philosophy of Descartes

The Rationalists and Kant 443 maintain, for example, that you can understand an argument only by studying the debates from which it grew, and the contemporary meaning of the terms used to express it. Such writers pay great attention to historical detail, and to the tracing of influences. Others, by contrast, lay hold of the great dead philoso- phers and shake them to life, impiously interrogating them as though they were our contemporaries. The second kind of commentator will be more useful to the student; but the first is not to be despised, and is beginning to have consid- erable influence on the subject.

1. DESCARTES

Descartes was born at La Haye, near Tours, in 1596, attended ajesuit college in Anjou, took a doctorate in law from the University of Poitiers in 1616, and in 1618 embarked on a military career, travelling to Holland to join the army of Prince Maurice of Nassau. He made no mark as a soldier and in 1619, while campaigning in Germany, discovered his vocation as a thinker. After a few unsettled years he returned in 1628 to Holland, where he lived for twenty-one years, composing works of cosmology, mathematics, physics, optics, meteoro- logy, and philosophy, and becoming celebrated as one of the greatest savants of his day. In 1649 he travelled to Sweden at the invitation of Queen Christina, whose exacting demands were partly responsible for his death in the following year. (The adjective 'Cartesian' records the fact that Descartes's name is con- densed from 'Des Cartes")

Descartes wrote in French and Latin. The works that are of particular impor- tance to the student of modern philosophy are The Discourse on the Method, pub- lished in French in 1637, the Meditations on First Philosophy, published in Latin in 1641, and the Principles ojPhilosophy, published in Latin in 1644. Although the Principles contains the most comprehensive statement of the Cartesian position, the Meditations is the key text, not only because of its relentless and concen- trated argument, but also because it represents Descartes's attempt to show the originality and importance of his philosophical method. Several sets of objec- tions to this work were published in Descartes's lifetime, together with his replies, and these too should be studied. As for the other works, the selections Contained in Cottingham's edition (see the Bibliography) are adequate.

Descartes was an accomplished scientist and mathematician, who laid the foundations for Newtonian mechanics, and revolutionized both number theory and geometry. It is worth bearing Descartes's scientific and mathematical achievements in mind, since they exerted a strong influence over his philosophy. Descartes believed that mathematics is a realm of' eternal truth', revealed to the intellect without reference to experience. He also believed that scientific theo- ries aim in the same direction, towards abstract and universal principles. By

444 Roger Scruton

what method, however, can we justify these claims to certain knowledge, and to knowledge of necessary and universal truths? This question plunges us into the heart of Descartes's philosophy, and to his ruling principle, which he for- mulated in these words: 'For right philosophizing ... the greatest care must be take~ n~t to admit anything as true which we cannot prove to be true' (Fifth Set of Objections and Replies).

. His quest for a method, therefore, was a quest for proof-and at the same time for a philosophy on which our many claims to knowledge could be founded.

1.1. The Method of Doubt

De~cartes believed that he must demolish all his beliefs and opinions, and begin ~ga~ from the foundations if he were to be sure of anything 'in the sciences' (i.e. in ~e recognized fields of inquiry) (Meditation 1, 17).1 To this end he pro- posed his method of doubt: not to accept anything as true ifhe could give a rea- son for .thinking it might be false. Two arguments persuade him that he can doubt VIrtually all his normal beliefs:

1. The dreaming argument. I believe that I am sitting by the fire with a piece of paper in my hand. Why? Because my senses tell me so. But could I not be dreaming? In dreams my senses present me with information of the same kind as I receive whe? waking. So how do I know that 1am not dreaming now?

There are beliefs that are not shaken by this argument-beliefs about what is most general, such as we encounter in mathematics: 'whether I am awake or asleep, two and three added together are five, and a square has no more than four. s~des. It s~ems im?OSsible that such transparent truths should incur any suspicion ofberng false (Meditation 1, 20).

2. The demon argument. I imagine that I was made, not by a good God, but b! a~ evil demon of the utmost power and cunning, who employs all his ener- gies m order to deceive me. Thus the demon produces in me the experiences that tell me that I am sitting by the fire-although there is no fire, and no body to be sitting there. He produces my memories, images, and thoughts, even though nothing in the world corresponds to them. He even deceives me 'in those matters which seem to us supremely evident', such as mathematics (Principles, 1. 5. 6).

This argument is immensely powerful, especially if it is true, as Descartes maintains, that we could be deceived even in that which seems to us most evi- dent. For this casts doubt on Descartes's own solution to the problem of know l- edge. (See below, Section 1.7.)

I Page references are to the CEuvres de Descartes, i-xii, plus supplement, ed. Charles Adam and Paul Tannery (Paris, 1897-1913). Good English editions will quote the page numbering of this edition in the margins of the translated text.

The Rationalists and Kant 445

The two arguments have the effect of transforming our local doubts about this or that into a global doubt about everything-and this is the result that Descartes requires.

1.2. The Cogito

So how is doubt overcome? The answer is contained in the famous phrase 'Co ito, ergo sum', 'I think, therefore I am'. 'I saw ... that from the mere fact thatI thought of doubting the truth of other things, it followed quite evidently and certainly that 1 existed' (Discourse on the Method, 32). Descartes's way of putting the point was later amended: 'this proposi~ion, .1am, I e~t" is necessar- ily true whenever it is put forward by me or conceived m my mrnd .

The following observations should be noted: 1. The original statement of the Cogito, as it is known, makes it look like an

inference. The premiss is 'I think', and the conclusion is 'I am': in which case we need another premiss if the inference is to be valid, namely: 'Everything that thinks exists'. But that is precisely what Descartes has to prove.

2. The statement in the Meditations is therefore often preferred: it is not that 1infer my existence from the premiss that 1think. It is rather that 1cannot think that 1exist without it being true that 1exist. The statement that I exist is 'self- verifying' .

Hintikka describes the statement that I do not exist as 'existentially inconsis- tent'. It is not that it is necessarily false-I might not have existed. Rather, the statement cannot be correctly made, except in circumstances that automati- cally refute it. It is the performance of making the statement that defeats it. And this applies also when the performance is carried out 'internally', when 1merely think that 1do not exist, without overtly stating it. The attempt to think one's own non-existence is necessarily self-defeating.

3. Descartes says 'I am, I exist, is necessarily true whenever it is put forward by me'. But it is not, in itself, necessarily true. The proposition that 1 exist expresses a contingent truth, one that might have been false. The Cogito is interesting for many reasons. Recent commentators have been par- ticularly impressed by the role of the word T (or the 'first-person case') in estab- lishing Descartes's desired conclusion. It seems that many sentences formulated in the first person are immune to error-or at least to certain kinds of error. One is 'I exist'; another is 'I think'; another is 'I am in pain'. Are these immune to error for the same reason, or in the same respect?At times Descartes seems to answer in the affirmative: 'I ask [my readers] to reflect on their own mind, and all its attrib- utes. They will find that they cannot be in doubt about these, even though they suppose that everything they have ever acquired from their senses is false' (Objections and Replies, 162; see also Principles, 1. 8. 9 and 11. 7-9).- ..•..--~--

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1.3. The Theory ofIdeas

Descartes takes the Cogito as proof of several things: first, that he exists, sec- ondly that he exists as a 'thinking thing', and thirdly that he has a criterion whe~eb?,to r~cognize a true belief This is the criterion of' clear and distinct per- ception. This phrase marks a point of great difficulty and controversy . D ' mescartes s argument, and the student should approach the matter with care.

1. .All. mental activity, for Descartes, is a form of thinking (cogitatio) (Meditation 2, 28-9). Thinking always involves 'ideas', which come before the mind, and are the immediate objects of thought. Thus when I think of a horse an ide~ of a horse is be~ore my mind; when I decide to go home, an idea of gOin~ home is before my mmd; when I see a green field, an idea of a green field is befor~ my mind. These ideas are the 'matter', so to speak, of thinking, and are ?rga~ed by the various activities of the mind (believing, desiring, doubting, lffiagmmg, etc.).

Descartes was probably the first philosopher to use the word 'idea' in this way, although the usage caught on, and was made common by Locke and Berkeley.

2. J\ll the modes of thinking that we experience within ourselves can be brought under two general headings: perception, or the operation of the intel- lect, and volition, or the operation of the will' (Principles, 1. 32. 17). Operations of the intellect include sense perception and imagination, and involve the direct confrontation with an idea, and the attempt to understand it. When I go on to affirm or deny the idea, then this involves an act of will in addition to the per- ception.

3. I perceive my ideas more or less' clearly and distinctly'. Alternatively; ideas themselves may be more or less' clear and distinct'. What is meant by 'clear and distinct'? Descartes gives the following definition: 'I call a perception "clear" when it is present and accessible to the attentive mind ... I call a perception "dis- tinct" if, as well as being clear, it is so sharply separated from all other percep- tions that it contains within itself only what is clear' (Principles, 1. 45. 22). That definition is certainly neither clear nor distinct. Immense controversy therefore surrounds the question what Descartes means by clear and distinct perception, or a clear and distinct idea, and why he should have regarded clarity and dis- tinctness as marks of truth.

4. What he seems to have in mind is the idea of a self-evident proposition. Certain things that come before my mind simply cannot be doubted-and in that sense bear an intrinsic mark of their own truth. The Cogito is one of them, and by studying it we come to see that any other proposition that is perceived as clearly and distinctly as this one must also be true. Its truth is revealed to the 'natural light' of reason.

The Rationalists and Kant 447

S is tryin g to give an account of a priori knowledge. But it is a very

Descarte atisfactory account. . .

uns artes also refers to adequate and inadequate ideas: an idea can be clear 5 Desc . f thin .'.dis' t without containing a full account of the essence 0 some g. i.e,

~d tlnbc. g 'adequate' to its subject-matter. The notion of an 'adequate' idea V/lthout em .' f Soition was to playa vital part in the philosophy 0 Spinoza or concep t also introduced into philosophy the concept of an innate idea,

6. Desca: e~lay an important role in the thought of Leibniz. Sometimes he which wastho gh all ideas are innate in us and that we derive no ideas from writes as ou .'. at all (See Comments on a Certatn Broadsheet, 358-9.)expenence . Th h t

of the theory of ideas is rationalism. Knowledge comes through e ups 0 ddi . . f

fl . on our own ideas, and so arriving at a clear an stinct perceptIOn 0

re ecttng . . he ' alii ht' f .fthings Our euide in this exercise is t e natur g t 0 reason,the essences 0 . b- .hich Provide only obscure and confused perceptions, can at bestthe senses, w . . show the world as it seems, but are silent concerning the world as It is.

1.4. The 'Real Distinction'

Having established his own existence, Descartes goes on to examine his nature. It is clear from the Cogito that I am a thinking thing. Moreover, I cannot con- ceivemyself except as thinking: any conception of myself that is a:-ailable to me is a conception of myself thinking. Hence it is of my essence to think. Howev~r hard I try, I can find nothing else that belongs to my ~ssence. For exa~ple, It seems to me that I have a body which I can move at will; but I can readily con- ceive of this body as not existing, without supposing my own non-existence.

Descartes then goes on to reflect upon the nature of physical things (bodies). Consider this lump of wax: it has a certain shape, size, colour, perfume-qu~- ities which I can perceive through the senses. Yet approach it to the fire and It changes in all these respects, while remaining the same piece of wax. Those sen- sory qualities do not therefore belong to the essence of the piece of wax. Indeed, no sensory experience enables me to perceive the essential nature of the wax or of any other corporeal thing: only by reasoning will I obtain the clear and dis- tinct perception which reveals the essence of the wax that I hold before me. And this reasoning tells me that, while the wax may change in respect of its shape, size, colour, perfume, or any other sensory 'mode', it cannot cease to be extended in space without ceasing to be. Extension belongs to its essence; but I can find nothing else that belongs to its essence. And the same is true of all phys- ical (corporeal) things.

Those two arguments occur in Meditation 2; in Meditation 6 Descartes adds the following observation: 'I know that everything which I clearly and distinctly understand is capable of being created by God so as to correspond exactly with my understanding of it. Hence the fact that I can clearly and distinctly under-

448 Roger Scruton

stand one thing apart from another is enough to make me certain that the two things are distinct, since they are capable of being separated, at least by God: (See also Principles, 1. 60. 28-9.) Since I clearly and distinctly perceive that thought is of the essence of mind, and extension of the essence of body, and nothing else is of the essence of either, I clearly and distinctly perceive that mind is essentially distinct from the body and therefore in principle separable from it. There is a 'real distinction' between mind and body.

The details of the argument are set out again in the sixth set of Descartes's Replies to Objections, and many are the fallacies that have been discerned, rightly or wrongly, in this immensely subtle piece of reasoning. The following points should be noted:

1. Mind, for Descartes, is a thinking substance, in the specific sense common to the rationalist philosophers: it is a bearer of properties, which depends for its existence on no other thing besides God (Principles, 1. 51. 24).

2. The body is not a substance in that sense, since it depends for its existence on other things besides God. Nevertheless, Descartes writes of 'extended sub- stance', meaning matter in general, and also of corporeal substances, meaning individual physical things.

3. Thought and extension are 'principal attributes', through which the sub- stances that possess them may be completely or adequately conceived (Principles, 1. 53. 25; see Section 2 below).

4. Given the truth of (1), (2), and (3), there is a problem as to how mind and body interact: reflection on this problem was one of the main motives behind Spinoza's philosophy.

1.5. The Cartesian Theory of the Mind

Descartes begins from the question 'How can I know, be certain of, the things that I claim to know?' Immediately his thought is turned inwards, to the con- tents of his Own mind and the certainties which attach to them. Although the peculiarity of the Cogito lies in its self-verifying nature, there lurks behind it a host of other certainties. (See Principles, 1. 8. 9 and 11. 7.) I am able to know what I think, feel, experience, desire, with an authority that you could never match. The first-person case is not merely a paradigm of certainty; it seems to show the essence of the mind-what it really and essentially is-through the inner awareness of 'ideas'.

Certainty about my own mind goes hand-in-hand with uncertainty about the external world. My mind is more immediately present to me than any physical thing, and I can have knowledge of it while presupposing nothing about a phys- ical reality. It seems as though my subjective viewpoint is a viewpoint on another realm-a realm that is no part of physical reality, an 'inner' realm, con- nected only contingently with 'outer' things.

The Rationalists and Kant

. . d ith 'Cartesian dualism'. Is it coherent? Manych· the picture associate WISU IS .. phers deny that It IS.philoso

449

1.6. God . Christian But it was not only for this reason that he

Descartes was a pIOUS. of God Without such a proof, he argued, there sought to prove th~;~~~t:e scepticism: nothing would be certain beyond a would be no way g If B establishing the existence of a supre~ely handful of truths about myse ~h Yh othesis of the evil demon. We obtam an good and wise God whedehstro

y l~ iS~ we take it to be, when correctly usingabsolute guarantee t at t e wor

our God-gihir~endpowdeprifts'hMeditations and elsewhere, Descartes gives two argu-In the T an f the existence of God:

ments or bei Whence came this idea? Not from 1. I have the idea of a most perfect embg. uch reality (perfection) in the. . rfect There must e as m .

me, since I .am 1m~e '. ed in it 'objectively' (i.e. in the object that It repre- cause of an Idea as IScon tam f mv idea of God which is as great as God. sents). Hence there must be a cau~e:m m~: and adds a new twist to the theory This argument is very strange an , cu 'of scholastic terminology ('formal'

. hid by Descartes s use . h of ideas. It ISnot e pe . . . d the most difficult step m t e' . ive') b his disposition to regar , and objective ,nor ! din ara raph) as self-evident. (Descartes sargument (sentence 4 m the prece g.p. g )

fhi ningis at Principles, 1. 17.11. best explanation 0 s mea . I have an idea of a most perfect

2 A version of the ontological argument. . all erfections be~g; I clearly and distinctly perceivHethat suhic.h~dbeea~~~~=::~st:nce, which

alirv i ry degree ence t s 1 and hence re ty m eve . f h thing Descartes adds can this' . t ist (0 no ot er, ,means that God s essence IS 0 exi .

be said.). . ill hi hly controversial; most philosophersThe ontological argument IS st g I think there is something wrong with it-but what exact y? d ill

Since God is no deceiver, it follows that my ~aculties~l;~:et~y ~~!~~~~e: w lead to truth rather than error. God underwntes my

1.7. The Cartesian Circle

. 11 onsidered to be the greatest stumbling-We now encounter what ISge~era y c . If I rely on my cognitive pow- bl k i , hilosophical enterpnse. can ,

oc in Descartes s p . h d I ot need to assume God s. h t God exists t en 0 n ers only on the assumption t a h' d . not Descartes's argument. . d l't) In ot er wor s, ISeXistence m or er to prove .

viciously circular? .. wn can be expressed in many ways. It was The Cartesian circle, as It. IS~o b'~ctions to the Meditations, and Descartesfirst diagnosed by Arnauld, m his 0 ~

450 Roger Scruton

~eplie~to it (Second Objections and Replies, 125-6, 140-6). In effect the objection IS sa~g th~ following: either clear and distinct perception is a guarantee of ~ruth, ~ whi.ch case we can know what is true without invoking God; or else it ISnot, ill which case we cannot prove God's existence.

Matters are made difficult by Descartes's admission that the demon could deceive me e:en abo~t those truths that seem most certain, including the truths of mathematlcs. For ISnot mathematics a realm of clear and distinct ideas?

.O~e way out of the circle is suggested by Descartes's own reply (and also by Princtples, 1. 13.9-10): we can doubt our clear and distinct ideas, but only in ret- rospect, when doubt concerns the reliability of memory. Truths that have to be proved by a series of steps may be doubted, in so far as we rely on our memory ~o~ssure.us that the proof was carried out. But when a proof'is before our mind m ItSe.ntlrety, we can be sure o~it; we are granted an 'intuition' of its validity, ~d ~ w~ cannot doubt. The Idea of intuition was to play an important part in Spinoza s theory of knowledge .

.Ev~n so, the cn:cl~points to a peculiar feature of Descartes's philosophy. His cntenon of truth ISinternal. to ideas. Locked within the realm of ideas, he none ~e less supP?ses that he can choose the true from the false among them. And hi~ test of this is that there are some that he cannot doubt. He then builds a bndge to God, and calls on God to guarantee his other claims to knowledge. But why does Descartes's inability to doubt that p show that p is true?

1.8. The Absolute Perspective

O~e. way. of .loo~g at Descartes's philosophy is suggested by Bernard Williams, m his stimulatinp commentary. Descartes's professed aim is to seek founda~ons for his claims to knowledge. And the only place in which these f~un~atlons could be found is his own mind-among the ideas which are before his mind when thinking. His very method leads him into the subjective realm.

~ut. his subjective point of view is unreliable: it is that of a sensuous being, the maJonty of whose beliefs arise through sensory experience. Tojustify any claim to knowledge he must rise to another perspective, in which he can confront t~gs ~s they.are, and not as they seem. This means acquiring an 'absolute' viewpoint, which does not merely reflect the world as it appears, but which sh?ws it as it is. Only reason can provide that viewpoint. To put it another way, things really are as they seem to reason. That is the hidden meaning of the doc- trine of' clear and distinct' ideas. (Hence the argument about the wax-precur- sor of so much later philosophy, from Locke's discussion of primary and secondary qualities, to Saul Kripke and Hilary Putnam on 'natural kinds")

But can we reach this absolute viewpoint, starting as Descartes does, from the narrow ~er~pective of a self-conscious and doubting individual? Maybe we could reach It, if we could prove the existence of God, whose perspective it is.

The Rationalists and Kant 451

The suspicion is, however, that no proof of God's existence is available from our erspective. Any proof must covertly assume that we have already obtained that

;bsolute conception' of reality to which we are in fact merely aspiring.

1.9. Other Matters

The following should be borne in mind by those who wish to make a special study of Descartes:

1. Descartes's theory of the will, and of the distinction between entertaining an idea and assenting to it. (See Meditation 4,59-60; Principles, 1. 33-5. 17-18.)

2. Descartes's theory of substance, and of the dependency of finite substances on God. (See next section.)

3. Descartes's theory of 'common notions', and his attempt at an axiomati- zation of his system. (See Appendix to the Second Replies, and next section.)

2. SPINOZA

Benedict (Baruch) de Spinoza (1632-77) lived in Holland, where his family, who were Spanish Jews, had come as refugees from the Inquisition. He was brought up in the Jewish faith, but was anathematized and cast out from the synagogue on account of his heretical views. These views had been acquired through his study of Descartes, and through friendships with Christian and Cartesian thinkers. His defence of freedom of conscience, in the anonymously published Theologico-Political Treatise (1670), caused him to fall out with the synod of the Calvinist Church, and hence with the civil authorities. As a result of these trou- bles, Spinoza withheld his masterpiece, the Ethics, from the press, and lived in retirement, refusing the offer of a professorship at Heidelberg, and developing his philosophy through correspondence with other scientific and philosophical thinkers. Spinoza had wide-ranging interests, in politics, law, biblical scholar- ship, and painting, as well as mathematics and physical science. He carried out experiments in optics, and the grinding of lenses for these experiments may have exacerbated the consumption which brought him to an early death.

An earlier treatment of some of the themes of the Ethics is contained in the short and unfinished Treatise on the Emendation of the Intellect. In addition to those two works, Spinoza wrote the Theologico-Political Treatise referred to above, an unfinished Political Treatise, and an exposition of the philosophical system of Descartes (Descartes's Principles of Philosophy, published in 1663). However, despite Spinoza's enormous importance as a political philosopher, we shall be concerned solely with his metaphysical theories and their ethical con- sequences.2

2 Spinoza wrote in Latin; the available translations are described in the Bibliography.