basis of
Thomistic Cosmology, 268-269 ; the
fight made by St. Thomas, in the
thirteenth century, for the then
needed reform of Catholic philosophy,
270 ; Pope Leo's advice on the
needed reform of Thomistic Cos
mology in our day, 273 ; St. Thomas
and cosmological kineticism, 298-
299.

Totality, the problem of, 158-159.

Traditionalism, 12 ; a recurring weak
ness of popular apologetics, 275,
note (8).

Transparency, 217-219.

Tycho-Brabe, 268, 271.

IT

Ubication, 246-249.
Union, the problem of, 157-158.
Universe, the Aristotelian, 89-97
medieval, 203-204, 256-258.

Vasquez, 179, 266-267.
Violent, motion, 251.
Virtual, actuality, 252-254.
Void. See Atomism, Greek.
Vortex, motion, 65-66.

W
Water. See Elements.

Young, 23.

Zeno, 57-58, 75-76, 195.
Zeller, Prof. E., 84-85.

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