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When Huxley declares that Descartes advanced v 
beyond his age and anticipated what would be the 
thoughts of all men three hundred years after him, 
he has mainly in view Descartes' achievements in/ 
the natural sciences. And in that relation the 
assertion is undoubtedly justified. In a more 
adequat©^ manner than even Galileo or Bacon, 
Descartes formulated the methods and defined the 
ideals of modern^flcignce. A very different estimate 
must, however, be made of his work in 
metaphysics. Though the new and definite concep- 
tion of nature which he derived from his studies 
in the sciences, enabled him to state the problem 
of perception, and the problem of the relation of 
mind and body, much in the form in which they 
persist to the present day, his metaphysical teaching 
is perverted, I shall try to show, by principles 
wholly at variance with his own positive scientific 


views. If the interpretation which I give of 
Descartes' philosophy be correct, it is no exaggeration 
to assert that all that lies outside his philosophy 
of nature, or is not illumined by a reflex light 
from it, remains in essentials scholastic in con- 

My original intention, therefore, was to dwell 
chiefly upon Descartes' philosophy of the sciences 
as the really important part of his system ; but 
realising more and more fully as I proceeded in 
my study of the subject, how very artificial is the 
connection between his metaphysics and his 
scientific views, I came to the conclusion that sepa- 
rate treatment of them would be advisable. His 
philosophy of nature I have reserved for future 
consideration, and i n this _^pre.flftnt .volume limit 
^, ^i^ myself, as far as possible, to his metaphysics. I first 
examine his metaphysical principles as they appear 
in his own writings ; and then, by tracing their 
influence on the thinking of ^ his successors, seek to 
determine further tljieir^iiiaphcations and conse- 

If we except the late Professor Veitch's volume 
of translations, the preface of which is written from 
a point of view no longer generally received, there 



is but one English work — that of Professor Mahaffy 
in the Blackwood Philosophical Series — exclusively 
devoted to Descartes. And as Professor Mahaffy's 
book is mainly biographical, I consider that no 
apology is required for this attempt to examine in 
detail the principles of the Cartesian Philosophy. 
I may add that though this volume is not designed 
to be an introduction to the study of Descartes, I 
have throughout presupposed only such knowledge 
of the period as may be gained from any history 
of philosophy. I may specially refer the reader to 
that section of Kuno Fischer's history, which has 
been translated into English under the title, Descartes 
and His School, 

To the late^ Professor Adamson I am indebted 
both for guidance in the literature of the subject 
and for assistance in special difficulties. On one 
point in particular, viz., Descartes* view of time and 
its significance in his metaphysics, I received from 
him invaluable suggestions of which I have sought 
to make good use. In the autumn of last year 
Professor Adamson read through my manuscript 
and made several important criticisms. Professor 
Henry Jones and Professor A. S. Pringle Pattison 
have rendered me the same service, and for 


their comments, by which my book has greatly 

profited, I am most grateful. My thanks are 

also due to my friend, Mr. William Menzies, for 
reading the proofs of the whole book. 

September y 1902. 





Aristotle and Descartes, l/ Augustine's treatment of 
the problem of knowledge, 4. The advance from 
Augustine to Descartes, 10. The influence of the 
mathematical sciences, 11 K The Cartesian dualism, 12. 
The cogito ergo sum a consequence of that dualism, 13. 
The dualism raises new difficulties as to sense-percep- 
tion, 15. Descartes' farther dualism of thought and 
sense, 17. 



True knowledge is certain and indubitable, 19. Such 
knowledge is involved in ordinary experience, 20. 
Descartes' method of separating out the indubitable 
from the doubtful, 22. Why the problem of method 
is so all-important, 23. ^The characteristics of the 
mathematical method, 27^ Descartes criticises the 
empirical method of Bacon, 27. Descartes' method 
though deductive is not syllogistic, 28. Deduction and 


intuition, 32. Intuition is the source of all our know- paok 
ledge, 33. Descartes' answer to the double question of 
the method and limits of knowledge, 35. The ' simple 
natures,* 36. They are all abstract conceptions, 38. 
Descartes seeks to make science purely conceptual, 39. 
Spontaneous generation from simple conceptions 
asserted to be their peculiar characteristic, 41. Greo- 
metrical science is perceptive, not conceptual, 43. So 
also is arithmetical science, 45. The ' simple natures ' 
cannot be isolated units, 46. Conclusion, 47. 



I. Introductory. 

The cogito ergo sunif 48. Can be interpreted in two 
ways, 49. Is a consequence of the dualism from which 
Descartes starts, 51. The criterion of truth, 52. Des- 
cartes' proofs of God's existence, 54. He interprets 
the criterion of truth in the light of the scholastic 
doctrine of essence, 60. Hence his occasionalism, 62. 

II. The concjeptions involved in our knowusdoe of 


Matter and extension, 65. Figure, motion, and ex- 
tension, 68. Descartes' dualism conceals a purely 
relative trinity of matter, motion, and mind, 70. Why 
Descartes yet asserts motion to be a mere mode of 
extension, 71. His view of time and of causation, 72. 
Descartes interprets motion in two ways, geometrically 
and mechanically, 75. And accepts occasionalism, 77. 


The relation of soul and body in sense-perception, 80. 
In bodily movement, 82. In feeling and emotion, 83. 
The conseqaences of Descartes' rationalism are em- 
phasised by Malebranche, 85. Conclusion, 88. 


Mind is identified with consciousness or thought, 89. 
Descartes' two views of consciousness, 90. Male- 
branche's criticism, 92. Space cannot be perceived by 
the mind as a state of itself, 92. Sensations, feelings, 
and emotions, the only known modes of mind, 94. 
Occasionalism again the outcome of Descartes' meta- 
physics, 95. Descartes' contention that mind is better 
known than matter disproved by Malebranche, 97. 
Malebranche asserts the possibility of a rational 
deductive science of mind, 101. This is the natural 
extension of the rationalism of Descartes, 106. Con- 
clusion, 107. 

IV. Thought and will. 

Descartes regards thought as passive, 108. The will 
must therefore be regarded as quite distinct from 
thought. 111. His rationalism is thus undermined, 113. 
General conclusion, 115. 

Appendices to Chapter III. 

A. Arnauld's denial of the doctrine of representative 

perception, 115. 

B. Descartes' theory of perception, and account of the 

relation between sense and understanding, 117. 


C. Descartes' view of time and of finite existence in paoe 

time, 128. 

D. The Cartesian views of consciousDess, 133. 




Spinoza — His fundamental position, 137. He denounces 
all explanation through general or abstract notions, 138. 
The conflict of tendencies in his philosophy, 141. He 
adopts the mathematical method of Descartes, 142. 
And therefore identifies causation with explanation, 
143. His doctrine of method, 144. The consequences 
of his rationalistic view of causation, 146. His theory 
of the attributes, 148. He adopts and extends Des- 
cartes' ideal of physical explanation, 149. And applies 
it to mind, 151. Qe gives no account of the causal 
relation proper, 152. He fails to carry out his method, 
153. His concrete view of God and of the attributes, 
156. Conclusion, 160. 

Leibniz — The fundamental argument for his monadism is 
derived from his rationalism, 160. The principle of 
identity and the principle of sufficient reason, 165. 
He combines his rationalism with an equally extreme 
spiritualism, 167* As a result modifies his rationalism, 

169. His treatment of the mechanical world in space, 

170. His view of the relation of thought and sense, 

171. His views on the innateness of knowledge, 172. 
He follows Descartes in regarding ideas as the objects 
of mind, 174. His introduction of the conception of 
the unconscious, 175. At times he indicates a different 
view of ideas, 176. He cannot on his principles account 
for sense-experience, 178. Conclusion, 180. 





Why Locke regards all sensations as isolated and 
atomic, 181. He adopts the Cartesian dualism, 184. 
His way of regarding ideas, and his spiritualism, 185. 
His method, 188. Locke on the cogito ergo sum^ 189. 
On the sources of experience, 189. His analysis of the 
conception of substance, 191. His doctrine of sub- 
stance partially frees him from the false rationalism of 
Descartes, 192. The limits of ^knowledge, 194. His 
views on the interaction of mind and body, 195. The 
bearing of his doctrine of substance on Descartes' 
proofs of God's existence, 199. He adopts Descartes' 
views as to the nature of rational science, 200. He 
asserts a twofold method to be necessary, 201. His 
views on nominal and real essence, 203. Criticism of 
his doctrine of real essence, 206. He condemns em- 
pirical knowledge, 208. The ambiguity in his views 
of substance and the primary qualities, 210. His 
reasons for declaring a science of nature to be im- 
possible, 211. His rationalism, 212. 


CIPLES, 215 

Hume's achievement, 215. The position of Berkeley, 
215. That position is the outcome of a consistent 
development of Descartes' principles, 216. Berkeley 
simplifies and develops the occasionalist system, 217. 
His spiritualism, 218. Hume on the principle of 
causality, 222. On the causal relation between parti- 



cular events, 226. His criticism of the occasionalist pags 
system, 229. His analysis of the Cartesian spiritualism, 
231. His criticism of the argument from design, 235. 
He overthrows the occasionalist system, 241. His own 
views on the causal relation, 242. His criticism of 
the views of Descartes, ^43. He raises an entirely new 
set of problems, 244. Criticism of Hume's theory of 
knowledge, 246. His true position is phenomenalism, 
not subjective idealism, 247. He yet practically retains 
the doctrine of representative perception, 249. Hence 
his sensationalism, 250. Conclusion, 252. 



ILant's Copernican idea, 253. He criticises the mathe- 
matical method, 255. His own method, 156. His views 
on causation, 257. His rationalism makes very modest 
pretensions, 259. At first Kant takes up the Cartesian 
position, 260. His true position, 263. His final 
conclusions, 265. 

Index, 267 



With Descartes philosophy made a fresh start: a 

new set of problems had ariseti, and it is as the 

first to face these problems that he has been called 

"the father of modern philosophy." To comprehend 

his position we must see how, from causes only in 

part themselves philosophical, a new view of the 

self and a new view of nature had grown up, 

demanding a reconsideration of the problem of 


If we seek to characterize the point of view of 

the Greek philosophers, it would probably, on the 

whole, be true to assert that for them man and 

nature are inwardly related. The soul, Aristotle 

teaches, realises itself in and through the body. 

Matter and form, the material and the immaterial, 

are two aspects involved in all natural existences, ji 

and are separable only by abstraction, Descartes' 




> <« < 

. '. A 


■);/{.«' U , 

attitude, on the other hand, is wholly different. 
Those aspects of reality, which Aristotle in dis- 
tinguishing reconciles, are by Descartes held apart 
as absolute opposites. Between man and nature, 
between soul and body, there is, on Descartes' view, 
no internal kinship. The mind does not spread 
itself over the body so as to become "Eoaterialised, 
nor does the body through a vital force become 
spiritualised. And the human body being, there- 
fore, as purely material as any other object in space, 
its conjunction with the immaterial soul must be 
regarded as an ultimate fact, explicable only as due 
to the arbitrary will of God. Thfe most absolute 
spiritualism is made to complement an equally ex- 
treme materialism. Souls are conceived as scattered 
points of life in a universe of dead matter. 

To trace this change of mental outlook in its 
growth, and adequately to determine its causes, 
would involve a history of the whole period from 
Aristotle to Descartes, and we can therefore do no 
more than name the main influences which brought 
it about. Speaking very roughly, it was in Stoicism 
and through Christianity that the antagonism be- 
tween man and nature came to be felt. Through 
the Christian conception of the value of each 


human soul, the individual was separated out from 
the cosmic whole, and given an independent reality 
and worth. Attention was turned more to morality 
and to the inner life, as distinguished from the 
outward, purely social, civic life of the Greeks. 
With the passing of the Greek civilization, men, 
we may say, became hermits; and consciousness, 
defeating its own ends, formed an inner world, 
independent of, and even antagonistic to, the outer 
world. This tendency towards subjectivity was 
highly developed by the fourth century A.D., and we 
need not, therefore, be surprised to find quite explicit 
in Augustine' the cogito ergo sum of Descartes. A 
mere list of the problems upon which Augustine 
wrote treatises — divine grace and individual sin, 
predestination and the freedom of the will^ — reveals 
the break that has meantime taken place with 
Greek modes of thought. As his treatment of the 
problem of knowledge, in its emphasis on the sub- 
jectivity of the process, is equally modem, and 
strangely similar to that of Descartes, it will repay 
us to dwell upon it at length. 

^AU of these are problems foreign to the Greek mind. 
Augustine's Confessions also form the first instance of what is 
an entirely modern form of literature, autobiography. 




« ' f ' < 


Augustine runs the problem of knowledge back 
into three mysteries, which he recognizes as being 
for him altogether insoluble. The first of these is 
how the unextendedj» mind can contain images of 
an extended world. Though the mind, in contrast . 
to the body, is unextended, it is not so in the 
sense of being oiU of space, for being finite it is 
always located at a particular point in space. It 
is out of space only in the sense of being a mathe- 
matical point in it,^ not of being free from all the 
limitations of it. Now since the mind has thus 
its own position in space, it cannot any more than 
a material body go outside its own boundaries — all 
the more so, as Augustine's friend Evodius would 
say, that it is not big enough to have boundaries. 
All knowledge must be in and through knowledge 

' ' 1 How small, Augustine notes, is the pupil of the eye which 
' yet illumines the whole heavens above us. The eye, too, of the 
eagle, though yet smaller, is far more powerful, which shows 
that size has nothing to do with the power of perception. 
Well, therefore, may the mind, which can contain in image not 
only the whole heavens, but innumerable immense spaces, be 
but a point {De Quantitate Animaey cap. xiv.). And, indeed, 
the point is of all existences in space the best and most 
powerful. In it the line begins and in it ends, line intersects 
line through it, the angle is formed hy it, and by it also, as 
centre, the direction of ^\exy part of that most perfect figure, 
the circle, is regulated {De Quant, An, cap. xii.). 


of the self, and if bodies outside it are to be 
^own by it, that can only be by there appearing 
i n it representations of them.^ The doctrine of V ^ 
representative perception is thus already full-blown 
in Augustine. Knowledge* is a subjective process 
going on separately in the mind of each individual. 
"Each sees one thing in himself such that another 
person may believe what he says of it, yet may 
not see it."^ And it is as a consequence o f this 
d octrine o f representative perception that Augustine 
f ormulates th e cogito ergo sum as the sole immediate 
certa inty. "We both are, and know that we are, 
a nd delight in our being, and our knowledge of it. 
Mor eover, i n these three things no true-seeming 


^ Cf. Malebranche, Recherche de la VeriU, liv. iii., pt. ii., chap. 
I., p. 377. (Our references throughout are to Jules Simon's 
edition of Malebranche's works.) " Our minds cannot issue out 
of the body in order to measure the magnitude of the heavens, 
and in consequence cannot see external objects save by the ideas 
that represent them. To this everyone must agree." Cf. Ibid. 
p. 373. " We see the sun, the stars and an infinity of objects 
outside us ; and it is not likely that the soul issues from the 
body, and goes, so to speak, wandering in the heavens in order 
to contemplate there all these objects (qu'elle aille, pour 
ainsi dire, se promener dans les cieux pour y contempler tons 
ces objets)." Cf. Descartes, Les Passions de lAme^ art. 33. 

^De Trinitate, lib. ix., cap. vi. Eng. trans, (ed. by Dods), 
p. 231. 

' , '" < I * 


tfo-y t(c <^/^{nusion disturbs us; for we do not come into 

contact with these by some bodily sense, as we 

perceive the things outside of us — colours, e,g. by 

'. ' ^'Prr.seeing. sounds by hearing. smeUs by smeUing. tastes 

^(f>- by tasting, hard and soft objects by touching — of 

cs.u ' A ., -'aU which sensible objects it is the images resembli^ 

'.. ^r/ ^ '>• " them, but not themselves which we perceive in the 

mind, and hold in the memory, and which excites 

us to desire the objects. But, without any delusive 

representation of images or phantasms, I am most 

certain that I am, and that I know and delight in 

this; In respect of these truths I am not at all 
^ — 
\ ^^^ ',-<• ' afraid of the Academicians, who say, What if you 

are deceived ? For if I am deceived, I am. For 

he who is not, cannot be deceived; and if I am 

deceived, by this same token I am. And since I 

am if I am deceived, how am I deceived in believing 

that I am ? for it is certain that I am if I am 


Augustine saw no difficulty in admitting that 

bodies, by acting on the senses, produce images of 

themselves in the mind. The problem, as it presented 

itself to him, leather was how if, as is inevitable, 

the images so produced conform to the nature of 

* Be Civitate Dei, lib. xi., cap. xxvi. Eng. trans., pp. 468-9. 


the unextended mind in which they appear, they 
can yet be images of, and so a£ford knowledge of, 
the extended. That is the problem over which he 
puzzled to the end, with the full consciousness that 
it wa^ for him insoluble. There is in the mind a 
certain wonderful power {mira guaedam vis) by 
which it can contain ta^da coeli, terrae, marisque 

It is true that at times Augustine resorts to a 
vague mystic solution of the difficulty, assuming that 
the mind is capable of overooming spatial differ- 
ences, and of being in many places at once — at 
once present in the bodily eye perceiving, and also 
present to the external distant object perceived* 
But so long as space is regarded as real outside 
the mind, and the physiological standpoint is main- 
tained in explanation of the origin of knowledge, 
such a view is meaningless. The really valuable 
part of Augustine's teaching lies in his emphasis 
on the necessity of taking the mind as unextended, 
and yet as located in the extended. 

The second mystery, which impressed Augustine, 
_i8 h ow mind can know external objects, and yet 

*Z>e Quant, An, cap. xiv. Cf. Confesdonum^ lib. x. cap. 



be ignorant of those internal parts of the body 
witJi which it is in immediate connection. "This 
is a very important question which I now ask, 
Why have I no need of science to know that 
there is a sun in the heavens, and a moon, and 
all the other stars; but must have the aid of 
science in order to know, on moving my finger 
whence the act begins — with my heart, or my brain, 
or with both, or with neither; why I do not 
require a teacher to know what is so far above 
me; but must wait for someone else to learn 
whence that is done by me which is done within 
me ? ... How is it that, while we can 
count our limbs externally, even in the dark and 
with closed eyes, by the bodily sense which is 
called * the touch,' we know nothing of our internal 
functions in the very central region of the soul 
itself, where that power is present which imparts 
life [and sensation to the body], — a mystery this 
which, I apprehend, no medical man of any kind, 
whether empirics, or anatomists, or dogmatists, or 
methodics (methodicos), or any man living, have any 
knowledge o£"^ 

^Be Anima et ejus Origine^ lib. iv. cap. vi. (Eng. trans, 
p. 305.) 



L4> <- 

The third myste ry, which is obviously connected^^ • ^ *'^'^^'; 
with the above, is the complement of the truth ^;.,^^^ , 
that self-consciousness is the essence of mind. . '^^*^-^- **"* ' 
"Neither the heaven of heavens, nor the measure ^,^ 
of the stars, nor the scope of sea and land, nor the f -^ ^tt^'-^ 
nethermost hell [are the tests of our incapacity] ; it ' ^ 
is our own selves whom ourselves are incapable of 
comprehending; it is our own selves who, in our 
too great height and strength, transcend the humble 
limits of our own knowledge; it is our own selves 
whom we are incapable of embracing, although ^ 
are certainly not outside ourselves."^ "We often 
assume that we shall retain a thing in our memory 
and so thinking, we do not write it down. But 
afterwards, when we wish to recall it,, it refuses to 
come to mind; and we are then sorry that we 
thought it would return to memory, or that we did 
not secure it in writing so as to prevent its escape; 
when lo, on a sudden, without our seeking it, it 
occurs to us. . . . Now how does it happen that 
I knew not how we are abstracted from, and 
denied to, ourselves ; and similarly are ignorant 
how we are restored and reproduced to ourselves? 
. . . For where do we make our quest, except in 

^Ihid, (Eug. trans, p. 306.) 


our own selves ? And what is it we search for, 
except our own selves ? ... Do you not observe, 
even with alarm, so deep a mystery ? And what is all 
this but our own nature — not what it has been, but 
such as it now is ? And observe how much wider 
the question is than our comprehension thereof."^ 

Now the advance from Augustine to Descartes, 
and the deepening of the problem in Descartes, 
consists just in this, that while these three problems 
remain, and remain at bottom as insoluble for 
Descartes^^ as for Augustine, there has arisen, 
through the growth of a scientific view of matter 
the further problem, how soul and body can pos- 
sibly interact, and how, therefore, the latter can 
produce sensations in the mind. Like the Scholastics 
after him, Augustine despised physical science as ixF 
no use for the attaining of the soul's salvation. 
What he alone sought was knowledge of God and 
of the self. Deum et animam scire cupio, NihUne 
plus? Nihil omnino^ And it was at least eight 

^Ihid, cap. VII. (Eng. trans, p. 307.) Cf. Confessuytiumy 
lib. X. cap. VIII. 

^Augustine does not seem to have exercised any direct 
influence upon Descartes. Nevertheless, these problems in- 
evitably reappeared in Descartes' philosophy. 

^ Soliloquiorum, lib. i. cap. ii. 



ce nturies b efore nature, through the love of her in 
the arts, and the study of her in the sciences, 
could b ecome the second reality, at once the 
opposite and the complement of mind, and so one 
further step be made in the problem of knowledge. 
The Eenascence philosophers, however, in their 
reaction against the theological view of nature as 
the principle of evil, wetit to the other extreme, 
and blurred its features by spiritualising it. It was 
a return to the Greek point of view, and so far a 
gain, a gain too in the restored respect for natural 
science; but the mathematical sciences had, through 
Galileo and Descartes, to speak more clearly, before 
the specifically modern theory of nature could be 
possible. In^ _ the sha rply outlined dualism of 
Descartes there is a plastic clearness that is in as 
great contrast to the mystic pantheism, all things 
interfused, of the Eenascence thinkers, as to the 
Aristotelian physics of the Schools. 

It is by the all-important r61e ascribed to mntion 7/ 
that the Cartesian physics distinguishes itself from 
Greek science.^ Matte r is perfectly homogeneous, 

^ Descartes' views we state, on this and the following pages, 
very summarily. They will be developed at length in chapters 
IL and III. 












: -^ 

and wh olly p assive : an inert continuous mass, it 
canno t in any essential way be distinguished, either 
by positive or by negative predicates, from the 
space which it fills. It is, indeed, capable of 
figure, but such differences of figure are due to 
motion, and depend on its continuance. Motion is 
the sole differentiating factor in nature, for it is 
it alone that breaks up the inert continuous mass 
into the different * kinds ' of material * atoms," and 
that, by impelling them one against the other, 
gives rise alike to the heavens and to the earth 
with all that they contain. "Give me," says 
[Descartes, "matter and motion, and I shall construct 
the universe." In nature one single event, motion in 
space, infinitely diversified with itself, alone takes place. 
All the manifold qualitative differences, that appear to 
be revealed by the senses, are the original creation of 
mind, and by it projected out into the external world. 
Nature is thus not merely dehumanised but also 
despiritualised, and becomes the direct opposite of 
the mind. All that is asserted of the one must be 
denied of the other. Matter is extended, infinitely 
divisible, purely passive : mind is unextended, in- 
divisible, active. Matter as being in space has all 
its parts external to one another: mind as being out 


o f space has its w hole content within itself. Each 
e xtend ed thing is dependent on what is beyond 
it; the self is independent of all else, and self- 
suflBcient. This dualism has been named the 
, Cartesian dualism, not because Descartes invented 
or discovered it, but simply because in him it 
gained its most thorough and perfect expression. 
It was involved in the scientific and general thought 
of bis time, and to it, as the then ascertainable 
truth about the self and nature, he had to adapt 
his thinking. He starts from this dualism, and his 
special metaphysical problem is to determine how 
under these conditions knowledge is possible. I^ 
the spiritual world and the material world are in 
absolute antagonism, how is the faxt of knowledge, 
a fact which involves their interrelation, their inter- 
penetration, to be accounted for? How can a 
material world be known by an immaterial mind ? 

Like Augustin e, Descartes regards the finite un- 
extended mind as set into an infinitely extended 
material world, and fixed down always to a particu- 
lar locality in it, namely, to the brain, along with 
which it moves to and fro in space. Without 
thought that any other was possible, he took up 
this physiological attitude, and doing so h^d no 





c it 

\ •/-•c 


/• r . 

I U 


option but also to adopt the doctrine of representa- 
tive perception. The self can know nothing but 
1^ its own states, and only indirectly by an inference 
from them establish the existence of any other being. 
Hence the utter misrepresentation of the internal 
dialectic of Descartes* thought, if we start, as 
Descartes himself does, with the cogito ergo sum as 
the really ultimate element in his system. The 
cogito ergo sum is simply one consequence of the 
doctrine of ^representative perceptio n, which is itself 
a consequence of his dualistic starting-point. 

But inevitable though the doctrine of representa- 
tive perception be as a consequence of Descartes' 
dualism, as a solution of the problem of knowledge 
it is a total failure. The problem is merely pushed 
further back. Since ideas are regarded as the 
objects of mind, and as exact copies of what exists 
outside mind, all those activities and processes, which 
the term *idea' was originally invented to express, 
have to be thrown back into a mind supposed to 
lie behind them, and the problem how the mind can 
know anything, be it only a mental image,^ is not 
so much as considered. 

^ And surely that is as great and as real a problem as how 
the mind should know a material body, for all the character* 




Even granting , however, the admissibility ofWrtiu 
regarding knowledge as consisting in the observation 
by a mind of images within it, the new and scientific 
v iew of mat ter throws special difficulties in the way 
of such a doctrine; for sense-perceptions can no 
longer be regarded either as caused by the external 
objec ts or as copies of them. The time-honoured^ 
theory that material bodies are known by way of 
the sense-organs ceases to have any meaning. Since 
the sense-organs are parts of the extended organism, 
t hey ar e as material as anything else, and therefore 
the assertion, that bodies are known by way of them, 
amounts to no more than the absurdity of saying 
that bodies become known to mind by acting on 
other bodies. Also, if this theory be taken as^ 
meaning that sensations are due to the action of the 
h rain o n the miTid, it is contradicted by the fact 
that, while the only form of action conceivable in 
matter is impact, no impact can be given to the 

istics of the external object are to be found in the image that 
copies it, not excepting, as Augustine insists, its extendedness. 
Saving the local difference between mind and external object, 
there is not one difficulty that is removed by naming the image 
* mental.' Even the mind * though very closely united to itself ' 
need not on that account, as Malebranche observes, be known 
by itself. 

€ V th 

<t c 


immaterial. All that takes place in the brain is 
motion of its material particles. These vibrations 
can obviously neither transform themselves into sen- 
sations, nor, while remaining as they are, hand over 
to the mind sensations ready-made. Descartes is 
therefore forced to regard all sensations as innate in 
mind, and as produced by it out of itsel£ 

Then, secondly, these sense-perceptions cannot be 
regarded as images of external objects. The visual 
image, for instance, of an object is coloured, whereas 
/the external ob[ect_is_ colourless. And what thus 
holds of the secondary qualities is likewise true of 
' ' the primary. We find in the mind, to use Descartes' 
own illustration,^ two wholly diverse ideas of the 
sun : the one idea, the sense-image, by which the 
sun appears extremely small, seems to come to us 
directly from the sun through the senses; the other 
idea, whereby it is represented as many times larger 
than the whole earth, we have constructed for our- 
selves in physical science. These two ideas cannot 
both resemble the same sun, and reason teaches us 

^Meditations, in. (Cousin's edition, i. p. 271) ; Veitch's trans, 
p. 120. As only the first three volumes of the new edition of 
Descartes' works have been published, our references through- 
out are to Cousin's edition. 


that the one which is given us in sense, and which , 
seems to have immediately emanated from the sun, 
is the most unlike. The true nature of the sun, as 
it exists without us, is thus revealed not by sense ^- 
but by though t. Our sense-imag es are but picture*^ 
in our minds, and do not represent, but misrepresent, 
t he true na ture of the real. There are two external 
worlds, the one rich with its bright variety of 
diverse qualities, appearing to the ' senses,' the other, 
poverty-stricken, constituted only of matter and 
motion, and discovered by the understanding. 

Now, it might be expected that Descartes, when 
driven by his physical theories to make this dis- 
tinction, would in the ordinary way assume that the 
mind by a 'faculty of thought' constructs for itself 
out of the materials of sense a conception of the ^ " ' ' 
reaL But it is not so. The conceptions, by which "!^*' 
we grasp the real, are not, in Descartes' view, 
activities whereby mind apprehends the non-mental, 
but, like sense-images, objects which it contemplates.,, 
within itself. Also they are not derived from the 
perceptions, but wholly distinct from them in nature, 
re semble t hem only in being likewise innate. By v 
this strange opposition of conceptions to perceptions, 

which he makes to be absolute, Descartes aggra- 


r. } r 






vates the difficulties, already great enough in all 
truth, of his dualism, and lands himself, founder 
though he be of the physical sciences, in a rational- 
ism more extreme in its antagonism to sense- 
experience than even the idealism of Plato. The 
causes leading Descartes to this position are to be 
found in his absorbing interest in the mathematical 
sciences, whose method he misconceived. 



Descartes in the Discourse states his method in 
f our short rules , with little explanation of how the 
reader is to interpret them, and for a more adequate 
treatment of it we must look to his earlier and less 
famous work, Begulae ad Directionem Ingenii? 

We may start from his second rule, which runs 
as follows: "We must attend only to those objects? 
of which our mind is capable of acquiring knowledge V 
that is certain and indubitable."^ Trivial and conp 
monplace as that rule appears, we might almost 
deduce from it Descartes' whole philosophy. The 
reason why he turned to philosophy is, he tells us, 
because his experience was a patchwork of true and 

^In this chapter, as throughout, we have in view only 
Descartes' metaphysics, and hence do not dwell on his method 
in its relation to his work in mathematics and physics. 

2 First published, fifty years after his death, in 1701. 

^ Reg. II. (Cousin's edition, xi. p. 204). 


/ . • v/ 


false, a mass of merely probable truths, opinion not 
j^ knowledge. The raison d'itre of philosophy lies in 
its attempt to carry us over from probability to 
knowledge, and if it fails to do that, it fails alto- 
gether. " He who doubts much is no wiser than he 
who has never thought." 

. .But further, since an assertion of probability can 

'. lie made only on a basis of indubitable fact, the 

'^^existence of probable knowledge proves that there 

also exist some absolutely certain trutha Take the 

y familiar instance of the die. The probability of its 

^ ^ X ^ ^ falling, say, with the four up is one to six, and rests 

v^ on the knowledge that the die has six sides, and 

\/ that there is no special reason in the die itself why 

it should fall on one side rather than janother. 
Should these facts, and the laws of arithmetic 
according to which we calculate the probability from 
them, be doubtful, the probability would cease to 
hold. ' Possibility and probability rest on certainty, 
"^ ^ and hence can only follow it, cannot precede it. At 
least a minimum of absolutely certain indubitable 
knowledge must be possessed by all, in order that 
ordinary experience, that patchwork of true and false, 
be possible. 

" We reject, then, according to this rule, all knov7- 


ledge that is only probable, and assume as a principle 
that we should trust only to those truths which are 
certain, and of which no one can doubt." ^ But, it 
is at once objected, that le^tves us with nothing but 
a petty pedantic philosophy ; all that has complexity 
and magnitude outstrips the mind ; and' hence all 
science that is of worth can be but probable tenta- 
tive knowledge. The lear ned under this prejudice, 
Descartes repeats over and over again, have neglected 
the^imple indubitable truths as too easy and within 
t he rea ch of all. "Yet I assure them that there 
is a greater number of such truths than they think, 
and that they sufiBce to demonstrate firmly a multi- 
tude of propositions, as to which they have hitherto 
been able to express only probable opinions." ^ 
Those t ruths that are so simple and universal and 
indubitable that no one can be ignorant of them, 
just those apparently trivial and worthless truths,_are i/ 
the springs of knowledge.^ 

^ Reg, II. (xi. p. 205). 

*^Reg, II. (xi. p. 205). 

^Cf. Reg. IX. (xi. pp. 249-51). " It is a common failing among 
men to regard the roost difficult things as the finest, and the 
majority believe they gain no new knowledge, when they ^ 
discover a very clear and very simple solution of their difficul- 
ties, while they admire the subtle and profound doctrines of the 
philosophers, although they frequently rest on grounds that on 




The method whereby the indubitable may be 
,..§yBparated out from the doubtful, Descartes discovers 
L. in a very simple manner. "All the sciences united 

f * 

^ ' are nothing but the human understanding, which 

/o c^>iic.'L^ remains one and the same however varied be the 
, 4 objects to which it applies itself, and which is no 
\.i '"V more altered than is the light of the sun by the 
..., '/ >r -Variety of the objects it illumines."^ That is, the 
/;.,i '^^-t^-t^jictivities are one and the same in the construction 

of all knowledge, and hence from any bit of true 
knowledge the universal nature of the intelligence 
which constructed it can be discovered. Now, in 
mathematics we have true knowledge, and therefore 
by separating off in the mathematical method what 
is due solely to the special nature of its subject- 
one has ever sufficiently verified : foolish admiration that 
prefers darkness to the light. . . . This is a point on which I 
would here insist more than on all others : namely, that every 
one be firmly persuaded that it is not from the great and 
difficult, but only from what is most simple and most easy that 
we must deduce even the most recondite sciences.'' That point 
of view is characteristic of all the great thinkers of the 17th 
and 18th centuries, who in their reaction against the mediaeval 
Gothic spirit hated obscurity, and misty or mystic vagueness of 
outline, more than aught else. Pascal has, in words strikingly 
similar to those of Descartes, given classical expression to this 
attitude in his Pens^ea (Havet, ii. pp. 307-8). 

1 lUg. I. (xi. p. 202). 



matter, what we shall have left in our hands will 
be the ex pression of the essence of mind in all '^ 
its_ j>urity an d universality, a complete analysis of^ 
the light whereby objects are revealed to us. It is 
with that high end in view that Descartes sets 
himself to examine the method of the mathematical 

But before we proceed further, let us try to dis- , » *y. ' '*'' 
cover why for Descartes the problem of method is* 
80 aU.impoitant He returns again and again to 
the point, until we almost grow weary of his repeated 
assertions that the supreme question for philosophy 
is that of method; for after all, we naturally think, 
is not method but the scaffolding, a means truly of 
attaining knowledge, but not meant to monopolise 
our attention? So long as that is our feeling, we 
are still very far from a true understanding of the 
position of Descartes. 

In the first place, it_is not true that the method 
is merely an instrument for constructing knowledge. 
Sather, as appears from what has just been said, it 
expresses the innermost essence of mind ; and the 
problem of method is therefore identical with the 
problem as to the nature and limits of knowledge. 
Since in the method we have a complete analysis of 



-^ the mind, in determining that method we necessarily 

^ yjf^y/c^lao determine the measure and scope of mind. 
" No question is more important than this of knowing 
what human knowledge is, and how far it extends; 
that is why we unite this double inquiry [that of 
method and that of the limits of knowledge] in a 
single question that we think ought to be examined 
before all others . . . ; it is an inquiry which 
^everyone who loves truth, be it ever so little, ought 
to make once in his life, since it contains the true 
organon of knowledge and the whole of method." ^ 

Secondly, Descartes declares that " we can know 
nothing [even of what is within our reach] until we 
know intelligence, since the knowledge of all thmgs 
^ depends on it, and not it on that knowledge."^ 
Though mathematical science existed before the 
nature of the intelligence was discovered, that was 
only possible through the prior discovery by the 
Ancients of the intelligence in a concrete form,^ the 
analytical method of the Greeks being just the one 
true method specialised in its application to number 
and extension. And, as an historical fact, only in 

^ Reg, VIII. (xi. pp. 245-6). » 

2 R&g, VIII. (xi. p. 243). 

3 Reg. IV. (XI. pp. 217-8, 220-4). 



these mathematical sciences was any knowledge of 
perfect certainty attained. 

Thitdly, there is a statement, which Descartes 
twice repeats in the Begvlae, which throws much light 
on this point, viz. that it is impossible to make a false 
i nference .^ What he means would seem to be this. 
It is want of data, or want of right arrangement of 
the da ta, that causes bad reasoning, never the failure 
to draw the true inference from what is actually ^ 
before the mind.^ To draw a conclusion that does 
not follow from the data considered would be for 
thought to break in two. The laws of identity and 
non-contradiction are not, as logicians assert, regula- 
tive merely, but belonging to the unchangeable essence 
of mind, not to its accidents, are therefore obeyed in 
equal perfection by all men. And that phrase gives 
us the key to Descartes' strange doctrine, jestingly 
stated, but seriously designed, at the opening of the ^^^j^ r^ 
Discourse on Method: "Good sense is, of all things 

1 Reg, II. III. (xi. pp. 207-8, 212). 

* What we mean by a false inference is an inference out of 
place. We reason falsely when we make one inference and 
think we have made another. The fault lies always in the 
falsity or inadequacy of the data — in the matter, that is, ^ 
and never in the form of reasoning. The inference drawn 
from such data, though correctly following from them, will be a 
false inference in the circumstances. 




among men^ the most equally distributed ; for every 
one thinks himself so abundantly provided with it, 
that those even who are the most difficult to satisfy 
in everything else, do not usually desire a larger 
measure of this quality than they already possess. 
And in this it is not likely that all are mistaken: 
the conviction is rather to be held as testifying that 
the powe r of judging^ aright and of disti nguish ing 
tnlth from error, which is_properly what is called 
V good sense or reason, is by nature equal in all men. 
. . . For inasmuch as reason is that alone which con- 
stitutes us men, and distinguishes us from the brutes, 
I am disposed to believe that it is to be found com- 
plete in each individual; and on this point to adopt 
the common opinion of philosophers, who say that 
the difference of greater and less holds only among 
the accidents, and not among the forms or natures of 
individuals of the same speciesJ* Since all men, as 
rational beings, are alike in the power of perceiving 
rational connection, the capacity for procuring and 

to say, the knowledge of method, is everything. It' 
is, Descartes adds, to his method and not to any 
surpassing genius that his own discoveries have been 





Thus, then, a fair case can be made out for the 
supreme importance of the problem of method, as 
understood by Descartea^ 

And now we may follow him in his examination /^)^, 
of the mathematical method. The characteristic of 
mathematical science is its c ertaint y, and its certainty 
consists in this, that it starts with truths that are 
so simple and so self-evident that they cannot be 
doubted by the mind, and that nothing else is 
accepted as true, until it has be en shown to^ follow 
necessarily from these ultimate self-evident trut hs. . 
The fault of all previous philosophers is that the^ 
have neglected this method, and instead of getting 
back to the ultimate simple truths, upon which all 
others depend, have attempted the more complex 
problems before they have solved the simpler ; have 
approached physical problems before they have 
mastered mathematics ; philosophical problems before 
they have analysed the conceptions of which they 
make use. 

Even Bacon reveals an ignorance of the true 
method, when he makes his successful attack upon 
the unfruitful conceptions of a false metaphysic the 
ground for a glorification of sense. Knowledge 
cannot rest upon a foundation of ignorance; and as 


< '^ 


c< ^* 


^ / the , sensi ble is the lea st amenab le to the demands 
J /of thought forconceplu&l clearness, it must remain 
/outside the sphere of science, till by an insight 
/ derived from other sources its obscure complexity 
I has been analysed. From experience we certainly 
learn that fire melts wax and hardens clay, that the 
magnet attracts iron, and innumerable other phe- 
nomena. Since these, however, are not ultimate 
' laws ' of nature, but only generalised statements of 
highly complex matters of fact, the whole work of 
science proper still remains to be done. Whereas the 
senses reveal to us a world full of unbridgeable 
qualitative differences, thought reveals the deeper 
fact, that one single phenomenon, infinitely diversified, 
motion in space, alone takes place. Before we can 
"^explain any physical phenomena, even the simplest, 
we mast therefore discover the laws of motion ; and 
when we have discovered them, we are able to deduce 
the various sensible appearances from them, and to 
demonstrate their necessity. Not complex brute facts, 
empirically verified, but the necessary truths involved 
in our simplest conceptions, constitute the medium 
of science. 
, Yet Dfiscartfisl^method though d eductive is not 

syllogistic. It is in intuition, not in the syl logism , 


that our knowledge develops. If a = 6, and 6 = c, then 
a = c. In symbolic reasoning the 'if comes in, but 
when definite quantities are set in the place of the 
symbols, it falls away, and the truth of each is 
intuitively perceived. Constructing a whole out of 4 
our data, we then intuitively perceive a new relation 

within it. ^^iT*-'* 

Such a view of reasoning is very different from the^//*^ ' 
scholastic theory that all knowledge is gained throng^ 
the syllogism. Take the syllogism: All things 
equal to the same thing are equal to one another. 
a and c are things equal to the same thing ((), 
therefore a and c are equal to one another. This h ^^'■^'^'''f 
syllogism states the whole of the conditions upon "^ "^/^ v:*// 
which the truth of the conclusion rests. There is 
th e ma terial condition expressed in the minor, that /^^^^ 
a_and c are both equal to the same third thing 6 : 
that, it will be noted, is the whole of the inference. 
To know the minor is practically to know the whole 
matter, and how that is done the syllogism makes no 
attempt to explain : only, once we know all we need 
to know, the syllogism will show what it presupposes.^ 

V^ "Logicians cannot form any syllogism to yield the true 

ncSnclusion, if they do not already have the matter, that is to say 

if they do not already know the truth which they deduce by 



Secondly, there is the fonrial condition expressed 
in the major, namely that it be necessary always 
and universally that whatsoever things are equal to 
a third be equal to one another. This major ex- 
presses the postulate that the laws of thought ac- 
cording to which we reason hold absolutely and 
universally, for ourselves at all times and also for 
all other men. The truth of the conclusion involves 
the truth of that postulate, and only on the assump- 
tion of its truth are we justified in asserting the 
conclusion. The function, therefore, of the syllogism 
is neither to state the reasoning process whereby we 
attain to a knowledge of the conclusion, nor to prove 
it, but solely to unfold all its implications.^ 

this means. Whence it follows that this form yields them 
nothing new, and that the common logic is therefore entirely 
useless to those who wish to discover truth, and can only be 
occas ionally of use for expounding to others truths already 
known, and should therefore be transferred from philosophy to 
rhetoric." Reg. x. (xi. p. 256). 

^Descartes' opposition to the syllogism may, in one way, be 
taken as following from his rejection of authority and^insistence 
on personal verification of all truth. In using the syllogism the 
mind is taught not itself to see truth but to believe it on the 
authority of the syllogistic rules. The syllogism is so con- 
clusive, logicians assert, from its mere form, that reason, while 
remaining itself idle, can by virtue of this form, withojiC needing 
to examine the evidence offered for the conclusion, accept it a.s 
proved. To this Descartes replies, that not only does the truth 


Since p articular truths are known by the same 
process by which we apprehend the axioms, namely 
by intuition, and possess therefore the same in- 
trinsic underived validity,^ they do not require to be 
deduced from the universal axioms. That two 
plus two and three plus one are both equal to 
four, and therefore both equal to one another, 
are truths as certain as the axiom that things 
equal to the same thing are equal to one another; 
and as a matter of fact we must intuitively 
perceive the certainty of such particular truths 
before we can possibly comprehend the truth of 
the universal principle. And if knowledge does 
not consist in deduction from axioms or general 
principles, still less does it consist in deduction 
from definitions. The intuitions with which we 

often escape these forms, but also that, as experience shows, by 
them sophistries, which would never deceive anyone who 
makes use only of the natural reason, entrap the sophists them- 
selves. " And that is why, fearing above all else that our reason 
should remain idle while we are examining any truth, we 
reject those forms as contrary to our end, and prefer rather 
to seek all the possible means of keeping our minds attentive." 
Reg. X. (xi. pp. 265-6). 

1 Here we are stating Descartes* attitude more explicitly than 
he himself does, for as regards the function of the axioms he is 
not very clear. Cf. below, p. 37, note 2. 




start must be simple and self-evident, and would 
therefore only be obscured by logical definitions.^ 

^' *^ '^ /" 'IXV Though Descartes adds to intuition deduction, 
'/a-* A I I he does not mean by the latter anything really 

tt^fcv/fyri, (distinct from intuition,^ We must, he admits, 

/, ; 

/; iO 


) distmguish between the self-evident truths and 
/ .V i those others whose certainty can only be dis- 
covered by deduction from them. The process, 
however, by which they are verified is in both 
cases the same. Deduction is but a series of 
intuitions, whereby terms not directly related are 
discovered to be related through their relations to 
intermediaries. Thus by a simple intuition the 
mind may apprehend that a = &, and by another 
intuition that 6 = c, and by a third that c = d, but 
in order to perceive that a — d the mind has to 
run back and forward quickly along the whole 
series, and thereby gathering them together as the 
content of a single more complex intuition render 
the relation of a to rf visible. The detection of 
that relation involves a positive increase in our 
knowledge, and therefore involves that intuitive 
process wherein alone knowledge can develop. 

'^Reg, XII. (xi. pp. 279-80). Cf. Principles, i. 10. 
'^Reg. III. (XI. pp. 213-4). 



When the series is too long thus to be gathered 
into a single fruitful intuition, the memory of the 
evidence previously verified in intuition has to be 
relied upon. 

Deductio n, then, is not the source of a special 
kind of knowledge, but simply the process b j 
which intuition extends itself so as. to take in the 
complex that at fi rst spears to lie outside its 
sphere. Thereby intuition shows itself to be not 
an isolated particular act, not an instantaneous 
photograph that once taken can develop no further, 
but a growing capacity of the mind for truth, 
each new truth serving as an instrument for the 
discovery of others. When the light of intuition 

C — 

has spread from the simple truths over into the 
c omplex, enlightening all that is obscure in them, 
then, an d only then, is science attained. Since 
it is by one and the same act of mind that 
every truth once reached is recognised, no part of 
knowledge is to be regarded as more obscure than 
any other.^ 

The word 'intuition' by keeping bad company, 
by mixing with the self-styled 'intuitional moralists,' 
has got a bad name. When we speak of intuition 

^Reg. IX. XII. (xi. pp. 250, 281-2). 


nowadays, we think of something unusual, of some 
special faculty in the individual, and that is just 

the very opposite of what Descartes means by it. 
Our intuitions are not an aristocracy with a pedi- 
gree other than the mass of the knowledge that 
is supposed to come to us in an ordinary and 
common way. For Descartes intuition is the source 
jo( all our knowledge. Being the name which he 
gives to the birth of truth in the soul, though it 
is for us a word and little more, it describes a 
very real fact. Certainly, as the intuitionalists 
aissert, it is miraculous and a mystery, but only 
in that sense of the miraculous according to which 
mystery is a universal element in things. The 
mystery of intuition lies in its being one case of 
growth, and therefore in its involving like all 
growth the miracle of creation. Intuition is not 
a fitting together of premisses, but a dialectic. 
Given certain data, they produce out of themselves 
a further truth ; it is a natural process, and that 
is why it is impossible to make a false inference. 
All that the conscious mind can do, says Descartes,^ 

^Reg, XIV. (xi. p. 295). Cf. Beg. iv. (xi. pp. 216-7). ("The 
science of method) cannot teach us how these operations (of 
intuition and deduction) are performed, for they are the 




is to prepare the con ditions for its appearance. 
Since to determine the nature of intuition is really 
to determine the nature of consciousness or mind, 
we must look for a further treatment of it to 
Descartes' metaphysics. 

F rQm this new theory of reasoning Descarte s //i^ 
g ains his answer to the double question 9f_j^k® '^^ 
method and lim its of know ledge. The limits lie, 
on the one side, in the simple truths than which ^ 
n othing can be conceived more ultimate, and which 
are so completely and certainly known, that no 
more perfect knowledge can be desired. .Descartesi 
calls them 'innate ideas' and also 'simple natures! 
They are the primary seeds of reason implanted in 
us by God, and ma nifest their di v ine righ t by the 
dearness and distinctness with which they present 
themselves to the mind. The limits, in the opposite 
direction, Ue first in the possible fruitfulness of 
the * simple na tures,' and thaJt^ if we may judge 

simplest and most primary ; so that if our intelligence could 
not previously perform them, it would not comprehend any of 
the rules of method, however easy they might be." * Intuition,' 
that is to say^ is the term which Descartes thinks most fitted to 
describe the fact, not a theory or explanation of it, and if we 
nowadays think good to reject the term, that is no refutation 
of Descartes' account of reasoning. The fact remains whatever 
be our theory about it. 

- J 

4<«<. /»//i 






from the proved fruitfulness of the conceptions 
of number, extension, figure, and motion, is inex- 
haustible;^ and secondly, in the adequacy of these 
' simple natures ' to the comprehension of the real. 
We can know nothing save through the few ultimate 
conceptions with which our consciousness is endowed, 
and hence only if they express the whole nature of 
"^ the real, can the real be completely known by us. 
Descartes' final answer to that last problem we shall 
learn in the next chapter. 
^^' ^^C <^ As to the method, the secret lies in the order and y 

disposition of our inquiries, so that we do not attempt 
^ ; any problem until we have the data requisite, that is, 
' ' x the simple intuitions in the light of which all ob- 
scurities of themselves vanish. Let us once get * the 
simple natures' into our hands, and we are the 
masters : they are the springs of knowledge, and from 
them we have only to follow down the widening 
V river of truth. 

Everything, then, depends on discovery of the 
* simple natures.' What are they ? The answer given 

* Cf. Malebranche, Entretteiu 9ur la M^taphysique^ lii. p. 45. 
"This idea (of extension) is so luminous, that geometricians 
and good physicists form themselves in contemplating it ; and 
it is so fruitful in truths, that all minds together can never 
exhaust it." 


by Descartes in the Regulae agrees with the answer 

which he gave later in the Principles,^ All 7/ . / 

things compound fall into three distinct series 

— material things,^facts of mind, and qu alities common '- 

to both. Analysing out from material things the 

ultimate conceptions, upon which knowledge of them ^ 

depends, t hey are the notions of " figure, extension, 

motion, etc." In the mental we have as ultimate 

notions — "knowledge, doubt, ignorance, volition, and 2* 

the like." Common to both mind and matter are 

"existence, duration, unity, and others similar." ^vB. a 

Since these conceptions are ' simple natures,' w e cannot / 

know them at all without knowing them completely. ^ ^ 

" Otherwise we could not call them simple ; each one 

would be a compound of that which we know in it 

with that in it of which we believe ourselves 

ignorant." ^ 

So far all is plain, but immediately we inquire how 

(xi. p. 269 flf.). 
Descartes here adds (cf. also the Principles^ i. 13) that to 
that third class belong " those common notions that are, as it 
were, bonds for uniting together the different simple natures, 
and on the evid ence of which rests every conclusion : for example 
tEis proposition : T? wo things^equaT'tb'a third are equal to one 
another." That, however, must be regarded as but a lapse back 
into the scholastic theory of reasoning, which he attacks. 
^Reg. XII. (xi. pp. 272-3). 

* «_ 

. .'. /> ^" 38 

.^^J& t 


I \ 




from these ' simple natures ' the rest of knowledge is 
' to be developed, diflR^^^jlHpf^ im^Hiplj^ Fro m any one 
f ^ taken separately nothing further can be derived. The 
conception of space may be contemplated in perpetuity 
without anything being thereby discovered. It is, so 
Ck far, in all truth ' simple.* If, again, we compare them 
together, we find indeed that figure necessarily involves 
space, and that motion necessarily involves both space 
and time, but other necessary relations than these 
there are none. Descartes would doubtless _reply to 
that difficulty, that the other simple natures -included 
above in his ' etcetera ' must be brought in, so that 
talking the angle, the line, and the number three, 
along with figure and extension, we may construct 
the complex figure, triangle,^ and thereupon, by com- 
parison of the elements making up its complexity, 
discover the varicjus properties necessarily holding 
between them. 
Ky i. If, however, we examine thes e diflFerent simplejiatures, 
we find that they have a characteristic in common, 
( namely, that they are one and all distract conceptions, 
and ' simple ' only so long as they remain abstract. The 
conception of space is certainly simple in the sense of 

1 Reg, XII. (xi. p. 276), " the nature of the triangle is com- 
posed of all these natures." 




being incapable of resolution into more ultimate con- 
ceptions ; but in no other sense is it simple, for its 
object is not only complex, but as a concrete reality is 
inexhaustible in its possible modifications, forming the 
inexhaustible subject-matter of the science of geometry. 
The conception of figure is not even simple as an J/ 
abstraction, since it involves the conception of space ; 
and it likewise owes its whole meaning to the particular 
and complex figures from which it is derived. Des- 
cartes, in fact, is committing the fundamental error of 
taking the general conceptions, through which we 
define and articulate the real, as being themselves ^in 

abstraction from the real ^the subject-matter of 
— ■ - — - / 

science. Thereby seeking to eliminate the concrete 
particularity of sense-perception, and so to make science 
purely conceptual, he falls back into the rationalistic 
view of k nowledge, which he criticises so excellently in 
his attack on the syllogism. It is as impossible to 
discover anything new from these 'simple natures,' 
as from axioms and definitions. 

Here, as elsewhere, we have to distinguish between 
Descartes' attitude in science, and his attitude in 
metaphysics. So long as he is treating concrete 
problems, he does not go far astray. Since the 
'simple natures' are never experienced in their 



purity, they can only be reached by a process of 
analysis that starts from the concretely real. And 
for this analytic process Descartes is careful to lay 
down rules, wherein he emphasises the importance 
of observing and enuinerating the various conditions 
involved in the particular phenomena examined. 

c *<<-<: r In these rules there is never any suggestion of an 
opposition between perception and conception, sense- 
experience being not only regarded as the source, 
I but also as the sole source of data. In metaphysics, 

/ on the contrary, his attitude is wholly different; 

for there the Descartes that declared his laboratory 
to be his library, and praised the empirical observa- 
tional method of Bacon as a valuable preparation 
S )|br his own deeper one, denounces sense as alien 
to thought, and asserts pure conceptions to be the 
only legitimate organa of science.^ And though in 
T^his metaphysics, just as in treating of physical 
problems, he starts from concrete experience, knd 
seeks by means of a universal doubt to analyse out 
its ultimate indubitable elements, he, in the process, 
omits the concrete detail, and is left only with a 
few empty conceptions, from which he has, in 
accordance with his stated method, to make a pre- 

1 Cf. below, Appendix B to chap. iii. pp. 124-6. 

V. N. 


tence of reconstructing experience. Sense-ima ges, 
he says, are of use to fix conceptions before 
the mind. He had perforce to admit so much, 
since he could not deny that in actual fact some 
use is made of sense-perception in mathematics 
and in physics. But the con ceptions are, he 
holds, not derived from the perceptions, and in dis- 
t inction fr om them form the subject-matter of all 

Hence, throughout his metaphysics, Descartes 
speaks as if the mind could from the conceptions^; 

of extension, figure, and motion, directly develop ^ 
all the particularity and variety of the real. We 
have only, he seems to say, attentively to contem- 
plate them, as a magician might gaze into a crystal 
sphere, and they will unfold from the bosom of 
their transparency the whole series of properties 
and modifications of which they are capable. Such 
spontaneous generation from simple conceptions of 
particular modifications he not only regards as 
possible to them, but also declares to be their 
peculiar characteristic. By that strange inner power 
of growth, the conceptions show that they have not 
been framed by us; since, had the finite mind con- 
structed them, it must have known from the start 

[It c < ■ 



>!( C H 


t.hftir wh olft fiontp.nt.^ Inevitably, however, to make 
such a view at all conceivable, he has surreptitiously 
to introduce into the barren conceptions the variety 
revealed in sense. He takes, for instance, the con- 
ceptions of the different geometrical figures as given, 
and has then to regard only their special properties 
as conceptually generated from them. And that 
change in point of view is marked by his speaking 
of the innate ideas as innumerable, citing as an 
instance the notion ' triangle ' : . " What I here find 
of most importance is, that I discover in my mind 
innumerable ideas of certain objects . . . which 
are not framed by me, though it may be in my 
power to think, or not to think them, but possess 
true and immutable natures of their own. As, for 
example, when I imagine a triangle ..." That 
idea, he proceeds to argue, though it cannot have 
come into the mind through sense, can just as little 
have been framed by the mind itself, for it is not 
"in any degree dependent on my thought, as 
appears from the circumstance, that diverse pro- 
perties of the triangle can be demonstrated, viz., 
that its three angles are equal to two right, that 
its greatest side is subtended by its greatest angle, 

* Cf. below, chap. iii. pp. 108-10. 

C I * r 


and the like, which, whether I will or not, I now 
clearly discern to belong to it, although before I 
did not at all think of them, when, for the first 
time, I imagined a triangle, and which accordingly 
cannot be said to have been invented by me."^ 

Now when the objects, by contemplation of which 
the mind acquires new knowledge, are thus regarded 
as conceptions, and opposed to perceptions, the view 
is utterly to be rejectedLfT^is a Platonic mysticism, /^//,^ 

and not a sane ratiorolism. Naturally enough it; JJtK*-> 

' fi 

led to the false rationalism of Spinoza and Leibniz, "' ' / 
both of whom believe in the generative power of 
deductive reasoning, Spinoza pretending to develop 
the whole order of nature and of man from the 
single conception of divine substance, and Leibniz 
insisting that every necessary truth is analytic. 

The radical error of Descartes shows itself plainly 
in his speaking of space and time as conceptual! 
units by the combination and comparison of which 
with others knowledge may develop. Space is never -,» ^ ^' ^ 
in geometry one of the elements compared, but i^ - / 
that which renders possible the organisation of give^ *^ 
d ata into wholes wherein new relations can be\ 
d iscove red. Also it is no conception, but a concrete 

1 Meditations V, (i. p. 310). Veitch's trans, p. 144. 



reality revealed in perception, its continuity and 
infinite complexity being the inexhaustible source 
of geometrical variety. Thus if we are told that 
a is to the right of 6, and h to the right of c, and 
we infer that therefore a is to the right of c, the 
mind does not, and cannot, derive that conclusion 
from the contemplation, be it ever so prolonged, of 
the two given separate facts, but only from the 
construction of a spatial whole which includes them, 
and determines them to have other relations besides 
i^u < / those given. It is because the spatial whole is not 
' * an abstract conception,^ but a concrete reality that 

' if not perceived must be at least imaged, that it 

can thus progressively reveal itself to the attentive 
mind in new determinations. Similarly in the con- 
ception of a triangle, even though we regard it as a 
complex of simpler conceptions, nothing can be dis- 
covered save what has been conceived from the start. 
It must, in order to yield new knowledge, be con- 

^A conception has just so much content and no more, and 
when clearly conceived is known completely. There cannot, to 
borrow a metaphor, exist in it unknown truths like opaque 
particles in water, that by finally dissolving may become trans- 
parent to the mind, and so reveal new relations in the old ideas. 
Not from a conception, which is always a completed content in 
mind, but only from a reality that in perception progressively 
reveals itself to the mind, can new knowledge arise. 


structed in space, and it is because as so constructed 
it is capable of infinite variation, the elements 
composing it being so organically connected that 
the least variation in any one necessitates corre- 
sponding variations in all the others, that it is, as 
Descartes says, one of the ' seeds ' of knowledge.^ 

Descartes' method may appear to be at least aiulf 
adequate account of reasoning in arithmetic and 
algebra, since in these sciences units conceptually 
fixed are by combination and recombination made to 

^ In the Regvlde Descartes insists most emphatically on the 
importance of constructing our conceptions. "If the intelli- 
gence seeks to examine anything that can be related to body, it 
should form for itself in the imagination the most distinct idea 
possible. To attain that end more easily, it should set before 
the external senses the object that the idea represents." Reg. 
XII. (xi. p. 268). Cf. Reg, xiv. Also, Descartes does not in 
the Regvlae separate imagination and conception as absolutely 
as he does later in the Meditations. (Compare his statements 
in Reg, xii. with his corresponding statements in Medit, v.) 
Still, spite of his being the creator of co-ordinate geometry, 
wherein algebra and geometry, conception and imagination, 
are made to co-operate, already in these Regvlae^ even while 
t hus emphasising the import ance of imagination, he speaks 
o f the co ncrete images, not as indispensable sources of data, 
but only as external aids for fixing and rendering definite, 
pure conceptions. For a different interpretation of Descartes' 
views as to the relation between imagination and understanding, 
cf. Natorp, Descarte^ Erkenntnisstheorie (Marburg, 1882). Our 
view is supported by M. Pierre Boutroux in his pamphlet, 
L^ Imagination et lea Math^matiques aelon Descartes (Paris, 1900). 


reveal new truths. But really, as Kant was the first 
to point out, just aa little in arithmetic and in algebra 
as in geometry can the combinations be derived from 
the isolated units. These sciences depend on the 
continuous nature of time, in and through which 
alone units are capable of combination. And it is, 
again, because time is a perception, not a conception, 
that it can render possible the discovery of ever new 
relations between the units in it. 
-7% We come, therefore, to the general conclusion that 
j if the 'pimple natures * are conceptions no new know- 
l ledge can be derived from them ; and that if they are 
\isolated units they cannot be combined. Media are 
necessary, and, when granted, render all talk about 
'simple natures/ as so many units, impossible. 
Whether outside the two concrete connecting media, 
space and time, intuition of necessary relations is 
possible, and if so, what are the media that render it 
possible, are questions that Descartes did not see deep 
enough to think of raising. How very far astray his 
belief in the conceptual nature of science led him, we 
shall see in his metaphysics. 

Yet while we assert Descartes' theory of method 
to be thus defective and incomplete, we must recog- 
nise the historical importance of his insistence on the 



necessity for clearness and certainty in physics and 
metaphysics as in mathematics, and of his consequent 
demand that all complex conceptions be capable of 
analysis into elements that are transparent to the 
mind. There was only one other thinker in his day 
inspired by such an intellectual ideal, and that was 
Galileo, who by his pursuit of it in the physical 
sphere created the science of mechanics. If, says 
Descartes,^ magnetism is a qualitatively distinct 
force, and not merely the resultant of a complex of 
mechanical conditions, we are forever debarred from 
knowing it;^ and we are debarred from knowin g 
all that which is not explicable in terms of the few 
ultimate conceptions with which consciousness is 
endowed. What these ultimate conceptions are, and 
how far they render knowledge possible, it is the 
work of his metaphysics to show. 

I ^ ^ 

1 Reg, XIV, (xi. pp. 294-5). Cf. Beg, xii. p. 281. 

* To know it " we should require either new senses or a 
divine mind." Loc. cit. 




The instrument which Descartes uses for analysing 
out from experience the ultimate conceptions upon 
which it rests, is doubt, and on applying it he finds 
that there is only one truth which is altogether 
\ indubitable, the cogito ergo mm of Augustine. * If 
nothing of all that I doubt exists, yet still my doubt 
remains. If all that I perceive is illusory, yet none 
the less my perception remains. If all that I imagine 
be purely fictitious, it is yet true that I imagine. 
And all these, doubt, perception, imagining, are 
forms of consciousness, modes of thought. Conscious- 
ness, therefore, or thinking, is that which is beyond 
^the possibility of all doubt/ We know our ideas face 
to face, and they are as we perceive them to be. It is 
only when we go out beyond them, and assert the exist- 
ence of something outside corresponding to them, that 
we can fall into error. The inner self-transparency 


of thought which sees itself, and can see nothing save ^ -J^ /->,<- 
as reflected in itself, is the s ole indubitable certainty, ' ^ ^ ' 
t he one form of existence directly known to us. 

Now the cogito ergo sum, considered as the primary 
certainty in our knowledge, can be regarded in two 
wayB; either as a ne cessary truth of reason^ and then //^ 
it must be universally expressed, y^erever there. 19 ' / r 
conscious ness there is existence, of; as conveying our 


certainty as to a p articular contingent fact, namely, 
that I in being conscious exist at this particular 
moment. Interpreting Descartes in accordance with 
his treatment of the intuitive truths of mathematics, 
we find that the two aspects of the cogito are insepar- jb^ 
able. A universal mathematical truth, we have seen, 
is always apprehended in and through the particular, 
the particular case being apprehended as an illustra- 
tion of the universal, and the universal truth as 
involved in the particular. So also is it in the cogito 
which Descartes uses in both interpretations. 

When used, h owever, to prove existence, the * I ' ; 
is illegi timately brought in. The present conscious- 
ness does not afford us any indubitable certainty of 
our having existed in the past or of continuing to --i ' 
exist in the future, and yet such implications of 
continuity of existence the use of the * I ' certainly 


^' (Xi.' , ■ 

^ r 



f t 

f ( 

involves. Still less does immediate consciousness 
prove the existence of the self as a simple indivisble 
.t* ^;a ('< -Substance. Descartes in so arguing really interprets 

■I ^ 



>bis 'ultimate' principle in accordance with an 
assumed principle yet more ultimate, in logical though 
not in temporal order, the principle namely, which he 
explicitly states in his Principles'^y as a truth 
manifest by the natural light of reason, "that Jo 
nothing no aflFections or qualities belong." Th ought 
he, without proof, assumes to be a quality, and 
therefore, in accordance with that principle, to imply 
a substance or self.^ 

Descartes, however, is also interested to derive 
from the co gUo a univ ersal criterion of truth, and in so 
doing interprets it in the universal way, as a necessary 
V t^ r-^w^ /*< \fy^ Qf reason, showing the inseparability of the idea 
of consciousness from the idea of existen/ze. Such 
inseparability in thought, if in this case a sufficient 
proof of in^separability in fact, must be so in all cases. 
And his universal criterion of truth and reality there- 
fore is, that all that in thought is clearly and 

^ r. II. (hi. p. 69). 

2 That, too, is how Malebranche and Regis interpret 
Descartes' argument. Cf . Malebranche, Entretiens sur la Meta- 
physique^ i. p. 5 ; and Regis, Cows Entier de Philosophie : la 
M^taphysiqiie^ liv. i. pt. i. chap. xi. p. 96, 

\^ C tA 


-i< -v 

> iT < *i ^ 







d istinctly conceived to be necessaril y connected must < 
be likewise inseparable in existence. It will be noted* ' 
that the universal truth (the idea of existence is in^ 
separable from the idea of consciousness) is not 
proved by the particular intuitive judgment, cogito 
ergo w/m^ but only illustrated in it, and still less, 
therefore, can the cogito prove the yet more universal 
criterion of truth. 

Now we must urge against the exaggerated im- 
portance which Descartes attaches to the cogito ergo 
Sfiirrby that we never need to prove existence, since we 
can never get away from it, but only to define it. 
When Descartes shows that consciousness involves 
existence he proves, only too truly, what can never be 
doubted, since, if existence is thus taken quite 
vaguely, it is. certain that all the objects we perceive 
even in dreams exist. When, on the other hand, he 
pretends to have proved by the cogito the existence 
of the self as a spiritual substance he asserts what 
it can never prove. As proving existence, therefore, 
the cogito is superfluous, and for defining it, it is useless. 

Descartes, indeed, by adopting the doctrine of 
representative perception^ as a necessary consequence 

* Descartes' argument in the first Meditation most evidently 
rests on an interpretation of knowledge in the light of that 

< y< 



i< * r 

< < « 

<-i. c< - f , / f/ 





of the dualism from which he starts, made inevitable 
for himself the view that only in conscio usness ca n 
come into direct contact with reality. And 


further, since throughout his metaphysics he almost 
invariably a ssumes that ideas are distinct from the 

mind, attH fhoTnypr agaVliat fr^^ gt-flnrls a Sglf th^ t 

contemplates them^ the existenc e of ideas is forhim 
sufficient pr oof of the selCa ^ JEt^dstence. In the 
doctrine of representative perception is thus con- 
tained all that is of importance in the cogito. We 
can know only ideas, but as we know them face to 
face we cannot doubt either their existence or the 
existence of the self whose thought they terminate.^ 
Since the criterion of truth is not proved by 



[he mgitn jnrgn sfiirn,^ but only illustrated in it, it sti 

doctrine. What is^impRed by Descatrtes is explicitly stated 
by Malebranche, viz., that the doctrine of representative per- 
ception is a self-evident truth. Cf. Recherche^ iii. pt. ii. chap. i. 
p. 377, which has already been quoted below in note to page 5. 
Arnauld was the only member of the Cartesian school who 
thought of questioning this doctrine. Cf. Appendix A to this 
chapter, p. 115. 

1 Leibniz, in diflfering from Descartes, is really only making 
Descartes' own position more explicit. Cf . Noivoeanx Easaia, liv. 
vi., chap. II. sec. i. (Gerhardt, v. p. 347) : " It is not only im- 
mediately clear to me that / thinh^ but it is just as clear to 
me that I have different thoitghta, . . . Thus the Cartesian 
principle is sound, but is not the only onVof-4^ kind," 


remains to be asked why, and with what right, we 
trust to that criterion. Why must that which is 
true for us and in the mind, be true for all others 
and outside the mind ? Descartes replies by unfolding 
the implications that underlie the acceptance of the 
cogito ergo sum as a necessary truth. Though we cannot 
doubt of any intuitive truth when it is present to y> 
the mind,^ we can yet when we look back in memory ^^ 
on a conclusion that has been established by a chain 
of such intuitive truths, distrust the validity of that 
conclusion,, so long as we do not repeat in thought 
and so verify in fact the necessity of belief in each 
of the intuitions that compel its acceptance. And, 
fur,ther, the doubt, when it is thus kept detached 
from special simple intuitions, can become perfeqtly 
universal : all our ideas, and therefore all the tijiths 
that we perceive to be necessarily involved in them, 
may one and all be false, being implanted in us by 
some evil genius. As the possibility that two and i< 
two should not make four, is only conceivable on the 
assumption that the faculty of knowing is in its 
essential nature deceptive, and that therefore all 
knowledge is an illusion, this general doubt is the [ 
only form of doubt applicable to our simplest intui- 

1 Principles^ i. 13 (iii. pp. 71-2). 


criterion in all cases or in npne. Between rationalism 
^ .jc and scepticism there is no alternative. 

Descartes, however, refuses to recognise this fact, 
and seeks to compound with reason in an impossible 
compromise. He will trust reason just so far as 
le sees to be necessary to establish the existence oT 
rod, and will then throw on God the responsibility 
^ Uof an unlimited trust. To avoid following him into 
the sophistries that such a view necessitates, we shall 
interpret his line of thought according to the higher 
truth that forces him to seek to conceal the petitio 
principii that such argument involves.^ .The accept- 
ance of any truth, the cogito ergo sum or any oth er, 
involves the acceptance of the universal criterion of 
truth, and therefore the acceptance of all that 
thought, in accordance with that criterion, shows to 
be necessary. Everything or nothing is what reason 
demands, and since to act is a necessity, the alter- 
native to be chosen is decided for us. 
'^^ , In his proofs of the existence of God Descartes' 


y.* - The petitio principii lies in his using principles, which hie 
*^ holds to be truths evident by the uatural light of reason, to 

prove God's existence, and then guaranteeing the validity of 

reason by the veracity of God. 



scholasticism comes to a height. Usually he conceives 
God as a-^reator; and when he dispenses with that 
obscure conception, it is only to fall back upon the 
equally obscure notion c^ubstance. As it is hopeless 
to attempt to disentangle the diverse lines of thought 
involved in his arguments save by means of the clari- 
fying analyses which Locke and Hume made of these 
fundamental conceptions, we shall in the meantime 
consider his arguments only so far as is necessary to 
maintain the continuity of his thinking. 

Starting with the assumption that creation is not 
only .intelligible, but also the sole conceivable ulti- 
mate explanation of origin, Descartes lays down as 
principles " evident by the natural light of reason," ^ 
that nothing cannot be the cause of anything, and /^ ' 
that the more perfect cannot arise from the less '*^ 
perfect, so as to be thereby produced as by its 
efficient and total cause, and that, therefore, ^1 that, 
Js contained, in an idea, or a s it were in a picture, 
must exist in its first and chief cause not only in 
idea but also in fact. ^ We find in the mind the idea 
of God as an absolutely perfect being, and as we do not 
in any way find in ourselves the perfections contained 
in that idea, we must conclude that they exist in 

^Principles, I. 17 (in. p. 74). 


*./ « 




some nature dififerent from ours, that is, in God, who 
\ must, therefore, be inferred to exist in order to cause 
the idea in us. 
f ^' And, again, starting from this other principle *in 
the highest degree self-evident,' that it is more 
difficult to create substance than any of the attri- 
butes of substance,^ it must be inferred that, J^f we- 
had made ourselves, we should have made ourselves 


^rfect in all our properties. But as we have the 


knowledge of many perfections which we do not 
possess, we must have drawn our origin from no 
^^ , other being than from him who possesses in himself 
*i • nU^Jall those perfections. Again, therefore, God must 

i«^\^*»^*' ^y And, thirdly, to meet the objection that the idea 
V'^^ . of an infinite all-perfect being may be derived from 

experience by a combination, and ideal completion, 
of the perfections we meet there, Descartes replies 
V that it cannot be so, since the idea of the infinite 
4s- involved in all consciousness of the finite as its 
prior condition, " For how," he asks, " could I know 

^Principlesy i. 20 (iii. pp. 76-7). Regis therefrom infers that 
"all substances, with the exception of God, are equally perfect 
in themselves" {Coura Entier: la M^taphyaiquey liv. i. pt. i. 
chap. XII. p. 100). 

jf\l /^ ^ t^kitf , ^-j. 



that I doubt, desire, or that something is wanting C\i^ 
to me, and that I am not wholly perfect, if I J f Im^ * * *■ ^ 
possessed no idea of a being more perfect than my- ^cjl <^^^' 
self, by comparison of which I know the deficiencies j 

of my nature ? " ^ The idea of God is, therefore, / 
the primary fact in our consciousness, and makes 
possible the consciousness of the self as a doubting 
finite being. It is not merely as clear and distinct 
as the c onsciousness of the selfs existence, but 
clear er, since only through its mediation is such 
conscio usness • possible. And with an over-emphasis 
that is highly significant, Descartes concludes that 
there can be no idea "more true or less open to the 
suspicion of falsity ." ^ U\ 

That last argument leads up to, and indeed iS^*- ; 
volves, the . pntological argument. ]^ we take any ^ [ 
geometrical conception, say that of a triangle, from^ 
the mere conception we can deduce with absolute' 
certainty that the sum of its angles is equal to two 
right angles. So, too, from the mere idea or con- ' 
ception of God we can deduce certain properties as 
necessarily belonging to Him, and one of these pro- 
perties is His ftxiat,ftnp.e. It is as impossible to 

c onceive a Being absolute ly perfect to whom the 

^Medit. III. (i. p. 281). Veitch*s trans, p. 126. ^Loc, cit. 






perfection of actual real existence is yet awanting, 
as to conceive a circle while denying that its radii 
are all equal. Consequently it is as certain that 
//God, who is this perfect Being, is or exists, as any 
demonstration of geometry can be. 

Now, the ontological argument by itself merely 
proves a necessity of thought, the necessity of think- 
iiig God as existing, if we think Him at dl " Th^ 
idea of God may be purely fictitious, and hence the 
necessity it lays upon the mind of adding the further 
idea of necessary existence may be a ^ctitiou§_iific«B- 
sity. There are certain laws of thought that we 
cannot escape even in the most imaginary of ideal 
worlds, but that in these ideal worlds we are still 
subject to the tyranny of some necessity or other 
does not make them to be real. It must be prove d 
that the idea of a perfect being is no such ar bitrary 
idea, but an idea which the mind has not fabricated 
for itself, and which it must think if it is to think 
at all. The ontological argument, therefore, rests on 
/and presupposes the preceding arguments whereby 
'^that has been proved.^ 

^ The connection should be noted of the ontological argument 
in the fifth Meditation with the proof that immediately pre- 
cedes it| that conceptions are all objective and given to the 


And now that Descartes has established the exist- 
ence of God, he is able to overthrow all the sceptical 
doubts, through which alone he was forced to reject 
the truths of reason as possibly false. This result 
he expresses in a very crude form, saying that one 
of the qualities belonging to God's perfection is 
veracity, and that, therefore. He cannot will to 
deceive us. What Descartes means thereby, is that 
God is the all-comprehensive absolute reality, in 

mind, not framed by its own finite powers. Cf. below, pp. 
108*10 in this chapter. 

It is not true, we have seen in the preceding chapter, that 
from the mere abstract conception of a triangle, as a space 
enclosed by three straight lines, the other properties of the 
triangle are discoverable, but only from the construction of it 
in space. It is because it is a perception that it can reveal new 
properties, not originally thought in it, to the mind. The con- 
ception of God, however, is a pure cfinception, and therefore if 
it involves existence, such necessary existence must have been 
explicitly conceived in it from the start. The bearing of this 
will appear in the chapter on Locke (p. 199). We shall see how 
the conception of God, regarded as the Unconditioned, is just 
the conception of absolute existence and nothing more, the 
quality of perfection being illegitimately used as a metaphorical 
synonym for absoluteness. Only because the idea of God can 
be interpreted in these two ways, either as denoting a personal 
moral agent, or as signifying the absolute reality in whom we 
and all other beings are* contained, can Descartes, while offering 
proofs of God's existence, still claim that no idea is '^ more true 
or less open to the suspicion of falsity.'' 





whom we as well as all other beings are contained, 
and that in Him truth and existence are one. The 
necessity which constrains us to think in a certain 
way is likewise a necessity which governs real ex- 
istence. The nature of things is rational, and hence 
rationalism is the true philosophy. All that we 
clearly and distinctly conceive to be true, we may 
safely accept as true. 

Descartes, however, not only interprets that 
criterion as meaning that what is inseparable in 
thought is inseparable in the real, but also adds the 
negative interpretation that in thd case of ideas 
between which the mind can perceive no connection, 
the existences corresponding to them must also be 
unconnected. What misled him was the scholastic 
doctrine that each substance has an essence peculiar 
to itself, which constitutes it what it is, and is 
inseparable from its existence, and that a sharp line 
can be drawn between this essence and all else. 
Though this teaching results in a conceptual atomism, >i 
which is the direct opposite of the modern scientific 
point of view, and of Descartes' own point of view 
in his physics, according to which to know any 
material thing we must relate it to other things 
and ultimately to the whole universe, it W£is estab- 


lished by an argument whose force, trifling as it now 
appears, Descartes was unable to withstand. A 
thing must either exist or not exist : there is no 
third alternative. Further, it must exist altogether, 
with the whole of its essence, or not at all. And 
so, too, the scholastic mind argued, if it be clearly 
and distinctly conceived, it must be conceived alto- 
gether, through the whole of its essence, since what 
we mean by essence is that without which a thing 
can neither be nor be conceived. Svistance, essence, 
and coneqption are all identical, and hence what is not V ^ 
essential to the conception of the thing is not essential 
to its existen^ce} Applying his criterion, interpreted 
in this negative way, Descartes argues, that since 

^Cf. Itegis, Cours Entier: la M^taph, liv. i. pt. I. chap. ii. 
axiom 4 : ^' that the essences of things are indivisible, and that 
we can neither add to them nor diminish them without destroy- 
ing them." Cf. Malebranche, Recherche, liv. iii. pt. ii. chap. 
VIII. p. 422 : ** Philosophers sufficiently agree that we ought to 
regard as the essence of a thing that which is recognised as 
primary in it, that w)^ich is inseparable from it, and on which 
depend all the properties that belong to it." Malebranche adds 
in a note that " if we accept this definition of the word essence, 
all the rest is absolutely demonstrated." Malebranche also 
explicitly states on p. 424, as an indubitable truth, the further 
principle, assumed both by himself and by Descartes, viz., that 
everything must either be a substance or the modification of a 





^ « < r r 



t/j»i»pure thought alone is inseparable from the mind,' it 
\yj itself constitutes its whole essence; and similarly 
that extension constitutes the whole essence of matter; 
and that the two, mind and matter, are wholly in- 
dependent of one another. Sensations and feelings 
must have been introduced into mind, and motion 
into matter, from the outside.^^ J^:^ 

One consequence of this identification of substance 
and conception is that there can be no mean for 
Descartes between complete knowledge and absolute 
ignorance.^ The continual reference to God for explan- 
ation of finite phenomena is no admission, as so many 
of his commentators assume, of ignorance of the true 
explanation, but is always based on the certain and 
absolute knowledge that they are due neither tomi] 

^A detailed account of Descartes' argument is given in 
Appendix B at the end of this chapter, p. 117. Those readers 
who are not acquainted with Descartes' theory of perception, or 
with his account of the relation between sense and understand- 
ing, are requested to read this appendix before proceeding, as a 
knowledge of Descartes' views on these points is presupposed 
in what follows. 

2 Consistently that is, for it need hardly be pointed out how 
inconsistent is his assertion of partial knowledge of God, since 
he tells us that the iSea of God is the clearest and most distinct 
we possess. Another difficulty for Descartes is how, if extension 
is completely known, new knowledge can continuously be acquired 
Nrf its ' modes.' Cf. below, p. 68, note 2, 


mor to matter (these being known completely), and that 
j therefore, so far as they have any reality, they must 
I be wholly dependent on what is outside both. It is 
.by such a process of excltman (a form of argument 
jvery important in the Cartesian system), that the 
phenomena are »ref erred to God as the only remaining /o/^ 
jreality . On this assumption of completed knowledge 
also rests, we may repeat, Descartes' negative interpre- 
tation of the criterion of truth. Since niind and body 
are in thought completely transparent to us, each 
being exhaustively known in conception, where no 
necessary connection is visible between them, or 
between either of them and what is conjoined with it in 
experience, there can be none, and such conjunction as 
is vouched for by experience must be regarded as 
external and contingent. There can, therefore, be no 
rationalising of Descartes* implicit occasionalism with- 
out desertion of his whole metaphysical position. His 
metaphysics is, we shall see, the demonstration of the 
impossibility either of explaining one finite fact from 
another, or of deducing the finite rationally from the 
infinite.^ There is required in order that his system, 

^ If it is to be rescued from such a suicidal adm^ion, mthout 
desertion of the doctrine of substance (as that which has all its 
reality and relations within itself), that can only be at the 


P.xJi tu.,^U^>Jt which thus comes to be not only dualistic but also 

r/i^^^J c^ atomistic, may march at all, even in an artificial gal- 

' y\^^\ vanised manner, the conception of a third kind of 

^ reality capable of bringing about such connection as 

the finite substances, be they spiritual or material, 

cannot by themselves achieve. That is the real 

ground for Descartes' inevitable assumption of God's 

existence, and in comparison his oflBcial arguments are 

of secondary importance. 

Having thus gained and guaranteed the criterion of 
truth, Descartes applies it at once to the concrete 
contents of mind, and the problem, under which I 
shall bring all the other points I wish to raise in his 
metaphysics, is the problem deferred from the last 
chapter, as to what he determines the ultimate concep- 
. , , "Ttions or innate ideas to be, under how many categories 
^^^ /,, he brings them, and how on his view they are 

. . , interrelated. In solving that problem, Descartes gives 



expense of the dualism. Either the finite substances must be 
made absolute or they must be taken up into the absolute. We 
must either with Leibniz pulverise the real into atoms (each 
of them conceived as a complete world in itself), or with Spinoza, 
identify it with the one indivisible divine substance. The 
Leibnizian position is (if we can make such comparisons) the 
more natural to Descartes, and that to which he most tends, the 
mystic synthetic religious pantheism of Spinoza being wholly 
alien to his plastic analytic purely intellectual cast of mind. 



his answer to the question as to the limits of know- 
ledge. Since, as he has shown in his doctrine of 
method, the only knowledge possible to the mind is 
that which is deducible from the innate ideas, our 
knowledge will reach just so far as they do and no 

Taking first the conceptions involved in the com- 
prehension of the material world, they can all be 
brought under the categories of matter, extension, 
figure, an d motion. Through these the whole nature 
of the material half of the universe is, Descartes 
holds, completely known. By regarding extension as 
constituting the whole essence of matter,^ Descartes 
destroyed the belief, almost universal in his day, that 
a tenuous and subtle fluid (such as air, and also fire as 
then conceived) approximates to the spiritual. When 

a gross substance is subtilised into a rare fluid, it does 
n ot, De scartes easily demonstrates, thereby become 
any the les s materia l This identification of space with 
matter has, however, found many opponents. Locke, 
for instance, t akes the feeling of resistance as revealing 
the objective quality of solidity. To that objection 
Descartes replies that, since the feeling of resistance is 
as variable as the sensations of colour and heat, and 

^Cf, Appendix B at the end of this chapter, pp. 117 ff, 



It V . 


' f 


f ) '^ -c 

S" ('A e ^. 


equally inconceivable save as in a mind that is capable 
of feeling, it must be regarded as likewise subjecti ve. 
Descartes further shows that by the solidity of a body 
we can mean nothing more than that it is extended, 
and so fills a certain space. Space cannot be filled 
twice over, and hence matter as filling space is ipso 
fou:to solid. Another criticism made is that (since no 
part of space can go outside itself to visit a neighbour- 
ing space) if matter is extension it cannot be moved. 
That objection, however, rests on a false inte^re^tion 
of Descartes' teaching. He does not say that matter 
is space, but contrariwise that spatial extension is 
the essence of matter. Matter alone has substantial 
reality, space being ' by a distinction of reasonj^cgn- 
ceived as its attribute. A particular space (definable 
and conceivable only as a particular set of relations 
holding between bodies at least relatively fixed) though 
inseparable from body, is not inseparable_ from_ any 
particular body. When water is poured from a vessel, 
the space vacated by the water is immediately taken 
by air, and hence the spatial relations holding between 
the sides of the vessel persist. Matter may move, 
though the space thus defined remains. Greulincx ^ gives 
a very subtle, but quite suflBcient answer to the one 

^Metaphynca Vera : ii. Quinta Scieutia. 


remaining difficulty : how, if space is body, we ca n yet, 
as we continually do, speak of body as in space. ^ 
Obviously body cannot be in body, since all body 
excludes body. When we thus speak of bodies being 
in space, we mean, Geulincx replies, particular bodies. 
Such particular things are material but not matter: 
they are distinguished from matter by their motion, 
and therefore are in matter like the motion that 
constitutes them.^ 

But, while we grant that the above objections 
can all be met, there is still one criticism that 
must be made, namely, that Descartes uses the 
conception of substance and attribute to define the 
relation of space to matter, and yet nowhere 
analyses this category. Just as his dogmatic use 
of the similarly unanalysed conception of causality, 

that principle 'evident by the natural light of 

reason ,' to denote the relation (on his theory in- 
conceivable) of soul and body, directly gave rise 
to the destructive criticism of it by the 
occasionalists and Hume, so too the difficulties 
involved in this identification of extension with 

^ Matter, it must be l)orne in mind, is regarded bj Descartes 
as homogeneous and continuous, motion being the sole differen- 
tiating factor. To mind all the secondary qualities are due. 
Cf. below, note 2, p. 68. 


A"^ V<^^ 


matter, as also of pure thought with mind, im- 
pelled both Locke and Leibniz to the examination 
of the conception thus employed,^ 

Figure is a modification of space, and is, there- 
fore, correctly enough described as__a Tnode of spac e, 
though of course that is a mere description and no 
adequate account of their connection.^ Descartes, 
however, also defines the relation of motion to 
extension, and therefore to matter, by that same 
term, and thereby commits one of his fundamental 

^ While Spinoza and Leibniz both retain Descartes' definition 
of substance, as that which contains all its relations within 
itself, the former drew the conclusion that it is only applicable 
to the Divine Being, and the latter (virtually regarding the 
distinction between the finite individual and Grod as merely one 
of degree) the similar conclusion that each finite substance must 
contain within its content the notion of the whole universe. 
Cf. Descartes' statements in the PrificipleSy i. 51 (iii. pp. 94-5) on 
the impossibility of applying the term substance in the same 
sense at once to God and to created beings. 

^ If bare extension is the whole essence of matter, then figure 
must be introduced from outside as well as motion, and as a 
^ ^^ matter of fact is so physically ^ since the differences of figure in 

matter result from motion, and depend on its continuance. And 
conceptually it must be so likewise, though Descartes ignores 
the difficulty by constantly speaking as if all figures were 
directly deducible by pure thought from extension. Malebranche 
as usual boldly faces the problem, and explains the appearance 
of figures in intelligible space as due to differences arising in 
sense (an exact parallel to the physical explanation of them as 
arising from motion). Under the stimulus of sense we attach 



errors. The great achievement of Ga lileo and-^ /*. y 
Descartes in physical science consisted rn^a new 
jheo ry of m otion. Whereas by the Greek A tomists 
a nd by Aristotle mot ion was anthropomorphically 
conceived, as, like human activity, coming into 
being, exhausting itself in exercise against obstacles, 
and ceasing to be — the fleeting activity of a matter 
that is alone abiding ; with Galileo and Descartes it 
asserts its full rights. It is, they show, in its 
ingenerable, indestructible nature, as different from 
human activity as matter is from mind. Galileo 
did not, however, realise the full significance of his 
discoveries; and it was left to Desc artes to state 
the diflBculties. involved in any attempt to derive 
motion from matter, or to connect it in any 
necessary way with matter. Matter and motion, 
as conceived by Descartes, are quite d istingt _m nature, 

different sensations of colour to the homogeneous unfigured 
space, and so there arise for us different figures in it. Male- 
branche's explanation applies, however, only to the perception of 
figure. If colour be removed figure disappears too, and only 
bare extension remains. The pure conception of figure is still 
left unaccounted for. Descartes' whole treatment of figure and 
its relation to space, whether in his method or in his meta- 
physics, is very unsatisfactory, and that by no accident, since 
'modes' of any kind are the crux of his philosophy. For 
Spinoza's attitude towards this problem cf. below, chapter iv. 
pp. 153 ff. 


and in origin ;^ and equally svhsiantial, since thej are 
equally ingenerable out of nothing, and equally in- 
destructible. Indeed, Descartes so far anticipated 
modem science as completely to reverse the r61es 
hitherto played by matter and motion. In Greek 
i V A /. science the differences between natural phenomena 

/ i are ascribed to differences in matter, either to differ- 

« - - 

ences between atoms or to differences between 
elements: in Descartes* philosophy of nature,^ in 
modem science, they are ascribed to differences of 
motion. Matter becomes the mere vehicle of motion, 
and motion the all-important reality. 

Strictly, therefore, Descartes' analysis of the real 
•^ 7-, lands him not in a dualism, but in a trinity, and 
.^ in a trinity one of whose elements mediates between 
the other two. Motion, like matter, is unconscious, 
but also, like mind, is unextended, immaterial, ^d 
active.^ The fictitious dualism conceals a purely 
relative trinity of the three substantial realities, 

matter, motion, and mind. 


^ Of, Appendix B at the end of this chapter, p. 121. 

^ At least as active as he shows mind to be. 

^ There still remains, of course, a dualism, with matter and 
motion on the one side and mind on the other, but once motion 
is admitted to be equally real with matter the dualism cannot be 
formulated in the absolute manner of Descartes. 


That, however, is only the position which Descartes 
takes up in his physics. In his metap hysical 
exposition of his physical views he inconsistently 
s peaks of motio n as a mere mode or form of ^.^/^ 
matter, his sole argument for so regarding it, as 
dependency of matter, being that while extension, 
which constitutes t he essence of matter, is conceiv- 


able apart from motion, motion cannot be conceived 
apart from it . That argument, even granting it to 
be a legitimate one,^ is disposed of by Kant when 
he shows that we can only conceive a line by 
drawing it in thought, a process which involves 
motion.^ The reason of this misrepresentation of 
his physical theory is to be found in his scholastic 
cally interpreted criterion of truth. The ideal of 
knowledge, which that criterion so interpreted in- 
volves, is wholly inconsistent with explanation by 
efficient mechanical causes. Rational connection and 
physical causation form two distinct kinds of know- 

^ -*^ "^ 1 ■ — Till I -IMII II ^^lll■■l■l I - - rp>v« wm ^ mm^i^mmm » — - «»aq» •rk<.»^««aw* 

ledge: the one yields necessary truth that justifies 
itself by its inevitableness for thought, the other 
(so Hume urges and Kant agrees), contingent for 

*The same argument would prove motion to be a mode of 

^The conceptions of time, space, and motion, Kant proves, 
mutually involve one another. 


^thought, can only be empirically ascertained.^ As 
Descartes' rationalistic ideal is constructed solely in 
the light of the first kind of knowledge, he has, in 
i order to maintain its universality, to explain the 
other away. That is what in his metaphysics he 
[has come, at least partially, to recognise.^ 

First, he admits that thought can never establish 
necessity of existence* Since never in the concep- 
tion of any finite thing is existence involved, we 
are forced in accordance with the criterion of truth 
to regard its existence as contingent, that is to say, 
as unaccountable by reason, and therefore, in 
Descartes' way of stating it, as due to the arbitrary 
will of God. But, further, not only is each finite 
thing contingent in its origin, so also is its continued 
existence, that also being inexplicable from its 
essence. Since each mo^nent of time is distinct 
from every other,* the persistence of an existence 

^ Whatever ultimately be the connectiou between the principle 
of sufficient reason and the law of causality, cause and reason 
certainly cannot be straight away identified ; and yet that is 
what Descartes by his principles is forced to do. 

^As we shall see in the next chapter, this consequence is 
recognised by Leibniz and Spinoza, both of whom identify 
causation with explanation. The same identification is at the 
root of the occasionalist denial of transient action. 

^ It may at first sight seem strange that Descartes, who so 


from one moment on to another demands an ex- 
planation as much as its first origin, and yet again 
none can be given, save only the will of God. 
Persistence in existence, says Descartes, is in all 
essentials perpetual and unceasing recreation.^ i*'' ^*^^ \\ ^-^ 

And if existence is thus in all its forms inex- C / 

* -_— > — / 

plicable, how much more so is causation ! Since "^ < « ' <r . 
persistence in existence is traced to God, so con- 
sistently must everything else. If finite bodies have 
so little hold on reality that they require at each 
moment to be recreated, they cannot be capable of 
causing phanges in one another : not having sufficient 

emphasises the continuity of space, should yet regard time as 
discrete, but the truth is that his atomistic rationalism is wholly 
inconsistent with the continuity of either space or time. (Cf. 
below, chap. iv. p. 170.) The view of time which Descartes is 
thus forced to advocate is also bound up with his scholastic 
theology ; and, as it casts some light upon his metaphysics, we 
have considered it more at length in Appendix C at the 
end of this chapter, p. 128. 

^Principles, i. 21 (in. p. 77), Veitch's trans, p. 202: "The 
truth of this demonstration [that the duration alone of our life 
is sufficient to demonstrate the existence of God] will clearly 
appear, provided we consider the nature of time, or the duration 
of things ; for this is of such a kind that its parts are not 
mutually dependent, and never co-existent ; and, accordingly, 
from the fact that we now are, it does not necessarily follow 
that we shall be a moment afterwards, unless some cause — viz., 
that which first produced us — shall, as it were, continually re- 
produce us, that is, conserve us.'' 


reality to persist, they cannot have sufl&cient force to 
act.^ The most ex treme occ asionalism is , therefore, 
t he o utcome of Descartes' metaphysjcs. The con- 
Ntinuity of existence, and therefore the continuity of 
time and of causal connection in time, is broken up by 
his atomistic doctrine of essence into a series of 
detached events upheld in their existence and connec- 
ticHi by God. God must, in his continuous recreation 
of things, be regarded a& continuously modifying them 
in accordance with a plan, the fixed though arbitrary ^ 
modes, in which He acts in the realisation of this plan, 
being what we mean by the laws of nature, 

1 Cf. below, Appendix (7, pp, 129-31. Even though bodies could 
act on one another, as they do not persist, they cannot bear the 
eflfects of other things, save as these are recognised by Grod in 
their recreation. 

^ Though Descartes recognises that the laws of motion, which 
are the sole ultimate laws of nature, are not, like the truths of 
mathematics, demonstrable as being rationally necessary, he 
still pretends to give a * deduction ' of them. They are, he says, 
necessary consequences of the unchangeableness of Grod^s will. 
Malebranche, at first, in a similar way, regarded them as con- 
sequences of the law of economy (the use of the simplest 
means to a fixed end) which God as divinely wise obeys in 
all His works ; but later, under the influence of Leibniz, he 
admitted that even such justification of them is impossible, and 
that it is only "by a species of revelation such as experience 
supplies" that they can be determined. Cf. Malebranche's 
Traits des Loix de la Communication des Mouvemens (published 


A more detailed examination of Descartes' treat- 
ment of motion will serve to confirm the above state- 
ments. Descartes really interprets motion in two 
ways, geometrically and dynamically, the resulting 
views being quite inconsistent with one another. 
From the geometrical point of view (which is • em- 
phjusised in his metaphysics) motion is mere trans- 
ference from one place to another. So regarded it is 
a TTwde of extension, and is even better known than 
figure, as is proved by its use in geometry to account 
for differences of figure. A further consequence is 
that, being a inode of the particular body moved, 
it cannot any more than the other modes of that 
body be regarded either as transferable or as inde- 
structible. Like figure, when it ceases to be in 
one particular body, it must cease altogether. 

Descartes could not, however, consistently hold 
to that geometrical view of motion, as a mode 
of matter, since it would have forced him to 
adopt one of two disagreeable alternatives. Either, 
first, motion being as untransferable as figure, he 
would have had to ascribe to each particular body 
the power of creating new motion in other bodies 
on impact. Or, secondly, he would have been 
forced to admit that body is incapable of acting 

^ ^. 


on body, and that therefore God is the sole 

To escape these alternatives, while still speaking 
of motion as a mode^ he inconsistently continues 
to conceive it as a separate entity, distinct both 
vf 'vv<v7 Vfrom God who has created it, and from the matter 
in which it may exist in varying quantities. It 
is to all intents and purposes conceived as existing 
in matter like a salt dissolved in water.^ Also, 
being known only through its mysteriously generated 
effect (motion in the geometrical sense, as change of 
place), it must be regarded as an unknown and in- 
comprehensible substance, divisible like matter, but 
incorporeal like mind. It therefore overthrows not 
only Descartes' dualism, but also his claim to com- 
pleted comprehension of material phenomena. " Do 
our senses teach us,** De la Forge asks, "how motion 
can pass from one body to another ? Why there is 
transferred only a part of it, and why a body cannot 
communicate its motion in the same manner as a 
teacher communicates his knowledge, without losing 
any of that which he gives ? The cause of the motion 

^ A metaphor actually i^ed by Bohault according to Leibuiz, 
though we have been unable to identify the reference. Cf. 
Leibniz, Nouveaux EssaU^ liv. ii. chap, xxiii. (Gerhardt, v. 
p. 208). 


of bodies is not then so simple a matter as one might 

It is worthy of note that, when pressed upon this 
point by More,^ Descartes has to admit the incon- 
sistency of his views, and that the alternative which 
he chooses is occasionalism. More is very definite 
and clear in his criticisms. He insists in his letter 
to Descartes on the distinction between motion and 
the force causing motion, and adds that if motion be 
identified with change of place, and so be regarded 
as a mode, it cannot any more than figure pass from 
one body to another. " And finally, I am filled with 
amazement, when I consider that so slight and mean 
a thing as motion, which can be separated from its 
subject and pass into another body, and which besides 
is of so feeble and transitory a nature that it would 
at once perish if it were not sustained by its subject, 
should yet affect it so powerfully, and drive it with 

1 TraiUde V Esprit de V Homme (pub. 1666X chap. xvi. pp. 242-3. 
It has been asserted (cf. Stein, Arcfdv fii/r Oeschickte der Fhilo- 
sophte^ I. p. 53) that this treatise was published in 1661, but as 
1666 is the date on the title-page, and as De la Forge in one of his 
notes (i, I, b) to the 1664 edition of Descartes' VHonvim himself 
speaks of his treatise a» about to appear^ we retain the later 

^ Henry More (1614-1687) was one of the Cambridge 



such force hither and thither."^ Descartes' reply to 

the first point is, so far as it has any definiteness, 

an acceptance of the extreme occasionalist position. 

vHe admits the distinction between motion as mere 

^/>t \'.' tfy — ' 

/ /. transference and motion in the sense of moving 
, , / >i%t?i^, u}^^^^' While the first is a mere mode of matter, 
<-^^JL ^ the second comes from God who continuously pre- 
serves the same amount of transference (translatio) in 
matter, as He has set into it at the first moment 
of Creation. Descartes further states that the 
reason why he has not emphasised this distinction 
in his writings is that it is rather beyond the reach 
of the vulgar, and might seem to favour the opinion 
of those who believe God to be the soul of the world 
and to be united to matter. 

In replying to More's second objection, Descartes 
makes his occasionalism still more explicit ''You 
rightly observe that motion, so far as it is a mode 

^ Lett X. p. 255. More is inclined to believe that there is 
no commanication of motion, and that the impact of one body 
on another is only the occasion whereapon the other is de- 
termined to move, just as the mind has this or that thought 
on the occasion of this or that motion in the brain. '' Motion 
is in relation to body that which thought is in relation to 
mind : neither the one nor the other is received into the subject, 
but both have their birth from the subject in which they are 




of body, cannot pass from one body to another. 
But neither have I asserted that. Eather I believe 
that motion, so far as it is such a mode, is 
in a state of continuous change. . . . WTien 
I have said thai the amount of motion in Tnaiter 
remains constanty I have understood that of the force 
impelling its parts, which force now applies itself to 
some parts of body, and tww to others. You need not 
therefore worry yourself over the transference of rest 
from one body to another, since not even motion, so 
far as it is a mode opposed to rest, can be so 

Descartes, however, had no liking for the occasionJt' 
alism in which he is thus entrapped by his rationalism. 
Not only does he still continue in his published 
works to speak as if bodies transmitted motion by 
impact, but also to assert that mind and body inter- 
act in sense-perception and in volition.^ 

^Lett X. pp. 294-6. ' 

'Descartes was led to believe that soul and body interact 
through one particular part of the brain^ namely the pineal 
gland, first by the fact that it seemed to be the one organ 
in the brain which is not double, and which, therefore, is 
capable of combining the impressions made on the different 
parts of the brain, and especially the twofold impressions from 
the double organs of sight and hearing ; and secondly, by 
the fact that having a central position in the brain, it is fitted 




u.'ii ^i f i( 

First, as to sense-perception. He had been able 
in his physics to reduce external objects to extension, 
figure, and motion, only by separating off from the 
objects all their other qualities and ascribing these 
to the mind. But later, when he had demonstrated 
that the whole essence of the self consists in pure 
thought, and that sense and imagination are quite 
distinct from pure thought,^ the problem arose how 
these sensations can exist in mind any more than in 
matter. To solve the difficulty he modifies his 
dualism. Just as external objects acquire the 
secondary qualities only through being brought into 
relation to the mind, so too, he holds, sensations and 
images can only arise in the mind WrbugE its union 
with a material body. Corresponding to our pure 
(conceptions there are, he dogmatically asserts, no brain 
processes. Conception is a purely spiritual process, 
and wholly independent of the body. Sense and 
imagination, on the other hand, are conditioned by 

to control the movements of those ' animal spirits/ which in his 
theory correspond to the nervous currents of modern physiology^ 
The animal spirits move the pineal gland, and thereby rouse 
in the mind sensations and feelings. Similarly the mind, by 
setting the pineal gland in motion, affects a change in the course 
of the animal spirits, and so brings about movement in the 
members of the body. 
*See Appendix B at the end of this chapter, pp. 126-7. 


brain-processes, and without them are not possible.^ ^ ,i 

This attempt, however, to explain the rise of sensa-*^ t' ^^ ri^i^'\ 

tions and images by the action of body on miner C^^^" i > , , 

wholly fails, since even in sense and imagination 

mind and body must be regarded as perfectly 

distinct. The states of the brain are but modes of 

matter and motion, and hence entirely different from 

the sensations and images which correspond to them 

in the mind. There can be no metamorphosis of 

the brain state into the mental state. Dead unfeeling 

matter cannot hand over to the mind sensations ready 

made. Noth ing, Descartes says in one_of his letters, c^^a*^''*, ' 

can come into the mind from outside through the '^'^' ' 

senses, whence it follows that " the ideas of pain, of ^ , 

colours, sounds, and a ll such things niust be natural 

to the mind," that is, innate in it.^ The action of 

the body on the mind in perception can at most be 

bjit the occasion or stimulus which determines the 

mind to produce the sensation out of itself at this 

^ See Descartes' curious statements, by no means reconcilable 
with the rest of his teaching, as to the nature of imagination, 
which are qaoted below in Appendix By note 2 to p. 126. 

^LetU X. p. 96. Cf. VHommey iv. p. 361. Thus Descartes isi 

in the end forced to give up the distinction, which he draws? z' 

in the third Meditation^ between innate and adventitious' 




particular moment rather than at any other. Now 
that is the very admission which Descartes sought to 
avoid. He violates his dualism so far as to admit 
that body can act on mind, but with no good result, 
since the same problem still remains, how sensations 
can arise in a mind whose whole essence consists in 
pure thought. Sensations he can explain as due 
neither to mind in itself, nor to body in itself, nor 
to the two in union. 

Secondly, with regard to the action of mind on 
body in volition, Descartes kept consistently to his 
dualism so far as to admit that the mind cannot 
originate motion in the brain. That would be a 
veritable creation of motion out of nothing by a mere 
fiat of the will. It would also be in direct conflict 
with Descartes' physical principle that only motion 
can produce motion, and that the sum of motion in 
nature is constant, and cannot be added to. Yet 
incomprehensible as is the action of mind on body, 
that does not prevent Descartes from most emphatic- 
ally asserting that it takes place. "That the mind , 
-which is incorporeal, is capable of moving the body, 
neither general reasoning, nor comparisons drawn 
from other things, can teach us, yet none the less 
we cannot doubt it, since so certain and so evident 


experiences make it manifest to us every day of 
our lives." ^ ^ 

Among the facts that thus make 'manifest' the 
incomprehensible, the most important are the feelings 
and passions. Had we only intellectual faculties, we 
should perceive any bodily injury in a purely intel- 
lectual way, as a captain perceives any damage to his 

^Lett, X. p. 161, cf. also Lett, ix pp. 132-4. 

*Some of Descartes' successors, however, Clauberg for 
instance (cf. Corporis et ArumcLe Conjtmctio, cap xvi.), did 
attempt by an analogy drawn from the material world to 
explain the action of mind on body. The driver of a wagon 
does not move the wagon, but only directs the motion of the 
horses that pull it. So, too, the mind needs not to cause motion 
in the brain, but only to direct the 'animal spirits' that 
already exist in the brain and are continually circling about in 
it. This analogy, however, as has often been pointed out, is 
quite misleading, since to be applicable at all to the relation 
between mind and body, the driver of the wagon would have to 
guide the movements of the horses by his mere wish. That the 
mind should divert a motion of the brain in a new direction is 
not a whit less mysterious nor less at variance with Descartes' 
physical teaching than that it should originate an entirely new 
motion. Leibniz {Essais de Theodicee, sec. 60, Gerhard t, vi. pp. 
135-6), and also many modern commentators, assert that 
Descartes himself tried to escape the difficulty in this way. 
But though Descartes frequently spea ks of the motion of thcj- 
* animal spirits ' as being merely directed (not originated) by 
the movements of the pineal gland, he never, so far as we are 
aware, suggests that those movements of the pineal gland, which 
are involved in voluntary action, can be explained in a similar 
manner as previously existing and merely guided by the mind, 



l^hip. It is the facts of pleasure and pain, and the 
emotions, that show the relation between mind and 
body to be closer and quite other than this. 
"Nature teaches me by these sensations of pain, 
hunger, thirst, etc., that I am not only lodged in my 
body as a pilot in a vessel, but that I am besides so 
intimately conjoined, and, as it were, intermixed with 
it, that my mind and body compos e a certain un ity. 
For if this were not the case I should not feel pain 
when my body is hurt, seeing I am merely a thinking 
thing, but should perceive the wound by the under- 
standing alone, just as a pilot perceives by sight that 
part of his vessel is damaged."^ The fee lings an d 
passions are thus the real ground of the knowledge 
we have of our dual nature, and to explain them m ind 
and body must be admitted to be, as Descartes says, 
'fused.* They reveal, therefore, the inadequacy of 
his dualism, for if he fails to account for the inter- 
action of soul and body in sense-perception and in 
volition, much more must he fail to explain what he 
regards as their still closer union in feeling and 
emotion. 2 

1 Medit. VI. (i. p. 336), Veitch's trans, p. 160. 

^ Descartes' treatise on the emotions is a good example of how 
little the delects in his metaphysics interfere with the excellence 


Though Desc artes thus inconsistently and vainly 
attempts to escape occasionalism, the inevitable c on- 
sequences of hia rationalism are one and all em- 
ph^ised by his successor, Malebra nche. We find 
nothing, Malebranche insists,^ in the conception of 
any finite thing which gives us the right to think 
that it can act on, and produce effects in, other 
things. This assumed power is a fiction, and there- 
fo re every ph ilos opher has been able to conceive it 
as he pleased, some by substantial forms, some by 
special powers or faculties, others by figure and 
motion; all of them alike, however, taking it as a 
fact proved by sense-experience that when one ball 

of his scientific treatment of particular problems, for the treatise 
is remarkable alike in its psychological analysis of the emotions, 
and in the treatment of their physiological conditions. 

^ Cf. Eclaircissement sur chap. Hi, pt. ii. liv. vi. de la Recherche : 
*' There are many reasons which prevent me from attributing to 
secondary or ruitural causes, a force, a power, an efficacy to 
produce any effect whatsoever. But the chief reason is that 
this opinion does not seem to me even conceivable. However I 
may strive to comprehend it, I fail to find in me any idea that 
can represent the force or power that is attributed to created 
things." Indeed, that is a most obvious consequence of Descartes' 
position. If we cannot find in the conception of a material 
body anything which can justify us in ascribing to it the powei 
of maintaining itself in existence, a fortiori we cannot hope t( 
find in it anything that would represent the power to modifj 
the existence of other bodies. 


strikes another it sets it in motion. But this pre- 
te nded demonstration fai t piM, Malebranche declares/ 
since it reveals the feebleness of the human mind, 
that even philosophers do not know that it is reason 
that must be consulted, and not those senses whose 
function consists only in revealing what is needful 
for the preservation of life. " When I see one ball 
strike another, my eyes tell me, or seem to tell me, 
that it is the true cause of the motion that it im- 
presses on it; but that is only because the true 
cause of motion in bodies does not appear to my 
eyes. When I interrogate my reason I see clearly 
that as boSies are not able to move themseTvesTand 
as their motive force is solely the will of God, who 
preserves them successively in different places,^ they 
cannot communicate a power that they do not possess, 
and that they could not communicate it even if they 
had it at their disposal. For the mind will never 
conceive how a body purely passive can transmit to 
another the power that transports it, whatever that 
^ower may be." Though God has established as the 
first law of motion, that bodies once in motion continue 

^ Loc. cit, Cf. also M^ditatiom Ckr^tiennes, vi. p. 67. 

' Cf . Meditations Chr^tiennes, v. p. 54 : " Qui lea cr6e ou qui les 
conserve successivement en diff^rents lieux." 


to move in a straight line, that does not mean that 
bodies of themselves persist in motion. Bodies have 
710 more inherent power of continuing in motion than 
of continuing in existence. It means only that God 
m^aintains and ' moves ' each body by creating it anew 
sfuxxessively in different places, Malebranche, that is 
to say, denies the reality of motion altogether, save 
as miraculously determined change. God is not 
only the first, but also the sole Mover. "When I 
consu lt reason I recognise clearly that my senses 
misle ad me, and that it is God qui fait tout en toiUes 
choses." ^ And since even within the material worliT 
all change is due to God, it does not require special 
proof that the interaction of mind and matter is 
also inconceivable, and that feelings, sensations, and 
ideas, have the same miraculous origin.^ 

1 Loc. cit Of. Entretiens, vii. pp. 159-60, 162. 

^Begis similarly distinguishes between the geometrical and 
the dynamical aspects of motion {Cours Entier : Physique^ liv. i. 
pt. II. chap. iv). Like De la Forge and Malebranche, he con- 
cludes that God is the sole cause of motion on impact. " When 
the body A moves the body By it is not by producing in it a new 
force, but by determining God, who moved the body -4, to 
commence to move the body 5" — Ibid. chap. vi. As regards 
the interaction of soul and body, De la Forge still holds that the 
human will is the direct and efficient cause of voluntary move- 
ments. Since Eegis and Clauberg in a similar manner ascribe 
to the mind a directive power, Cordemoy and Geulincx must 


Thus only, then, can Descartes, wten consistent, 

make the transition from his geometry to his physics. 

yerything that is in nature over and ab ove its m ere 


be regarded as the first consistent and thorough occasionalists. 
(Cf. the article by Stein — Zwr Genesis dea Occasioncdigmns — ^in the 
Archivfiir Geschickte der PhdasopkU^ i. p. 63.) As we have not 
been able to procure a sight of Cordemoy's first and chief work 
— Dissertations Philosophiques sur le Dtscemenient du Corps et de 
VAme (pub. 1666)—- we give a sentence from it that is quoted by 
Bouillier {Histoire de la PhUosopJde Cartesienne (3rd edition), 
chap. XXIV. pp. 516-6): "To consider the matter exactly, it 
seems to me that we should not find the action of mind on body 
more inconceivable than that of body on mind; for we 
recognise that if our souls cannot move our bodies, bodies are 
just as incapable of moving other bodies; and as we should 
recognise that the meeting of two bodies is an occasion upon 
which the power that moved the first moves the second, we 
should have no difficulty in conceiving that our will is an 
occasion upon which the power that already moves a body 
directs its motion in a certain direction corresponding to our 
thought." Stein states evidence, in the article above quoted, to 
show that though Cordemoy's Dissertations were published in 
1666, that is to say, a year later than the first part of the Ethica 
of Geulincx, Cordemoy had already developed his views as early 
as 1658: It was, however, by Geulincx that Occasionalism was 
first elaborated into a system. From his fundamental principle, 
that a cause can only produce that which it knows how to 
produce — impossibile est ut is faciat qui nescit quomodo fiat — 
it at once follows that spirit is the only conceivable agent, and 
that as the human soul, though conscious, is ignorant how bodily 
movements are brought about, it cannot be the cause even of 
its voluntary actions. Cf . Metaphysica Vera^ i. Quinta Scientia 
(Land's ed. ii. p. 150). The first volume of Malebranche*8 
Recherche was published in 1674, and the second in 1675. 


extendedness, all individuality and all change^ have to, /r/i^^ 4,^ v 
be traced to, and find their sole ground in, the -i? . -/ r- 
miraculous intervention of God. Nature is not ex-/^^"^^^'^-^* ' ' 



plained, but explained away. The conceptual theory ^'^ 'Yp^ 
of mathematical knowledge may conceal its defects so ^ ^^^ ^ 
long as it is tested only by those facts in the light of 
which it has been formulated, but immediately we 
come with it to the treatment of the sensible there is 
a complete breakdown. 

Turning now to the conceptions involved in our ^^^ y 
apprehension of the mental, let us see whether 


Descartes here applies his rationalistic ideal with any t ^ ry,^ ^ 
better success. These conceptions are mind, which ho' 
identifies with consciousness or thought, imagination, . 
a nd sense. Since imag ination"and sense are as com-^ 
pletely distinct in nature and origin from thought,^ 
as motion is from matter, Descartes again resorts to 
the vague term * mode ' to describe their relation to 
their common attribute. The term 'mode' he also 
uses to define the relation to thought of particular 
conceptionSy and the special difi&culties resulting there- 
from we shall note immediately. 

Already in the BegtUae, as still more emphatically 
later in the Meditations, Descartes takes intelligence 

^ See Appendix B at the end of this chapter, pp. 124 ff. 



• V 


< i 


as that which is alone ultimate in our knowledge. 
"We can know nothing/' he says in the Begulae,^ 
" until we know intelligence, for the knowledge of all 
things depends on it, and not it on this knowledge/^ 
Or, as he expresses it in the Meditations, all forms of 

1 "perception, imagination, and conception, that is, all 
forms of knowledge are forms of consciousness or 
thinking, and hence consciousness is known in know- 
ing anything. And he adds in the Meditations, that 
mind is therefore better known than matter. 

Now thought or consciousness is used in two senses 
by Descartes. Sometimes it is used as a gen eral nam e 
for all states of consciousness. All the contents of 
consciousness, as ideas or states of the self, are known 
directly face to face, and are necessarily such as they 
appear to the mind to be. And on this view the un- 
conditioned nature of consciousness is shared in by 
all its ultimate and irreducible contents. These 
contents, indeed, are regarded as being identical with 
it, and the necessary expression of its nature. " All 
the sciences united are nothing but the human 
understanding" — the rest of the sentence, however, 
indicates the want of clearness in Descartes' view 
of consciousness — " All the sciences united are 

^ Eeg. VIII. (xi. p. '243). 


nothing but the human understanding, whose light 
remains one and the same whatever be the objects to 
which it applies itself."^ Consciousness is here dis- .. 
fcinguished from its contents. They are its objects, £; 
a nd it is but the light by which thej are revealed to 
the mind.^ It is in this way, as an ultimate 
unanalysable simple force or light, that Descartes 
conceives consciousness, when he takes it as 
one member of his dualism and defines it in 
opposition to extension. When regarded as expressing 
itself in and through its innate ideas, and therefore 
partially in and through the conceptions of matter and 
motion, it obviously cannot be so defined in opposition 
to them. And to have attempted to define it in 
abstraction from all its contents, when indeed it is the 
merest abstraction, is another of the fundamental 
errors of the Cartesian philosophy.^ 

^ Reg. I. (xi. p. 202). The latter part of the sentence is con- 
densed in order to bring out more clearly its essential meaning. 
The complete translation is given in the chapter on Descartes' 
Method, p. 22. 

2 Of. Norris : Theory of the Ideal World, ii. pp. 113-4. 

3 While Descartes thus in his metaphysics takes consciousness. / 
as a simple unanalysable light, Kant regards the unity of con- * 
sciousness as, of all things in the universe, the most complex, 
since it involves irreducibly in its unity the distinction of 
subject and object, the object again involving the element of 


If now we first follow Malebranche in his criticism 
of Descartes, and see how space (even ' intelligible ' 
space) with all its contents is the object of mind and 
not a modification or state of it, is not a self but a 
not-self, and so clear up the ambiguities involved in 
Descartes' use of the term 'mode' to denote the 
relation of the objects of mind to itself,^ we shall then 
be able to bring to a clear issue the question whether 
or not Descartes is justified in assertii^ that mind is 
better known than matter. 

Malebranche has no difiScultj in showing that 
Descartes, on his own principles, cannot assert that 
the mind knows extension by perceiving it in itself, 
as a state or modification of itself. We can conceive 
extension alone without thinking of any other thing, 
and we can never conceive modes without conceiving 
the subject of which they are the modes. And not 

space, and implying the categories of substance and causality. 
By means of this analysis of Descartes' ultimate, Elant provides 
a sure basis for the rationalism which Descartes fails to found, 
and solves many problems which for Descartes and his 
successors had been insoluble. The CSartesian views of conscious- 
ness are treated more at length in Appendix D at the end of 
this chapter, p. 133. 

^We must see how ideas cannot any more than motion be 
regarded as modes, and that just as figure is the only possible 
modification of extension, so feeling is the only known modifi- 
cation of mind. 


only do we thus conceive extension without thinking 
of mind, we cannot even conceive how it could be a 
modification of mind. We can conceive space as 
limited, and so as having figure, and that mind cannot 
have. We must also conceive it as divisible into 
parts, and we see nothing in mind that is so divisible. 
And lastly, while space is infinite, the self is finita 
For all these reasons, space cannot be seen in mind> 
and, therefore, cannot be a modification of it.^ The 
mind cannot contain extension without itself becoming 
extended, and, what is more, infinite in extent.^ 

Also, we have only to appeal to our experience to 
assure ourselves that when we apprehend extension, 
we apprehend something distinct from the self. When 
we perceive the sun for instance, though we cannot see 
the actual material sun, since it is not in itself know- 
able, that which we do see, and with which the mind 

^Malebranche adds also the further argument, that we can 
think on a circle or triangle in general, though it is a contra- 
diction that the soul, which is a particular thing, should have a 
modification in general. 

* Cf. Meditations Chr^tienneSf i. p. 13 : " Do you think you 
have sufficient scope to contain in yourself even that which you 
can conceive in what is called an atom ; for you conceive clearly 
that the smallest part of matter that you imagine, being in- 
finitely divisible, potentially includes an infinity of different 
figures and relations.'' The study of Augustine brought this 
difficulty home to Malebranche, 


is immediately united, we perceive clearly to be 
something distinct from us ; and therefore we fly in 
the face of all the evidence {^'eontre notre lumidre et 
contre notre conscience") when we say that the mind 
sees in its own modifications all the objects that 
it perceives.^ 

Separating, then, from the mind all ideas in which 
space is involved as being the objects of mind and 
non-mental, what is left on the mental side ? Male- 
branche answers, and we must agree with him, nothing 
but feelings. " Pleasure, pain, taste, heat, colour, all 
our sensations, and all our passions, are modifications 
of the mind " ^ They are not involved in the concep- 
tion of matter, and as it would be impiety to ascribe 
them to God, arguing by exclusion, we must refer them 
to the mind. And in spite of the differences between 
sensations and emotions, they must (since we in no 

^ Eclairdssement sur chap. viii. pu it. liv. in. de la Recherche. It 
will be noted that the above criticism presupposes that concep- 
tions are objects of mind, and it is in that way that Descartes 
also views them (cf. in this chapter, pp. 108-9), saving on the few 
occasions when he interprets consciousness in the first and non- 
dualistic manner. Either, then, his dualistic view of conscious- 
ness as the opposite of extension must be given up, which would 
involve the complete transformation of his system ; or this 
criticism of Malebranche must be granted as unanswerable. 
Cf. below, Appendix 2), p. 133, 

2 JjOC, cit, 


case know them) be all alike called feelings. Can we 
compare heat with taste, odour with colour, or even 
one colour with another?^ With these modes of 
mind it is not as with figures, that being known in 
conception can be compared one with another and 
their relations clearly recognised. Between those 
intelligible figures, which are clear and distinct ideas, 
and these modes of mind, which are only confused 
feelings, there is no community. And that being so, 
why, Malebranche asks, pretend that those intelligible 
figures can only be known if they are modes of mind, 
when the mind knows none of what alone undoubtedly 
are its modes by clear conception, but only by inner 
sense ? ^ Instead of the sensations and feelings being 
related to mind, as Descartes would fain make out, as 
motion is to matter, and pure conceptions being its 
proper modes, it is just the reverse. 

If Descartes is to separate, as in his metaphysics he 
continually does, ideas (taking ideas in the strict sense 
as distinguished from feelings) from the mind, and to 
define the consciousness, whereby they are supposed to 
be revealed to mind, as the opposite of that element of 
extension, which is the fundamental and only real 

^ Cf. R^ponse d Amauld, chap. viii. 

2 " Par conscience oii par sentiment interieur," loc, cit 


element in all of them,^ then of course the above 
criticism of Malebranche is unanswerable.^ Conscious- 
ness cannot contain its opposite as a state of itself, nor 
indeed know it at all, unless God be again regarded as 
miraculously intervening, and presenting to mind what 
could never otherwise be known by it.^ 

^ Malebrauche's proof that, on Cartesian principles, strictly 
interpreted, we can have no * ideas ' of the spiritual, will be given 

^ The same criticism was made by Gassendi in his excellent 
Objections to Descartes' Meditations^ and Descartes in his reply 
caref ally avoids the main issue. 

' Malebranche's own solution, that we know space by partici- 
pation in God's knowledge of it, explains nothing, for the same 
diflSculty recurs with the same force in the case of God. How 
can space exist in the mind of God without God becoming 
thereby material ? That difficulty, which he could not solve, he 
escapes by asserting the unknowableness of Grod. " God includes 
in Himself the perfections of matter without being material 
. . . He possesses also the perfections of created spirits, without 
being spirit, in the manner we conceive spirit : his true name is, 
He that is, that is to ^ say, Being without restriction. All Being, 
Being infinite and universal." Recherche, liv. iii. pt. ii. chap, ix., 
at the end. Cf. Entretiens, viii. p. 185. The futility of Regis' 
reply to Malebranche, iu defence of their common master, is an 
interesting demonstration of the unanswerableness of Male- 
branche's criticisms. Begis admits that the mind cannot know 
space of itself and by its own natural powers, since not being 
extended, extension does not belong to its essence. But after 
proving that no known faculty will account for the appearance 
of extension in mind, he concludes by exclusion that it must 
belong to the essence of sovl as distinguished from mind, and 


Now, as a consequence of this removal of the 
objective content of knowledge to the not-self, it 
follows that so far is Descartes' contention that the 
mind is better known than matter from being true, 
that it must now be admitted that it is not known 
at all, but only felt> When Descartes asserts that 

that therefore the soul knows it by itself, and by its own proper 
nature. {Cours Bntier de Philosophte: la Metaph. liv. ii. pt. 
I. chap. III.) Soul (Vdme) he distinguishes from mind {Vesprit) 
as being the mind temporarily modified by its union with the 
body. Experience tenches us, he says, that it is one of the laws 
established by the Author of Nature, that the mind {V esprit)^ so 
long as it is united to the body, have the idea of extension 
{Ibid, liv. I. pt. II. chap. vi.). It is in accordance with this 
condition that the soul {Vdme) thinks always on some body. 
But how it is possible for the mind thus to be modified Eegis 
makes no attempt to explain. The empirical fact, spite of its 
inexplicability, is ultimately his sole reply to Malebranche's 
and GassendPs criticism. The problem of how the unextended 
mind can know extension remains as insoluble for Descartes and 
Malebranche as for Augustine. Of. N orris : Theory of the Ideal 
World, I. pp. 296-7. Arnauld (cf . Appendix A, p. 115) asserts 
that it is as ridiculous to ask how the mind, whose essence con- 
sists in the power of perception, can perceive objects, as to 
demand how matter can be divisible or have figure {Des Vraiea 
et des Fausses Id4es, chap. ii.). He forgets that consciousness 
has been defined as the opposite of extension, while extension 
has not been defined as the opposite of divisibility or of figure. 
Also, while our knowledge of extension is clear and distinct, we 
have, as Malebranche and Hume both show, no distinct know- 
ledge of mind ; and still less, if that be possible, of any 
* faculty ' or * power ' of mind. 
' Even the fact of the self s existence is, Malebranche holds, not 


we know it completely, and even better (the 
over - emphasis is significant) than extension, he 
is viewing consciousness in .the dualistic manner as 
a simple unanalysable light, and therefore as better 
known in its simplicity than is the extension 
that requires a science of geometry to unfold its in- 
exhaustible multiplicity.^ As all forms of knowledge 
are forms of it, must it not, Descartes asks, be known 
in knowing anything ? This, however, according to 
Malebranche, does not follow: that by which all 
things are known need not be itself known.^ As 

kDown, but only felt. Though universal axioms are recognised 
through the intuition of particular quantities, the same can 
hardly be said of the universal truth, that all consciousness in- 
volves existence, for the assurance, which the self has of being 
conscious at a particular moment, is not an ' intuition ' in the 
seuse of being the apprehension of necessary relation between 
particular given quantities, but only the immediate assurance 
in feeling of a contingent fact. This is likewise emphasised by 
Leibniz. Cf. N<mveaux Essais^ liv. iv. chap. ii. sec. 1, also chap. 
VII. sec. 7 (Gerhardt, v. pp. 347-8 and 391-2). And to such 
criticism Descartes cannot reply. Since, on his own admission, 
existence (save as regards the Divine Being) falls altogether 
outside the sphere of rational knowledge, the self s existence can 
be no exception. The ambiguities involved in Malebranche's 
use of the term * feeling,' as not knowledge and yet a form 
of knowing, we cannot here discuss. 

^That too, doubtless, would be Descartes' answer to the 
question why, if mind is better known than matter, there 
is no science of it corresponding to the mathematical sciences. 

^This contention of Malebranche certainly holds against 


Augustine points out, the eyes, by which we see all 
things, cannot see themselves directly, and, if there 
were no mirrors, would never see themselves at all. 
The absence of the knowledge to which Descartes 
here pretends is well brought out by Malebranche*s 
English disciple, Norris: "What this formal thought 
or perception is, as to the reality of the thing, you 
will ask me in vain, because 'tis in vain that I ask 
myself! I know, or rather feel by inward sentiment 
that I think, and I make a shift in a rational method 
to find out what it is that thinks in me; but what 
that act of mine which I call thinking is, I want, 
I will not say words ta express, but penetration of 
thought to comprehend. Sometimes my fancy 
whispers me that 'tis a kind of application of the 
mind to its ideal or intelligible object; but then I 
reject that again as ia figurative way of speaking, 
borrowed froin the position or conservation of one 
body to another. Then, again, I say to myself, that 
sure 'tis an intellectual sight, a kind of vision of the 
mind. But here I correct myself again, as soon as I 
consider the meaning of what I say. . . . But what 
then shall I say that it is ? Or without oflfering at 

Descartes, so long as Descartes interprets consciousness 
abstractly as something real apart from its contents. 


anything further, shall I own my ignorance ? That 
I find I must do, since there is no seeing without 
light. I enter into myself again and again^ I consult 
myself over and over, but can have no answer." ^ 

Indirectly the same conclusion may be proved in 
three ways. First, this consciousness that is supposed 
to be so clearly known can only be defined by 
negatives, all of which gain meaning through 
that opposite, extension, which is asserted to be the 
less clearly known. It is defined by Descartes 
as ^nextended and ^divisible. Though he adds the 
positive predicate ' active,' that is just what later he 
shows that consciousness is not;^ and being there- 
fore forced to introduce an obscure faculty of 
will, distinct from thought, he destroys what little 
clearness was remaining in his analysis of mind. 

Secondly, the indirect manner in which Descartes 
proves the secondary qualities to be modes of mind,^ 
itself indicates our ignorance of mind. " Since we are 
obliged to consult the idea of extension, in order to 

^Norris: The Theory of the Ideal World (pub. 1704), vol. ii. 
pp. 109-10. 

2 Cf. below, pp. 108 ff. 

^ Descartes' argument is that, as they are not involved in our 
idea of extension, they must belong to the only other substantial 
form of existence, viz., mind. 


discover whether the sensible qualities are modes of 
mind, is it not evident that we have no clear idea of 
mind ? Otherwise would we think of taking this 
roundabout road ? When a philosopher wishes to 
discover whether figure belongs to extension, does he 
consult the idea of mind or any idea save that of 
extension ? Does he not see clearly in the very idea 
of extension that figure is a modification of it ? And 
would it not be absurd if, to enlighten himself, he 
argued thus : there are two kinds of existence, mind 
and matter, figure is not a mode of mind, therefore it 
is a mode of matter ? " ^ 

From this unavoidable acceptance of the feelings 
and sensations as modes of mind Malebranche 
draws his third argument for its unknowableness. 
As they are modes of mind, they must be deducible 
from the conception of mind, just as the different 
figures and their necessary relations are deducible 
from the idea of that of which they are the modifi- 
cations. But since it is obvious that no such 
deduction can be made, and that (as was pointed 
out above^) between the different sensations and 
feelings no relations can be perceived, the conclusion 

^ EclairdasemeTU sur chap. vii. pt, it. liv. Hi. de la Recherche, 
2 p". 95. 


is unavoidable that the archetypal idea of mind, 
upon which they are dependent, is unknown to us. 
"Without this archetypal idea of mind I cannot 
know that I am capable of feeling the taste of 
melon, the sensation of red, the pain of toothache, 
unless I have actually experienced these feelings: 
feelings, I say, that are confused and make them- 
selves felt, without making either themselves or the 
substances which they modify known." ^ To the 

^B^nse d Amauld^ chap. xiii. Cf. Norris : Theory of the 
Ideal Worlds ii. pp. 213-5 : " What the nature of that pleasure 
or pain is which we feel . . . that we know no more of than 
if we had never felt either of them. Not but that this is an 
intelligible thing, because God knows it, and we ourselves may 
possibly know it hereafter, when we come to have a sight (a 
great and engaging sight indeed) of that archetypal idea, upon 
which our souls were formed. ... I need not scruple to say 
that he that can see knows no more of light or colour than he 
that is bltndJ^ This tendency to regard the sensations of the 
secondary qualities as illusory appearances of intelligible realities 
runs through the whole Cartesian school. At times Spinoza and 
Leibniz even speak as if they regarded sound, light, and colour, 
as illusions that would completely vanish on perfected know- 
ledge. Geulincx alone, of all the Cartesians, insists on 
their intrinsic reality and worth. Cf. Geulincx's Annotata ad 
Metaphysicam (Land's edition, ii. p. 288) ; " So God has 
in a sense made two worlds, one in itself. . . The other 
God has made in us and in our senses, endowing it with 
wonderful and most beautiful images and phantasms (spectris 
et phantaamatihus) ; and this latter world is far more lovely and 
more artistic ; in it there breathes more wisdom and goodness 
than in that other world." 


natural question, what such conceptual knowledge 
of sensations and feelings would be like, Malebrancbe 
may of course reply that as we are wholly 
ignorant of the nature and essence of mind, we 
cannot expect to be able to form any notion of 
what a rational science of mind, corresponding to 
the rational sciences of matter, would reveal^ Only 
we can assume, he adds, that , as mind is a creature 
infinitely more perfect than matter, we should, iff*^ 
we knew it, in our absorption in the gradual clari- 
fication of the mysteries of mind, despise all other 
knowledge, even mathematics. If the properties of 
unintelligent space are so marvellous, so luminously 
interconnected and yet so inexhaustively varied, a 
very image of Deity in the combination of necessary 
unity with inexhaustible variety, what may we not 
expect from the unknown idea of mind ? ^ " Could 

^From this impossibility, in the actual limitation of our 
knowledge, of a rational science of mind Malebranche drew 
the conclusion that an empirical method is the only possible one 
in psychology ; and so became one of the founders of the 
science of empirical psychology, anticipating Berkeley in his 
analysis of sense-perception. 

^M^itations Chr^ennes^ ix. pp. 120-21 : "If a mathe- 
matician has so much delight when he compares magnitudes 
among themselves that he often sacrifices his pleasures and his 
health to find out the properties of a line . . . what pleasure 
would men npt take in compariug among themselves by a clear 



we attend to the preservation of a body that would 
trouble incessantly the sweet delights of contemplat- 
ing the inconceivable perfections of an intelligent 
nature ? " ^ 

And therein we find the reason, which Augustine 
sought in vain, why a benevolent Deity has revealed 

view of the understanding so many different modifications [of 
their own being], of which the bare feeling, although feeble 
and confused, does so strangely busy and employ them. For 
you must know that the mind contains in itself all the beauty 
which you see in the world, and which you attribute to the 
objects which surround you. Those colours, those odours, those 
tastes, and an infinity of other feelings by which you have 
never been affected, are nothing but modifications of your 
substance. That harmony which carries you away is not in the 
air that strikes your ear, and those infinite pleasures, of which 
the most voluptuous have only a feeble feeling, are included in 
the capacity of your mind." The possible modes of mind are, 
Malebranche believes, like the possible modifications of exten- 
sion, unlimited in number. Cf. Norris' Ideal Worlds ii. 
pp. 259-60 : " How many more [senses] we may be capable of, 
if the power of the soul were wholly reduce^i to act, who can 
say? . . . And what more [impressions] we might experi- 
ence if God should create, not new organs of sense in us, but 
only new bodies to make different impressions upon those we 
have already, is a vast abyss which no line of thought can ever 
fathom. But then consider what a great and noble being this 
soul of ours is, and how large is its capacity, that carries enclosed 
in its single self the beauties of a whole world ; those I mean 
which we ascribe to it, and distribute among the several parts 
of it, and withal think a sufficient furniture for the adorning 
of that immeuse fabrick." 
^ R^ponse d Atyiaidd, chap. xxii. 


to US the knowledge of what is without us, and 
yet has left us in utter darkness as to what is 
within: our knowledge is suflBcient for the perform- 
ance of our duties, and any further knowledge 
would only distract us from the work that has to 
be done.^ 

1 Cf . Norris : Theory of the Ideal Worlds ii. pp. 263-4 : " Happy 
time indeed, when we shall know both God and ourselves, 
and ourselves in God, whose superlative beauty will not allow 
us to grow proud of our own. . . . Now our feeble eyes 
would be dazzled with our own light, and we should fall in love 
with the dear image of oor own being ; but when the looking- 
glass shall be so much more charmingly beautiful than the face, 
we may then securely behold ourselves in it. In the meantime 
let us esteem that the best knowledge of ourselves is to have 
a deep sense of our infirmities, and not be ashamed of that 
ignorance which is the guardian of our humility." Perhaps, 
too, it might be suggested, we have here the explanation of 
Augustine's problem, how we should know the stars so far 
above us, and yet remain ignorant of the bodily processes 
* within 'us. We have the knowledge which we lequire (the 
modem theory of evolution explaining further the reason why), 
and no other. 

From our knowledge of extension Malebranche derives even 
such knowledge of mind as is required to prove its independence 
of body and its immortality. (Cf. RSponse d Amatddy chap. 
XXIII. and also M4ditatio7is Chrdtiennes^ ix. p. 122.) Descartes' 
reply to Gassendi, when the latter made the same objection, that 
the substance of the self is not known, is utterly helpless. (Cf. 
Gassendi's Objections to the Meditations^ and Descartes' reply 
thereto.) For Begis' defence of Descartes, cf. Covrs Entier : la 
Metaph. liv. ii. pt. i. chap. vi. 


Now, such a romantic conception of the possi- 
bilities of rational science, which significantly 
reappears in the English matter-of-fact Locke, ^ 
cannot be put aside as a mystic dream of the 
Malebranche that is a follower of Plato and 
Augustine: it is also the natural extension of the 
rationalism of Descartes. Either there is a limit 
set to his rationalism in sense, with a resulting 
dualism between the intelligible and the sensible,^ 
or such a deduction of the sensations and feelings 
from the conception of mind is as possible as is 
the deduction of mathematical truths from the 
conception of space. This application, however, of 
the mistaken conception of mathematical method to 
mind and its states, brings out the fantastic nature 
of the rationalism that necessitates such a con- 
clusion. It appears to the undisceming mind 
^\possible enough from the conception of space, or at 
least from the conceptions of the different figures 
in space, by sheer power of reasoning to deduce all 

^Cf. Essay : iv. iii. 27, and iv. xii. 12. 

''^ Descartes only kept this difficulty out of sight by a 
persistent ignoring of sense, and an alternate reference of it 
now to matter and now to mind. If we keep to his criterion of 
truth, and to his presupposed doctrine of essence, this theory of 
Malebranche of a rational science of mind is the only possible 


the content of geometrical science, but the illusion 
wears thin, and the teaching becomes doubtful, 
when in like manner the possibility is asserted of 
deducing from the conception of mind all the 
various sensations and feelings that we experience 
in it. We see how long a road it is from such a 
rationalism to the rationalism of Kant : we are 
still under the influence of the mystic idealism 
of Plato. ^ 

Thus we come to the general conclusion that, alike > 
in the metaphysics of matter and in the metaphysics 
of mind, Descartes' rationalism reveals its inadequacy, 
for while in the one we are brought to an irresolvable 
dualism between the geometrical and the mechanical, 

^ Malebranche's rationalism ought consistently to be carried 
yet further. Since souls are modifications of consciousness, the 
different souls and their relations to one another must be 
deducible, as well as the content of each separate soul. The 
idea from which deduction must start is not the idea of a 
particular concrete self, which as concrete and particular is 
complex and derivative, but the simple, and therefore ultimate, 
idea of consciousness in general. Thus impossible as Male- 
bran che's rationalism seems, it is outdone by that of Spinoza 
who takes that last step. The perpetual interchange of the 
most simple with the most complex, to which Cartesian thinking 
was condemned, is here again apparent. It is also illustrated in 
t he position of Leib niz. Regardin g the idea of the individual 
soul a s the datum from which de3Siction must proceed, he is 
forced to infer that it involves in its content the notion of the 
whole universe. 


iu the other we reach a similar dualism of thought 
and sense. And if we follow him a step further, 
while he states the relation in which he 
regards thought as standing to its intelligible 
contents, when, that is, he approaches the problem 
seriously, and ceases to pretend to dismiss it by the 
co,nveniently indefinite term * mode,' we shall see how 
he is forced not only to recognise the limitations of 
his rationalism, but also to undermine its very 

Thought, Descartes emphasises, is purely passive in 
knowledge, being governed wholly by its o bject s.^ If, 
he says,2 I conceive a triangle, even supposing there 
is not and never was in any place in the universe 
apart from my thought any such figure, nevertheless 
it remains true that the conception possesses a certain 
determinate immutable nature or essence, which is not 
framed by me, and is not in any way dependent on 
my individual thinking. Though the mind is free to 

\^Cf. Lett IX. p. 166 :" I do not distinguish oth erwise betwee n 
^inind and its ideas than between a piece of wax and the 
-*^different figures that it can receive ; and as it is not properly 
an action, but a passion in the wax to receive different figures, 
it seems to me that it is also a passion in the mind to receive 
such and such an idea, and that only its volitions are actions." 
Cf. Lett, VIII. p. 513. 

2 M^it, V. at the beginning. 


think or not to think such ideas, once thought .they 
control and govern our minds, there being in each 
of them a necessity that forces us to develop it in 
one particular way. It is thus that conceptions 
separate themselves out from the subjective life of 
feeling and imagination, and set themselves over 
against the mind as something objective.^ 

That, then, is the fact : h ow is it to be explained ? 
How is it possible that the mind should at will 
bring into consciousness ideas which yet it has not 
formed or created, and over whose development it has 
no control ? Descartes' answer is that they must / 
h^ve been implanted in the mind by God. They^*, 
are innate, and therefore the mind has not to form 
them, but simply by its attention to throw on them 
the light of consciousness.^ The understanding is 

^ Note how entirely Descartes agrees with Malebranche that 
couceptions are objects of mind. 

2 Malebranche's objections (Recherche, liv. iii. pt. ii. chap iv. 
p. 390 ff.) to this position are, first, that it would involve the 
existence of an infinitely infinite number of ideas in the finite 
mind ; and, secondly, that even if the mind had stored up in it 
all these ideas, it would be impossible to explain how it could 
at any moment find among them those it wanted. The kinship 
of Descartes' position to the monadism of Leibniz may be noted. 
How near Descartes can yet at times come to Malebranche's 
own position appears from the following : " Intuitive knowledge 
is an illumination of the mind by God, by which it sees in the 


purely passive alike in the reception of its innate 
ideas and in their development. All we need to do 
is to keep our minds fixed on them, and out of them 
spontaneously all truth will arise.^ 

light of God the things which he pleases to reveal to it, by a 
direct impression of the divine clearness on our understanding, 
which in that is not considered as agent, but only as receiving 
the rays of the divine Being" {Lett x. p. 130). 

^ It is because Descartes regards the mind as passive in 
thinking, that the problem of accounting for error is felt so 
strongly by him, and is dwelt upon at such length in the fourth 
Meditation and in the Principles. If God cannot deceive us, 
-> and is the ultimate source of ideas, must not all our ideas be 
^ true and error impossible ? Descartes' reply is th at error ne ver 
ri'iQa. i- O ^^®® "^ ^^^ ideas, but only in the judgments which we make 

about them. And according to Descartes all judgment is an 
act of t he wil l. Though the understanding furnishes the ideas, 
before these ideas, which are but subjective appearances in the 
mind, can become knowledge, the will must intervene and 
confer upon them by affirmation that objective reference which 
in themselves they do not possess. If the un derstanding alo ne 
conceives, the will alone affirms. Truth is the united pr oduc t 
of the understanding and the will. Now since the faculty of 
will is the faculty of a rational being, the active side of a mind 
whose essence consists in pure thought, its activities ought to be 
guided by the understanding. The will, however, being infinite 
V (cf. below, p. 113) rouses in us an infinite desire for knowledge. 
, And error arises when, impelled by this desire, we do not 
restrain the will within the same limits as the understanding, 
but give our assent or denial also to those ideas of which we 
^^^' *^< have only an obscure and confused apprehension. Error thus 
consists in a wrong use of the freedom of the will. All deception 
is self-deception. 

.' ' . I* t 


In order to make out the opposition to matter C- i< ,,. > 
Descartes has to take the self as active, and on its /^ ^ U4/..i.(^ 
activity he all along insists. But now that he has ) 
s hown the mind in thinking to be passive, he has 
either to deny that it is really any more active than 
material bodies, or to withdraw his definition of 
its essence as consisting in pure thought, and in pure 
t hought alon e.^ This internal dialectic of his system 
is reinforced, and the alternative to be chosen decided 

^ Here again Malebranche is the more consistent Cartesian, 
though, of course, as a student of Augustine, he would be pre- 
disposed to question the freedom of the will. " Will is a 
property which always accompanies the mind, be it united with 
the body or be it separate from it ; but yet it is not essential to 
it, since it presupposes thought, and we can conceive a mind 
without will, just as we can conceive a body without motion " 
{Recherche^ liv. in. pt. i. chap. i. p. 342). Will is as externally 
related to mind as motion is to matter. " Not only are bodies 
incapable of being the true causes of anything whatsoever, spirits 
the most noble are equally powerless. They can know nothing 
uuless God enlightens them. They can feel nothing unless 
God affects them. They are capable of willing nothing 
uuless God moves them towards the good in general, that is to 
say, towards himself" {HM. liv. vi. pt. ii. chap. iii. p. 327). 
His fifth Meditation (p. 50) opens with the prayer, " Increase my 
love for the truth, in order that my attention be renewed, and 
that you may grant this natural prayer after you have formed it 
in me.'' Malebranche's attempt, in spite of these admissions, 
still to vindicate the freedom of the will is sincere but sophis- 
tical. It is interesting to compare Malebranche's view of the 
self both with that of Spinoza and with that of Hume. 




for him, by the emphasis laid on the will in the 
religious thought of his time. Being always careful 
to respect, even in minor matters, the doctrines of the 
Church, he not only conforms to the theological 
doctrine of the freedom of the will in all its absolute- 
ness, but insists on it in a way that shows his con- 
formity to be complete.^ To it he is ready to sacrifice 
his most cherished convictions, even his rationalism. 
y *^ Since thought is passive, necessarily the will must 
^ ^ be altogether different from it. If the will were 
j^ , . ^/ identical with thought, or determined by it, it would 
/ .. ,' like thought be determined by an impersonal authority 
ti.^Xi,< s^ outside and above the self, and so would not be will 
-at all, not anything which could express the reality 
of the self as an independent agent. In this way 
Descartes, immediately after having declared that 
the whole essence of the self consists in pure thought, 
is forced inconsistently to assert that it is something 
quite distinct from thought that form^ its essence, 
namely, an inconceivable occult will.^ The power 

1 Cf . Principles, i. 39 (in. pp. 86-7). 

'^ The contradiction Descartes conceals by the assertion that 
thought reveals itself as being of a twofold nature, at once 
active and^ passive. Principles^ i. 32 (in. p. 83). Cf. Lett viii. 
pp. 275 and 513, where he asserts that action and passion are 
one and the same thing. Cf. also below, pp. 135-6. 

' i K t 


of will alone of all faculties in us is infinite and 
perfect,^ the necessary truths of reason being but an 
eostemal limit set to it by God.^ 

Also, as a further consequence, he had to interpret d^y^<^ 
the nature of God in the same impossible way. Ideas, - et.tu^ ■ < ^ 
and the 'necessary' truths of reason which they 
involve, cannot be regarded, Descartes holds, as the 
objects of divine thought, for in that case they would 
be an alien necessity governing God's mind just as 
they do ours, and we should thereby commit the 

^ M4dit. IV. (i. pp. 300-2) VeitclVs trans, pp. 137-8 : " If I 
consider the faculty of understanding which I possess, I find 
that it is of very small extent and greatly limited. ... In the 
same way if I examine the faculty of memory or imagination, 
or any other faculty I possess, I find none that is not small and 
circumscribed. ... It is the faculty of will only, or freedom of 
choice, which I experience to be so great that I am unable to 
conceive the idea of another that shall be more ample and 
extended ; so that it is chiefly my will which leads me to dis- 
cern that I bear a certain image and similitude of Deity.'* Cf. 
ibid. p. 140: **As the will consists only of a single element, 
and that indivisible, it would appear that this faculty is of such 
a nature that nothing could be taken from it [without destroying 
it]." Spinoza gives an interesting, and very complete, criticism 
of Descartesncloctriiie <»f the will. Ethica^ ii. 49, Scholium ; cf. 
below, chap. iv. pp. 138-9, and note to p. 139. 

2 That God, through the innate ideas which He has implanted 

in the mind, should concur with us in forming our acts of will, 

is, Descartes is careful to add (loc. cit. pp. 140-1), bo cause of 

complaint, " since those acts are wholly good and true, in so far 

as they depend on God." 



absurdity of subjecting Gfod " to destiny and Styx." ^ 
The ideas of God's mind, .and the ' eternal * truths of 
reason which they involve, must be regarded as 
created by God, and therefore as who lly depe ndent 
on His will : — though how God's mind could exist 
r^ without ideas over against it, any more than ours 
could, Descartes did not stop to inquire. As Norris 
remarks, Descartes conceives God as working in 
darkness to create the light. " For if even necessary 
truth be the effect of God, then antecedently to the 
eflPecting of it there was no truth, and consequently 
no knowledge, because nothing knowable. And so 
God in the production of truth (if, indeed. He did 
produce it) must be supposed to act in the dark, and 
without intelligence to order even an intellectual ' 
system." 2 Thus does Descartes' ration alism, af ter 
showing itself to be inadequate to the treatment of th e 
real, either as matter or as mind, end in the suicidal i 
admission of the absolute relativity of all knowledge. i 
His rationalism, which gave as answer to the problem i 
of the limits of knowledge, that there are none, and 
that the material and the mental are alike transparent 
to us, changes into a complete agnosticism. 

1 Lett VI. p. 109. 

2 Norris ; Theory of the Ideal World, i. p. 337. Cf. pp. 343 ff. 





Ip Descartes' system, then, as we have tried to show, 
there are three fundamental tenets, viz., the doctrine 
of representative perception, a very peculiar form of 
rationalism, and the conception of spirit as an active 
creative agency. In these three doctrines his whole 
system may be regarded as summed up. The dualism, 
which forms his problem, inevitably gave rise to the 
first ; from his studies in mathematics he derived 
the second ; and by the third (based on immediate 
experience, but interpreted chiefly in the light 
of certain scholastic principles) he constructs a 
completed system, spite of all the insoluble difficulties 
in which he is landed by the first two. We shall 
seek, in the following chapters, to confirm this inter- 
pretation of Descartes' teaching by an examination 
of these three fundamental principles as they re- 
appear in the systems of his successors. 



The only thinker within the early Cartesian School 
who called in question the doctrine of representative 

^ To p. 52, above. 


perception was Arnauld. In his TraiU des Vraies et 
des Fausses Id4es} which was written as a criticism of 
Malebranche's Recherche de la VeriU, he states in the 
most definite manner that there is no direct evidence 
of the existence of subjective states, acting as inter- 
mediaries between mind and matter, and that the 
sole (and on his view insufficient) ground for their 
assumption is (as we have already seen in the Chapter 
on Descartes' problem) the local difference between 
object known and the brain through which it is 
known.2 But as Arnauld himself accepts the Car- 
tesian dualism in all its absoluteness, his denial of 
this fundamental tenet of the Cartesian system comes 
to no fruitful result. His assertion that the mind's 
faculty of knowing objects distinct from it constitutes 

^Published in 1683. , 

2 Des Vraies et des Fausses Id^es, chap. iv. Even the ground 
that objects cannot be known directly, since they are material 
and therefore wholly different from the immaterial mind, 
reduces to this one ground. For it is because the mind is 
unextende<i, that, even though it be locally present to a body, 
it still remains external to it. As Malebranche remarks, 
though the mind were to issue out of the body in order to visit 
the sun, being uuextended it could not contain that star 
within itself, and would therefore, even though it got inside it, 
still remain as external to it as one body is to another. Also, 
as Arnauld, following Augustine and Malebranche, emphasisesi 
the mind knows least of that to which it is most closely united, 
namely the brain, Cf. Arnauld, chap, viii. 


its very essence, and ought therefore to be accepted 
as an ultimate, is an arbitrary and dogmatic attempt 
to set a limit to legitimate scientific analysis.^ In 
that assertion the Cartesian assumption of the self 
as an abiding, simple, substantial agent again reveals 
itself. It is interesting to compare Malebranche's 
reply to Arnauld ^ with Hume's criticism of the same 
theory.^ Eeid's position is in essentials identical with 
that of Arnauld, the flagrant unfairness in his state- 
ment of the latter's theory* being indirect proof 


The criterion of truth Descartes first applies to the 
content of perception. What is it, he asks, that we 
clearly and distinctly perceive when we perceive an 
external object ? " Take, for example, this piece of 
wax; it is quite fresh, having been but recently 

^ Cf . above, note 3 to p. 96, at the eud. 

* Edaircissement 9v/r la Nature des IdUes : 1" Objection. 

3 Given below, cbap. vi. pp. 228 ff. 

^Essays on the Intellectual Powers of Man: Essay ii. chap. 


^ To p. 62, above. 


t aken from th e bee-hive ; it has not yet lost the 
sweetness of the honey it contained-; it still retains 
somewhat of the odour of the flowers from which it 
was gathered; its colour, figure, size, are apparent 
[to the sight]; it is hard, cold, easily handled; and 
sounds when struck upon with the finger. In fine, 
all that contributes to make a body as distinctly 
known as possible, is found in the one before us. 
But, while I am speaking, let it be placed near the 
tire — what remained of the taste exhales, the smell 
evaporates, the colour changes, its figure is destroyed, 
its size increases, it becomes liquid, it grows hot, it 
can hardly be handled, and although struck upon, 
it emits no sound. Does the same wax still remain 
after this change ? It must be admitted that it does 
remain, no one doubts it, or judges otherwise."^ 
What, then, is it that remains the same ? It can be 
^ none of the original sensible qualities, since they have 
all disappeared. It must be that we distinguish in 
the piece of wax a body which appeared to us a 
moment before under these sensible qualities, and 
now appears to us under others : and if we remove 
all the changeable qualities from it, nothing remains 
but a body, a something, extended, flexible, and 

^MSdit. II. (i. pp. 256-7) Veitch's trans, pp. 110-11. 



moveable. The wax in all its possible forms, so long 
as it exists at all jnnat fill apflpp hp it a larger or be it 
a smaller space, for otherwise it would exist nowhere, 
and therefore not at all. So too, though the number 
of different shapes it may take on are infinite, it 

miiRf. un der all finnditinns p oaapRfi anVnft figiirp And 



finally, as a consequence of its being extended, it ii 
alway s capable of being moved : since it is always 
somewhere, it can always be shifted somewhere else. 
These three qualities are the only qualities, which the 
piece of wax preserves throughout all its changes, 
and must therefore constitute the 'it' we refer to, 
when we say that ' it ' remains the same spite of 
its transformations. These qualities constitute the 
essence, the self-identity, of the piece of wax. That 
argument Descartes strengthens by a second applica- 
tion of his criterion of truth, showing that all the 
other sensible qualities are known only obscurely and 
cmfusedly. Thus to take as an example the quality, 
yellow. Though as a sensation in the mind it is w 
perfectly clear, as a quality in the wax it is in its 
exact nature unknown. And further, the knowledge 
we have of the wax through that quality is also 
confused. Colour exists in the mind, not in materia];},^ 
things, and when we refer colour as a quality to a 





material thing, we confound together mind and body, 
the spiritual and the material. The object exists 
apart from our perception, and hence apart from the 
qualities with which we clothe it in the act of 
perception. The three qualities, then, of extension, 
figure, and motion, are alone known clearly, as they 
exist in the external object, and distinctly, as apart 
from the mind, and together must constitute its 
whole essence. 

Descartes next proceeds to determine the rela- 
tions in which these qualities stand to one another, 
and to the material bodies whose qualities they 
are ; and that he does by means of the three 
scholastic terms, substance, attribute, and mode. 
As regards their relation to one another, though we 
can conceive extension apart from any particular 
figure, and apart from all motion, we cannot in a 
similar way conceive figure and motion apart from 
extension. To extension^ figure and m otion ar e 
related, Descartes therefore concludes, as mod ej^ to a 
common attribute. Again, Descartes takes the 
relation of extension to matter as that of 
attribute to substance. Extension is the attribute, 
-^and, further, it is the sole attribute, of body. 
Matter is perfectly homogeneous ; having no inner 


determinations or qualitative differences, its whole 
nature is exhausted in the fact that it fills space. 

From this identification of matter and extension 
there follow several important consequences. First, 
since space is related to body as attribute to sub- 
stance, and since save in substance no attribute 
can exist, there can be no empty space. Secondly, 
matter, like space, must be continuous, and there- 
fore both infinite in divisibility and infinite in 
extent. Thirdly, since there cannot be different 
kinds of extension, there cannot be different kinds 
of matter. There are different planetary systems, 
but the material substance constituting them all 
is one and the same. Fourthly, it is obvious that 
)ody as thus identified with extension is purely 
issive. Motion must therefore have been intro- 
duced into the material world by some cause outside 
it, and that cause can only be God. Also, since 
bodies have no power to produce motion, they 
cannot increase or diminish it. The quantity of 
motion in nature therefore remains constant. And 
lastly, since all bodies are thus passive, with no 
inner forces, the only causes of motion are the ex- 
ternal efficient causes, impact and pressure. 

The material world, then, on Descartes' view is 





ju a world that has lost all the sensible qualities 
under which it appears to us, and preserves only 
its geometrical qualities, extension and figure, and 
as introduced from outside, motion. Yet what the 
natural world loses in richness and variety, it gains 
in simplicity and clearness; what may appear an 
aesthetic loss is an intellectual gain, since instead 
of the confused bewildering world of the senses, 
we have a world in which one single phenomenon, 
motion in space, infinitely diversified with itself, 
alone takes place. And if the m aterial wor ld 
seems to be impoverished by being t hus reduced 
to a dead mechanism, the mental is thereby enriched. 
All that can find no home in nature must be 
ascribed to the mind. 

Having thus shown that the only qualities of 

* ^ ^ -M , bodies that are clearly and distinctly known in per- 
\' ception are extension, figure, and motion, Descartes 

'.' "/!.' prc^ceeds to ask whether these qualiti 

by sense or by thought. Since * imagination ' may 
be taken as a general name for the whole sense- 
side of our nature, the question runs: Is the real 
essence of the piece of wax known through imagin- 
ation or through pure thought ? Is it sufficient 
I that I imagine (that is, image or picture) the wax 

iies are known 


now as round, now as square, and now as triangular ? 
Certainly not, says Descartes, for " I cannot by my 
imagination run through the infinite number of 
possible shapes the wax may take on, and conse- 
quently the essence of the wax cannot be realised, 
compassed, adequately expressed, through the imagin- 
ation." Onlv in conception, not in an image, nor 
i£^.a_8jiie§^i)f imagp%..caa it ba.knnwn.. ., So, too, 
with the attribute of extension. Since the piece of 
wax can (under the influence of heat and cold) 
increase or decrease in size in an infinite number of 
degrees, we do not apprehend its essence according 
to the truth, if we do not think it as capable 
of receiving more varieties of figure and extension 
than we can ever imagine in a series of particular 
images. By the understanding alone can the real 
essence of a material body be known. "The per- 
ception is neither an act of sight, of touch, noi 
of imagination, and never was either of these, though 
it might formerly seem so, but is simply an intuition 
{inspectio) of the mind, which may be imperfect and 
confused, as it formerly was, or very clear and 
distinct, as it is at present,"^ when the attention 
has separated off what is clearly and distinctly 

^ M4dit. II. Veitch's traiis. p. 112, 


conceived in it, from what is obscurely and confusedly 
felt . 
/^v<^f u^^^ In the sixth Meditation Descartes develops further 
/ d. c<^<;,v,l his distinction between ' imagination and pure con- 
ritcG^ j/^? ception. First he shows that they are quite distinct 
* from one another. So long as we keep to such 

simple figures as the triangle, it is hard to dis- 
tinguish between the conception and the image. 
The radical distinction between them at once appears, 
however, when we pass to more complex figures. 
If we wish to think of a chiliogon, though we can- 
not picture the thousand sides as we can picture 
the three sides of a triangle, we can yet, Descartes 
asserts, conceive the chiliogon just as easily as we 
pan conceive the triangle. That is to say, the more 
complex the figure the more indistinct becomes the 
image, while, on the other hand, the conception 
remains just as clear and distinct as ever.^ In 
order that this be possible, the conception and the 
image must be quite distinct from one another. 
If they were one and the same, or essentially 

^GassendPs criticism of this argument is very much to the 
point (ii. p. 21 2). All that it establishes, he there points out, 
is that we can comprehend in a more or less adequate manner 
the meaning of the word chiliogon, but not that we can conceive 
t\i^ figure any better than we can image it. 


connected, necessarily the confusion of the image 
would bring confusion into the conception. 

Further, in the case of complex figures, it becomes 
obvious that it is through the conception alone that 
we can have knowledge. The indistinct image ^//<^^'^:*^A^. 

■ f ' < « » 

whereby we represent to ourselves a chiliogon diflers 
not at all from the image whereby we represent to /^ 
ourselves a myriogon or any other figure of a great ^-7' ^' 
many sides, and can, therefore, be of no use for dis- *^ < • ' • < 
covering the properties which distinguish a chiliogon 
from all other polygons.^ And that is equally true, 
though not so obvious, even in the case of the simplest 
figures. The image even of a square is always 
inexact, and can therefore only be used in so far as 
we have compared it with the conception as its 
standard, correcting in it what is false and sup- 
plementing in it what is incomplete.^ The con- 
ception is all the while the true object of the 
mind, and the image is really only of use as an -^ 

^ Here Descartes' false view of geometrical science as derived 
from jg^ure conceptions instead of from their construction in per- 
ception^ and therefore, in image, is again leading him astray. 

2 That, however, it will be noted, does not prove that the 
conception has any meaning apart from the concrete material 
that it thus organises. In denying the existence of such 
^pure,' that is, abstract conceptions, Berkeley is altogether in 
the right. 



external aid in fixing and rendering more vivid 
the conception.^ 

Having thus shown that imagination and concep- 
tion are separate and distinct from one another, and 
that imagination is quite unessential to adequate 
knowledge of the objects with which the mind deals, 
Descartes proceeds to prove that the essence of the 
; mind consists in pure thought apart from all sense 
^Jand imagination.^ In the proof he applies the same 
method of argument as he has applied to determine 

'Cf. above, note to p. 45. 

2 We need not be afraid to interpret quite literally Descartes' 
strange utterances as to the nature of imagination. He is much 
too emphatic on the point to allow of our regarding them as 
metaphorical merely. There are, he tells us, no brain- processes 
corresponding to pure intellection, whereas save through brain- 
processes imagination is not possible. In order to form imxiges 
the mind, he further adds, has to look outside itself at the im ages 
J formed on the pineal gland (and it must be borne in mind that 
I Descartes believed that in visual perception there are not only 
j two images impressed on the surface of the brain exactly corre- 
. sponding to the images impressed on the two retinae but also a 
^ single image, combining them, on the pineal gland). This, 
according to Descartes, is the reason of the effort involved in 
imagining complex figures, an effort that is not required for the 
conception of them, conception being a process natural to the 
spiritual nature of the mind, and wholly immanent. Cf . MSdit. 
VI. (i. pp. 323-5), Veitch's trans, pp. 151-3 ; Descartes' Reply to 
Oassendi (ii. p. 297) ; Reg. xii. (xi. pp. 265-6). Descartes obviously 
here retains much of the curious scholastic doctrine of the subtilisa- 
tion of material into mental images. Descartes, however, could 



the essence of matter. In the soiil are the three 
cognitive faculties, thought, sense, and imagination. 
These together constitute its nature, and through them 
does it exist. But of these only one is inseparable 
from it, namely, thought or conception. Since^ we 

h ave a clear and distinct conception of the soul apa rt 
f rom sense and imagination, neither c an belong to its 
essence. Pure thought is the one attribute of mind as 





^ / 


extension is the one attribute of body. But while 
thought can thus be conceived apart from sense and 
imagination, sense and imagination , as both involving 
some form of intellection, cannot be conceived ap art 
f rom it. Sense and imagination are, therefore, related 
to thought in the same way that figure and motion are 
related to extension, that is, as modes to their common 
attribute.^ ' In this way Descartes completes the J 

not help seeing that the above view applied only to figure, and 
that resistance, colour, sound, and the other secondary qualities, 
bear no resemblance to their physiological causes ; and hence, in 
treating of the physiological conditions of these sensations, he 
inevitably developed the more consistent occasionalistic view. 
Cf. Le Mondky chap. i. 

^ Strictly, the different conceptions or ideas are for Descartes 
the only proper modes of thought, corresponding to figures as 
the proper modifications of extension ; while sense and imagina- 
tion, together with the feelings and emotions, constitute the 
external modifications of thought, corresponding to the motion 
that is externally introduced into matter, 


absoluteness of his dualism. On the one hand there 
exists a material world whose whole nature consists in 
extension and in extension alone. On the other there 
exists a spiritual world whose whole essence consists 
in pure thought, and in that alone. Each stands 
sharply outlined over against the other, and they have 
nothing whatsoever in common. 



Descartes' view of time rests on the scholastic 
distinction between time and eternity. " To be 
eternal is to possess entirely, perfectly, and all at once, 
all the attributes and perfections that the thing called 
eternal can possess."^ Since God is absolutely perfect, 
and also absolutely simple. His perfection can neither 
be added to nor subtracted from without total destruc- 
tion. All His qualities are essential qualities, and 
can in no way be modified by accidents that may be 
one moment real and another moment unreal, and so 
gi^e rise to temporal succession in the mode of his 
existence. Finite things, on the other hand, are so 

1 To p. 73, above. 

2 That is the definition given by De la Forge, following 
Boethius, Cf, Traits de V Esprit de VHomme^ chap. xii. p. 178. 


imperfect that they are unable to possess at one and 
the same time all the attributes, modes, and accidents, 
of which their nature is capable. A material body 
cannot be at one and the same time round and square, 
at rest and in motion ; the mind cannot by a single 
act of thought perceive all the things that it is capable 
of knowing. Whereas created things can be con- 

ceived through the three modes of time, fuisse, esse, 
fore, the first and last of which involves the notion of 
not-being; to God, the absolutely real (maosime ens, 
sive ens simpHciter), is ascribable only esse, esse sine 

Now since God, the absolutely real, cannot be con- 
ceived save as being, He must contain in Himself the 
ground of His own being, and so be Causa Sui, rinh;e 
things, which are as easily conceived non-existent 
as existent, do not contain in their conception the 
ground of their existence, and must therefore be 
brought into existence by something else. That 
something else cannot be another finite thing, which 
as finite cannot create itself, and therefore a fortiori 
cannot create anything distinct from itself. The 
ground must therefore be God, the sole Cavsa Sui? 

^ Cf. Clauberg : Exerdtationes, xxxiii. 

2 Cf . R^onsea aux Premieres Objections, i. pp. 382-3, 


That argument is strengthened by appeal to the 
scholastic principle, which Descartes employs in 
the proof of God's existence, viz. that it is more 
difficult to create substance than any of the attributes 
of substance. But while it was there argued that 
as the self has not given to itself all the perfections 
with which it is acquainted, it cannot have given 
to itself its existence, it is now urged ^ that as many 
of the qualities and states of the self are beyond 
our power to create, it is absurd to hold that the 
self can create that of which these are only the 
modes. And what holds of the self s first existence 
holds likewise of its continued existence. Since 
there are many states of the self that the self 
is unable to maintain, still less can it have the 
power to conserve that of which they are the 

Descartes himself adds the further argument,^ that 
as the self which is nothing but a thinking thing, 
and therefore necessarily conscious of all its activities, 
is unaware of actively preserving itself in existence, 
it cannot really do so. Since we cannot act with- 

^ Cf. Regis : Coun Entier : la Metaph, liv. i. pt. i. chap, xii 
Clauberg : Exercitatumes^ xxiv. 

^ H^fxmses aux Fremiires Objections, i. p. 383. 


out being conscious that we act, absence of 
consciousness proves absence of activity. To the 
objection that neither are we conscious of the 
activity whereby God preserves us, Clauberg (follow- 
ing Clerselier) gives the reply,^ that what is not, 
when it is being created for the first time, cannot 
feel the act creating it at the moment of creation, 
since it is not yet, and when it has been created, 
and so is able to perceive it, already God has ceased 
from the work of creation. The same holds true 
of preservation in existence, since it is due, as 
Clauberg consistently argues, to such separate and 
distinct acts of creation repeated in the separate and 
successive moments of time. t/ ^^ (u i '^ 

Since Descartes' assertion that the parts of time 
are independent of one another really rests, though 
he nowhere explicitly says so, on the assumption 
that time is discrete,^ such argument defeats itself 
by its own internal self-contradictoriness. As the 
moments of time in which God recreates us are 
separate and distinct, either they must be indivisible, 
and so having no duration be incapable of composing 

^ Exercitationes, xxvii. 

^ Regis, it is significant, speaks of time as divisible into a great 
number of parts. Loc. cit 



time, or self-continuance in existence, however short 
that continuance be, is admitted. To recognise, on 
the other hand, the infinite divisibility of time is 
to recognise its continuity, and therefore to deny * 
that assumption of independent real parts upon 
which the argument proceeds. This assumption of 
the discreteness of time Descartes partly conceals 
by speaking of God as continually conserving us. 
If his view of time be correct, our existence is 
like a line composed of dots, a repeated alternation 
between the state of being and the state of not- 

This whole line of argument is of value only as 
an illustration of the impossible demands of Descartes' 
rationalism, and of the absolute occasionalism which 
is its only refuge. By conceiving God through the 
unanalysed, and mystically formed, conceptions of 
absolute perfection (that includes the perfection of 
self-caused reality), and of perfect simplicity (that 
does not exclude the richest variety), Descartes 
assumes all that is required to account for what 
he has made unaccountable in the finite. 



The two views of consciousness, which we have 
traced in Descartes, by commingling gave rise to a 
third view of great importance in the Cartesian 
development, the view, namely, that consciousness 
is no mere general name for the varying states of /, 
consciousness, but that it includes in its essence all '^ ^' ^^ ^ ^ 
ideas, particular ideas being but limitations or modes of ^ -^ '^^/-^ ' 
it. This view, which is an excellent illustration of the 
Cartesian tendency to hypostasise abstract and empty 
conceptions into absolute realities, first appears in 
De la Forge, and was developed by Spinoza. " Just 
as every particular body has necessarily during 
every moment of its existence some figure that 
limits its extension, in the same manner the mind 
has always some idea that is present to it, and 
terminates its thought ; and just as extension in 
general is indivisible, body in general being insepar- 
able from any of the parts that it contains one and 
all at every moment within itself, and that cannot 
be removed outside it, and as no bounds or limits 
can be assigned to its extension, so likewise the 
thought of the sovereign and infinite Mind cannot 

^ To p. 92, above. 


be divided by any particular idea; and as it is 
JCwithout bounds and without limits, it has no need 
of being terminated by any of those forms ; but it 
includes in one single and identical thought all 
that can be known: so that those who deny that 
the mind of man has always some particular idea 
that limits its consciousness and determines it, un- 
wittingly render it in a manner infinite."^ This 
view of consciousness corresponds to Descartes' view 
of extension as the reality of the material world, at 
once including all bodies, and yet at the same time 
being quite indifferent to any particular form of 

These conceptions, however, of extension and of 
consciousness, which the Cartesians would fain make 
the richest, are in reality the emptiest in content. If 
bdre extension is the reality of the material worlds all 
figure and motion are illusion ; and if consciousness in 
general is the whole essence of mind suc h consciou s- 
ness is the consciousness only of being in general. " At 
the very time when we believe that we are thinking of 
nothing, we are necessarily full of the vague and 
general idea of being . . . this idea of leivig^ greasy vasty 

^ De la Forge : Traits de V Esprit de VHommey chap. x. pp. 


real avd positive though it be, is so familiar to us and 
affects us so little . . . that we judge it to have little 
reality, and to be formed by the confused assemblage 
of particular ideas, although in reality it is in it alone 
and hy it alone that we perceive all particular eadstences" ^ 
Certainly, as Malebranche here asserts, consciousness 
of being in general is logically prior to the conscious- 
ness of particular kinds of being ; but consciousness of 
being in general is in the above quotation from De la 
Forge, and still more explicitly in Spinoza, regarded as 
an absolute reality that forms the whole essence and 
content of particular concrete states of consciousness. 
Berkeley was the first clearly to demonstrate the 
unreality of such general notions. Being in general 
(and the same holds of extension in general and of 
consciousness in general) is, he shows, no more capable 
of existence than is colour in general. 

A fourth view of thought, as a faculty capable of 
creating ideas, also appears in De la Forge,^ as well as 
in Arnauld,^ and had some ground in several of 
Descartes' inconsistent utterances. Spite of his proof 
of the passivity of mind in knowing, he asserts * that 

^Malebranche : Recherche^ liv. in. pt. ii. chap. viii. p. 419. 

2 Traits, pp. 137-8. 

^Cf. Appendix -4, pp. 116-6. 

* R^onses aux Troidhnjes ObjectionSy i. pp. 492-3. 


it possesses the faculty of producing ideas. And again 
he says in one of his letters: "I have never either 
written or believed that the mind has need of innate 
(' natural ') ideas, which are anything different from its 
faculty of thinking."^ Descartes' frequently quoted 
statement,^ that ideas are innate in mind in the same 
sense that generosity or some disease is innate in 
certain families, is as unenlightening as it is indefinite. 

^ Lett X. p. 94. ^Lett, x. loc, cit. 




In his fundamental conception of the reaL Spinoza 
completely transcends the atomistic conceptualism of 
Descartes. The infinite he throughout insists (develop- 
ing the important line of thought that is no more than 
suggested in Descartes' Medita>tions) is prior both in 
idea and in existence to the finite. Finite beings are 
not independent substances, constituted by private and 
peculiar qualities, but as manifestations of a common 
substance are inwardly related. Their interaction is 
not the incomprehensible passing over of influence 
from one self-centred being to another, but the result 
of their mutual participation in the universal nature 
of things. The aim of Spinoza's philosophy is, there- 
fore, to show how all things live and move and have 
their being in the all-comprehensive reality, that may 


indiflPfirently bft naniftH P.if.hftr an(\ nr yTfltnrp At one 

time he speaks with the tongue of the religious devotee 
to whom God is all in all;^ and at another in the 
language of science teaches the inexorable universality 
of natural law.^ 

The finite, which is thus neither self-explanatory nor 
self-active, cannot, Spinoza further insists, be explained 
through general or abstract notions. "It is above 
everything necessary for us to deduce all our ideas 
from things physical or from real entities, by advancing 
as strictly as possible according to the sequence of 
causes from one real entity to another real entity, 
and not passing over to abstracts and universals, neither 
for the sake of deducing anything real from them, nor 
of deducing them from anything real, for in either way 
we interrupt the true progress of the intellect."* 
Even Descartes has been guilty of attempting to 
explain real phenomena from general notions. The 
power of will which he ascribes both to God and to 

^ Cf . EMca^ V. t)rop. 36. The love which we bear towards God 
is part of that very love whereby God loves Himself. 

^Spinoza denies what is ordinarily understood by the free- 
dom of the will. Both man and God act from the necessity of 
their nature. Hence also Spinoza's denial of all final causes and 
of miracles. 

3 Tractatus delntellectug Emendatione : Van Vloten and Land's 
edition, i. p. 33 (Stirling's trans, p. 55). 


man, being a purely occult quality, is, like all occult 
qualities, a mere general notion or entity of the 
reason. "Will dififers from this or that particular 
volition in the same way as whiteness differs from 
this or that white object, or humanity from this or 
that man. It is, therefore, as impossible to conceive 
that will is the cause of this or that volition, as to 
conceive that humanity is the cause of Peter and 
Paul."^ "Man thinks himself free because he is 

^ Epistula 2. Cf. Ethica^ ii. 48, Scholium (White and Stirling's 
trans, pp. 94-5) : "In the same manner it is demonstrated that 
in the mind there exists no absolute faculty of understanding, 
desiring, loving, etc. These and the like faculties, therefore, are 
either altogether fictitious, or else are nothing but metaphysical 
or universal entities, which we are in the habit of forming from 
individual cases. The intellect and will, therefore, are related to 
this or that idea or volition as rockiness is related to this or 
that rock, or as man is related to Peter or Paul." Spinoza also 
gives a very complete criticism {Etkica, ii. 49, Scholium) of 
Descartes' attempt (cf. above, chap iii. note to p. 110) to combine 
a passive process of thinking with unlimited power of will. 
There is no such thing, Spinoza points out, as a general faculty 
of will, which is the source of all particular affirmations. Such 
a will is an hypostatised abstraction. Affirmations differ just as 
greatly as do the various ideas affirmed. Secondly, even grant- 
ing that a general faculty represents anything real, there are as 
good grounds for believing that we possess an infinite faculty of 
perception, as there are for Descartes* contention that we possess 
an infinite wilL " For as by the same faculty of will we can 
affirm an infinite number of things (one after the other, for we 
cannot affirm an infinite number of things at once) so also by the 


conscious of his wishes and appetites, whilst at the 
same time he is ignorant of the causes by which he 
is led to wish and desire, not dreaming what they 
are." ^ A similar criticism must be passed when men 
take refuge in that other sanctuary of ignorance, final 
causes and the will of God. " When men behold the 
structure of the human body, they are amazed ; and 
because they are ignorant of the causes of such art, 
they conclude that the body was made not by 
mechanical but by a supernatural and divine art, 
and has been formed in such a way so that the one 
part may not injure the other." ^ In this opposition to 
general notions, Spinoza even goes so far as to deny all 

same faculty of feeling we can feel or perceive (one after another) 
an infinite number of bodies." And thirdly, Spinoza, in agree- 
ment with many of the best modern logicians, denies Descartes' 
distinction between conceiving and judging. We have no free 
power of suspending our judgment. Suspension of judgment is 
itself an act of perception or judgment. **For when we say 
that a person suspends judgment, we only say in other words 
that he sees that he does not perceive the thing adequately. 
The suspension of the judgment, therefore, is in truth a percep- 
tion and not free will" 

1 Etkicay I. Appendix (White and Stirling's trans, p. 39). 

2 Loc, cit pp. 42-3. Cf . in the same Appendix, p. 41 : " This 
opinion alone would have been sufficient to keep the human race 
in darkness to all eternity, if mathematics, which does not deal 
with ends, but with the essences and properties of forms, had 
not placed before us another rule of truth." Cf. Descartes, 
Regvlae ad Directionem Ingenii, iv. 


objective validity to the moral and aesthetic categories. 
In using the general term * man/ we leave out of sight 
the differences between individuals, and therefore 
wrongly assume that those individuals who have the 
same outward appearance are equally capable ot 
attaining the highest perfection possible for the genus ; 
and according as their actions are in agreement or 
at variance with such perfection, declare them to be 
good or bad. " But as God does not know things 
abstractly, or through such general definitions, and as 
things have no more reality than the divine under- 
standing and power bestows upon them," ^ it follows 
that all such conceptions, good and bad, beautiful and 
ugly, perfect and imperfect, are but modes of thinking, 
and have no application to real things. Since each 
individual acts according to the necessity of his nature, 
it is as absurd to blame an individual for any of his 
actions as to condemn a triangle for not having the 
properties of a circle.^ 

There is, however, a curious conflict of tendencies 

1 Epistvla 19. 

2 Spinoza was, of course, also forced to this position by the 
exigencies of his pantheism. As all things are in God, and 
therefore all things divine, evil must be mere privation. Simi- 
larly such freedom as Descartes ascribes to the individual is not 
only inconceivable in itself, but also incompatible with the 
supremacy of God. 


in Spinoza's philosophy. Though he maintains that 
we must view things in the concrete setting of their 
constitutive relations, he was yet himself driven to 
deny the existence of the finite, the knowledge of 
which he thus sought to complete; and though he 
denounces any attempt to explain the concrete through 
the general and abstract, he himself in the end 
hypostatises, as the sole reality, a few merely abstract 
conceptions. The cause of this strange contradiction 
between the results at which he aims and the con- 
clusions which he establishes, lies, we shall try to 
show, in those rationalistic principles which he shares 
with Descartes. The mathematical method is, he 
believes, the sole possible method and of universal 
application. '^ I shall therefore pursue the same 
method in considering the nature and strength of the 
afifects and the power of the mind over them which 
I pursued in our previous discussion of God and the 
mind, and I shall consider human actions and 
appetites just as if I were considering Unes, planes, 
or bodies."^ And since he interprets this method in 
the same mistaken manner as Descartes, he likewise 
believes that from a pure conception (such as is un- 
folded in the definition of a geometrical figure, and 

^ Ethica, III. Preface (White and Stirling's trans, p. 105). 


such as he would distinguish sharply from merely 
general or abstract notions) further knowledge can be 
directly derived. An adequate conception or defini- 
tion is such " that all the properties of the thing, 
when the definition is considered by itself alone and 
not conjoined with others, may be inferred from it, as 
we observe is the case with the definition of a circle." ^ 
From ultimate conceptions, by pure deduction, all 
true knowledge is derived. If we can now show that 
this Cartesian method is at variance with the views 
which Spinoza seeks to maintain, we shall afford 
further proof of the correctness of our interpretation 
of that method, and also at the same time bring out 
more clearly its implications and consequences. 

One consequence, inevitably resulting from the 
mathematical method, is the identification of a causa- 
tion with explanation. If all things follow from their 
grounds in the same way that the different properties 
of a triangle follow from its definition, the one possible 
form of connection between real existences must be 
that of logical dependence. And that all-important 
consequence (implied though not openly recognised in 
Descartes' system) Spinoza states in the most explicit 
manner. Like Leibniz, he takes the principle of 

^ Tractatvs de Intellectua Emendatione (Stirling's trans, p. 53). 


causality as being a necessary truth of reason, and as 
identical with the principle of ground and consequent.^ 
The effect is that which can be deduced with logical 
necessity from the notion of the cause. When no 
such necessary conceptual relation exists between 
phenomena, they cannot be causally related.^ 

This view of causation comes out clearly in 
Spinoza's own statement of his method in the un- 
finished Tractatvs de Intellectus Hmendatione, Method, 
he there tells us, is knowledge arising from reflection 
(cognitio refleodva), or the idea of an idea : it is the 
knowledge of an idea in the mind as being true, and 
hence as being an instrument whereby we can acquire 
other true ideas. It is with the idea as it is with the 
reality corresponding to the idea. As all things in 
nature are connected with other things, their ideas will 
necessarily have the same connections. If anything^ 
is a cause, the effect as arising out of the cause will be 
deducible from the idea of the cause, and arise out of 
it. Ordo et conneodo idearum idem est ac ordo et 
conneodo remm. 

1 Considered in the manner of Spinoza, it in the end resolves 
itself into the law of identity, the effect being one ^f the 
qualities constituting the substance of the cause. Cf. below, 
pp. 146-8. 

2 Cf. EihyxLy i. 3 ; also Epistula 4. 



But from the fact that every idea must altogether 
agree with the reality which it represents, " it is clear 
that in order that our mind may exactly reproduce 
the pattern of Nature it must draw all its ideas from 
that idea which reproduces the origin and fountain of 
the whole of Nature, so that it may also become the 
source of other ideas." ^ That primary idea is the 
idea of God. Ex nihilo nihil Jit, that from which 
reality is to be deduced must contain within itself all 
that is developed out of it. We must, if knowledge 
of the finite is to be possible, " have a knowledge of 
God equal to that which we have of a triangle."^ 

Now though it be undeniable that that from which 
all knowledge is deducible must be the idea of an all- 
comprehensive Being, to affirm that is very different 
from saying that we must, as Spinoza implies, start 
straight away with an adequate idea of God, and in it 
by analysis discover all else.^ Spinoza's position 

^ Tractattbs de Intellectus Evnervdatione : Van Vloten and Land, 
I. p. 14 (Stirling's trans, pp. 20-1). 

2 De Intellectus Emendatione : Van Vloten and Land, i. p. 27 
(Stirling's trans, p. 44). Cf. Epistvla 56. 

^That is all that deduction can mean for Spinoza. The 
deduced is discovered to constitute that from which it * follows.* 
Cf. De Intellectus Emendatione : Van Vloten and Land, i. p. 31 
(Stirling's trans, pp. 61-2). " For in truth the knowledge of the 
effect is nothing else than the acquisition of a more perfect 
knowledge of the cause." 






involves him in a dilemma. Only if we start with 
the idea of an absolute all-containing reality, can we 
deduce all reality from it ; yet, on the other hand, if 
we start with it, we have it already, and need not to 
proceed further.^ Spinoza, like Descartes, is here 
confusing the two meanings of the term ultimate. It 
may mean that upon which all else depends, that in 
and through which other things are alone conceivable, 
or it may signify that which contains within itself all 
else, not merely the condition but also the conditioned. 
As a matter of fact, Spinoza, in the same way as 
Descartes, starts from certain abstract conceptions 
(these include extension and consciousness, which 
Spinoza does not, and cannot, deduce from his idea 
of God), and explains away all that cannot be reduced 
to them. 

That this perpetual interchange of the simple with 
the most complex, to which all Cartesian thinking 
seems condemned, should thus in Spinoza find its 
most pronounced expression, is in great part due to 

^This dilemma would not apply all-roiiud. It applies to 
Spinoza in so far as he believes that we start in knowledge from 
conceptions that are known clearly and adequately, and that 
from them by logical * deduction ' we derive all else. As we 
have seen in considering the method of Descartes, nothing can 
be derived from a conception that has not been thought in it 
from the start. 


the consistency with which he develops the conse- 
quences of the Cartesian interchange of real cause and 
logical ground. The relation of cause and effect, he in 
the end shows, is not only identical with that of 
ground and consequent, but also with that of substance 
and quality.^ Since the cause is that in whose notion 
the effect is necessarily and timelessly involved, the 
effect must be an inherent and permanent quality of 
the substance that is its ground.^ The * simple,' from 

1 Spinoza explicitly adopts the Cartesian doctrine that every- 
thing is either a substance or the quality of a substance. 
Mkica, I. 6 coroll. Cf. Epistvla 4 : '* Besides substances and 
accidents, nothing exists really or externally to the intellect." 
Though the term * accident' is here used in a very general 
sense, we can still assert of Spinoza's philosophy as a whole that 
it leaves no place for the conception of relations between sub- 
stances relatively indepeudent. 

^One point, therefore, at which a critic might attack the 
closely-woven web of argument that forms the metaphysics of 
Spinoza is this identification of cause, reason, and substance. 
The criticism would then be the criticism of Hume, that a cause 
is never a reason, and an effect never a quality of its cause. 
Since the fundamental fact at the root of all causal connection 
is change, even if the cause be regarded as itself being or 
becoining the effect, the phenomenon is still a process in time, 
and therefore something which the relation of logical depend- 
ence cannot completely express. Even though it were granted 
(cf. Bosanquet's discussion of the relation of cause and reason. 
Logic, I. pp. 264 ff.) that ultimately the causal relation may 
merge in that of ground and consequent, that would not justify 
us in directly equating them, as in all forms identical. Spinoza 
shows that change takes place only wiihin a system that itself 


which we start, must comprehend as its constitutive 
qualities all the complexity that is * deduced ' from it. 

From this view of causation follows with equal 
inevitableness, and for the same reasons, the pantheism 
of Spinoza. Creation, conceived as a form of transient 
action, whereby God might bring into existence a 
reality that lay outside the circle of His own essence, 
is as inconceivable as any form of transient action 
between independent finite existences. As an effect is 
always an inherent quality of its cause, all causation 
without exception is immanent causation, and the 
created world the revelation of the Divine Being 
whose essence it constitutes. 

From Spinoza's view of causation follows likewise 
his theory of the attributes. Since neither extension 
nor thought involves the other in its conception, there 
can be no causal relation between them.^ Motion can 
produce nothing but motion, and an idea can give rise 
to nothing but other ideas. As both attributes, how- 
is unchanging, but as the finite and changing is related to the 
completed system through its changing relations to other finite 
elements, the causal interaction of finite existences is one that 
still requires its own special analysis. Only when the diffi- 
culties raised by Hume's analysis of causation have been taken 
into account can any genuine reconciliation of causation with 
explanation be brought about. 
1 Cf . Ethica, i. 3. 



.ever, necessarily inhere in God, and follow from the 
absolute unity of His nature, they must in Him find 
the ground of their connection. And the only way 
which Spinoza can see of reconciling their absolute 
diversity with God's unity is by regarding each as co- 
extensive with the whole essence of God, expressing it 
in its own way. Since substance is that which exists, 
and is intelligible, in and through itself, it will then 
follow that each attribute that expresses it must be so 
likewise. Each will be found to obey laws that follow 
solely from its own essential nature. But though only 
these two attributes of extension and thought are 
known to us, God as infinitely real expresses His 
nature through an infinite number of such infinite 
attributes. And as every finite being, so far as it has 
real existence, shares in the essence of God, it also 
must be expressed through all the infinite attributes of 
God, and therefore, in our experience, through both 
the attributes of extension tind of thought. . That is 
the ground of Spinoza's fundamental principle, cn^do 
et conneodo idearum idem est Uc ordo et connexio rerum, 
Spinoza thus adopts and extends Descartes' ideal of 
physical explanation. Everything material, however 
complex or highly organised, is brought into existence 
through the operation of universal mechanical laws. 


Mind can neither act on matter nor govern it. 
*' When men say that this or that action of the body 
springis from the mind, which has command over the 
body, they do not know what they say, and they do 
nothing but confess with pretentious words that they 
know nothing about the cause of the action, and see 
nothing in it to wonder at." ^ To the objection that 
it is impossible that solely from the laws of the 
material world we should be able to deduce the causes 
of pictures or other works of art, and that the human 
body is not capable, unless it is determined and led by 
the mind, of building a single temple, Spinoza replies : 
" I have shown that [those who make this objection] 
do not know what the body can do, nor what can be 
deduced from the consideration of its nature alone, 
and that they find that many things are done merely 
by the laws of nature which they would never have 
believed to be possible without the direction of the 
mind. ... I adduce also here the structure itself of 
the human body, which so greatly surpasses in work- 
manship all those things which are constructed by 
human art."* 

^Bthicaj III. 2, Scholium (White and Stirling's trans, 
p. 109). 

^Loc. cit. (p. 110). As we have seen, Spinoza denies that 
matter is organised according to ideas which lie outside it 


This ideal of scientific explanation Spinoza also 
applies to mind. Since mind and matter are two 
different expressions of one and the same reality, and run 
parallel to one another throughout all existence, the 
mind is as much a part of nature as the human body. 
If the human body is determined to be what it is by 
its relation to all other bodies in infinite space, the 
complex organisation of ideas which forms the human 
soul must similarly be determined by its relation to the 
other infinitely varied ideas that constitute the infinite 
attribute of thought. Spinoza's theory of mind is, 
however, less developed than his theory of matter, and 
constantly he fills up the gaps in his knowledge of 
the mental by analogies taken from the material 
world. ^ 

in the mind of God. It is interesting to compare Spinoza's 
position with that of Hume. Cf. below, chap. vi. pp. 235 ff. 

^ Cf. above, Appendix D to chapter in. pp. 133-5. As has 
been pointed out in that Appendix, the view of particular ideas 
as modes arising by limitation of universal consciousness is 
formed on the analogy of the relation of geometrical figures to 
the space in which they are constructed. Cf. also below, note 1 
to p. 152. Spinoza retains Descartes' view of understanding as a 
special faculty quite distinct from imagination. Imagination is, 
on Spinoza's view, associative thinking, and involves a more or 
less explicit mental atomism. Just as he makes no attempt to 
reconcile his assumption of mechanical action with his theory of 
causation, so likewise he ignores the problem of reconciling his 
view of association with his doctrine of pure thought. 


Now there is involved in this mechanical explana- 
tion of body and of mind that other kind of causality 
in which the effect follows in time upon the cause. 
One body is assumed to be able to move another 
through impact, and one idea to be capable of 
recalling another associated with it in the past.^ 
How such causation is possible, and in what it con- 
sists, or how it stands to the relation of logical conse- 
quence, Spinoza tells us absolutely nothing. Yet, even 
though Spinoza had clearly recognised that this form 
of relation is distinct from that of logical dependence, 
and had admitted his incapacity to give any definite 
account of its nature, he would not, for that reason, have 
been forced, like Descartes, to deny its possibility. ^ 
Finite existences being, on his view, manifestations 
of a single substance, transient action ceases to be 

1 Spinoza simply takes over from ordinary experience the fact 
that bodies are set in motion on impact, and that ideas recall one 
another. The laws of motion he regards as necessary truths of 
reason, and the laws of association he interprets (and it is an 
illustration of his tendency to fill up gaps in our knowledge of 
the mental by analogies taken from the material) as the subjec- 
tive counterpart of the objective connections between brain 

2 That, as we have seen in the preceding chapter, Descartes is 
forced to do when he consistently develops his fundamental 
principles. The occasionalist solution is the attempt to intro- 
duce in an external form that necessary relation to the infinite, 
which ought to have been kept in view from the start. 


inconceivable. As has already been said, it need no 
longer be regarded as the mysterious passing over of 
influence from one self-centred being to another, but 
rather as a natural consequence of their mutual partici- 
pation in the common nature of things. Descartes' 
diflBculty reappears, however, in Spinoza's system in a 
new form. As Spinoza starts from the assumption of 
a single substance, of which all finite existences are 
but modes, his problem is not so much to explain 
their interaction as to account for their independence. 
And it is in his failure to vindicate their independence, 
that those rationalistic principles which he shares with 
Descartes e^gain reveal their inherent insufficiency. 

Though Spinoza's position, as formulated in his 
method, is that from the conception of God, known as 
adequately as we know a triangle, all else is deducible, 
he really makes his start from the two attributes, as_ 

revealed in experie nce, of extension and thought. But 
even irom these two conceptions he does not dire ctly 
develop out the variety of the real. Instead of that 
progressive course to which his method commits him, 
he starts from the actual nature of finite existences, 
and by a regressive process, wherein the qualities con- 
stituting their finitude are explained as purely nega- 
tive, reduces their essential reality to the continuous 


TifttiirP of P.Yt.P.nainn and nf t.hmight As regards the 

material world Spinoza carries out this process of 
reduction by first of all regarding motion as merely 
change of place, and therefore as purely geometrical 
The sole differences in nature are diSerences of position 
and of figura Figure, again, arises by limiting off 
from infinite space one finite portion of it; and as 
this limitation is mere negation, the finite figure qud 
finite is unreal.^ In extension, viewed 'concretely,'^ 
no divisions or distinctions can be asserted to exist. 
Similarly all particular ideas are unreal limitations 
of universal consciousness,^ and therefore in their 
finitude have no more than a negative existence. 
Finite existences are illusions of the imagination that 
vanish when their essence is realised to be continuous 
with, and indivisible from, the one reality. This 
tendency to explain finite existences, not through their 

^Cf. EpUtvla 50: "He who says that he perceives figure, 
says only that he has before his mind a limited thing, and the 
manner in which it is limited. But this limitation does not 
pertain to a thing in its * esse^ but contrariwise in its ' Tion-esse ' 
\i,e. it signifies, not that some positive quality belongs to the 
thing, but that something is wanting to it]. Since, then, figure 
is but limitation, and limitation is but negation, we cannot say 
that figure is anything." We give Dr. Caird's translation of 
the passage {Essays^ p. 354). 

^Cf. Ethicay i. 15, Scholium : also Epistvla 12. 

' Cf . above. Appendix D to chapter in. pp. 133-5. 


relations to other finite beings within an organised 
system, but directly as modifications of an unchanging 
reality, finds very definite expression in the Tractatus 
de Intdlectus Hmendatione in a passage which we have 
already partially quoted.^ After saying that "it is 
above everything necessary for us to deduce all our 
ideas from things physical or from real entities, by 
advancing as strictly as possible according to the 
sequence of causes from one real entity to another 
real entity, and not passing over to abstracts and 
universals," Spinoza adds : " It is to be observed, 
however, that 1 do not here understand by the 
sequence of causes and real entities the sequence of 
individual, mutable things, but the sequence only 
of things fixed and eternal." And he proceeds : 
" Moreover, it is not necessary that we should under- 
stand the sequence [of individual mutable things], 
since the essences of individual mutable things are 
not to be drawn from their sequence or order of 
existence, for this gives us nothing but external 
marks, relations, or at the best, unessential properties, 
all of which are far from being the internal essence 
of things." 2 That last sentence is specially signifi- 
cant Spite of Spinoza's emphatic adoption of the 

^ Cf. above, p. 138. * Stirling's trans, pp. 65-6. 


point of view of physical science, and of his extension 
of it to the mental, his thinking is still ruled by the 
Cartesian opposition between internal and external, 
between the unchanging essence of things and their 
contingent changing relations. He fails to adapt the 
timeless relation of necessary consequence, which is his 
sole conception of causal connection, so as to account 
for these ' external ' relations. All determination, he 
is forced to conclude, is mere negation, and hence can 
cause nothing. There is no transient action between 
finite existences, since finite existences there are none. 
Differing from Descartes only in the more consistent 
development of his rationalism, Spinoza equally fails to 
account for the facts of our time-experience. 

These results, however, as we have already stated, 
by no means express the point of view which Spinoza 
seeks to establish. To represent adequately the 
meaning and significance of his teaching, we must also 
recognise the alternative view of God, and of the 
attributes, which it presents. When he develops the 
above view, finite existence and change in time are 
regarded as illusions, and so far as they are 
explained at all, even as illusions, are accounted for 
by a ghostly remnant of the spiritualism of Descartea 
They are unrealities pictured by the mind, so far as the 


mind is individual, and therefore itself unreal.^ To 
^ certain extent also, the understanding is made to 
account for the attributes, or rather to reconcile the 
variety of the attributes with the simplicity of God's 
nature. " By attribute, I mean that which the 
intellect perceives as constituting the essence of 
substance." Thereby Spinoza would at times seem to 
imply that the understanding is the prism that breaks 
up the white light of the Divine Substance into the 
variety of its appearances. But with that view 
Spinoza is not altogether in earnest. So soon as the 
problem of reconciling the unity of God with the 
variety of the attributes falls into the background, he 
brings forward his alternative view of God as contain- 
ing in the fullness of His being all possible reality, and 
declares that the defect in our knowledge lies not in 
our apprehending His unity through two wholly diverse 
attributes, but in our knowing only these two, and not 
an infinite number of others equally diverse. There 
is, however, do analogy possible between our know- 
ledge of such a God and our knowledge of a triangle. 
As regards the two attributes of extension and 

^ Spinoza, like Leibniz, declares sense to be confused thought. 
All the secondary qualities would presumably, on his view, 
cease to exist for perfected knowledge. 


thought, a similar duality of view appears in Spinoza'a 
teaching. When he applies his geometrical method, 
extension, we have seen, is regarded as simple, exclud- 
ing motion and figure. Since all determination is 
negation, on adequate knowledge differences of figure 
vanish, leaving only continuous and empty space. 
And, in that same way, the uniform light of conscious- 
ness is regarded as known completely in any and 
every act of thought. When, on the other hand, 
Spinoza seeks to maintain the concrete reality of God, 
he denies that extension is the passive extension, or 
thought the passive thinking of Descartes. Motion is 
not added from outside to a passive extension, nor are 
the ideas, that give variety to the uniform light of 
consciousness, external to the nature of consciousness. 
Since both attributes are expressions of the Divine 
Substance, they reveal its inexhaustible creative energy 
by unceasingly giving rise, through the divine power 
that is in them, to all possible bodies and to all possible 
ideas. "From the supreme power of God, or from 
His infinite nature, infinite things in infinite ways, 
that is to say, all things, have necessarily flowed, or 
continually follow by the same necessity, in the same 
way as it follows from the nature of a triangle, from 
eternity and to eternity, that its three angles are 




fqiia) tn two righfc anglfis. The omnipotence of God 
has therefore been actual from eternity, and in the 
same actuality will remain to eternity/'^ Though 
this view of extension as involving motion is not 
developed by Spinoza,^ and though the relation of the 
particular ideas to their attribute is also left quite 
obscure, in both cases he dwells upon the active 
nature of the modal existence. Each body is a 
cmiatus quo unaquaeque res in suo esse perseverare 
conatur. Similarly, each idea is regarded as having 
an independent existence. Containing its essence 
within itself, it is neither a shadowy image of an 
external reality nor a mere state of a mind or subject. 

^Ethica^ I. 17, Scholium (White and Stirling's trans, pp. 20-1). 

2 When Tschimhausen (Epistulae 80 and 82) demanded of 
Spinoza how from the conception of extension there can be 
deduced a priori the existence of bodies that possess figure and 
motion, Spinoza replied (Epistula 83) : " As to your question, 
whether the variety of existing things can be demonstrated a 
priori from the mere conception of extension, I think I have 
already sufiSciently shown that that is impossible, and that, 
therefof*e, matter is ill-defined by Descartes as consisting in 
extension. It must necessarily be explained by an attribute 
which expresses an eternal and infinite esseuce. But this I 
shall, perhaps, some day, if my life be prolonged, discuss more 
clearly with you. For hitherto I have not been able to set 
down anything orderly on this matter." The above (written 
15th July, 1676) is, however, the last letter which we possess 
from Spinoza's hand. 







It is an activity expressive of the divine nature, and 
as such involves an affirmation.^ 

There are thus two interpretations in Spinoza of 
God and the attributes — a concrete interpretation in 
which he adopts the scientific point of view and 
anticipates modern thought, and the abstract inter- 
pretation to which he is forced by the inadequacy of 
the rationalistic principles which he inherits from 

^A.*-^l«<. '• N \ 

{',',, '--.n- ■ M.--' r ,1 --t;,) coexir 


We m|iy now proceed to indicate, with equal 
brevity, ' the influence exercised by the Cartesian 
principles upon the thinking of Leibniz.^ Like 
Malebranche, he holds that from the conception of the 

^ Cf. Ethica^ II. 43, Scholium : ii. 49, Scholium. 

^Though Leibniz is certainly a systematic thinker, it is his 
many-sided snggestiveness that has been most remarked. Our 
aim, however, is merely to show that his system is in its main 
outlines based upon Cartesian principles, and that in his 
philosophy these principles, so far as they remain in essentials 
unmodiBed, inevitably lead to the same unsatisfactory con- 
clusions. While, therefore, we must omit all detailed reference 
to those other parts of his teaching which are not closely bound 
up with these principles, this omission must not be taken as 
implying any desire, on our part, to minimise their significance 
and importance. 


self all its different states must be capable of direct 
deduction. That, however, is not, as in Malebranche, 
a final consequence to which his thinking leads, but 
the fundamental doctrine upon which his system is 
based. Quite unafraid of any apparent paradoxes in 
his contention, he maintains that from the idea of the 
self must be deducible not only its different possible 
experiences — a capacity for the different sensations 
and feelings — but also the reason of the actual happen- 
ing of every single 'contingent' experience, past 
present, and to come. " The nature of an individual 
substance, or complete being, is to have a notion so 
completed that it suffices to comprehend, and to render 
deducible from it all the predicates of the subject to 
which this notion is attributed. . . . God, seeing the 
individual notion or hecceity of Alexander, sees in it 
at the same time the foundation and the reaiSon of all 
the predicates which can truly be attributed to him, as 
e,g. whether he would conquer Darius and Porus, even 
to knowing a priori (and not by experience) whether 
he died a natural death or by poison, which we can 
only know by history."^ This position of Leibniz is 

^Gerhardt, ii. p. 433 (Russeirs trans, p. 214). Cf. iv. p. 436. 
" The notion of an individual substance involves once for all 
everything that can ever happen to it, and in considering this 
notion, we can see all that can be truly predicated of it^ just as 



based on the atomic conceptualism, which, as we have 
seen, results from the scholastic doctrine of essence. 
Every true predicate must be included, implicitly if 
not explicitly, in the notion of the subject, since other- 
wise to assert that it belongs to the subject would 
necessarily be false. Even predicates that aflSrm 
relations hold true only if they express some attribute 
inhering in each of the substances so related, the 
essence of the proposition consisting in the assertion of 
that inherent quality. 

But if everything that can happen to an individual 
is included in its notion, and follows necessarily 
from it, if "our thoughts are the consequences of 
the nature of our soul, and come to birth in virtue 
of its notion, it is useless to demand in explanation 
of their appearance the influence of another particular 
substance, besides that this influence is absolutely 
inexplicable."^ Each soul must be a world apart 
All our perceptions and feelings would arise in 
order as they do now, even though the whole 
external world were annihilated, and only God and 
the self remained.^ 

we can see in the nature of the circle all the properties that can 
be deduced from it." 

* Grerhardt, ii. p. 69. 

2Cf. Gerhardt, iv. p. 440, 


Now just as Spinoza argues that only from the 
one all-comprehensive idea can the real be deduced, 
so Leibniz is forced to conclude that if everything 
is deducible from the notion of the individual, that 
notion must be all-inclusive*^ Since, as experience 
shows, everything is bound up with everything 
else, and varies with it, every individual having 
some relation, direct or indirect, to every other 
individual, the above theory of predication can only 
be maintained through the counter-assertion that 
each concrete and completed notion is infinite, and 
mirrors in its complexity the whole Universe. 
Further, in order that the so-called external and 
accidental relations to other individuals similarly 
complete in themselves, be deducible from even this 
infinite notion, there is required, as the objective 
counterpart of the above assumption, the hypothesis 
of concomitance or pre-established harmony, the 
hypothesis, namely, that to every experience in one 
soul there must exist a corresponding experience in 
every other. And combining that last hypothesis 

^Thus common to both Spinoza and Leibniz is the view of 
substance as that which is conceived in and through itself. But 
while Spinoza starts from the idea of Divine Substance to 
deduce the finite individual, Leibniz starts with the conception 
of the individual to reconstruct the Universe. 




with the truth that no two individuals can be 
altogether alike without being identical, we may 
finally conclude that while each individual mirrors 
the same universe, each must mirror it from a 
dififerent point of view. "Thus the universe is in 
a manner multiplied as many times as there are 
substances, and the glory of God is at the same 
time redoubled by as many representations, all 
different, of His work."^ These conclusions may, 
Leibniz repeatedly states, appear paradoxes; but as 
they follow necessarily from the indubitable principle 

^Gerhardt, iv. p. 434. Leibniz adds that each substance 
imitates according to its nature the infinite wisdom and omni- 
potence of God. " It expresses, although confusedly, all that 
happens in the universe, past, present, and to come, that which 
has some resemblance to an infinite perception or knowledge ; 
and as all the other substances express it in their turn and 
accommodate themselves to it, it may be said that it extends its 
power over all the others in imitation of the omnipotence of the 
Creator." That last sentence indicates Leibniz's mode of 
explaining, and justifying, the ordinary notions of causal inter- 
action. Since the dififerent monads mirror one and the same 
universe with dififerent degrees of distinctness, change of 
state may well find its explanation, not in the monad in which 
it occurs, but in some other. One thing may be said to act in so 
far as it has perfection, and to be acted upon in so far as it is 
imperfect. And one created thing is more perfect than another 
when, having more distinct perceptions, there is found in it that 
which serves to explain a priori what takes place in the other. 
Causation is thus always ideal ; it is identical with explanation. 
Cf. Spinoza, Ethica, iii. 3 ; v. 40. 


that every true predicate inheres in the notion of 
the subject, they must be accepted by all those 
who desire to think consistently.^ 

What specially concerns us is to determine more 
exactly Leibniz's meaning in the assertion that all 
predicates follow from, are a priori consequences of, 
the notion of their subject. In seeking the relation 
of predicates to their subject, two points of view 
are, according to Leibniz, possible. If we consider 
the direct relation of the predicates to the subject, 
the principle of their connection must be that of 
identity. The predicates follow from, are conse- 

^Our attention was first drawn by the late Prof essor Adamson 
to those letters of Leibniz to Arnauld in which the above 
argament is stated. The importance of this argument has, 
however, recently been pointed out by Mr. Russell. Mr. Russell 
{The Philosophy of Leibniz, p. 8) holds that this argument "is 
alone capable of explaining why Leibniz held that substances do 
not interact." Leibniz denies interaction because it is wholly 
inconsistent with the rationalistic principles which he shares 
with Descartes. Leibniz's argument that the existence of the 
composite (as it appears in ordinary consciousness) necessitates 
the assumption of simple elements as its constituents — which is 
the argument upon which he chiefly relies in his later works for 
proof of the existence of monads — is by no means satisfactory, 
since the composite is what, on his principles, cannot be 
accounted for. Cf. La Monadologie, sec. 2 (Latta's trans, p. 
217) : " And there must be simple substances, since there are 
compounds ; for a compound is nothing but a collection or 
aggregatum of simple things." 


quences of, the notion of the subject, in the sense 
that by analysis they can be discovered in it, and 
be found to constitute it. Were anyone of the predi- 
cates changed, the subject, whose notion they 
express, would cease to be the same individual. In 
those cases, however, in which we fail to discover 
the predicate in our notion of the subject, we are 
forced to adopt a second point of view, namely, to 
consider the predicates in relation to the other 
predicates, either coexisting or preceding, and in 
that indirect way to determine their relation to 
their common subject. Though these other predi- 
cates may not involve it in their notion, and so 
justify it by the law of identity, they may yet 
supply a sufl&cient reaso'n why it should be so, rather 
than otherwise. The problem which the philosophy 
of Leibniz sets to the commentator is to connect 
these two points of view, to reconcile the purely 
logical attitude expressed in the law of identity 
with the more empirical expressed in the law of 
sufficient reason. The universal application of the 
first would destroy both time and space, and allow 
only of eternal and logical, never of temporal or 
causal, connections. The application of the second 
on the other hand, implies the existence of space 


and time, and allows, as having at least phenomenal, 
practical, validity, explanation by efficient causes. 
From the point of view of the first, monads are 
notions with an eternal and completed content. 
From the point of view of the second, each is an 
activity that progressively realises its notion in time 
through its tendency towards the good. This opposi- 
tion is identical with the opposition, which we have 
considered at length in our treatment of Descartes, 
between rational connection and temporal causation. 
Leibniz, following Descartes, combines his peculiar 
rationalism with an equally extreme spiritualism. 
While an analysis of what is involved in true 
predication leads to the assumption of individual, 
completed, and all-comprehensive, notions, it is only 
in inner experience, Leibniz believes, that such indi- 
viduality is to be found. In the Cogito, and there 
alone, do we find a unity such as those notions, 
if real, must possess.^ Combining, therefore, these 

^In it we have experience of a unity that is capable of 
maintaining itself throughout the variety of its states, and of an 
activity that progressively unfolds that unity in the realisation 
of desire. Further, within the unity of each perception there 
id always involved a multiplicity, infinitely complex. In thus 
insisting that in mind the two opposites, unity and variety, are 
inseparable, and that all reality— dA distinguished from the 
unreal abstractions of thought — has that twofold aspect, 



two truths, that of general reasoning and that of 
inner experience, Leibniz constructs a system that, 
however different in detail from the philosophy of 
Descartes, still maintains unchanged its fundamental 
principles. When his rationalism comes short, active 
spirit is made to fill the gaps. 

Leibniz does not prove that spirit has the 
capacity of infinite inner development. Having 
shown that the notion of the individual must be 
all-comprehensive, and that spirit is the only 
form of unity in variety known to us in the real, 
he at once identifies the two. In the logical 

Leibniz, like Spinoza, prepared the way for a truer and more 
organic point of view. The impossibility of explaining the 
unity of consciousness in any mechanical fashion is strongly 
insisted upon by Leibniz. Cf. La MoTiadologie^ sec. 17 (Latta's 
trans, pp. 227-8) : " It must be confessed that perception and 
that which depends upon it are inexplicahle on mechanical 
grounds^ that is to say, by means of figures and notions. And, 
supposing there were a machine so constructed as to think, feel, 
and have perception, it might be conceived as increased in size, 
while keeping the same proportions, so that one might go into 
it as into a mill. That being so, we should, on examining 
its interior, find only parts which work one upon another, and 
never anything by which to explain a perception. Thus it is in 
a simple substance, and not in a compound or in a machine, that 
perception must be sought for." That the spiritualism and the 
rationalism are very externally conjoined in Leibniz's system is 
not surprising, since at bottom, as interpreted by Leibniz, they 
are utterly at variance with one another. 


notion are involved all its predicates : in the self 
must therefore be contained the complete conditions 
of all that it realises through its activities. The 
relation of the predicates to the subject is logical: 
from the self all actions must be similarly deducible. 
From this point, however, in Leibniz's argument the 
spiritualism takes the upper hand. His rationalism 
aflFords the basal argument for his monadism, but 
the monad being further interpreted as spirit, his 
rationalism is in the resulting system greatly modified 
to suit this deeper and more adequate conception of 
the nature of the individual. Since he now declares 
all substances to be active entities, endowed with 
desire and with perception, he no longer conceives 
the process by which the various predicates are 
deduced from the notion of each individual as 
purely, and entirely, logical. Though he still speaks 
of the process as a priori, the a priori reasons are 
such as incline without necessitating. As the 
development of the conscious being is ruled by the 
contingent principle that what is sought is the 
good, each of its activities is to be deduced (in 
accordance with that principle which inclines with- 
out necessitating) from the individual's prior know- 
ledge of what is for the best. But in order to 


maintain his rationalism, even in that highly 
modified form, Leibniz has to make good the 
extreme assertions that all change in nature is the 
outcome of desire, and that nothing has absolute 
reality save subjective experience. 

From his spiritualism Leibniz derives what little 
metaphysical explanation ,he is able to give of the 
mechanical world in space. Accepting as an empiri- 
cal fact that bodies do appear to us as interrelated 
in space, he asserts that this appearance has its 
source in the confused perceptions of the monads. 
Thus condemning the mechanical world as pheno- 
menal, he escapes the demand that his theory of 
causation be tested by the peculiar facts which it 
reveals. Since the mechanical world would resolve 
for complete knowledge into purely ideal relations 
between spiritual monads,^ knowledge of it as 
appearance can only proceed according to the con- 
tingent laws of its actual nature. These, as experi- 
ence shows, are the laws of motion. All change in 

* Leibniz indirectly proves that the atomistic conceptualism of 
Descartes is as incapable of accounting for space, as, on 
Descartes' own showing, it is of accounting for time. The 
essentially relational nature of space and time, as revealed in 
their continuity, is inconsistent with any interpretation of 
reality that is exclusively based on the conception of sub- 


the material world arises upon impact, and the 
sufl&cient reason for any change is therefore to be 
found in a preceding change capable, according to 
the laws of motion, of bringing it about. But just 
as Leibniz fails to explain how the obscurity and 
confusion in the perceptions of monads should trans-, 
form the discrete harmony of the universe into the 
continuous form of space,^ so he fails to connect in 
any real way the laws of motion (which must in 
the end be regarded as the phenomenal manifesta- 
tion of the inner striving of the monads) with the 
choice of the good.^ 

As regards the problem of knowledge, Leibniz's 
contribution is very suggestive, and in many respects 
anticipates modem views, ^ but when interpreted 

1 Cf . below, pp. 34-6. 

2 Cf . Russell : The Philosophy of Leibniz^ p. 89 : " Leibniz has 
acquired much credit for the vaunted interconnection of his 
views in these two departments [Dynamics and Metaphysics], 
and few seem to have perceived how false his boast really is. As 
a matter of fact, the want of connection is, I think, quite one of 
the weakest points in his system." 

3 Such anticipations of more modern views are for the most 
part due to the principle of continuity which Leibniz applies 
with great acuteness and originality in all departments of know- 
ledge. It leads him, in his theory of knowledge, to deny the 
absoluteness of such distinctions as those between the conscious 
and the unconscious, between thought and sense, between the 
necessary and the contingent. 


quite strictly, in the light of his fundamental 
principles, proves less important than at first sight 
appears. Though he rejects Descartes' impossible 
opposition of thought and sense, he does so only 
in order to support the equally extreme contention 
that sense is confused thought. On complete know- 
ledge, colour, sound, and the other secondary qualities, 
would, he believes, become transformed into something 
fundamentally dififerent from themselves. Thinking, 
if it could be thoroughly carried out, would consist 
in a progressive elimination of sense by clarification 
of the confused perceptions into the distinct ideas of 
which they are composed. By that view of sense he 
seeks to mediate between Descartes and Locke, asserting 
with the one that the mind possesses innate ideas, 
and with the other that all knowledge is based on 
concrete sense-experience, and develops from it. 

Three different views of the innateness of know- 
ledge can be detected in Leibniz. First, there is 
that view which has always gone along with 
subjective idealism, namely, that the self is an 
independent substantial agent, and by reflection on 
its own nature acquires those notions through 
which it interprets all else. Since we are, so to 
speak, innate to ourselves, in apprehending the self 


we necessarily apprehend those ideas which are 
implied in the idea of the self, such as being, sub- 
stance, unity, sameness, activity, perception.^ This 
theory, however, seems to be propounded by 
Leibniz simply as a step towards the second and 
deeper view which he develops at length in the 
Nouveavx JSssais in opposition to ^the teaching of 
Locke. The necessary truths of reason are not, 
and cannot be, guaranteed by generalisation or in- 
duction from particular instances supplied in sense- 
experience. They have their source in the under- 
standing alone, and do not require for their 
establishment anything beyond the intelligible ideas 
between which they hold.^ But since Leibniz's 

^ Cf. Nouveaux Essais, liv. ii. chap. i. sec. 2 : Gerhard t, v. 
pp. 100-1 : " NihU est in intellectu, quod non fiterit in senm, 
excipe : nisi ipse intellectus. Now the soul contains being, 
substance, unity, identity, cause, perception, reasoning, and many 
other notions, which the senses cannot give." Leibniz here 
practically asserts that all those ideas which Locke ascribes to 
reflection are innate. Such reflection extends, however, on 
Leibniz's view, not only to the operations of the mind, but also 
to the mind itself. This is a view of innate ideas which Kant 
overthrows, one of the most important results of his philosophy 
being that we know objects directly, and the self only indirectly 
through objective experience. 

2 Though Locke cannot possibly, from his sensationalistic 
principles, account for such necessary intuitive knowledge, he 
shows himself in the fourth book of the Essay quite ready to 


argument, that these necessary truths are therefore 
innate, implies, as he himself admits, that the ideas 
between which they hold are likewise innate, his in- 
terpretation of the innateness of knowledge depends 
upon his mode of regarding ideas. 

Now Leibniz retains the Cartesian view of ideas as 
mental existences, the objects and not the acts of 
thought. "If the idea were the form of thought, it 
would spring up and cease with the actual thoughts 
which correspond to it ; but being the object, it must 
be before and after the thoughts."^ Each idea, 
further, is to be regarded as in itself perfectly distinct. 
Since experience is confused perception, and the con- 
fused presupposes distinct elements as its constituents, 
all our sense-perceptions must be composed of distinct, 
prior-existing, that is to say, innate, ideas;^ Hence, 
though Leibniz himself suggests, as we shall see im- 

accept Leibniz's contention that necessary truths carry their 
proof in themselves, and are not formed like general truths by 
induction from experience. Cf. below, chap. v. pp. 15 ff. 

^ Nouveaux Esaaia, liv. ii. chap. i. sec. 1 : Gerhard t, v. p. 99. 
Cf. IV. p. 451. As Mr. Russell {The Philosophy of Leibniz, p. 
165) expresses Leibniz's view. "An idea, though it is in the 
mind, is neither knowledge nor desire ; it is not a thought, but 
what a thought thinks about." The above references are given 
by Mr. Russell. 

*Cf. Boutroux in his preface to the Nouveaicx Essais, p. 94 
(Paris, 1886). 


mediately, a still higher and truer view of the nature 
of the innate ideas, he is in the end forced by his 
principles to adopt a view that is in essentials identical 
with that of Descartes. " In every soul there exist 
from all eternity the distinct ideas of all things. . . , 
The sum of these ideas constitutes reason which, in 
this way, is innate in us." ^ 

When Leibniz is thus strictly interpreted, his most 
important advance upon Descartes consists in the 
introduction of the fruitful conception of the uncon- 
scious. Descartes had never faced the difl&culty, how 
if, as he asserts, the essence of mind consists in self- 
consciousness, there can yet be innate in it ideas of 
which it is not at every moment conscious. It is this 

^ Boutroux, ibid. p. 82. As Leibniz thus retains Descartes' 
view of ideas as the objects, not the acts, of thought, the 
doctrine of representative perception also remains an integral 
part of his system. Indeed, it fits in perfectly with his .view of 
the self as an isolated monad, reproducing in picture within 
itself ati independently existing world. Yet while thus retain- 
ing the doctrine, he was not concerned to discuss either its 
grounds or its implications. Though he refers to Berkeley's 
philosophy as an absurd paradox, he has himself no better 
reason to offer for his own belief in an external world than the 
general principle that since being is preferable to not-being, the 
more existence there is the better. (Cf. Spinoza, Ethica, i. 
Appendix, at the end.) Spinoza takes up, as regards the nature 
of ideas and their relation to the real, a position so peculiarly 
his own that we have considered it needless for us to enter upon it. 




unsolved diflBculty which gives Locke's objections to 
his teaching what little force they may have.^ By the 
assumption of unconscious mental states Leibniz meets 
these objections, and again mediates between Descartes 
and Locke. 

But though Leibniz thus usually ascribes indepen- 
dent existence to the different innate ideas, and regards 
them, in a mechanical fashion, as constituting the 
mind, there is cdso suggested in the Nouveaux JSssais a 
third view, one that approximates more closely to the 
Kantian position. For occasionally Leibniz speaks 
of the ideas, not as separate entities, but as " habi- 
tudes and dispositions " of the mind.^ " The general 
principles enter into our thoughts, of which they are 
the soul and organising bonds {Vdrm et la liaison). 
They are necessary to our thinking as muscles and 
tendons are for walking, though we do not think upon 

^This is one of the problems dwelt upon by Augustine. 
Of. above, chap. i. pp. 9-10. When Descartes touches t>n this 
problem, he solves it in an unsatisfactory manner by ascribing 
to the mind a power or faculty of producing ideas. (Of. 
B^ponses aux Troisihnes Objections, i. pp. 492-3.) Against all 
such faculties Leibniz, like Spinoza, carries on a vigorous polemic. 
A faculty must, he insists, if it is anything real, be continously 
in action in some form and degree — qtiod non agit, non earistiU 

2 Of. Preface to the Nouveaux Essaia, Gerhardt, v. p. 45, 
Latta's trans, p. 367 ; also, in the first book, chap. i. sec. 26 ; 
chap. III. sec. 20 ; Gerhardt, v. pp. 79, 97. 


them. The mind supports itself upon these principles 
at every moment."^ Knowledge of the concrete 
and contingent precedes, as Locke rightly asserts, 
knowledge of the universal and necessary; and yet, 
as Descartes holds, it is the latter which renders 
sense-experience possible.^ The mind rejects the self- 
contradictory, even though it has never formulated to 
itself the law of non-contradiction. Principles rule 
and govern the mind long before it acquires definite 
consciousness of them. Since Leibniz, however, believes 
that all necessary truths are analytic, and are justified 
by the law of identity, he could not really develop 
this Kantian theory of the innateness of the connec- 
tions binding the parts of our experience to one 
another. By his assertion that the predicate must 
always be involved in the subject, he virtually reduces 
the judgment to the concept ; whereas Kant's teaching 
has the contrary effect of transforming the concept 
into the judgment. The judgment is the fundamental 
act of mind, and being essentially an act of synthesis 
involves synthetic connecting principles.* This higher 

^ Nouveaux Esmisy liv. i. chap. i. sec. 20, Boutroux's text, p. 
190. This passage is omitted in Gerhardt's edition. 

2 This twofold truth Leibniz certainly states much more 
clearly and emphatically than does Descartes. 

^ Also when an idea is interpreted as a judgment, it can no 



view of the innateness of knowledge is therefore, like 
so many other of Leibniz's views, a suggestion merely, 
and for its development would involve the rejection of 
those Cartesian principles with which alone we are 
here concerned, and upon which, as we have tried to 
show, his monadism is based. Only the first two 
views are consistent with Leibniz's principles; and 
since when he develops the second view, that all ideas 
are innate, his ascription of innateness to those ideas 
which are implied in the idea of the self ceases to have 
special significance, we are justified in interpreting his 
doctrine in that second way as in essentials identical 
with the teaching of Descartes.^ 

From this theory of the innateness of knowledge 
Leibniz has obvious diflBculty in accounting for sense- 
experience. As in the explanation of our apprehension 
of space, he assumes that the innate ideas in coming 
to consciousness appear first of all in a confused form. 
So appearing, they give rise, he asserts, not only to 
space but also to the secondary qualities, through which 

longer be regarded in the Cartesian manner as a separate 
existence, the object and not the act of mind. 

1 It depends on which of the three interpretations of Leibniz's 
doctrines we adopt, what value we assign to his famous reply to 
Locke — nihU est in intellectu, quod non fuerit prtris in sensUj 
nisi ipse intellect%Ls, Only on the last interpretation, which is 
no more than suggested in Leibniz, is it an anticipation of Kaut. 


space is apprehended. What are the causes of this con- 
fusion in our perceptions, and in what exactly it 
consists, Leibniz does not, however, satisfactorily 
explain. It must be assumed, he seems to say, 
because only by its means can either the finitude 
or the variety of the monads be established.^ If all 
the innate ideas came to consciousness at once, each 
monad would be as God, and all monads identical. 
Though two explanations of such confused perception 
are indicated in his writings, neither can be accepted. 
Sometimes he speaks as if the confusion were due to 
the finitude of the monads, but as it is it alone that 
constitutes their finitude, the argument assumes all 
that it pretends to prove. His second mode of 
explanation is by the assumption of * minute * percep- 
tions. Confused perceptions result, he says, from the 
massing together of perceptions that separately are too 
minute to affect consciousness; the roar of the sea, 
for instance, is composed of the noises made by the 
separate waves. This explanation is, however, equally 

^ The variety of the monads is also due, according to Leibniz, 
to differences in their points of view. Each represents clearly 
that which is near at hand, and confusedly that which is distant. 
This difference, however, seems to depend, as Mr. Eussell points 
out (The Philoiophy of Leibniz^ chap, x.), on the surreptitious 
reintroduction of that spatial relation whose validity Leibniz 


unsatisfactory. For though differences of intensity 
may be ascribed to sensations and feelings, they can 
hardly be ascribed to the innate ideas, all ot which 
are intelligible.^ 

No explanation, indeed, consistent with Leibniz's 
principles can possibly be devised of confused percep- 
tion. It is postulated by Leibniz simply as a 
plausible means of reconciling an inadequate theory 
of knowledge with the admitted facts. Just as spirit 
is regarded as the source of all activity and change, so 
likewise obscurity in its perceptions is made to 
account for the secondary qualities of bodies, for space, 
for the finitude of the monads, and for their variety. 
Spirit is in the system of Leibniz, as in that of 
Descartes, the devs ex machina that solves all the 
irresolvable difficulties caused by a rationalism that 
is based on the scholastic doctrine of essence. If 
Leibniz's spiritualism is to be maintained, it must be 
upon principles fundamentally different from those 
which he inherits from Descartes. 

1 Cf. Russell : The Philosophy of Leibniz, p. 159. 



Though the English development is one of grow- 
ing empiricism, it remained to the end under the 
predominant influence of the Cartesian philosophy ; 
and Locke, the first of the school, is on the whole 1/ 
more rationalist than empiric. His empiricism all- 
important, and alone emphasised, at the start of 
the Essay, but dwindling in extent and in importance 
as the Essay proceeds, is fixed by the attitude which 
he takes up towards the originals of our knowledge. 
They consist, he says, of sensations which as simple 
are all isolated and atomic, and between which 

1 We shall treat Locke at greater length than we have treated 
Spinoza and Leibniz, partly because the connection between 
his philosophy and that of Descartes has been less dwelt upon 
by commentators, and also because a fuller statement of his 
philosophy is necessary in order to enable us to understand the 
point of view adopted by Hume in his criticism of the Cartesian 




therefore, no necessary relations can ever be perceived 
by us. That assertion is obviously true, so long as 
we have in view the secondary qualities of bodies. 
As we have found Malebranche also insisting,^ 
between the different sensations of the different 
senses, and even between sensations of the same 
sense, no relation can be discovered. But it is 
not at all obvious why Locke should attempt to 
/ interpret our whole experience in the light of the 
secondary qualities.^ Why does he ignore the 
spatial and causal relations whereby our sensations 
are united to one another? They are equally 
evident, and were alone emphasised in the Cartesian 
philosophy from which he starts, and yet are quite 
inconsistent with such a view. Two reasons may 
be suggested. First, the influence of Bacon with 
his teaching that the inductive method, starting 
from the particular facts and cautiously advancing 
to the more and more general, is the only fruitful 
one. Such a method was much more congenial to 
the English matter-of-fact temperament of Locke 
than the adventurous a ^priori mathematical method 

^ Cf . above, chap. iii. p. 95. 

2 That Locke does so appears very clearly in the section in 
which he defines the nature of simple ideas (ii. ii. 1). 




of Descartes. Locke's ignpranco of mathematics and 
interest in the purely empirical sciences of medicine 
and politics, and also the predominantly empirical 
tendency of scientific study in the England of his 
day, would all strengthen this influence. Still more 
important, however, is the physiological attitude 

which, Locke adopt ed in the explanation of _ the 

origin of knowledge, £m(l .which is the natural 
complement, of a_...belief in the empirical method. 
All knowledge, however ^bs tract or general, must 
be traced back to that sense-experience which is 

HiTpp1]pfi tn i^fl 1TI t.hp. pnnf-pnf-. of rlpt.flp.hpfl sensatlOn* 

mrn^pg at fliffp.fftrif-. moments of time through the 
different. 3Yenues,.i)L sense. To admit any other 
source of knowledge is surely, Locke held, illegitimate, 
unless it can be shown (and the burden of proof 
he not unfairly regarded as resting on his opponents) 
that this, the one undoubted, and sole obvious, source 
of experience is incapable of accounting for it. 
Indeed so convinced is he of the correctness of this 
attitude, that he applies it also in the explanation 
of the mind's knowledge of its own states and 
activities, holding that the mind's so-called 'power 
of reflection' is due to an inner sense corresponding 
to, and to be explained on the analogy of, the outer 









senses.^ Now that physiological attitude naturally 
leads Locke to his atomistic view of sensations. If 
sensations come to us one by one, in detached 
moments of time, and through different senses, then 
each (such we may believe is the unformulated but 
implied reasoning) must be capable of existing and 
being known separately, and being thus a completed 
existence cannot be essentially related to any other. 
If that is a true interpretation of the movement of 
Locke's mind, he would thereby be brought to hold 
that what is true of the unbridgeable qualitative differ- 
ences between the secondary qualities must be true of 
all sensations regarded as complete mental states.^ 

Locke takes .directly., nypj from T)ft5!ff>.^r tfts his 
view of the world according to. j shich particular 
minds exist on the one side^ ._and— an — extended 
, ^ material world exists independently on the_ otWj 
and therefore also adopts the doctrine of r^jresenta-^ 
tive perception. For the most part he follows 

iCf. below, note 3 to p. 189. 4 

^The conflict between Locke's attitude in the second book 
of the Es%ay and that which he takes up in the fourth, is due 
almost entirely to the fact that while he considers only the 
secondary qualities in formulating his theory of the materials 
of knowledge, in advancing to the examination of scientific 
knowledge in the fourth book he finds that the only existing 
sciences are those rendered possible by the primary qualities. 


Descartes in the interpretation which he makes ol^^ 
that doctrine. Bringing within the mind itself 
the distinction between subject knowing and object I ' 
known, he assumes that over against ideas there 
exists a mind that knows them directly in some 
unexplained way, the assertion that only ideas can 
be objects of mind being grounded in certain un- 
formulated assumptions of a naive realism. Locke, 
however, at times seems to interpret the doctrine 
in another and very different way, basing it on 
what he takes to be a self-evident postulate, that 
knowledge is only possible mediately by way of 
ideas, or, in other words, that the mind must 
always have an idea of the object known. Now 
that postulate may be correct, everything depending 
on the meaning given to the terms used, only it 
cannot on any interpretation be reconciled with 
Locke's other and more usual view that only ideas 
are known, and that they are known as the (Ejects 
of mind. For if the postulate be granted, we can 
never know any object directly, not even an idea ; 
and the two views combined would therefore result 
in the position that all knowledge is indirect and 
inferential, which is absurd, involving as it does 
an. infinite regress. Some immediate knowledge must 



be postulated in order to make indirect representa- 
tive knowledge possible. We may therefore ignore 
thia^ second view, and interpret Locke solely in 
accordance with the first. ''[Idea] being that term 
which, I think, serves best to stand for whatsoever 
is the object of the understanding when a man 
thinks, I have used it to express whatever is meant 
by phantasm, notion, species, or whatever it is which 
the mind can be employed about in thinking."^ 
Ideas are thus given a certain independent existence, 
at once illuminating the mind and being illumined 
by it. The mind, as Malebranche says,^ is not 
' lumUre illuminante ' but * lumUre iUumin4e * ; and 
. that far from luminous distinction does full justice 
to what is carefully kept in the half-light of a 
conscious indefiniteness by both Descartes and Locke. 
Since all those occult qualities, powers, and activities, 
that are driven by Descartes out of the material 
world, have gone to harbour in this inner world of 
the mind, it is a region in which no precise thinking 
need be expected till the coming of Hume. What 
is alone definite in Locke is that he is no sensationa- 

^i. I. 8. 

^ M^itations GkrMenneSy i. p. 15. The phrase is quoted by 
Malebranche from Augustine. 




list, if that means one who regards the mind as 
consisting of its sensations. He is, like Descartes 
before him, and like Berkeley after him, a spiritualist 
in that he assumes the existence of an abiding self 
that observes and compares its everchanging ideas.^ 

1 It is from this spiritualism and not from his sensationalism, 
that Locke gains an explanation of our consciousness of relations, 
including those of space and time. As there is a self behind 
ideas that observes them, any relations of resemblance or of 
sequence that hold between them must, he believed, be visible 
to this self, immediately they are by it set side by side and 
compared. As regards consciousness of space Locke is very 
indefinite in his utterances. Of his description of the idea 
of space as simple, much the same criticism must be 
made as was passed upon Descartes' corresponding assertion. 
There is an ambiguity involved. Certainly the idea of space 
cannot be resolved into simpler ideas ; but that does not prove 
space itself to be simple in the sense in which the term ^simple 
is applied to the sensations of the special senses, namely that 
each is a completed existence and involves no complex of 
relations within its content. This difiiculty in the way of 
describing the idea of space as simple is practically admitted by 
Locke (II. XV. 9). In both Berkeley and Hume the dependence 
of our knowledge of space on a self behind ideas observing 
them, becomes quite explicit. Such knowledge is due, they 
assert, to the mind's consideration of the distribution and 
arrangement of visual and tactual points. This explanation 
by reference to a self behind ideas does not, however, account so 
plausibly for consciousness of space as for consciousness of time. 
It is impossible to hold that a variety of visual or tactual points 
can lie within a * simple' sensation, and equally impossible to 
conceive how the mind should apprehend the different coexistent 
simple sensations (minima) of sight or touch, as forming a single 




In mfi^od- Locke, is .alsQ the disciple of Jlfiscartes, 
both of them seeking by an analysis ^f the 
materials at. the disposal of the mind to determine 
the extent and limits of knowledge. There are, 
however, important differences in their standpoints. 
While Descartes seeks the simple conceptions from 
which all other knowledge may be deduced, Locke 
as an empiricist seeks to classify the simple sen- 
sations through the mechanical .combination of which 
all complex ideas are formed. And that difference 
of aim explains the greater emphasis which Locke 
lays on the observation by the individual of his 
own mind and what goes on there. Whereas the 
conceptions which Descartes analyses are common 
property, and capable of definition, sensations- can 
only be known to each individual through his 
immediate personal experience of them. All know- 
ledge must start from observation of the facts to 
be accounted for, and in this sphere each must 
observe the facts for himself.^ 

continuous field. The sensationalist theory, being formulated 
in the light only of the secondary qualities, is as incapable 
as the Cartesian rationalism of accounting for the essentially 
relational nature of space. 

^ Tlie same emphasis was inevitably laid upon inner observa- 
tion by Malebranche when he set himself to analyse the concrete 
sense-experience that Descartes had very insufficiently treated. 


What Locke first discovers in looking into his 
own mind is the truth of the cogito ergo sum. He 
does not, however, like Descartes, regard it as a 
self-evident truth of reason, but simply as a fact 
revealed and guaranteed by introspection. "Every 
man being conscious to himself, that he thinks, and 
that which' his mind is applied about, whilst 
thinking, being the ideas that are there, it is past 
doubt that men have in their mind several ideas, 
such as are those expressed by the words 'white- 
ness, loudness, sweetness, motion, man, elephant, 
army, drunkenness,' and others."^ And as Locke 
assumes that ideas imply a self that has them, 
the existence of the self he takes as likewise in- 
dubitable. ^ 

Locke's answer to the question — how we acquire 
these ideas ? — is that they come into the mind 
from outside through two avenues, sensation and 
reflection. In sensation we get ideas of external 
sensible objects, and from reflection ideas of the 
mind's own operations and passions.^ The mind 

* II. I. at the beginning. ^Cf. iv. ix. 3. 

3 There are many ambiguities and difficulties in Locke's view 
of reflection. It is by no means clear whether reflection is to 
be taken purely as an inner sense, corresponding to outer sense, 
or as a kind of self -consciousness that includes both inner and 



' cannot create for itself a single new simple idea. 
All that it can do is to unite the ideas, given 
through these two sources, so as to form out of 
them complex ideas. ^ 

outer experience. The first view is prominent in his treatment 
of simple ideas. There he is concerned to show that all our 
simple ideas are passively received by the mind ; and there also 
he seeks to get behind them, so as to give a mechanical explana- 
tion of their origin. According to this theory, just as external 
objects by affecting outer sense cause sensations, so too our 
mental operations by affecting inner sense give rise to another 
and independent series of impressions. What this * inner 
sense* is, Locke, it need hardly be said, is no more able to 
explain than he is able to explain what ^ outer sense' 
is, and how different from the mind, nor does he pretend 
to. On the second view, * reflection ' is identified with 
self-consciousness. "We can surely, Locke says, reflect on 
what goes on in the mind, and so have knowledge of 
the mind's operations. To think without being conscious that 
we think is as impossible as that a body should be extended 
without having parts (ii. i. 19). Thus identified with self- 
consciousness, reflection must be regarded as an ultimate fact, 
and the previous mechanical explanation as but a preliminary 
metaphorical expression of what is now seen to constitute the 
very essence of mind. And that involves, it may be noted, the 
giving up of the doctrine of representative perception as regards 
knowledge both of ideas and of the mind's operations upon 
them. They are known directly, and not, like material bodies, 
mediately by way of intervening ideas. Also, on this second 
view, the separation of ideas of reflection from ideas of sensa- 
tion becomes impossible. Reflection is coextensive with all 
knowledge, revealing not only the operations of mind, but also 
all the ideas upon which it operates. 

^In describing the mind as being, prior to all experience, a 


Locke fails, however, to maintain that position. 
As an example of his failure, and also for other 
reasons that will appear immediately, we may 
consider his account of the origin of the idea of 
substance. It is, he says, due to the fact that we 
perceive sensations to exist together in clusters (an 
orange, for instance, consists of the different but 
coexistent sensations of yellowness, roundness, soft- 
ness, sweetness or bitterness, etc.), and being unable 
to conceive how these different sensations can sub- 
sist by themselves, or in one another, "we accustom 
ourselves to suppose some substratum, wherein they 
do subsist, and from which they do result ; which, 
therefore, we call 'substance.'"^ The idea of sub- 
stance Locke thus traces back to an ultimate fact 
of consciousness, to a thought-necessity, which in- 
capacitates the mind from conceiving the contents 
of sensation as other than qualities, as existing 

tabula rasa — a metaphor which we find also in Aristotle and in 
Descartes : cf. Aristotle, Be Anima, iii. 4, 4296 30 ; Descartes, 
Beg. XII. (xi. pp. 265, 267), Recherche de la V4rit4'par les lumi^res 
naturelles (xi. p. 345) — Locke does not mean to deny that the 
mind has a nature of its own, and ways of acting peculiar to 
itself. All that he implies is that the mind (and Descartes also 
agrees thereto) cannot invent a single new simple idea, and 
therefore must be passive in the reception of all 'simple 
Mi, xxiii. 1. 



otherwise than in a something else. Sensations, he 
practically says, are but the occasion whereupon 
the mind is necessitated to produce the category of 
substance and quality out of itself. There is here 
revealed the existence of an original conception that 
is only ei^plicable as having been created by the 

This analysis of the conception of substance, in- 
consistent though it be with his general theory of 
knowledgie, is in itself most valuable, and frees him at 
least partially from the false rationalism of Descartes. 
If the analysis be correct, our idea of material sub- 
stance is, spite of all that Descartes may assert, 
neither simple, nor clear and distinct. It is a com- 
plex idea, consisting of the sum of the sensible 
qualities belonging to it plus the obscure and con- 

^ That Locke also speaks of the idea of substance as consist- 
ing, in so far as it has any positive content, of the very abstract 
idea of 'a something' plus the empirical notion of its acting as 
a bearer or support, does not destroy the fact that its formation 
and application is traced by him to a necessity of thought. 
The formal necessity only gains concrete expression through, it 
does not originate from, such empirical notions. 

The explanation which Locke derives from his spiritualism 
(cf. note to p. 187) of our consciousness of relations (including 
those of space and time) is another example of his failure to 
develop his sensationalistic principles. These ideas of relation 
are additional, as Locke himself admits (it. xxv. 1), to the ideas 


fused idea of the unknown substrate which is their 
bearer. We are as completely ignorant of what 
constitutes the substance of a thing as the Indian 
philosopher was of what the world rested on ; and our 
explanation is no better than his tortoise,^ if we think 
that by talking of a substance we have explained 
anything. Since the idea of substance is an idea 
which arises from the necessitated regress of the 
mind beyond any and all known qualities out into 
the void, we are simply concealing our ignorance by 
means of a word.^ 

It is the same exactly with the idea of the self. 
It also is a complex idea, consisting of the sum of the 
mental states of which alone we are conscious plus the 
obscure and confused idea of the unknown self that 
is their bearer. "He that considers how hardly 
sensation is, in our thoughts, reconcileable to extended 

1 II. XIII. 19. Cf. XXIII. 2. 

2 This distinction between substance and the primary qualities 
is the cause of much confusion in the Essay, If substance be 
unknown and unknowable, the primary qualities cannot be 
regarded as copying the external object. On this second view 
they are effects of substance acting on our minds, and, as sub- 
stance is unknowable, must be entirely different from their cause. 
The same consequence follows from Locke's doctrine of repre- 
sentative perception. Inasmuch as we know only ideas, any 
assertion that they resemble their unknown cause must be 

arbitrary and dogmatic. 



matter, or existence to anything that hath no exten- 
sion at all, will confess that he is very far from 
certainly knowing what his soul is."^ And this 
ignorance " conceals from us, in an impenetrable 
obscurity, almost the whole intellectual world ; a 
greater, certainly, and more beautiful world than the 
material/' ^ 

This discovery of our ignorance, though it limits 
the sphere of our knowledge, extends the bounds of 
imagination, for it establishes the possibility (which 
Malebranche accepted against Descartes as regards 
mind^) of conceiving the qualities of things as un- 
limited in number and variety. Beyond the simple 
ideas that come to us 'in this little canton, this 
system of our sun,' through the ' few and narrow 
inlets ' of sensation and reflection, " what other 
simple ideas it is possible the creatures in other 
parts of the universe may have by the assistance of 
senses and faculties more or perfecter than we have, 
or different from ours, it is not for us to determine." 
" Only this, I think, I may confidently say of it, 
that the intellectual and sensible worlds are in this 
perfectly alike — that that part which we see of 
either of them holds no proportion with what we see 
1 IV. III. 6. 2 IV, HI. 27, 3 Cf. above, chap. iii. note 2 to p. 103. 


not ; and whatsoever we can reach with our eyes or 
our thoughts of either of them, is but a point, almost 
nothing, in comparison of the rest." ^ 

Here, then, is " the horizon found which sets the 
bounds between the enlightened and the dark parts 
of things." 2 Experience, like an electric spark, is the 
small circle of light caused by the interaction of two 
unknowns. Eadiating out from the double but co- 
incident poles of the here and the now,^ it enables 
us to establish the existence of a self and of a not- 
self, but not to discover the nature of either or their 
connection. This setting of the light of our know- 
ledge against a background of darkness gives Locke's 
system that appearance of solidity and depth which is 
so markedly absent from the unreal transparencies of 
the Cartesian conceptualism. 

How far Locke is from regarding the metaphor of 
impression as a suflBcient explanation of the rise of 
sensations in the mind appears very clearly from a 
tract* which he wrote in 1693 (that is, three years 
after the publication of the Essay). If, he there 
says, it be demanded, what are the causes and manner 

1 IV. III. 23. Cf. II. II. 3. 2 1, I, 7^ 3cf. II. XV. 12. 

* Remarks upon some of Mr. Norri^s Boohs, wherein he asserts 
P. Malehranch^s Opinion of our Seeing all Things in God, vol. x. 
of the 180J edition, p. 248. 


of production of ideas in the mind, "I answer, no 
man can tell ; for which I not only appeal to experi- 
ence, which were enough, but shall add this reason, 
viz., because no man can give any account of any 
alteration made in any simple substance whatsoever; 
all the alteration we can conceive, being only of the 
alteration of compounded substances; and that only 
by a transposition of parts." Malebranche asserts* 
that the marigold we perceive exists as a divine idea 
in the understanding of God, and the ignorant assert 
that it exists in the garden, but " either supposition, 
as to this matter, is all one ... for wherein [the 
alteration of the mind, we call perceiving], consists, is, 
for aught I see, unknown to one side as well as the 
other." Later on in the same tract Locke seems to 
say that our sole certainty is that the production of 
sensations is in some way conditioned by our having 
sense-organs. The blind man has no sensations of 
sight Only in what way the sense organs aid in 
the producing of knowledge, that we do not know.^ 

It must be noted that Lo«ke does not base this 
incomprehensibility of the production of ideas in 
mind, as does Descartes, on a dualism between soul 

^ Cf. Locke's other tract, An Examination of P, Malebranche's 
Opinion of Seeing all Things in Oody vol. ix. pp. 214-7. 


and body which renders interaction inconceivable, 
but on the much deeper ground that all interaction 
is incomprehensible. "For in the communication of 
^ motion by impulse, wherein as much motion is lost 

to one body as is got to the other, which is the 
ordinariest case, we can have- no other conception 
but of the passing of motion out of one body into 
another; which, I think, is as obscure and incon- 
ceivable as how our minds move or stop our bodies 
by thought, which we every moment find they 
do. . . . The communication of motion by thought, 
which we attribute to spirit, is as evident as that 
by impulse which we ascribe to body. Constant 
experience makes us sensible of both of these, 


though our narrow understandings can comprehend 
neither. For when the mind would look beyond 
those original ideas we have from sensation or re- 
flection, and penetrate into their cause and manner 
of production, we find it still discovers nothing but 
its own shortsightedness."^ We are tempted to 
ascribe the position, which Locke here takes up, 
largely to the influence of Malebranche, for the 
passage above quoted occurs immediately after a 
lengthy section in which Locke criticises Male- 

^ II. XXIII. 28. 


branche's acute theory of the cause of cohesion of 
the solid parts in bodies.^ But, at the same time, 
it must by no means be overlooked that Locke's 
departure from Descartes' purely dualistic argument 
is also a necessary consequence of his own doctrine 
of substance. Since we know not^- the substance 
either of matter or of mind, to assert (and Male- 
branche asserts it still more emphatically than 
Descartes) their absolute diversity of nature, and 
consequent incapability of union, is illegitimate. As 
Locke says in this same section, "it may be con- 
jectured that created spirits are not totally separated 
from matter," or as he puts it elsewhere,^ it is, "in 
respect of our notions, not much more remote from 
our comprehension to conceive that God can, if He 
pleases, superadd to matter a faculty of thinking, 
than that He should superadd to it another sub- 
stance with a faculty of thinking." These sections 

^ Cf . Recherche de la V4rit4^ liv. vi. pt. ii. chap. ix. Professor 
Fraser asserts that in these sections Locke is criticising the 
theory propounded by James Bernoulli. We are not aware 
that there is any positive evidence that Locke was acquainted 
with Bernoulli's De Gravitate Aetheria^ and in any case Bernoulli 
in the preface to that work points out that his theory is 
identical with that stated by Malebranche in the Recherche, 
And with the Recherche Locke was, of course, acquainted. 

^iv. III. 6. 


are valuable, both as showing how Locke has broken 
with the rationalistic dualism of Descartes, and also 
as preparing the way for the empirical phenomen- 
alism of Hume.^ For the most part, however, Locke 
expresses himself as personally of the belief that 
the self is an immaterial spirit, and frequently, in 
his inconsistent way, he even speaks as if we had 
immediate certainty of the existence of such an im- 
material substance.^ 

Though Locke does not point it out,^ his analysis 
of the conception of substance has also a direct 
bearing upon Descartes' proofs of (rod's existence. 
When Descartes speaks of an absolutely perfect 
being, he does not use the term perfect with any 
definite meaning, but solely, like the term infinite, 
as a synonym for absoluteness. Now the impossibility 
of defining ultimate reality is what (if this analysis 
of the conception of substance be granted to be 

^ Of. also in same chapter of Essay^ section 32. 

*Cf. in the same chapter, from which the above quotations 
are taken, section 15 at the end. To the objections of the 
materialists as to the obscurity and incomprehensibility of the 
notion of spirit, he has the counter -argument that as great 
difficulties are involved in the notion of matter. Cf. sections 
31 and 32. 

3 Locke indeed refuses to express an opinion as to the validity 
of the ontological argument. 


adequate) is here established by Locke. Since God 
is thought as substance and so as absolutely real, 
necessarily His very conception involves existence. 
The absolutely real must be real — true, but altogether 
trivial The important question is as to what is 
the nature of absolute reality, and towards the 
answering of that question Descartes' proofs can 
yield no aid.^ Spiritualism and materialism — such 
must be Locke's final conclusion — ^alike pretend td 
knowledge where none is possible. 

When we turn to Locke's account of scientific 
knowledge in the fourth book of the Essay, we at 
once discover how overwhelmingly strong was the 
influence exercised upon his thinking by the ration- 
alism of Descartes. He holds, with Descartes, that 
knowledge is of two kinds, intuitive and demonstrative. 
We perceive intuitively that white is not black, that 
a circle is not a triangle, that three are more than 
two, and equal to one and two. Such truths are 
given together with the ideas compared, and im- 
mediately on the presentation of the two ideas the 
mind cannot but intuitively perceive the relation 
between them. "This part of knowledge is irresis- 
tible, and like bright sunshine forces itself immediately 

^ Cf . above, note to p. 58. 


to be perceived as soon as ever the mind turns its 
view that way."^ Demonstrative knowledge is formed 
of an unbroken series of such original intuitions, 
whereby the mind is led on from one intuitive truth 
to another. Since we cannot perceive directly the 
relation of equality between the three angles of a 
triangle and two right angles, we must "find out 
some other angles, to which the three angles of a 
triangle have an equality; and finding these equal 
to two right ones, come to know their equality to 
two right ones."^ 

But though thus adopting Descartes* views as to 
the nature of rational science, Locke yet considers the 
demand that all truth be discovered by a deductive 
method to be impossible of realisation. A twofold 
method is necessitated by the difference between 
our knowledge of modes and our knowledge of 
substances.^ Take the abstract conception of a 

*IV. II. 1. 

2 IV. II. 2. Obviously Locke in this illustration regards 
mathematical knowledge as gained not from abstract con- 
ceptions, but from the construction of them in perception, the 
intermediate links being added as required. How this reconciles 
with his view of mathematical knowledge as purely conceptual, 
dealing with abstract ideas, it never occurred to Locke, any 
more than to Descartes, to inquire. 

3 Modes are those complex ideas which, however compounded, 
contain not in them the supposition of subsisting by them- 


triangle as a figure formed by the interseiction of 
three straight lines in space. The mind, Locke holds, 
needs not to call in experience, nor to go beyond 
the idea with which it starts, in order to discover 
innumerable new properties belonging to it. To 
the attentive mind it develops out spontaneously 
according to an inner logical necessity. That view 
of our knowledge of modes is the explanation of 
those statements in the Essay which sound so 
strangely in the mouth of Locke, the sensationalist. 
( "It is the contemplation of our own abstract ideas 
that alone is able to afford us general knowledge."^ 
"The true method of advancing knowledge is 
by considering our abstract ideas." ^ Quite other- 
wise is it with the conception of a substance, say 
of gold. As the simple ideas which make up this 
complex conception bear no relation to one another, 
it is barren and unproductive: the yellow colour, 
for instance, has nothing to do with its coldness to 
the touch, and no connection is visible between either 

selves, but are considered as dependencies on, or affections of, 
substances, e.g. the mathematical conception triangle,' and 
the ethical conception * gratitude.' The ideas of substances are 
such combinations of simple ideas as are taken to represent 
distinct particular things subsisting by themselves. 

^iv. II. 16. '^iv. XII. 7. 


of these qualities and its malleability. Whereas the 
conception of the triangle is an organic conception, all 
its properties presupposing one another, the complex 
idea of gold is but a cluster of disconnected sensations. 
This diflerence Locke further unfolds by his dis- 
tinction between nominal and real essence. While 
the nominal essence of a thing consists only of the 
sum of the external characteristics, whereby we 
identify it, the real essence contains the primary and 
fundamental qualities from which all the others 
result. Now in the case of modes the nominal and 
the real essence are always the same. From the 
conception of a triangle, as a space enclosed by three 
straight lines, all its other properties can be directly 
deduced. As a real essence the conception is the 
cause and ground of each and every one of them. 
In exactly the same way Locke conceives substance. 
He did not hold as we do now that each substance 
is in its peculiar nature constituted by the relations in 
which it stands to other substances. Influenced by 
that same doctrine of essence that clung, as we have 
seen, to the thinking of Descartes, the fundamental 
category through which Locke regards nature is* not 
that of causality, but that of substance. Locke asks, 
not for a cause of becoming, but for a cause of being, 


the unchanging ground of the unchanging nature of 
the thing. Each material substance is regarded as 
having a real essence quite as much as any mathe- 
matical construction.^ Did we know the real essence 
of gold "it would be no more necessary that gold 
should exist, and that we should make experiments 
upon it than it is necessary for the knowing the 
properties of a triangle, that a triangle should 
exist in any matter; the idea in our minds 
would serve for the one as well as the other." ^ 

^ It is true that no one could be more emphatic than Locke 
himself in stating the objections to such a view. " Put a piece 
of gold anywhere by itself, separate from the reach and 
influence of all other bodies, it will immediately lose all colour 
and weight, and perhaps malleableness too : which, for 
aught I know, would be changed into a perfect friability. 
Water, in which to us fluidity is an essential quality, left to 
itself, would cease to be fluid" (iv. vi. 11). Yet these facts 
do not lead him to discard the view of things as separate 
substances each with an essence peculiar to it, but only to 
reinforce in his mind the hopelessness of ever getting to know 
the real essences upon which the purely intrinsic qualities as 
well as these powers of producing effects on neighbouring 
bodies depend. For he concludes in the immediately following 
paragraph : " If this be so it is not to be wondered that we 
have very imperfect ideas of substances ; and that the real 
essences on which depend their properties knd operations are 
unknown to us." Cf. iii. vi. 6: — " [The real essence is] that 
particular constitution which everything has within itself, 
without any relation to anything without it." 

2lV. VI. 11. 


It is because we are ignorant of this inner essence 
that we are incapable of discovering the necessary 
connection which exists between the different sensible 
qualities, or of deducing from them any quality 
that we have not experienced to coexist with 

The same distinction Locke expresses in yet 
another way, which brings out the difference in 
the universality of the knowledge which each yields. 
The idea of the triangle is not only a real essence, 
revealing necessary connection between its different 
properties, but also an archetype formed by the 
mind for its own use, and hence yields an unfailing 
test of the universality of ideal judgments. It 
enables us to distinguish in any concrete image 
between the properties that follow from the par- 
ticular length of its sides and the size of its 
angles, and those which, as involved in, and follow- 
ing from, the archetype of all triangles, hold with 
complete universality. Of substances, on the other 
hand, the archetype exists without us, and is un- 
known, and hence in their case we can have no 
such criterion whereby to distinguish accidental from 
real connection. It is with our knowledge of 
substances as it would be with our mathematical 


knowledge, if the mind possessed only particular 
concrete images and not also the conception of the 
ideal which is but imperfectly realised in any one 
of them. Each proposition would hold of the 
particular triangle from which it was taken, but no 
further. In the case of substances we are reduced 
for increase of knowledge to induction, and to an 
induction that is always precarious and uncertain. 

Thus, then, while in mathematical science all 
knowledge develops from within, from contempla- 
tion of our abstract ideas, in physical science all 
knowledge develops from without, through the senses. 
In the one our method is purely deductive ; in the 
other purely inductive. 

The criticism to be made of this position is that 
when Locke asks the all-important question — Wherein 
lies the cause of this difiference between our know- 
ledge of modes and our knowledge of substances ? — 
he has no other answer to give than the fanciful 
rationalistic one, that there must be real essences 
in the case of substances as well as of modes, and 
that the discovery of these would render all know- 
ledge equally certain and equally rational. Had 
Locke been able to free himself from this false 
rationalism, and instead of interpreting the facts 


through a fanciful theory, asked how any real 
essence can have this strange power of yielding 
new and certain knowledge, he would have found 
that this peculiar characteristic of our ideas of 
modes ^ depends on the nature of space and time, 
and a thorough analysis of space and time is the 
proof of the incompleteness of his theory of sensa- 
tions as all simple and relationless. That theory 
is true to the facts so long as we have in view 
solely the unbridgeable qualitative differences between 
our special sensations, but it ignores, and leaves 
unaccounted for, the spatial and temporal connec- 
tions, as well as the categories of substance and 
attribute, cause and effect, whereby they are all 
bound together in organic connection one with 
another. Locke's Cartesian theory of mathematical 
reasoning as purely conceptual and deductive is 
false, while his Baconian theory of physical reasoning 
as purely inductive is incomplete. Still, though 
Locke's theory of both is thus unsatisfactory, and 
though he misinterprets both in the light of an 
inherited rationalism, it is his merit that he so 
dwelt on the difference between them, as to force 

^ Locke adds moral conceptions to the number of the modes, 
but the discussion of that addition lies outside our inquiry. . 


the problem of their relation on the attention of 
his successors. 

If we now follow him in his further analysis 
of our empirical knowledge we shall see how his 
empiricism strangely dwindles, until it almost dis- 
appears. To the question, — Can experience afiford 
us universal propositions such as this, that *all 
gold is malleable ' ? — Locke is forced to reply in the 
negative. All that experience shows is that in 
the particular bits of gold, which we examine, 
malleability goes along with the other properties 
by which we identify gold; but as it reveals no 
necessary connection between malleability and the 
other properties, it can give us no ground whatsoever 
for asserting that they will coexist in all other 
bits of gold which we may care to examine in the 
future. "General certainty is never to be found 
but in our ideas. Whenever we go to seek it 
elsewhere in experiment or observations without 
us, our knowledge goes not beyond particulars. It 
is the contemplation of our own abstract ideas that 
alone is able to afiford us general knowledge."^ 

Locke's position here is open to misunderstanding. 
It will be objected that it is nonsense to say that- 

1 Essayy iv. vi. 16. 


it is only probable that all men will die or that 
the sun will rise to-morrow. Gold always does 
act in the same way, and therefore the possibility 
of its not doing so in the future is not worth 
attending to. But that is not the point. Locke 
is not doubtful as to the practical certainty of many 
generalisations from experience. The distinction, 
which he wishes to make, lies not between cer- 
tainty and probability, but between demonstrative 
certainty and empirical certainty, the difiference in 
kind between empirical and conceptual knowledge. 
In the case of connections between ideas it is im- 
possible to conceive the opposite ; the nature of 

each idea related involves within itself its relation 


to the other, and to change the relation would be 
to change the nature of the ideas related. In 
the case of matters of fact no connection can 
be perceived between subject and predicate save 
only that of cle facto conjunction in our experience, 
and the opposite is quite conceivable. Hence the 
defect in our empirical knowledge is not that we 
cannot tell whether the connection asserted will 
remain the same in all future cases, but that we 
can never discover by experience, however extensive, 
any connection at all between them. 


Yet Locke remains so much under Descartes' 
influence that he goes to the extreme of holding 
that this empirical knowledge is not entitled to the 
name of knowledge at all, and that sense-experience 
can perform no function in scientific knowledge. 
The only hope for natural science lies in its assimi- 
lation to mathematics by discovery of .the real 
essences of substances. This hankering after a 
knowledge of the real essences of bodies comes out 
again and again in the Essay. "The essence of a 
triangle lies in a very little compass, consists in a 
very few ideas; three lines, including a space, make 
up that essence. ... So I imagine it is in sub- 
stances, their real essences lie in a little compass, 
though the properties flowing from that internal 
constitution are endless."^ "In the knowledge of 
bodies, we must be content to glean what we can 
from particular experiments ; since we cannot, from 
a discovery of their real essences, grasp at a time 
whole sheaves, and in bundles comprehend the nature 
and the properties of whole species together."^ 

Here the ambiguity in Locke's doctrine of sub- 
stance, according to which at one time substance is 

1 II. XXXII. 24. 

2 IV. XII. 12. Cf. IV. VI. 11, already quoted on p. 204. 


identified with the primary qualities, and at another 
taken as something wholly unknown behind them, 
is again apparent. For the most part, throughout 
the fourth book of the Essay y substance is identified 
with the primary qualities, and by knowledge of 
the real essence of body, he means knowledge of 
those modifications in the primary qualities upon 
which the secondary qualities and powers depend. 
Thereby the qualitative element in experience would 
be subjected to the mathematical method, and all 
the various facts of experience could be deduced 
from the ultimate constitution of bodies. 

But that is impossible, Locke finds, for three 
reasons. First, because we do not know that con- 
stitution of the minute parts on which all the other 
qualities depend : and secondly, because even if we 
did, we would not be able to perceive any connection 
between it and the sensations which the body pro- 
duces in us. Primary and secondary qualities are 
not related as substance to its properties, but as 
cause to effect, the two being quite heterogeneous. 
Also, thirdly, we cannot even assert, Locke admits, 
that the secondary qualities do depend upon the 
primary: the real essence may lie deeper in "some- 
thing yet more remote from our comprehension." 


According to his doctrine of substance in the second 
book of the Essay, he ought to have said, not that 
they may, but that they do depend upon something 
more remote than the primary qualities. The primary 
qualities are themselves effects, and therefore may 
not at all resemble their causes. 

For these three reasons, therefore, anyone of 
which is by itself sufficient, we cannot apply the 
mathematical method in natural science ; and hence 
Locke 'suspects* that a science of nature is not 
possible. Falling himself into the error of Descartes, 
he seeks entirely to exclude the empirical element, 
and to make science purely rational and deductive. 
For Locke, as for Descartes, mathematical reasoning, 
falsely interpreted, remains the ideal of knowledge. 
Empirical knowledge when compared with this ideal 
is condemned in every respect. 

Considering now, in conclusion, Locke's philosophy 
as a whole, we see how his theory of mathematical 
knowledge is borrowed from Descartes and incor- 
porated practically without change into his sensa- 
tionalism. He was of course forced by his 
sensationalistic starting-point to assert that ultimately 
all our mathematical conceptions are derived from 
experience, but how that is possible he nowhere 


explains in any satisfactory way, his treatment of 
space and time being among the least consistent parts 
of a very inconsistent system. Yet we are not 
justified in regarding Locke's theory of mathematical 
reasoning as brought externally, as an altogether 
foreign element, into his system. Good grounds can be 
given for taking up exactly the opposite attitude and 
regarding Locke as a rationalist, and his sensationalism 
as but externally tagged on to his rationalism. These 
grounds are his spiritualistic view of mind as an 
active agent combining and comparing ideas ; his 
belief in the absolute certainty and intuitive evidence 
of mathematical truths ; his use of mathematical 
knowledge throughout the Essay as the ideal of 
all scientific knowledge, and the standard whereby 
empirical knowledge is condemned and found wanting; 
and, lastly, his suggestion that by a conceivable, though 
not practicable, extension of our knowledge (by the 
discovery of the real essences of substances) our 
sensations would cease to be all relationless, and would 
appear as necessarily bound up one with another, and 
so as capable of rational deduction from one another. 
In that last position Locke shows himself to be 
a more complete rationalist than even Descartes, who 
despaired of the possibility of thus rationalising the 


sensible. But as all that is really fruitful in Locke 
is due to his empiricism, and as nearly all these 
rationalistic elements are survivals weak in their 
falsity, it is perhaps more charitable still to call 
him a sensationalist. 




Hume's achievement is, we shall try to show, two- 
fold. In the first place, by his analysis of the causal 
relation he refutes the fundamental assumption 
involved in the Cartesian rationalism, viz., its identifi- 
cation of causation with explanation. And, in the 
second place, by his complementary analysis of mental 
activity he demonstrates the illusoriness of that 
spiritualism by which Descartes and his successors 
seek to conceal the radical defects in their teaching. 

^ How much of the Cartesian system remains when its 

spiritualism and its rationalism are thus excised, and 
what effect these remaining doctrines have on Hume's 

j own thinking, we shall then decide. 


f We shall best lead up to Hume's criticism by first 

'^ considering the position of Berkeley. Berkeley's 



endeavour is to reconcile the teaching of philosophers, 
that the only possible object of mind is an idea, with 
the belief of the vulgar, that the mind immediately 
perceives the real things. " I do not pretend to be 
a setter-up of new notions. My endeavours tend only 
to unite and place in a clearer light that truth which 
was before shared between the vulgar and the 
philosophers . . . the former being of opinion that 
those things they immediately 'perceive are the real things^ 
and the latter that the things immediately perceived 
are ideas which eodst only in the mind. Which two 
notions put together do, in effect, constitute the 
substance of what I advance."^ This reconciliation 
Berkeley claims to have achieved by his assertion that 
perceived ideas are the real. Nothing exists but 
minds and their ideas. 

That position is specially significant for us as being 
the outcome of a consistent development of Descartes' 
principles. Descartes* three fundamental principles, 
viz., his doctrine of representative perception, his 
spiritualism, and his rationalistic view of causation, all 
combine to compel its acceptance. An immediate 
consequence of the doctrine of representative per- 

^The Third Dialogue between Hylas and Philonous : at 
an end. 


ception, recognised by Descartes himself, is that 
though the whole material world were annihilated, 
provided sensations were still produced in our minds 
in the same orderly manner as now, we should never 
suspect that such an important event had taken place. 
The doctrine of representative perception detaches the 
mind from the material world. Though we may infer, 
we can never perceive its existence. 

Secondly, if by a cause we mean that from which the 
efiect can be deduced, and through which it can be ren- 
dered comprehensible, material bodies must be admitted 
to be €U3 inefficacious as they are invisible. Just as 
they cannot be perceived, so neither can they cause 
perceptions. If the material world exists, it is an 
addition to the sum of creation that, so far as man is 
concerned, is altogether superfluous. It can fulfil no 
function that will justify its existence. It uselessly 
mirrors in shadowy projection, without the bright 
variety of sensuous appearance, what takes place quite 
independently in the minds of men. As incapable of 
ordering itself as of producing sensations, it demands 
continuous divine intervention for the transmission of 
motion, and so serves only to increase twofold the 
labours of God. By abolishing this superfluous 
material world Berkeley simplifies and develops the 


occasionalist theory. As spirit is the sole conceivable 
cause, so also it is the sole possible form of existence ; 
and ideas are its states. 

Like the occasionalists, Berkeley bases his system 
upon the principle of causality, assumed to be a self- 
evident truth. That principle he interprets as 
meaning that every idea is produced by a will.^ The 
only intelligible causation is creation.^ God produces 
in our minds from moment to moment the various 
sensations that constitute for us the real world in 
space. And creation out of nothing is the prerogative 
of finite as well as of infinite spirit.^ When we call 
up this or that idea we recreate it, painting it anew, 
as Locke says, upon the mind. It is no more than 
a fiat of the will, and it is done. Similarly the finite 
spirit is capable of creating its own desires, and upon 
these desires God produces new sensations in it and 
other minds. 

From this conception of spirit Berkeley also gains 
an explanation of our knowledge of relations.* Ee- 

^ Commonplace Book (Fraser's edition), p. 462. 

2 Which is also the central principle of the metaphysics of 

3 Commonplace Book, loc. cit. 

* " All relations including an act of the miud, we cannot so 
properly be said to have an idea, but rather a notion of the 
relations and habitudes between things,'' PHnciples^ sec. 142. 

Hume's criticism of cartesian principles 219 

cognising the very obvious fact that relations cannot 
exist between ideas that, following Locke, he has 
described as all simple and relatiojiless, he regards 
them as superinduced upon the ideas by the activities 
of the occult mind behind them. The impossible 
thus being made possible, they are apprehended 
(though not known) through * notions/ ^ 

Berkeley's system is thus the most absolute 
spiritualism and occasionalism conceivable. An 
occult self, supposed to lie behind our ideas, observ- 
ing and comparing them, is brought in to solve the 
difficulties arising from his atomistic sensationalism, 
and an infinite mind to solve all the difficulties that 

That Berkeley took little trouble to establish the 
reality or to define the nature of spiritual substance 
need not be found surprising, since this spiritualism 

^Berkeley also uses the term * notion' to signify the conscious- 
ness, distinct from knowledge proper, through which we appre- 
hend the self as an active agent. In this way, by what is on his 
principles a quite unmeaning term, he was able to keep out of 
sight the fact that the self is a hypothetical existence, assumed 
in order to account for what would otherwise be unaccountable 
in our experience, and that it is therefore on the same basis 
as material substance, requiring for its conception all those 
abstract notions that he has denounced as unintelligible. 

2 Just as spirit is introduced by Descartes and Leibniz to 
solve the difficulties of their atomistic conceptualism. 


existed complete, though latent, in Descartes and 
Locke. After Berkeley's negative criticism of them, 
it simply remains as his one valuable inheritance 
from their philosophies. Now, however, that it has 
thus in Berkeley shown itself in its true colours, it 
is clamant for the criticism of Hume. Certainly, if 
we suppose spirit to be capable from its very nature 
of doing all the things demanded of it by Berkeley, 
capable when infinite of creating sensations, and 
when finite of creating images, the effects will be 
explained, but it will be the illusory explanation by 
the occult. 

Just because of that false view of spirit Berkeley's 
attitude towards the ' external ' world is also quite 
untenable.^ So long as the self is regarded as a 
particular finite existence, distinct from all other 
selves, the bringing of reality within it is impossible, 
and is really the direct opposite of the position of 
ordinary consciousness. For it is by no chance that 
Berkeley calls the known objects ideas. He may 
insist that they are also the realities which all 
people believe in ; they are yet ' realities ' that exist 

^ With the most valuable parts of Berkeley's teaching, viz., 
his analysis of sense-perception and development of empiricism, 
we are not here concerned. 

Hume's criticism of cartesian principles 221 

separately, numerically and existentially distinct, in 
the mind of each person perceiving them.i They 
are created anew by God in the mind of each 
observer, and pass into nothingness when that 
individual ceases to observe them. Also, though 
Berkeley insists that mind knowing and ideas known 
are inseparable in their antithesis, practically all the 
reality is given to mind. It is not the sensations 
that constitute the real, but infinite spirit, on the 
one hand, that creates them from moment to 
moment, and the finite spirits, on the other, in 
which they are thus given a momentary existence. 
He adopts the extreme occasionalist position. There 
are as many different worlds as there are minds, and 
the only connection between these completely isolated 
minds is through the external agency of a miraculously 
acting Deity .2 

^Berkeley's frequently attempted denial of this is nothing 
better than a mystification of his readers. Cf. Dialogues, iii. 
(Fraser's edition), i. pp. 343-4. 

^The real problem is not whether, when ideas are con- 
ceived as the objects of mind, a second kind of objects is also 
necessary — in his answer to that question^ Berkeley may be in 
the right — but whether such subjective ideas have any reality. 
That Berkeley never thought of asking that last' question is the 
proof that he has not been able to free himself from the physio- 
logical point of view which he attacks. For only the assumption 
of the truth of that point of view (cf. below, note 3 to p. 249) could 


We may now pass to Hume's criticism of the 
Cartesian principles. In attacking the Cartesian 
identification of causation with explanation, Hume 
throughout emphasises the time-aspect of the causal 
relation.^ As there is no necessary connection or 
inseparability (and this must be admitted by all) 

have driven his predecessors to the conclusion, which he shares 
with them, that knowledge is a purely subjective process in the 
mind of the individual. The physiological point of view may, 
or may not, be an impossible one for the explanation of know- 
ledge, but there is no question that it cannot be overthrown by 
arguments that tacitly assume its truth. In a word, Berkeley's 
idealism can offer good grounds for itself, if we grant the doctrine 
of representative perception. That doctrine, however, Berkeley 
does not prove, but assumes ; and it rests on those very grounds 
which Berkeley rejects. 

* Berkeley had already denounced the Cartesian doctrine of 
essence, " the current opinion that everything includes within 
itself the cause of its properties ; or that there is in each object 
an inward essence which is the source whence its discernible 
qualities flow, and whereon they depend ." Of the existence of 
such substances we have no proof, and of their nature we can 
form no conception. The only conceivable objects of mind are 
disconnected sensations, each of which (such as in an orange, 
the colour yellow, or the sensation sweet) is a unit complete in 
itself. The separate sensations are not qualities of, but units 
constituting, the clusters or * things' to which they belong. 
And the relation of substance and quality being thus eliminated 
by Berkeley, the category of causality became all-important 
both in his own and in Hume's system. Berkeley also prepared 
the way for Hume's view of causation by his contention that 
sensations can never be necessary causes, but only arbitrary 
signs one of another. 

Hume's criticism of cartesian principles 223 

between the idea of an event as something happening 
in time and the idea of a cause, Descartes' assertion 
that the principle of causality is a self-evident truth 
of reason must be categorically denied. Since what 
we call cause and effect are always distinct events, 
each of which is known separately in a single 
impression, they can always be thought apart without 
contradiction.^ Hume's contention is implicitly re- 
cognised by those philosophers who have offered 
demonstrations of the principle — demonstrations which, 
as Hume found, are all fallacious and sophistical. 
Hobbes argues that ,as all the points of time and 
space, in which we can suppose any object to exist, 
are in themselves equal, unless there be some* cause, 
which is peculiar to one time and to one place, and 
which by that means determines and fixes the 
existence, it must remain in eternal suspense ; and 
can never begin to be for want of something to fix 
its beginning. To which argument Hume has the 
unanswerable reply : " Is there any more difficulty in 

^We may note, in passing, that the final value of Hume's 
analysis of the causal relation is seriously affected by the 
dogmatic psychological atomism upon which it is made to rest. 
In describing causal connection as merely sequence, even though 
it be invariable sequence, he ignores — to mention only one 
factor — the continuity of time. 


supposing the time and place to be fixed without a 
cause, than to suppose the existence to be determined 
in that manner? ... If the removal of a cause 
be intuitively absurd in the one case, it must be so 
in the other: and if that absurdity be not clear 
without a proof in the one case, it will equally require 
one in the other. The absurdity, then, of the one 
supposition can never be a proof of that of the other ; 
since they are both , upon the same footing, and must 
stand or fall by the same reasoning." ^ 

The argument of Clarke is that if , anything 
wanted a cause, it would produce itself \ that is, 
exist before it existed ; which is impossible. And 
in a similar fashion Locke argues that if anything 
is produced without a cause, it is produced by 
nothing, or, in other words, has nothing for its 
cause, which is absurd, since nothing can never be 
a cause, any more than it can be something or 
equal to two right angles. Now both these argu- 
ments are, Hume holds, plainly inconclusive, and, 
like that of Hobbes, assume the principle which 
they pretend to establish. " When we exclude all 
causes we really do exclude them, and neither 
suppose nothing nor the object itself to be the 

1 Treatise, i. in. in. pp. 381-2. 

Hume's criticism of cartesian principles 225 

causes of the existence ; and consequently can draw 
no argument from the absurdity of these supposi- 
tions to prove the absurdity of that exclusion."* 

The remaining argument, that every effect must 
have a cause, because that is implied in the very 
idea of effect, is merely verbal. "Every effect 
necessarily presupposes a cause ; effect being a 
relative term, of which cause is the correlative. 
But this does not prove that every being must be 
preceded by a cause; no more than it follows, 
because every husband must have a wife, that 
therefore every man must be married." ^ 

The universal principle is, then, not demonstrable 
by reason. That the mind instinctively frames its 
demands in accordance with it, and that until these 
demands are fulfilled, the mind remains intellec- 
tually dissatisfied, Hume is not concerned to deny.^ 
He maintains only that if the principle is thus 
neither self-evident nor demonstrable by reason, such 
dissatisfaction, even though inspired by the principle, 
cannot be regarded as proving its validity. 

^ Treatise^ loc, cit. p. 383. ^Ibid. 

^ Hume himself traces this instinctive demand to the ultimate 
constitution of our human nature. Expressing only the practical 
demands of our human nature, it affords no knowledge of reality 
either within or without the limits of experience. 



Beason as little avails to prove the necessity of 
the causal connection between particular events. 
Dwelling on what Malebranche, Locke, and Berkeley 
had already made clear, Hume shows how never in 
a single case can we by a priori reasoning discover 
in our idea of a cause any capacity to produce a 
particular effect.^ Every efifect, without exception, 
is a distinct event from its cause, and hence can 
never by reason be discovered in it^ But if 
reason here comes short, so also does sense-experi- 
ence, since from it we can never extract one jot of 
evidence in support of our belief in necessary con- 
nection. Though that was admitted of all material 
processes by Locke and Berkeley, they had yet 

*Cf. Enqmry, sec. iv. pt. i. pp. 26-6 : "We fancy that were 
we brought on a sudden into this world we could at first have 
inferred that one billiard ball would communicate motion to 
another upon impulse ; and that we needed not to have waited 
for the event, in order to pronounce with certainty upon it. 
Such is the influence of custom, that, where it is strongest, it 
not only covers our natural ignorance, but even conceals itself, 
and seems not to take place, merely because it is found in the 
highest degree." 

^Here again Hume's atomistic sensationalism affects the 
statement of his argument. Whereas Locke had rightly limited 
himself to the assertion that /or tis, owing to the incompleteness of 
our knowledge^ the connection between cause and effect is in- 
comprehensible, Hume frequently seems to imply that the 
actual relation of causation consists of nothing but mere 
sequence, and i« therefore in itself necesasLrily incomprehensible. 

Hume's criticism of cartesian principles 227 

held that we are conscious of internal power,^ 
when by the simple command of our will we move 
our limbs, or call up an idea. Apprehending in 
that way what causal agency is, we are able, they 
believed, to infer to it elsewhere. Now certainly 
the motion of our limbs follows upon the command 
of our will. Of that we are every moment conscious. 
But of the means by which it is effected, of the 
energy by which the will performs so extraordinary 
an operation, we are very far from being conscious, 
and must indeed admit the causal agency to be 
here, even more than elsewhere, unknown and in- 
conceivable. The connection between the volition 
in the mind and the movement in the body, 
instead of being the key to all other causal con- 
nections, is what most calls for explanation. "Were 
we empowered by a secret wish to remove moun- 
tains or control the planets in their orbit, this 
extensive authority would not be more extraordinary 
nor more beyond our comprehension."^ 

* Cf. Locke's Essay, ii. xxi. sees. 4 and 5. 

2 Enquiry, sec. vii. pt. i. p. 54 : Geuliucx {Ethica, Tract i. 
chap. II, sec. ii. § 14) similarly asserts that it is no less 
miraculous that upon the command of my will, when I seek to 
pronounce the word earth, the tongue in my mouth should 
tremble, than if the whole earth had thereupon trembled. Cf . 
Malebranche : MMUations, ix. pp. 111-3. 


Nor can we pretend to be acquainted with any 
power in the soul by which it is able to produce 
an idea at will. That would be "a real creation, a 
production of something out of nothing."^ " So far 
from being conscious of this energy in the will, it 
requires as certain experience, as that of which we 
are possessed, to convince us, that such extraordinary 
effects do ever result from a simple act of volition."^ 
As Malebranche points out, such creation is not 
even conceivable. "I deny that my will produces 
in me my ideas; for I cannot even conceive how 
it could produce them, since my will, not being 
able to act or will without knowledge, presupposes 
my ideas and does not make them."* "Is there 
not here," Hume asks, "either in a spiritual or 
material substance, or both, some secret mechanism 
or structure of parts, upon which the effect depends, 
and which, being entirely unknown to us, renders 
the power or energy of the will equally unknown 
and incomprehensible ? "* Or as Hume in accord- 
ance with his theory of association might have gone 

* Enquiry, loc, ctt. p. 56. ^ Enquiry, loc. cit. p. 57. 

^ Eclaircissemeiit sur chap. in. pt. ii. liv, vt. de la Recherche. 
As Malebranche adds, the mind does not even * create' its 

* Enquiry, loc, cit p. 57. 



on to explain, the mind produces no ideas; it is 
the ideas in consciousness that by virtue of their 
mysterious associative quality, themselves attract 
others into consciousness; and as this associative 
quality is as unknown in its workings, and as in- 
comprehensible, as the force of gravity between 
material particles, we must admit that causal agency 
is not known in the mental any more than in the 
material world. 

It has frequently been asserted that Hume in 
his theory of causation in no way advanced beyond 
the occasionalists, or at least not beyond Malebranche 
and Berkeley. The falsity of such a view is suf- 
ficiently indicated by the criticisms which Hume, 
in accordance with his new views, is compelled to 
make of the occasionalist system.^ It is the 
occasionalists, he shows, who are the most flagrant 
of all offenders in making use of the idea of 
causation as if it represented something positive and 
conceivable. Eesorting on all occasions to a creative 
intelligence, they use it unrestrainedly to explain 
anything and everything, as in its occult indefinite- 
ness it is only too well fitted to do. They assume 
that we gain in immediate experience knowledge of 

^ We shall have more to say on this point. Cf. below, pp. 241-5. 



the self as an active agent, and conceiving God on 
the analogy of the self, they ascribe to Him all 
those effects of which the self is found to be in- 
capable. They differ among themselves only in the 
division they make of power between the self and 
God. Berkeley regards the self as creative with 
regard to its images, God as creative in all else; 
whereas Malebranche goes so far as to deny eflScacy 
to any of our volitions, and regards God as the 
cause of our ideas, as well as of our sensations and 
of the motions of our limbs. And if we try to 
estimate which is the more unsatisfactory position 
of the two, it is hard to decide. Malebranche has 
the virtue of siding with Hume and the facts in 
his denial of all creative power to the self; but 
since knowledge of spirit as endowed with creative 
power is only to be derived from the self, he just 
thereby renders his theology the weaker.^ Descartes 
applied the principle of causality to connect the uncon- 
nectable soul and body, and also to connect God with 
the self and with the world. The first application of 
the principle easily yielded to criticism, but it was 
Hume who first saw that exactly the same criticism 
holds with still greater force against the asserted relation 

^Cf. below, note 2 to p. 241. 

Hume's criticism of cartesian principles 231 

of God to the self and to the world. We only 
deceive ourselves when we pretend to explain any- 
thing, not to speak of everything, by a God that 
is a magnified projection of an occult self. 

Since Hume by his analysis of that spiritualism 
whose influence we have traced in Malebranche, 
Leibniz, Locke, and Berkeley, reveals the ungrounded 
nature of Descartes' view of the self as a substance 
distinct from its experiences, and of the comple- 
mentary view of God as a separate existence, the 
cause and creator of all else, we may proceed to 
consider his arguments in detail. The self is only 
to be found in the organised unity of its concrete 
experiences, and not in a substance behind them.-^ 

^ The self is not simple and indestructible, but infinitely com- 
plex and continuously changing. It is in order to emphasise 
against Descartes and his followers this fact of the complexity 
and changeableness of the self that Hume asserts that it is 
"nothing but a bundle or collection of different perceptions, 
which succeed each other with an inconceivable rapidity, and 
are in a perpetual flux and movement. Our eyes cannot turn 
in their sockets without varying our perceptions. Our thought 
is still more variable than our sight ; and all our other senses 
and faculties contribute to this change, nor is there any single 
power of the soul, which remaius unalterably the same, perhaps 
for one moment. The mind is a kind of theatre, where several 
perceptions successively make their appearance ; pass, re-pass, 
glide away, and mingle in an infinite variety of postures and 
situations. There is properly no simplicity in it at one time. 


" I cannot compare the soul more properly to any- 
thing than to a republic or commonwealth, in which 
the several members are united by the reciprocal 
ties of government and subordination, and give rise 
to other persons, who propagate the same republic 
in the incessant changes of its parts. And as the 
same individual republic may not only change its 
members, but also its laws and constitutions ; in like 
manner the same person may vary his character 
and disposition, as well as his impressions and ideas, 
without losing his identity. Whatever changes he 
endures, his several parts are still connected by the 
relation of causation.^ And in this view our identity 
with regard to the passions serves to corroborate 

nor xdcTUity in different ; whatever natural propension we have 
to imagine that simplicity and identity. The comparison of the 
theatre must not mislead us. They are the successive per- 
ceptions only that constitute the mind ; nor have we the most 
distant notion of the place, where these scenes are represented, 
or of the materials of which it is composed" {Treatue, i. iv. vi. 
pp. 534-5). Hume's analysis of the self has often been very 
unfairly treated by being considered only in relation to the 
later views of Kant. It ought rather to be interpreted in the 
light of his opposition to the views of his predecessors and 
contemporaries. When Hume's arguments are so regarded, it 
must be admitted that, whatever error his own views contain, 
he is altogether in the right against Descartes, and is really 
working towards the position of Kant. 

^ It must be borne in mind that Hume maintains his right to 
speak of events as ' causally ' connected. Cf . below, pp. 242-3. 

Hume's criticism of cartesian principles 233 

that with regard to the imagination, by the making 
our distant perceptions influence each other, and by 
giving us a present concern for our past or future 
pains or pleasures."^ The theory, that ideas may 
be explained as the modes of a simple substance, 
refutes itself, as explanation by the occult always 
does, when more universally applied. There are, 
Hume points out,^ two systems of things, the real 
and the ideal, that demand explanation. In the 
real world there exist the sun, moon, and stars ; 
the earth, seas, plants, animals, men, ships, houses, 
etc. These, Spinoza asserts, must all be regarded 
as only modifications inhering in a simple, uncom- 
pounded, and indivisible substance.^ Similarly, Hume 
proceeds, in the ideal world, viz., the universe of 
my mind, I observe another sun, moon, and stars, an 
earth, seas, towns, houses, etc. ; and in short every- 
thing that I can discover or conceive in the first 
system. These, according to the theologians (among 
whom must be counted Descartes and his followers), 
are also modifications, and modifications of one 

* Treatise^ i. iv. vi. p. 542. ^Ihid, i. iv. v. p. 525 flf. 

^This statement, it need hardly be pointed out, is not quite 
fair to Spinoza. That, however, does not really aflfect Hume's 
argument. The Cartesians certainly take an abstract, not a 
concrete, view of the unity and simplicity of the self. 


simple, uncompounded, indivisible substance. Now 
is it possible to discover any absurdity in the one 
hypothesis that is not common to both ; and if the 
Spinozistic hypothesis fails to advance our compre- 
hension of the material a single step, must not the 
same admission be made as regards the spiritualistic 
interpretation of knowledge ? 

If instead of calling thought a modification we 
give it * the more antient and yet more modish 
name of an action ' nothing whatsoever is gained 
by the change. As we know only ideas, and have 
no conception either of a mind that is distinct from 
them, or of action in any form, to call the ideas 
actions of the mind is both meaningless and useless. 
Also, since the theologians cannot pretend to make 
a monopoly of the word action, the 'atheists' may 
"likewise take possession of it, and aflSrm that 
plants, animals, men, etc., are nothing but particular 
actions of one simple universal substance, which 
exerts itself from a blind and absolute necessity. 
This you'll say is utterly absurd. I own 'tis un- 
intelligible ; but at the same time assert, according 
to the principles above-explained, that 'tis impossible 
to discover any absurdity in the supposition, that 
all the various objects in nature are actions of one 


simple substance, which absurdity will not be 
applicable to a like supposition concerning impressions 
and ideas." ^ And that being so, it goes without 
sajdng that the explanation of our knowledge of 
relations as due to the activity of a self that takes 
the different ideas out of their externality, and 
holding them together in its own indivisible unity 
observes their relations, must equally be rejected. 
We have no knowledge of any such abiding self 
behind our ideas, capable of observing them, nor 
can we form any conception of those activities that 
are here ascribed to it. 

Hume further analyses the notion of mental 
agency in his criticism of the argument from 
design.^ That argument rests, he points out, on 
the assumption that material bodies cannot give 
order and arrangement to themselves, and that in 
mind or reason alone is an organising principle to 
be found. Experience is appealed to. "Throw 

* Treatise, i. iv. v. pp. 528-9. 

2 It is the only general proof of God's existence unnoticed 
hy Descartes, and that for the obvious reason that it is 
irreconcilable with his elimination of all final causes from 
his physics. It became prominent in Leibniz. Spinoza's 
arguments against final causes are in many respects curiously 
analogous to those of Hume. Of. below, chap. iv. p. 140 and 
pp. 149-50. 


several pieces of steel together, without shape or 
form; thej will never arrange themselves so as to 
compose a watch ; stone, and mortar, and wood, 
without an architect, never erect a house. But 
the ideas in a human mind, we see, hj an un- 
known, inexplicable economy, arrange themselves so 
as to form the plan of a watch or house. Experience, 
therefore, proves, that there is an original principle 
of order in mind, not in matter. From similar effects 
we infer similar causes. The adjustment of means 
to ends is alike in the universe as in a machine 
of human contrivance. The causes, therefore, must 
be resembling.'*^ Admirable conclusion ! — ^until we 
reflect. No principle of order in matter ? What 
about the forces of attraction and repulsion, which 
we daily observe at work ? No organising principle 
save mind ? " In this little comer of the world 
alone, there are four principles, Reason, Instinct, 

^ Dialogues concerning Natural Religion, pt. ii. p. 395. These 
dialogues have been strangely neglected by Hume's com- 
mentators. And yet they represent the maturest results of 
Hume's thinking. They were repeatedly elaborated by him 
throughout a period of twenty-seven years. "The work, 
penned in the full vigour of his faculties, comes to us with 
the sanction of his mature years, and his approval when he 
was within sight of the grave " (Burton's Life of Hunie, 
I. p. 326). 

Hume's criticism of cartesian principles 237 

OcTieration, Vegetation^ which are similar to each 
other, and are the causes of similar effects. What 
a number of other principles may we naturally 
suppose in the immense extent, and variety of the 
universe, could we travel from planet to planet 
and from system to system, in order to examine 
each part of this mighty fabric?"^ A tree bestows 
order and organisation on that tree, which springs 
from it, an animal on its oflTspring, a bird on its 

To say, Hume further urges, that this order 
in animals and vegetables proceeds ultimately from 
design, is begging the question, unless it can be 
proved by a priori arguments, that order is in- 
separably attached to thought, and can never of 
itself belong to matter. Neither of these positions 
can, however, be established.^ The order into which 
our ideas fall ' of themselves ' is no more an ultimate 
fact than is the organisation of an animal or plant.^ 
The order in all three cases depends upon an 
inconceivably complex variety of causes. "Nothing 
seems more delicate with regard to its causes 
than thought. ... A difference of age, of the 

^ Dialogues^ pt. vii. pp. 422-3. ^ Ibid. p. 423. 

5 Cf . Dialogues, pt. viii. p. 430, quoted below in note to p. 239. 


disposition of his body, of weather, of food, of 
company, of books, of passions ; any of these 
particulars, or others more minute, are sufficient to 
alter the curious machinery of thought, and com- 
municate to it very difierent movements and 
operations. As far as we can judge, vegetables 
and animal bodies are not more delicate in their 
motionis, nor depend upon a greater variety or 
more curious adjustment of springs and principles."^ 
And just as we have experience of order alike in 
mind and in matter, so have we also of disorder 
in both, of madness in the one, and of corruption 
in the other. Why then should we think that order 
is more essential to the one than to the other ? So 
far as we can pretend to penetrate into the nature 
of mind, ideas tend to fall into order because they 
obey the laws of association, which correspond to 
the law of gravity between material particles. " But 
reason, in its internal fabric and structure, is really 
as little known to us as instinct or vegetation ; 
and perhaps even that vague, indeterminate word, 
Nature, to which the vulgar refer everything, is not 
at the bottom more inexplicable."^ 

The argument from design therefore assumes 
^Dialogues, pt. iv. p. 408. ^ Ibid. pt. vii. p. 423, 


everything in asserting that intelligence is known 
as a principle, and the sole principle, of order ; and 
when that assumption is detected, it becomes obvious 
that to explain the world as created is merely to 
push the problem further back, and that it is every 
whit as reasonable to * explain ' the world as having 
been generated, or as having grown from a seed. 
The Creator, in order to work intelligently and with 
design, must first have created a plan, but in order 
to create that plan intelligently, he must plan it 
also, and so on in infinitum.^ If it means any- 

* Hume's argument is an interesting inversion of the Platonic 
argument, used to prove the reality of an ideal archetypal 
world. Cf. Norris's Theory of the Ideal Worlds pt. i. pp. 27-9 : 
"Tho*, considering the power of its Almighty Author, 
[the world] was made out of nothing^ yet, considering his 
wisdom, it must be made according to something^ and he that 
raised this stately fabric without any praeexistent matter^ could 
not yet be conceived to do it without any praeexistent form or 
idea. For as he could not make it without forethinking of it) 
so neither could he think of it without having something to 
terminate that thought, which must be the nature or essence of 
the thing that was to be made. . . . Hence the sensible must be 
made according to some other prae-existent nature that was so 
essentially exhibitive and representative of it, as to be after 
the manner of an original pattern or model of it, as having all 
that intelligibly which itself has sensibly, which is no other 
than that ideal world we are contending for." Hume here shows 
how this argument cuts both ways. The real cause of its 
failure is that we can form no conception of ideas as archetypes 


thing to say that the dififerent ideas which compose 
the reason of the Supreme Being fall into order of 
themselves and by their own nature, why is it not 
as good sense to say that the parts of the material 
world faU into order of themselves, and by their 
own nature ? Can the one opinion be unintelligible 
when the other is not so ? It is, of course, replied 
. that what produces the order in the ideas of Ood 
"is a rational faculty, and that such is the nature 
of the Deity. But why a similar answer will not 
be equally satisfactory in accounting for the order 
of the world, without having recourse to any such 
intelligent creator, as you insist on, may be difficult 
to determine. It is only to say, that sv^ih is the 
nature of material objects, and they are all originally 
possessed of a faculty of order and proportion. 
These are only more learned and elaborate ways 
of confessing our ignorance; nor has the one 

preceding reality. The order of our ideas depends on experience ; 
and the assumed Creator, as there is nothing outside his mind, 
can have no such experience. Cf. Hume's Dialogues^ pt. viii. p. 
430 : " In all instances which we have ever seen, ideas are 
copied from real objects, and are ectypal not archetypal, to 
express myself in learned terms. You reverse this order, and 
give thought the precedence. In all instances which we 
have ever seen, thought has no influence over matter, except 
where the matter is so conjoined with it, so as to have an equal 
reciprocal influence upon it." 


hypothesis any real advantage above the other, except 
in its greater conformity to vulgar prejudices."^ 

With Hume's destruction of. the occult self, that 
is the ultimate source of all occult qualities, the 
occasionalist system of Descartes collapses like a house 
of cards. "I cannot perceive any force in the 
arguments on which this theory is founded. We 
are ignorant, it is true, of the manner in which 
bodies operate on each other : their force or energy 
is entirely incomprehensible. But are we not 
equally ignorant of the manner or force by which 
a mind, even the supreme mind, operates either 
on itself or on body ? . . . Is it more difl&cult to 
conceive that motion may arise from impulse than 
that it may arise from volition ? All we know is 
our profound ignorance in both cases." ^ A causal 

1 Dialogues^ pt. iv. pp. 409-10. 

^Enquiry, sec. viii. pt. i. pp. 59-60. Cf. Malebranch^, 
MSditationSy ix. p. Ill : " How stupid and ridiculous are the 
philosophers I TLey imagine that creation is impossible because 
they cannot conceive how the power of God can be sufficiently 
great to create something out of nothing. But can they 
conceive how God is capable of stirring a straw? If they 
attend thereto, they will find that they cannot comprehend the 
one more clearly than the other, since they have no clear idea 
of eflScacy or of power ; so that if they follow out their false 
principle, they should conclude that God is not even sufficiently 
powerful to give motion to matter. But this false conclusion 



explanation of things as due either to matter or to 
a divine infinite mind is equally illusory. We 
have no idea of what a sufl&cient cause would be 
like: certainly mind is as little as matter known 
to be the sufl&cient cause of anything. If, on the 
other hand, we are content to regard a cause merely 
as that which always precedes an eflPect, and never 
accounts for it, then, so far as our experience goes, 
only a mind that is united to a body can cause 
anything; and in this union matter has as much 
influence on mind, as mind on matter.^ Such causal 
interaction of soul and body is as conclusively proved 
by experience as any causal connection can be, 
and the denial of it is an instance to what arbitrary 
denial of the most evident facts the pretence of 
comprehending causal connection will lead philo- 
sophers. Matter and motion, it is argued, however 
varied, are still matter and motion, and can cause 
nothing but change in the position and situation of 
bodies; it is absurd to imagine that motion of 

would land them in opinions so foolish and so impious, that 
they would become an object of scorn and of indignation even 
to the most ignorant." Yet Malebranche declares God to be 
unknowable and incomprehensible alike in His nature and in all 
His ways, and so is himself in the end forced to the agnostic 
conclusion of Hume. 

^Cf. Dialogues concerning Natural Religion, pt. viii. p. 430. 

Hume's criticism of cartesian principles 243 

brain particles in one direction should be a passion, 
and in another direction should be a moral reflection.^ 
Irresistible as that argument may seem, we have 
only to recall the preceding reasoning to be reminded 
that so far as our insight goes anything may 
produce anything, and that though there appear 
no manner of connection between motion and thought, 
the case is the same with all other causes and 
effects. The connections, which Berkeley dogmatically 
names arbitrary, are in fact only incomprehensible. 
Locke was altogether in the right in asserting that 
incomprehensibility is no ground for denying the 
causal connection in either case. "This communica- 
tion of motion by thought ... is as evident as 
that by impulse. . . . Constant experience makes 
us sensible of both of these, though our narrow 
understandings can comprehend neither."^ 

For Descartes an effect is that which can be 
deduced with logical necessity from the notion of 
the cause. Like all the other Cartesians (and the 
occasionalists are not exceptions to the rule), he failed 
to see that since by an effect we mean that which 
follows in time upon its cause, or in other words that 

1 Treatise, i. iv. v. pp. 529-30. 

^ Essay, ii. xxiii. 28. Of. chap, on Locke, pp. 196-9. 


since the principle of causality is the law of change, 
such logical relation cannot possibly express its nature. 
As the logical relation is timeless, not only is it wrong 
to assert that where it is not to be found causal 
relation must be absent, we can on the contrary 
affirm that where it does hold the relation cannot be 
that which is properly denoted by the term ' causal.' ^ 
The first to perceive this was Hume; and from the 
conclusions which he thereby established far-reaching 
consequences follow. If causation, which is the bond 
connecting the phenomena of our time-experience, 
cannot be rationalised, the Cartesian rationalism, and 
therewith its spiritualism, must fall to the ground. 

An entirely new set of problems is, indeed, raised 
by Hume. If the principle of causality is neither 
self-evident nor demonstrable by reason, with what 
right does the mind interpret experience in the light 
of it ? Also if the mind can never form any concep- 
tion of what would be a cause adequate to produce an 
effect, how can it decide in particular cases that 
phenomena are so related ? By the former question 
Hume inspired Kant in the establishment of a 
rationalism that, unlike the scholastic rationalism of 
Descartes, is reconcilable with the facts of our time- 

^ Cf. above, chap. iv. note 2, to p. 147. 

Hume's criticism of cartesian principles 245 

experience; and by the latter question became the 
founder, in a much truer sense than Bacon, of the 
modem theory of induction. In both he transcends 
the rationalism of Descartes. 

Hume is here, we may say, introducing into meta- 
physics the point of view of physical science. The 
Cartesian identification of causal connection with 
logical dependence inevitably involves its further 
identification with the relation of substance and 
quality. The efiect, regarded as a logical consequence, 
must be a permanent quality of the substance that is 
its ground. And being thus dominated by the 
category of substance, Cartesian thinking results, as 
we have seen, either in an atomism or in an empty 
pantheism. Through Hume's analysis, however, the 
relative position of the two categories is inverted. 
Throughout modern thinking all qualities tend to be 
regarded as effects due to causal interaction between 
substances that apart from such relation are granted 
to be inconceivable. The centre of gravity is shifted 
from the separate things to the organised system in 
and through which they exist. This is the real 
meaning, or at least (thanks to Kant) the final out- 
come, of Hume*s analysis of causation and of spirit. 

So far we have merely been stating Hume's 


position, and may now pass to criticism of it He 
adopts Locke's view of the materials of knowledge 
as consisting of isolated atomic impressions ; but as 
he denies that we can form any conception of a self 
that might take such ideas out of their externality, 
and holding them together, thereupon perceive 
relations between them, he has to admit that he is 
incapable of accounting even for our consciousness of 
time. " All my hopes vanish, when I come to explain 
the principles, that unite our successive perceptions 
in our thought or consciousness. 'I cannot discover 
any theory, which gives me satisfaction on this head." ^ 
That admission must not, however, be taken as justi- 
fying the Cartesian view of the self. Bather we may 
hold that such a view of experience disproves itself 
in demanding as its indispensable complement the 
assumption of an occult self.^ Hume's false view of 

^ This confession occurs in the Appendix to vol. iii. of the 
original edition of the Treatise (i. p. 569 of the edition of Green 
and Grose). 

2 Though Kant was unacquainted with Hume's examination in 
the Treatise and in the Dialogues of the Cartesian spiritualism, 
he in the end developed, under the pressure of his own prin- 
ciples, views very similar to those of Hume. At first, however, 
his adoption of Hume's view of the materials of sense forced 
him to maintain the Cartesian view of the self as a separate 
existence, preceding knowledge and rendering it possible. Cf. 
b«low, chap. VII. pp. 260-2. 


experience, as consisting of atomic impressions, 
itself results from what was the really serious 
limitation to his thinking, namely his reten- 
tion of the fundamental Cartesian doctrine that 
knowledge is a purely subjective process, and that 
all we can ever know are our own subjective 
states. That that position is inconsistent with his 
general principles and with many of his explicit 
utterances, only shows how deep-rooted it was in his 
mind, and how completely unconscious he was of 
therein making assumptions. He starts oflf excellently. 
Though he retains from his predecessors the terms, 
impression, perception, and idea, to denote the objects 
known by us, they are, he insists, to be regarded as 
perfectly neutral terms. By ' ideas ' he does not 
mean, like Descartes, Locke, and Berkeley, the objects 
or modes of mind. As we can form no conception of 
a mind or subject, we cannot so view them. Nor are 
they ideas of objects, for that implies that there 
exist ideas and. objects, and such a duality of existence 
Hume demonstrates to rest on an illusion, and to be 
the error that gives rise to all the contradictions of the 
Cartesian dualism. Hence, instead of Hume's con- 
tention being that we know nothing but purely 
subjective states, it is rather that nothing subjective 


as distinguished from objective is conceivable by wL 
His true position, if only he had been able to maintain 
it, is, like that of Kant, phenomenalism, and not 
subjective idealism. 

Such an objective view of knowledge appears in 
the following passage. "As every perception is dis- ^^ 
tinguishable from another, and may be considered 
as separately existent ; it evidently follows, that Dhere 
is no absurdity in separating any particular percep- 
tion from the mind; that is, in breaking off sU its 
relations, with that connected mass of perceptions, 
which constitute a thinking being. The same reason- 
ing affords us an answer to the second question. If 
the name of perception renders not this separation from 
a mind absurd and contradictory, the name of object, 
standing for the very same thing, can never render 
their conjunction impossible. External objects are 
seen, and felt, and become present to the mind ; that 
is, they acquire such a relation to a connected heap of 
perceptions, as to influence them very considerably in 
augmenting their number by present reflections and 
passions, and in storing the memory with ideas. The 
same continued and uninterrupted Being may, there- 
fore, be sometimes present to the mind, and sometimes 
absent from it, without any real or essential change in 


the Being itself." ^ That view is, however, only 
stated in order to be refuted, and proofs, that prove 
nothing of the kind, are given to show that percep- 
tions have no continuous existence, but are "dependent 
on our organs, and the disposition of our nerves and 
animal spirits." ^ " All impressions are internal and 
perishing existences and appear as such." ^ *' Let us 

* Treatiaey i. iv. ii. pp. 495-6. ^ Loc. cU. p. 498. 

^Loc. cit pp. 483-4 In Descartes and Locke, we have seen, 
as before them in Augustine (cf. above, chap. i. pp. 4-6, 13-14), 
the problem of knowledge is pushed further back without being 
in any way solved. They adopt the physiological point of view 
in the explanation of knowledge, and as a consequence of that 
point of view formulate the doctrine of representative perception. 
The elementary facts of physics and physiology seem to make 
the assumption of the truth of that doctrine unavoidable (cf. 
above, p. 116). If the mind knows by means of the brain, and 
if (as these sciences prove) the brain is only stimulated indirectly 
by the vibrations transmitted to it from distant objects, the 
objects themselves can only be indirectly known through the 
mental states they thus cause. Reasoning in this way^ Descartes 
and Locke feel compelled to bring the external objects within 
the mind in the form of images, and to assume that it is by 
looking at these mental images that it acquires knowledge of 
the real objects they represent. What the nature of these 
images can be, which allows of their copying material extended 
bodies, and yet at the same time of their appearing in an 
immaterial unextended . mind, they never explain, save by 
asserting that they are ideas and therefore naturally capable of 
existing in mind. Similarly they as little explain what mind 
is, or how it knows these mental images ; here again the de- 
scription of mind, as that which knows, is supposed to suffice. 


fix our attention out of ourselves as much as possible : 
Let us chase our imagination to the heavens, or to the 
utmost limits of the universe ; we never really advance 
a step beyond ourselves, nor can conceive any kind of 
existence, but those perceptions, which have appeared 
in that narrow compass." ^ Spite, then, of Hume's 
assertion to the contrary, he still holds to the Cartesian 
trinity of mind, ideas, and matter, and is therefore still 
within the Cartesian system, still at the point of view 
of naive realism and physiology. In all essentials he 
takes up the position of Locke, that all we can know 
of human nature are certain of its qualities, propensi- 
ties, or instincts, and that we can never penetrate into 
the nature of bodies or know them otherwise than by 
those external properties which discover themselves to 
the senses. 

Now it is really that belief in the subjectivity of 
knowledge, with the retention of the physiological 

The only diflBculty, however, that is removed thereby, even in 
appearance, is that of local difference between mind knowing 
and objects known. All other difficulties remain as unsolved 
in this dualism of mind knowing and ideas known, as they were 
in the previous dualism which it is assumed in order to explain, 
of mind knowing and external objects known. Hume, like 
Berkeley, in admitting the subjectivity of knowledge, assumes 
the truth of Descartes' dualism even while attacking it. 
^ Treatise, i. ii. vi. p. 371. 



point of view which it implies, that has prevented 
Hume from discarding Locke's definition of the 
materials of knowledge. Like Locke and Berkeley, 
he believes that in the distinction between the 
different senses he has supplied to him a means for 
the analysis of our concrete experience, and for the 
classification of its ultimate elements. The different 
sensations supplied to the mind one by one through 
the different senses constitute experience, and hence 
any idea that cannot be regarded as capable of 
transmission into the mind through one or other 
of these distinguishable avenues must be denied. 
And it is by taking Hume's own point of view 
(and purely physiological it undoubtedly is), that 
we shall most fitly reply to him. Is the brain, we 
may ask, that reacts upon peripheral stimuli, to 
count for nothing? If the single, central brain, in 
reacting upon stimuli, transforms them, what be- 
comes of the supposed isolation and unrelatedness 
of the given sensations ? 

Owing to this oscillation between phenomenalism 
and subjective idealism, Hume's thinking frequently 
becomes very confused. Invariably he distinguishes 
between mental and physical laws, comparing as- 
sociation to the force of gravity, and yet obviously 



if perceptions alone are known, the only known 
'causal' laws are those of association. Especially 
does confusion appear in his views as to the inter- 
action of soul and body. Mentally connected our 
sensations and our perceptions of our bodily states 
undoubtedly are, but this connection between per- 
ceptions Hume tacitly interprets as a connection 
between mental states and bodily antecedents. 

Hume is thus only half-emancipated from the 
Cartesian system that he attacks. His conception 
of knowledge is still that of a process which takes 
place separately in each individual, and which, if 
perfect, would recreate the external world in picture 
within each individual mind. "We never really 
advance a step beyond ourselves, nor can conceive 
any kind of existence but those perceptions which 
have appeared in that narrow compass." So long 
as that fundamental tenet of the Cartesian philosophy 
has not been called in question, its dualism of mind 
and matter, of internal and external, cannot be over- 
thrown. It was left to Kant to explode the theory 
which Hume had undermined. 



KA.NT, like Hume,^ regards all systems previous to 
his own as being either dogmatic in their principles, 
or else purely negative and therefore self-contradictory 
in their scepticism. But, Kant further adds, both 
schools have certain presuppositions in common, pre- 
suppositions in which Hume also shares. Dogmatists 
and sceptics alike believe that it is the function of 
knowledge to reproduce an external world in picture 
within each individual mind; and when they find 
it impossible to account for such knowledge from 
the nature and constitution of the external world, 
they either fall back on a pre-established harmony, 
the most shallow of all explanations in Kant's opinion, 
or, ignorant of their own ineradicable dogmatism, 
triumph in their self-caused failure. Kant was the 

^ Treatise^ i. iv. i. pp. 474-5. 


first to call in question this assumption, that the 
function of knowledge is to reduplicate an inde- 
pendent reality.^ May it not be, he asks, that the 
world we construct in thought is* altogether different 
from the real outside us? And if so, is it to be 
condemned on that account? May not the material 
world exist only for us, and yet be a very real 
world with a nature and structure of its own, which 
it will be the work of our human science to deter- 
mine ? That is what Kant calls his Copernican 
idea. Since the history of philosophy has demon- 
strated that it is impossible to make cognition 
conform to objects, we must reverse the supposition, 
and suppose objects to conform to our ways of 
knowing. On that hypothesis we may hope to ex- 
plain better the facts of knowledge. Locke and 
Hume, as they admit the nature of the self to be 
unknowable, have no fight to follow Descartes in 
his assertion that it is unoriginative in the pro- 
duction of knowledge; and immediately their naive 
realism is rejected, the opposite is seen to be the 
more natural view. If the self, in relation to which 

^Even though Hume holds that the function of our actual 
knowledge is purely practical, he still preserves, as we have 
seen, the Cartesian ideal of knowledge as a subjective repro- 
duction of an external world. 


experience exists, has a nature of its own, it will 
like everything else have its own peculiar organisa- 
tion and modes Of activity, to which objects, if they 
are to be known at all, must conform. Nothing 
can enter into the mind, save by conforming to the 
laws of mind. 

The complement of that new view of the nature 
of knowledge was a fresh theory of philosophical 
method. As early as 1764 we find Kant strongly con- 
demning the mathematical method. "Nothing has 
been more injurious to philosophy than mathematics; 
that is, than the imitation of its method in a sphere 
where it is. impossible of application."/ While 
mathematics starts from conceptions (such as that 
of a triangle or a square), which, as arbitrarily 
constructed by the mind, are known exhaustively ; 
philosophy deals with given conceptions (such as 
those of space, time, and spirit), that in their 
obscure complexity resist complete analysis.^ Such 

^ Untersuchung iiber die Deutlichheit der Orundsatze der natiir- 
lichen Theologie und der Moral, WerJce (Hartenstein), ii. p. 291. 

2 Though in mathematics a few such irresolvable conceptions 
(those of magnitude, unity, space, etc.) are also involved, they 
are presupposed by it, not its objects, and therefore do not 
require to be mathematically defined. It is just where mathe- 
matical definition becomes impossible, that philosophy has to 


conceptions are known, but known only as problems. 
" As Augustine has said, ' I know well what time 
is, but if anyone asks me, I cannot tell.' " ^ We 
have the conception of spirit, but whether the 
object of that conception is or is not distinct from 
matter, we cannot from the mere examination of it 
decide.^ Philosophy must start from the obscurely 
apprehended actual, not from the conceptually 
necessary. Kant names his own method the ' trans- 
cendental,' which outlandish title need not conceal 
from us that it is simply the hypothetical method 
of physical science applied in the explanation of 
knowledge. Taking our actual knowledge as the 
fact to be accounted for, we must discover what are 
the conditions that can alone render it possible. 

The most characteristic feature in Kant's treat- 
ment of knowledge has still, however, to be 
mentioned, namely, that he takes as the fact to 
be explained not experience in all its multiplicity, 

^Quoted by Kant, Werke, ir. p. 292. 

*Cf. Trdume eines Oeist&riehera (1766), Werhe^ ii. pp. 327 ff. 
359, 378. Much of Hume's criticism of the Cartesian spiritual- 
ism (that criticism being of course developed quite independently 
by Kant) is to be found in this treatise. Kant repeats it in a 
more systematic and extended form in the Critique of Pure 
Reason, as his criticism of rational psychology and of rational 


as revealed by introspection, but the simplest act of 
knowledge, that which is involved in all knowledge 
whatsoever, developed and undeveloped, simple and 
complex, viz., consciousness of time.^ That we 
possess such consciousness, has never been denied 
by any philosopher, and is, therefore, the really 
indubitable fact, by the analysis of which Descartes 
ought to have started. By its actuality it will 
substantiate the reality of all that can be proved 
to be its indispensable conditions. This method, 
which may be regarded as a deepening and correcting 
of the analytical method of Descartes, is the 
reverse of Hume's ; for instead of setting out, like 
Hume, from a theory of the ultimate constituents 
of experience to construct experience, Kant starts 
from our actual consciousness to discover its condi- 
tions. Hume's method is a priori and dogmatic, and 
Kant's alone the truly empirical. 

As an illustration of Kant's method we may briefly 
consider his reply to Hume. Much of Hume's criticism 
Kant is quite prepared to accept. Thfi gp.n eral prin- 

^ This is made specially clear in the Principles of the Under- 
standing which form the central part of the Analytic Con- 
sciousness of time is there taken as the ultimate fact, as 
conditions of which the objective validity of space and the 

categories can be established. 



I ciple of causality is, he agrees, neither intuitively 
I certain nor demonstrable by general reasoning. Like 

1^ all other synthetic judgments a priori, it can only 
l/oe proved by reference to the contingent fact of our 
^ actual experience. Also we can never by analysis of 
a particular effect discover any reason why it must 
necessarily be preceded by one particular cause. The 
nature and possibility of causal connection — the 
explanation, that is, how one event, the cause, should 
be able to give rise to another and different event, the 
effect — ^is in all cases beyond our powers of compre- 
hension.^ Tet while admitting the incomprehensibility 

^Cf. Versuch den Begriff der negativen Grossen in die 
WdtweUheit eimufukren (1763): Werke, ii. pp. 104-6:— "I 
very well understand how a logical consequent flows from its 
antecedent by the law of identity : an analysis of the antecedent 
shows it to contain the consequent. . . . But how something 
follows from something else, and not in virtue of the law of 
identity, is what I should like to see explained. . . . The 
former species of ground 1 term the logical, the latter the real, 
antecedent. . . . My conclusion is : that the connection 
between a real antecedent and something which is thereby 
created or annihilated can never be expressed by a judgment, 
but only by a conception. No doubt this conception may by 
analysis be reduced to simpler conceptions of real antecedents : 
still, after all, our knowledge of this connection always cul- 
minates in simple and irreducible conceptions of real antecedents, 
of which the relation to their consequents can never be made 
clear/* (The above is the translation given by Wallace in his 
Kant^ pp. 127 ff.) Cf. Trdume eines Oeistersehers : Werke, 
II. p. 378. 



of causal connection, or, in other words, that it can 
never be rationalised, Kant establishes against Hume 
our right to postulate its existence. Conafiim iflnpaH nf 

timp is invnlvftd in all mnflfiinnsnftafl whatsoftvpr And 

since consciousness of time can be proved to involve, 
as the condition of its possibility, the consciousness of 
objects as being all causally connected in space, the 
principle of causality must have universal validity 
within our experience. This principle does not, how- 
ever, carry us very far. Though it justifies us in 
postulating that for each event a cause must exist 
among the events immediately preceding, in order 
to discover what that cause is, we are entirely 
dependent upon sense-experience.^ Hume is in the 
right against the occasionalists. Experience being the 
sole test of what connections are or are not causal, 
we must, if experience seems so to indicate, accept 
any two events, however different, as standing in that 

The rationalism of Kant is thus a rationalism of 
very modest pretensions. It by no means attempts, 

^The assertiou that one particular preceding event is the 
cause must rest on empirical grounds (such as that it is the only 
preceding condition which is known to be invariable), and ig 
therefore always liable to be overturned by further experience. 

^Cf. below, note to p. 260. 


like that of Descartes, Spinoza, and Leibniz, to make 
reality transparent to the mind. As the principles 
which it establishes are quite formal, though they may 
suffice to simplify and arrange, they cannot serve 
either to construct, or to explain, even the simplest 
phenomena of sense. Also, since those principles are 
proved only as conditions of our actual experience, and 
as we can conceive other kinds of experience than that 
which we possess, besides being limited in their 
powers of explaining experience, they are further 
limited to experience. They must never be used (and 
here again Kant is in agreement with Hume) as 
instruments for the metaphysical explanation of our 

But Kant did not at once manage to fulfil the 
demands of his own method, and his first position, 
which is also in great part his last, is itself dogmatic. 
He adopts the sensationalistic view of the materials of 
knowledge as consisting of atomic sensations, and 
recognising the impossibility of deriving space, time, 

*The physiological explanation of the origin of knowledge 
must therefore be rejected. Causal connections between mental 
states and brain-states must, on Kant's principles just as on 
those of Hume, be accepted as actual ; but such connections 
between particular elements within our experience yield no 
proof of the existence of conditions outside experience determin- 
ing it to be what it is. 


and the categories, from such data, he asserts, as the 
sole remaining alternative, that they are supplied by 
the mind — the mind being conceived in the Cartesian 
manner as a separate entity, preceding knowledge and 
rendering it possible. This position, crude though it 
be, is (thanks to Hume) at least free from the worst 
defects of the Cartesian rationalism. The innate ideas 
that on Descartes' view are the God-given means of 
knowledge of ultimate reality, are for Kant empty 
forms, of use only for application to the matter of 
sense. Since the distinction between sense and 
thought is not a distinction between two kinds of 
knowledge, but between two elements involved in all 
knowledge, there can be no purely conceptual think- 
ing. The empiricism of Hume and the rationalism of 
Leibniz must be regarded as supplementing and limit- 
ing one another. In all other respects, however, Kant's 
position closely resembles the subjective idealism of 
Locke and Berkeley. Each individual constructs out 
of given sensations according to inborn laws a subjec- 
tive world, the objectively real being that which under 
the same circumstances appears the same to all minds 
similarly constituted. The understanding, Kant 
says, creates nature; and each individual creates it 

anew, he might have added, in his own individual 



mind.^ " All objects without exception with which we 
busy ourselves are in me — ^that is, are determinations 
or modes of my identical self." ^ 

Now, though not explicitly withdrawing from that 
position, Kant yet points the way in the ' Objective 
Deduction ' of the categories to a much deeper one, 

1 Knowledge is explained as resulting from the superinduction 
upon relationless impressions of the rational forms of thought, 
the superinduction being due to an active self, whose existence 
is supposed to be * transcendentally ' proved by its indispensable- 
ness for this impossible function. In so far as that is Ei^nt's 
position we must regard it as a step backward into pre-Humian 
illusions and not by any means an advance. As the self which 
Kant here postulates is the occult Cartesian self, he is making 
use of means that Hume saw clearly to be illegitimate. All that 
Kant really establishes is the necessity of * synthesis,' that is, of 
that unity in experience which is required to render conscious- 
ness of time, with all that it involves, possible. But how such 
synthesis is brought about (if indeed it requires to be brought 
about), we cannot by general metaphysical reasoning decide. 
Should synthesis according to the categories be proved not to 
be due to the direct activity of a iioumenal self, but to be the 
outcome of complex associative processes, such proof would in 
no wise nullify Kant's conclusions. The self may be, for all 
that Kant shows to the contrary, not a prior-existing agent that 
constructs its own experience, but, as Hume urges, the resultant 
of a preceding complexity of conditions. That, indeed, Kant 
virtually proves, as we shall see immediately, when he shows 
that only in and through a complex objective experience is self- 
consciousness possible. 

2 Werke^ iii. p. 585. This passage was omitted in the second 
edition of the Critique. 


that is inconsistent with it. Passing from the 
problem, how consciousness of objects distinct from 
the self is possible, to the question how self- 
consciousness is possible, he discovers that this 
objective experience, which the self is supposed to 
create, conditions the very existence of the self. 
Since the self can only exist as a conscious being, 
and as all consciousness involves consciousness of 
objects, it is as true to assert that nature makes 
the self possible, as that the understanding creates 
nature. Self and not-self presupposing one another, 
neither can precede the other, so as to render it 
possible. Experience in its totality, as the unity 
of self and not-self, is undoubtedly conditioned by 
the non-phenomenal ; but since the manifold of 
sense and the forms of thought are elements that 
involve one another, and that cannot even be 
conceived apart, there is no sufficient reason for 
the assumption of a noumenal self and of a nou- 
menal not-self as their separate sources. The 
materialistic and the spiritualistic explanations of 
knowledge, even when thus combined, are alike 

In the end, therefore, the only attitude which 
Kant justifies towards experience is the purely 


analytical one, which results in a higher em- 
piricism. Without making any assumptions, we 
must start from an analysis of actual experience, 
and when we do so we find, Kant shows, that it 
is made up of qualitatively distinct elements in 
necessary interconnection in the homogeneous forms 
of space and time ; that however far back we 
may trace it, both these elements of content and 
form are found mutually to involve one another ; 
and that no explanation can be given how this 
experience came into existence, or what are the 
conditions beyond it, determining it to be what it 
is. Sense-experience, thus constituted, is the whole 
sphere of knowledge, and of those realities of 
which we have no sense-experience nothing can 
be discovered. As all ' necessary * connections are 
synthetic, and so de facto in their necessity,^ where 

^Cf. Kritih der reinen Vemunft: Werke, iii. pp. 150-3. 
Mathematical knowledge rests on intuition or sense-per- 
ception, and it is because such intuition takes place within a 
datum that is from its very nature constant and uniform for all 
possible experience (homogeneity and continuity being the 
fundamental characteristics of space and of time), that though 
the connections which it reveals are, like all other real 
connections, synthetic, they can yet be asserted to hold with 
universal validity. Kant still claims that some truths 
are purely analytic, and therefore are justified by the law 
of identity. Such teaching, however, is merely a survival of 


sense fails to yield reality, thought must cease to 
yield triith.^ 

Such are Kant's final conclusions in the Critique^ 
and by them the transition is at last made quite 
out beyond one and all of the Cartesian assumptions. 
Since consciousness of time involves consciousness 
of objects interconnected in space, so far is it from 
being true that we can only be conscious of sub- 
jective states, that on the contrary, we can never be 
conscious of anything purely subjective. The distinc- 
tion between self and not-self, between inner and 
outer, is not a distinction between our experience 
and what lies outside it, but a purely relative 
distinction within the unity of our objective ex- 
perience. Our knowledge of external objects is as 

his earlier views, and being inconsistent with his fundamental 
principles may be ignored. 

^In the Prolegomena Ei.nt formulates the fundamental 
principle of his philosophy in a way that brings out in a 
striking manner his agreement with Hume in opposition to 
Descartes. " The principle of all genuine Idealists, from the 
Eleatic school to Bishop Berkeley, is contained in this formula : 
* All knowledge by sense and experience is nothing but mere 
appearance, and truth is to be found only in the ideas of pure 
understanding and reason.' The principle which throughout 
governs and determines my Idealism is : * All knowledge of 
things from pure understanding or pure reason is nothing 
but mere appearance, and truth is to be found only in 
experience'" : Werke, iv. p. 121. 


certain and immediate as that of our own thoughts. 
From these results, in the light of which Kant's 
own philosophy requires to be almost as radically 
transformed as does that of Hume, modem philosophy 
makes a fresh start 


Abstract ideas^ Cartesian tendency 
to hypostasise, 38 ff. , 133-5 : con- 
demned by Berkeley, 135 : con- 
demned by Spinoza, 138 ff. : 
Spinoza himself hypostasises 
abstract ideas, 142 ff. 

Activity, see Will. 

Arithmetical science perceptive 
not conceptual, 45-6. 

Aristotle, 1-2, 191. 

Amauld, 115-7, 96 note 3, 135, 
165 note. 

Association of ideas, Spinoza on, 
151 note, 152 note 1 : Hume's 
account of, 228-9, 251-2. 

Attribute, Descartes' use of the 
term, 120, 127 : Descartes fails 
to analyse the category of sub- 
stance and attribute, 67 : Spin- 
oza's doctrine of the divine 
attributes, 148 ff. 

Augustine, his treatment of the 
problem of knowledge, 3 ff. : on 
doctrine of representative per- 
ception, 5-6 : exercised no direct 
influence on Descartes, 10 note : 
his problems reappear, 96 note 

3, 105 note, 176 note 1 : quoted 
by Kant, 256. 

Axioms, Descartes on the function 
of the, 31, 37 note. 

Bacon, Francis, on method, 27-8 : 
his influence on Locke, 182. 

Bernoulli, James, 198 note. 

Body, see Matter, Soul. 

Boutroux, ;^mile, 174, 175. 

Boutroux, Pierre, 45 note. 

Brain and pineal gland, 79 note 
2, 83 note 2 : imagination de- 
pendent on the brain, 126 note 

Causation and explanation prac- 
tically identified by Descartes, 
71-2 : mechanical causation in- 
explicable on Descartes' prin- 
ciples, 73 ff. : Malebranche asserts 
God to be the sole Mover, 85-7 : 
views of Descartes' immediate 
successors, 87 note 2 : Spinoza 
escapes Descartes' difficulty, 137, 
152-3 : Spinoza's identification 
of causation with explanation, 
143 ff. : Spinoza gives no account 
of mechanical causation or of 



association, 151 note, 152 : rela- 
tion of cause and reason, 147 
note 2 : Leibniz's identification 
of causation with explanation^ 
164 note : Locke asserts all 
interaction to be incomprehen- 
sible, 196-7 : Berkeley's view of 
causation, 216-8 : Hume's criti- 
cism, 222 ff.: Hume shows that 
the general principle of causality 
is not a self-evident truth, 
223-5 : the causal relation can- 
not be rationalised 243-4 : the 
relative position of the two cate- 
gories of substance and causality 
inverted by Hume, 245 : Kant 
on causation, 257-9. 

Clauberg, 83 note 2, 87 note 2, 
129 ff. 

Cogito ergo sum, a consequence of 
the doctrine of representative 
perception, 5-6, 14, 51-2 : inter- 
preted by Descartes in two 
ways, 49 ff. : its relation to the 
criterion of truth, 50-1 : exag- 
gerated importance ascribed to 
it by Descartes, 51 : Leibniz's 
view of, 52 note 2 : Malebranche 
and Leibniz assert self s exist- 
ence not known but only felt, 97 
note : Locke's view of, 189. 

Conception, its relation to imagina- 
tion, see Thought, Imagination. 

Conceptualism, Atomic, of Des- 
cartes, 46, 60-4 : of Leibniz, 63 
note, 161-2, 170 note, 177. 

Consciousness, Descartes' two views 
of, 89 ff. : a third view, 133-5 : 

a fourth view, 135-6 : De la 
Forge and Malebranche on the 
nature of consciousness, 133-5: 
problem of relation of contents 
of mind to consciousness, 4-7, 9, 
14, 90 ff., 175-6: contrast be- 
tween Descartes' and Kant's 
views of consciousness, 91 note 
3 : Spinoza's view of conscious- 
ness, 133, 154, 158. See Mind, 

Consciousness of extension, see 

Cordemoy, 87 note 2. 

Creation and persistence in exist- 
ence, 72-3, 128 ff. 

Criterion of truth and the cogito 
ergo sum, 50-1, 52 ff. : the cri- 
terion is interpreted by Descartes 
in the light of the scholastic 
doctrine of essence, 60-3. 

Deduction, its relation to intuition, 
32-3 : Descartes' method though 
deductive not syllogistic, 28 ff. : 
Spinoza's view of, 145, 153 ff. : 
Leibniz's view of, 160 ff. : Locke's 
view of, 200 ff. 

De la Forge, on motion, 76-7 : his 
occasionalism, 87 note 2 : on the 
nature of God, 128 : his views 
of consciousness, 133-6. 

Design, Hume's criticism of argu- 
ment from, 235 ff. See Final 

Dualism of mind and matter forms 
Descartes' problem, 13 : conceals 
a purely relative trinity, 70 : 
necessitates doctrine of repre- 



sentative perception, 5, 13-4, 
51-2, 116, 249 note 3. 

Emotions, Descartes' treatise on 
the; 84 note 2. See Feelings. 

Empiricism of Locke, 181 ff., 208 
ff. : of Kant, 259, 261, 263-5. 

Error, Descartes' theory of, 110 
note : Spinoza's criticism of 
Descartes' theory, 139 note. 

Essence, Scholastic doctrine of, its 
influence on Descartes, 60-4 : 
on Spinoza, 155-6 : on Leibniz, 
161-2 : Locke's doctrine of nomi- 
nal and real essence, 203-4 : 
Locke's belief that each sub- 
stance has an essence peculiar 
to it, 210 : Cartesian doctrine of 
essence denounced by Berkeley, 
222 note. 

Eternity, see Time. 

Explanation identified with Causa- 
tion, see Causation. 

Extension constitutes the essence 
of matter, 120-2, 65-7 : its rela- 
tion to figure, 68 note 2 : know- 
ledge of extension, Augustine's 
view, 4-7 : extension not known 
as a state or modification of the 
self, 92-6 : Malebranche's view 
that we know space by partici- 
pation in God's knowledge of it, 
and Regis' reply, 96 note 3 : 
from our knowledge of extension 
Malebranche derives all know- 
ledge of mind, 105 note : Locke's 
failure to account for our con- 
sciousness of space and time 
from his sensational! stic prin- 

ciples, 187 note, 207 : conscious- 
ness of space Kant asserts to be 
involved in consciousness of 
time, 257, 259, 265, 71. 

Feelings and passions are the real 
proof of our dual natur^ 83-4 : 
are the only known modes of 
mind, 92 note, 94-5, 127 note: 
their nature is not known, 102 
and note. 

Final causes, Spinoza's condemna- 
tion of, 140-1, 150: Hume's 
criticism of the argument from 
design, 235 ff. 

Freedom of the will, see Will. 

GaUleo, 11, 47, 69. 

Gassendi, 96 note 2, 105 note, 124 

Geometrical science perceptive not 
conceptual, 43 fiP., 264 note. 

GenUncx developed occasionalism 
into a system, 87 note 2 : de- 
fends Descartes' identification of 
matter and extension, 66 : 
ascribes intrinsic reality to the 
secondary qualities, 102 note : 
on action of mind on body, 227 
note 2. 

God, Descartes' proofs of His 
existence, 54 ff. : ontological 
proof, 57-8 : proof from duration 
of our lives, 73 note: the real 
ground for Descartes' assump- 
tion of God's existence, 63-4, 74, 
88-9, 96, 128-32: thought and 
will in God, 113-4: perfection 
and simplicity of God's nature, 
128, 132 : Spinoza's view of God, 



137-8, 146, 149, 153, 157: 
Spinoza's condemnation of final 
causes, 140-1, 150 : Locke's doc- 
trine of substance and Descartes' 
proofs, 58 note, 199: Hume's 
criticism of the argument from 
design, 235 fif. 

Ideas are regarded by Descartes 
as the objects not the acts of 
mind, 14, 17, 91, 94 note, 108-9 ; 
innate ideas are characterised 
by an inner power of growth, 
41-2, 108-9: are innumerable, 
42 : cannot be isolated units, 46 : 
Descartes admits sensations to 
be innate, 81, 34: Malebranche's 
criticism of Descartes' doctrine 
of innate ideas, 109 note 2 : 
Descartes at times approximates 
to Malebranche's position, 109 
note 2 : Spinoza on the nature 
of ideas, 133, 151, 164, 158: 
three views in Leibniz of innate 
ideas, 172 fif. : Leibniz retains 
Descartes' view of ideas as the 
objects of mind, 174-6 : Leibniz 
suggests at times a different 
view, 176 : Locke on the nature 
of ideas, 185-7 : Locke and Ber- 
keley ascribe to the self the 
power of creating ideas, 218 : 
the criticism made by Hume 
and Malebranche of that view, 

Imagination, Descartes on, 122 ff., 
40-1, 45 note, 89 ff. : imagination 
quite distinct from understand- 
ing, 124-6, 45 note : imagination 

dependent on the brain, 126 
note 2 : Spinoza's treatment of 
imagination, 151 note: Locke 
and Berkeley ascribe to the 
mind the power of creating 
images, 218. 

Inference, Impossibility of making 
a false, 25-6, 34. 
, Innate ideas, see Ideas. 

Introspection, Locke's emphasis 
on, 188-9. 

Intuition, Descartes' view of, 31 
ff. : intuition and the syllogism, 
28-31 : intuition and deduction, 
32-3 : intuition is the source of 
all our knowledge, 33-4 : intui- 
tion perceptive not conceptual, 
44 ff. : Locke adopts the views 
of Descartes, 200 ff. 

Limits of knowledge, Descartes 
raises the problem of the, 23-4, 
35-6, 47 : Descartes' answer to 
the problem, 64 ff., 61-3, 114: 
no mean for Descartes between 
complete knowledge and ab- 
solute ignorance, 62-3 : the 
problem in Locke, 188 : Locke's 
answer, 192 ff. , 226 note 2 : 
Hume's answer to the problem, 
226, 227-9, 236, 238 ff., 250: 
Kant's answer, 268-60, 263-5. 

Magnetism is unknowable if a 
qualitatively distinct force, 47. 

Malebranche, on the doctrine of 
representative perception, 5 
note, 51 note, 116 note 2 : on 
the mind's ignorance of itself, 
14 note : on the fruitful nature 



of extension, 36 note : his inter- 
pretation of the CogitOf 50 note : 
his proofs that the nature of the 
self is not known, 97 ff. : even 
the self's existence not known 
but only felt, 97 note : that the 
essences of things are indivisible, 
everything either a substance or 
the modification of a substance, 
61 note : on perception of figure 
and on the relation of figure to 
extension, 68 note 2 : on the 
laws of motion, 74 note 2 : his 
views on mechanical causation 
and his occasionalism, 85-7, 
197-8, 226-31, 241 note 2, 111 
note : his criticism of Descartei^' 
view of mind and of its relation 
to intelligible space, 92 S. : 
secondary qualities all relation- 
less, 94-5, 182: that we know 
space by participation in God's 
knowledge of it, 96 note 3: asserts 
the possibility of a rational de- 
ductive science of mind, 101-7 : 
is one of the founders of em- 
pirical psychology, 103 note 1, 
188 : asserts the possible modes 
of mind to be unlimited in 
number, 103 note 2, 194 : from 
our knowledge of extension 
derives all knowledge of mind, 
105 note : his objections to Des- 
cartes' doctrine of innate ideas, 
109 note 2 : that will is not 
essential to mind, 111 note : 
that consciousness of being is 
prior to consciousness of any par- 

ticular form of being, 134-5 : his 
influence on Locke, 197-8 : his 
views on the causal relation 
developed by Hume, 226-31 : 
his spiritualism criticised by 
Hume, 231 ff. : on creation and 
causation, his agnostic con- 
clusion, 241 note 2. 

Matter, Descartes' theory of , 65 ffl , 
117 ff. : criticisms of his theory, 
65-8 : his view of matter raises 
new problems as to sense-percep- 
tion, 15 ff. 

Mechanical causation is inexplic- 
able on Cartesian principles, 
71-2. See Causation. 

Method, according to Descartes 
there is one universal method, 
22 : why the problem of method 
is so important for Descartes, 
23-6 : his method in its relation 
to the analytical method of the 
Greeks, 24 : the characteristics 
of the mathematical method, 27 ; 
Descartes' criticism of the 
empirical method of Bacon, 27-8: 
Descartes' method not syllo- 
gistic, 28 ff. : he seeks to make 
science purely conceptual, 
39 ff. ; contrast between Des- 
cartes' method in science and in 
metaphysics, 39 ff. : Spinoza's 
doctrine of method, 144 ff. : 
Spinoza fails to carry out his 
method, 153 ff. : Locke's intro- 
spective method, 188 : Locke 
asserts a two-fold method to be 
necessary, 201 ff. : Kant's criti- 



cism of the mathematical 
method, 255-6: Kant's own 
method, 256 ff. 

Mind, its essence consists in pure 
thought, 126-7, 89 fP. : is better 
known than matter, 90 ; why 
on Descartes' view there is no 
science of mind, 98 : belief in 
the possibility of a rational 
science of mind is the natural 
extension of the rationalism of 
Descartes, 101-7 : Malebranche's 
criticism of Descartes' view of 
mind, 92 ff. : no actual direct 
knowledge of mind, 97 ff. : Male- 
branche and Norris assert the 
possible modes of mind to be 
unlimited in number, 103 note 
2 : Descartes' view that thought 
forms the whole essence of mind 
contradicted by his theory of the 
will, 111-4. See Consciousness, 
Thought, Self. 

Modes are the crux of Descartes' 
philosophy, 68 note 2, 89-108 : 
and of Spinoza's, 153 ff. 

Monadism, Leibniz's argument for 
it derived from his rationalism, 
160 ff. 

More, Henry, 77. 

Motion, its all-important role in 
modern science, 11-2: it is on 
Descartes' view equally sub- 
stantial with matter, 70 : yet in 
his metaphysics is asserted 
to be a mode of extension, 
120-2, 68, 71 : motion is really 
regarded in two ways by Des- 

cartes, 75 ff. : Descartes and 
Malebranche on the laws of 
motion, 74 note 2: Spinoza's 
treatment of motion and its re- 
lation to extension, 154, 158-9 : 
Leibniz on the laws of motion, 

Motion, its causes. See Causa- 

Natorp, Paul, 45 note. 

Nature, Influence of modem view 
of, on Descartes, 10 ff. See 

Norris, John, 91 note 2 : in what 
the process of thinking consists 
is not known, 99-100 : follows 
Malebranche in asserting the 
possibility of a rational science 
of mind, 102 note, 103 note 2, 
105 note : more senses are pos- 
sible than those which we 
possess, 103 note 2 : his criti- 
cism of Descartes' view of the 
relation of thought and will in 
God, 114 : his argument for the 
reality of an ideal world criti- 
cised by Hume, 239 note. 

Occasionalism of Descartes, 63-4, 
71-4, 77-9, 81-2, 95-6, 109 
note 2, 126 note 2, 128 ff. : 
attempts to escape it, 79 ff. : 
occasionalist denial of transient 
action due to the identification 
of causation with explanation, 
72 note 2 : the occasionalism of 
Malebranche, 85-7 : the occa- 
sionalism of Descartes' im- 
mediate successors, 87 note 2 : 



occasionalism developed and 
simplified . by Berkeley 217-8, 
221 : occasionalism criticised by 
Hume, 229-30, 241-5: Kant's 
attitude towards occasionalism, 

Ontological argument, 57-8, 199. 

Pantheism of Spinoza, 148. 

Pascal, 21 note 3. 

Perception, Descartes' theory of, 
117 ff. : Descartes' view of 
matter raises new problems as 
to sense-perception, 15 ff. : in- 
teraction of soul and body in 
perception, see Soul : Leibniz's 
account of sense-perception, 
172, 174, 178-80. 

Perception, Representative. See 
Representative perception. 

Phenomenalism, not subjective 
idealism, the true position of 
Hume, 247 ff. : and of Kant, 

Physiological standpoint of Augus- 
tine, 6-7 : of Descartes, 13-4, 
116 : of Locke, 183-4, 195-6 : of 
Berkeley, 221 note 2 ; of Hume, 
249 ff., 249 note 3 ; the attitude 
of Kant, 260 note, 263. 

Pineal gland, 79 note 2, 83 note 2, 
126 note 2. 

Pre-established harmony, Leib- 
niz's theory of, 163. 

Qualities, primary and secondary, 

* Descartes' views of, 117 ff., 121- 
2, 100 : resistance is not a 
primary quality, 65-6: secondary 
qualities usually regarded by 

the Cartesians as illusions, 102 
note, 157 note, 172, 180 ; Male- 
branche shows the secondary 
qualities to be all relationless, 
94-5 : Locke bases on this fact 
his atomic sensationalism, 182 : 
Malebranche and Norris assert 
the possible secondary qualities 
of bodies to be unlimited in 
number, 103 note 2 : Locke does 
so likewise, 194. 
Rationalism of Descartes is based 
on the scholastic doctrine of 
essence, 60-4 : Descartes seeks 
to make science purely concep- 
tual, 39 ff. : Descartes practi* 
cally identifies causation with 
explanation, 71-2 : Malebranche 
asserts the possibility of a 
rational science of mind, 101 ff. : 
this is the natural extension 
of the rationalism of Descartes, 
106-7 : Descartes' answer to the 
question why there exists no 
science of mind corresponding 
to the mathematical sciences, 98 
note 1 : Descartes' rationalism 
undermined by his doctrine of 
the will, 111 ff. : the rationalism 
of Spinoza, 142-3: Spinoza's 
identification of causation with 
explanation, and its conse- 
quences, 143 ff. ; the rationalism 
of Leibniz yields the basal argu- 
ment for his monadism, 160-5 : 
Leibniz identifies causation with 
explanation, 164 note : the 
rationalism of Leibniz is modi- 



fied by his spiritaalism, 169, 
180: the rationalism o( Locke, 
106, 200 ff., 213 ; Locke par- 
tially frees himself from the 
rationalism of Descartes, 192 ff. ; 
Hume overthrows the Cartesian 
rationalism, 244 : Kant's ration- 
alism is of very modest preten- 
sions, 259-61, 263-5. 

Reason and cause, see Causation. 

Reflection, Locke's doctrine of, 
183, 189 note 3 : Leibniz's view 
of reflection, 173 note 1. 

Regis on the Cogito, 50 note 2 : he 
asserts that all substances with 
the exception of God are equally 
perfect, 56 note : that the 
essences of things are indi- 
visible, 61 note : his occasion- 
alism, 87 note 2 : his replies to 
Malebranche's criticisms of 
Descartes, 96 note 3, 105 note : 
on finite existence in time, 

Reid on Arnauld, 117. 

Renascence philosophers, 11. 

Representative perception. Doc- 
trine of, 5-6, 13-4, 51-2 : is one 
of the three fundamental tenets 
of Descartes' philosophy, 115; 
Malebranche regards it as a self- 
evident truth, 51 note : the 
doctrine is denied by Arnauld, 
1 15-7 : the doctrine is retained 
by Leibniz, 175 note : and by 
Locke, 184-6, 189 note 3 : the 
influence of the doctrine on 
Berkeley's philosophy, 216-7, 

221 note 2: and on Hmne's 
philosophy, 247 ff., 249 note 3 : 
the doctrine is called in ques- 
tion by Kant, 253-4, 265-6 : yet 
traces of it remain in Kant's 
philosophy, 261-2. 
/Russell, Bertram, 165 note, 171 
note 2, 174 note 1, 179 note, 180 

Secondary qualities, see Qualities. 

Self, its nature is not known, 9-10, 
97 ff. : nor its existence, 97 note : 
the Cogito does not prove the 
existence of the self as a 
spiritual substance, 49 ff. : • 
Descartes regards the self as 
active. 111: dependence of the 
self on God, 73 note, 129 ff. : 
the occult nature of the Car- 
tesian conception of self or 
spirit, 14, 52, 112, 115, 128-32, 
180, 186, 187 note, 218-21, 228 
ff., 241, 246 note 2, 249 note 3, 
256 note 2, 262 note 1 : Hume 
on the nature of the self, 231 ff. 
See Soul, Mind. 

Sensationalism, Atomic, of Locke, 
181-4, 187 note : of Hume, 246 
ff. : of Kant, 260-1. 

Sense-experience, Descartes'failure 
to account for, 80-2, 106-7 : Des- 
cartes asserts all sensations to 
be innate, 81 : the sensations, 
feelings, and emotions are the 
only known modes of mind, 92 
note, 94-5, 127 note : the nature 
of sensations and feelings is not 
known, 102 and note : Spinoza's 



view of sense, 157 note ; Leib- 
niz asserts sense to be confused 
thought, 172, 174-5, 178-80: 
Locke on the nature of sensa- 
tions, 180 ff. The relation of 
sense to thought, see Thought. 

Senses other than those which we 
possess may be possible, 103 
note 2, 194. 

Simple and complex, Cartesian 
interchange of, 41-2, 107 note, 
134, 146-7. 

Simple natures, see Innate ideas. 

Soul and body, The relation be- 
tween, is one of the problems 
of Augustine, 7-8 : Descartes on 
their relation in sense-percep- 
tion, 10, 15-6, 80-2: in voluntary 
action, 82-3, 83 note 2 : the feel- 
ings and emotions prove soul and 
body to be * fused,' 83-4 : the 
views of Descartes' immediate 
successors, 87 note 2 : Spinoza's 
treatment of the problem, 149- 
50 : Locke on the interaction of 
soul and body, 195-9 : the views 
of Hume, 227, 241-3 : Geulincx 
on the action of mind on body, 
227 note 2. See Occasionalism. 

Space, see Extension. 

Spiritualism of Descartes, 115, 
128-132: of Spinoza, 156: of 
Leibniz, 167 ff., 167 note, 180: 
of Locke, 186-7, 187 note: pf 
Berkeley, 218 ff. : Hume's criti- 
cism of the Cartesian spiritual- 
ism, 228 ff. : Kant at first adopts 
the Cartesian view of spirit, 

260-1 : Kant's criticism of it, 
246 note 2, 256 and note 2, 
262-3,265-6. See Occasionalism. 

Stein, Ludwig, 77 note 1, 87 note 

Substance, essence, and conception 
are all identical for Descartes, 
61 : the Cartesian position that 
everything is either a substance 
or the modification of a sub- 
stance, 61 note : consequences of 
Descartes' conception of sub- 
stance, 62-3, 63 note, 68 note 

1, 170 note : Descartes fails to 
analyse the category of substance 
and attribute, 67 : it is more 
difficult to create substance than 
any of the attributes of sub- 
stance, 56, 130 : Locke's ex- 
planation of the origin of the 
idea of substance, 191-2 : Locke 
on the relation of substance and 
the primary qualities, 193 note 

2, 210-2 : the fundamental cate- 
gory in Locke's philosophy is 
substance, not causality, 203-4 : 
Locke holds that the difference 
between our knowledge of modes 
and our knowledge of substances 
renders a twofold method neces- 
sary, 201 ff. : Berkeley on the 
relation of substance and quality, 
222 note : the relative position 
of the categories of substance 
and causality is inverted by 
Hume, 245. 

Sufficient reason. The principle 
of, in Leibniz, 166-7. 




Syllogism, Descartes' criticism of 
the, 28 ff. 

Tabula ram, 190 note, 195 ff. 

Thought, its relation to sense and 
imagination, 89 ff., 122 ff., 45 
note : Descartes' daalism of 
sense and thought, 17-8, 80-2 
the only escape from it, 106-7 
thought is passive, 108 ff. 
thought and will are quite dis- 
tinct, 112 ff. ; the relation of 
thought to its modes, 126-7, 127 
note, 92 ff : Malebranche's criti- 
cism of Descartes' view of the 
relation of thought to its con- 
tents, 92 ff. : Spinoza on the 
relation of thought and sense, 
157 note : Leibniz's view of the 
relation of thought and sense, 
172, 174-5, 178-80 : Kant on the 
relation of thought and sense, 
260-1, 263-5. See Conscious- 

Time, Descartes' view of, 72-3, 
128 ff., 170 note : the duration 
of our life suffices to demonstrate 
God's existence, 73 note : the 
scholastic distinction between 
time and eternity, 128-9 : the 
explanation given by Locke and 

Berkeley of our consciousness of 
time and space, 187 note : 
Hume's failure to account for 
consciousness of time, 246 :. con- 
sciousness of time is the ulti- 
mate datum for Kant, 256-7 : 
consciousness of time involves 
consciousness of space, 257, 259, 
265, 71 note 2. 

Unconscious, The notion of the, 
introduced by Leibniz, 175-6 : 
the problem is raised by Augus- 
tine, 9-10 : Descartes' attitude 
towards the problem, 176 
note 1. 

Understanding, see Thought. 

Will, as it appears in bodily move- 
ment, 82-3 : is quite distinct 
from thought, 112 : is the only 
faculty which we possess in per- 
fection, 110 note, 113 note 1 : 
thought and will in God, 113-4 : 
Malebranche on the will. 111 
note, 228-30: Spinoza's criti- 
cism of Descartes, 138-9, 139 
note : Spinoza's denial of the 
freedom of the will, 138-9, 141 
note 2 : Hume on the will, 
226 ff. , 235 ff. 


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