Descartes’s Meditations is among the most influential texts in the history of Western philosophy. Many thinkers have challenged or rejected his thought, some of them almost totally, but his rigorous questioning of traditional certainties is at the source of most subsequent philosophical developments. The criticism he has received and continues to receive is a backhanded compliment he would not have appreciated, but an index, nonetheless, of the power of his philosophy.
Descartes was born in 1596, in La Haye, a town in Touraine (central-western France): the family home was in Châtellerault, in the neighbouring province of Poitou.1 France was emerging from a civil war between Catholics and Protestants that had lasted for over thirty years. His family’s background was in the legal profession and the royal administration. The office held by his father conferred noble rank, but such office-holding nobles had far less prestige than the military nobility. Yet Descartes, as Ian Maclean observes, derived a sense of status from this background, borne out in his later attitudes, including a tendency to refuse to be identified as a professional scholar.2 In 1607 he entered the Jesuit college of La Flèche, near Le Mans, where he received an excellent education, which he describes in Part I of A Discourse on the Method. After leaving school in 1615 he attended the University of Poitiers for a year, emerging with a degree in law. But he did not follow a legal career: instead, in 1618 he did what many young gentlemen did, namely volunteer for military service. He enlisted first in the army of the United Provinces (the Netherlands) under Prince Maurice of Nassau. During his stay in the Netherlands he met the mathematician and scientist Isaac Beeckman, who became an intellectual inspiration for him. In January 1619 he left Maurice’s army, and travelled to Germany, where he joined the army of the Catholic Maximilian, duke of Bavaria. While billeted at Neuburg in November 1619, sheltering from the winter in a stove-heated room, he began, he tells us in Part II of the Discourse, his search for a new method of seeking truth. On the night of 10 November he had a series of dreams which he associated with intellectual inspiration. He may have been present at the Battle of the White Mountain near Prague in November 1620, the first engagement in what became the horrific Thirty Years War. He returned to France in 1622, travelled to Italy in 1623, returned to France in 1625, and in 1628 left for the Netherlands, where he would spend the next twenty years in various places. He seems to have relished the isolation of being a foreigner, and the United Provinces was a more tolerant society than most. In 1635 he had a child, Francine, by a servant called Helena: Francine’s death in 1640 seems to have been a source of great grief. For much of the 1640s he was engaged in controversy, with Dutch Protestant theologians and with his former disciple Regius. He also conducted a sustained correspondence with Princess Elisabeth of Bohemia, whose intelligent and critical engagement with his philosophy encouraged him to develop the psychological and ethical aspects of his thought. In 1649 he travelled to Sweden to take up a position at the court of Queen Christina. He died in Stockholm of pneumonia in February 1650.
Throughout the 1620s and the early 1630s Descartes was developing his scientific work, without publishing it. He was committed to the mechanistic conception of the physical world, which has been excellently defined as follows: ‘All natural phenomena … can be explained in terms of the arrangement and motion (or rest) of minute, insensible particles of matter (corpuscles), each of which is characterized exclusively by certain fundamental and irreducible properties—shape, size, and impenetrability.’3 His plans to publish Le Monde, a treatise explaining the universe on mechanistic principles, had to be shelved when, in 1633, the Roman Catholic Church condemned Galileo for supporting the heliocentric view of the universe, to which Descartes himself was committed.4 In 1637 he published Discours de la méthode pour bien conduire sa raison et chercher la vérité dans les sciences (A Discourse on the Method of Correctly Conducting One’s Reason and Seeking Truth in the Sciences), accompanied by three essays on optics, geometry, and meteorology. True to its title, the Discourse sets out a programme and method for scientific research, but does so in the unusual form of an intellectual autobiography designed to justify the apparently strange project of approaching the search for knowledge by rejecting what currently passes for knowledge. Four years later Descartes published the Meditationes de prima philosophia (Meditations on First Philosophy, in which the existence of God and the distinction of the human soul from the body are demonstrated). This was followed in 1644 by the Principia Philosophiæ (Principles of Philosophy), which expounded his metaphysical and scientific theories in textbook form, and in 1649 by Les Passions de l’âme (The Passions of the Soul), which examines mind–body interaction with particular reference to the emotions.
In a letter of 1629 Descartes refers to ‘a little treatise’ he is working on (to Gibieuf, 18 July 1629, AT 1. 17);5 this is normally identified with the unfinished ‘little treatise on metaphysics’, dedicated to proving the existence of God and the soul (to Mersenne, 25 November 1630, AT 1. 182). This work has been lost or destroyed. In any case, he explains to Mersenne that he wished to postpone publishing his metaphysical discoveries until he had some idea of how his work in physics would be received (15 April 1630, AT 1. 145).
Part IV of the Discourse on the Method describes the author’s attempt to find metaphysical positions solid enough to serve as foundations for the edifice of the new science. Here Descartes narrates his project of rejecting all those beliefs in the slightest degree open to doubt; his discovery of the Cogito (‘I think, therefore I am’, or ‘I am thinking, therefore I exist’) as a first principle for his new philosophy; the conclusion from the Cogito that he is, essentially, a thinking thing, a soul entirely distinct from the body; and the generalization, from the experience of certainty afforded by the Cogito, a truth clearly and distinctly conceived, that whatever we clearly and distinctly conceive is true.6 The experience of doubt is an experience of imperfection: but this presupposes the idea of a being more perfect than oneself. Such an idea, Descartes argues, can only come from outside ourselves—from an actually existing perfect being, God. In fact, as an imperfect being, he himself cannot be independent; he could not even exist, were there not a perfect being on which he, and indeed all other finite beings, depended. Subsequent investigations in geometry reinforce the lesson that certainty depends on clear and distinct conception, and suggest a further argument for the existence of God: the concept of a perfect being involves existence, just as the concept of a triangle involves having three angles the sum of which is equal to two right angles. From the concept itself, we can thus infer God’s actual existence. Descartes goes on to argue that all knowledge depends on that of God. If we do not know of his existence, we cannot ward off sceptical doubts about the reality of our bodies and the physical world: indeed, it is only because he exists, and is a perfect being, from whom all our properties derive, that we can be sure that whatever we clearly and distinctly conceive is true. Once, however, we know he exists, veracity being one of his perfections, all sceptical doubts fade away.7
Stated thus baldly, these arguments may seem unconvincing. And certainly Descartes himself was not satisfied with the formulation of them in the Discourse. He explains to a correspondent that he only decided at the last minute to include this section at all, implying that he wrote it under pressure; more importantly, he says he had toned down the sceptical arguments he there considers, as being unsuitable for a general readership, and had not sufficiently explained some of his principles.8 The sceptical case—an indispensable preliminary to his own reconstruction of knowledge—is given its full force only in the Meditations—written in Latin for the learned.9 But the Meditations are more than an expanded version of Part IV of the Discourse. The substance of the argument is very similar: but its ordering is altered, in ways that are philosophically significant.
The Meditations on First Philosophy are as original in philosophical form as in content. ‘First philosophy’ would have been recognized by Descartes’s readers as synonymous with ‘metaphysics’, the study of being in general, rather than particular kinds of being: but although he speaks of the work as his ‘metaphysics’, he prefers the title ‘Meditations on First Philosophy’, because the book deals ‘not specifically with God and the soul, but in general with all the first things we can know by philosophizing’.10 And indeed, Descartes’s ‘metaphysics’ or ‘first philosophy’ foregrounds questions of what we can know (what would nowadays be classed as ‘epistemology’ rather than ‘metaphysics’) as a prelude to discussion of what exists. But the word ‘Meditations’ itself suggests a radically new approach to philosophizing, affecting the whole form of the work. A typical scholastic treatise would have been composed in forms based on scholastic pedagogical techniques, in which debate or ‘disputation’ on opposite sides of the question played a key role. The subject-matter would have been divided into a series of ‘questions’, or debates, which might themselves be subdivided. Arguments on both sides of the question would be given, supported by accepted definitions and principles, and quotations from authoritative sources, especially Aristotle. The author’s eventual resolution of the problem would thus be situated explicitly in relation to the views of other scholars, from the recent or remote past: he would be seen, and would have seen himself, as contributing to an ongoing debate.
Descartes’s approach is utterly different. He makes no reference in the body of the text to other thinkers’ views, in accordance with his opinion that everyone is entitled to write what they think true, without worrying about whether they are disagreeing or agreeing with others.11 Moreover, the title ‘Meditations’ presents the work as something other than a chain of philosophical argumentation, and links it, rather, to religious exercises.12 In the Second Replies, Descartes explains the importance of his distinctive approach: ‘I wrote Meditations, rather than Disputations, as philosophers normally do, or Theorems and Problems, in the manner of geometers, so that by this fact alone I might make clear that I have no business except with those who are prepared to make the effort to meditate along with me and to consider the subject attentively’ (p. 101). Thus, in the First Meditation Descartes is not simply putting forward abstract arguments in favour of distrusting the senses. In the Second Replies, he suggests that ‘readers [should] dwell on the matters contained in it, not simply for the short period of time required to read it, but for several months, or at least weeks, before they go on to the rest of the work’ (AT 7. 130). The temporal dimension is marked in the text itself by such expressions as ‘yesterday’ (p. 17), ‘these last few days’ (p. 38), ‘these past days’ (p. 63), suggesting that each Meditation is the work of a day (even though the reader may need to extend these ‘days’ in order to assimilate the material properly). The ‘withdrawal of the mind from the senses’ Descartes recommends as a precondition of the search for truth may well seem more reminiscent of spiritual techniques than of scientific enquiry:13 yet it is essential, he thinks, if our search for truth is not to be vitiated at the start by the long-held habits of thought, in which what we know by the senses is the most accessible and most solid reality.
Descartes was well aware that the novelty of this approach would be liable to arouse suspicion in a learned readership for whom what we might value as originality might well appear mere eccentricity and arrogance. He adopted various strategies aimed at overcoming this resistance. He hoped to receive the endorsement of the Sorbonne, the highly influential Theology Faculty of the University of Paris (for his letter to the Faculty see p. 3 below), and the first edition claims the work was so approved.14 Another strategy bore more abundant fruit. The Meditations eschew the scholastic practice of formally setting out objections to one’s position and replies to these objections. Instead, Descartes prevailed upon his friend the theologian, philosopher, and scientist Marin Mersenne, one of the great intellectual networkers of his age, to solicit objections from a variety of competent readers. The objections and Descartes’s replies to these would be printed along with the main text of the Meditations.15 Descartes’s hope, repeatedly expressed in the Replies, was that the objections would be sufficiently comprehensive and searching to convince readers that his text had been as rigorously examined as possible, while his replies would convince them that it was invulnerable. The Objectors were, indeed, a varied and mostly distinguished group, including Mersenne himself, Pierre Gassendi, the English philosopher Thomas Hobbes, and Antoine Arnauld, who would soon win fame as a powerful and controversial theologian.16 The Objections and Replies are of vital assistance to the understanding of the Meditations. They are therefore summarized, and the most important passages quoted, in this edition. Two sets, the Third and the Fourth (Hobbes’s and Arnauld’s respectively), are included unabridged, Hobbes’s because of his standing as a philosopher, and Arnauld’s because Descartes thought him the most penetrating of his readers (to Mersenne, 4 March 1641, AT 3. 331).
The first edition of the Meditations, including six sets of Objections and Replies, was published by Michel Soly in Paris in late August 1641. Descartes seems to have been dissatisfied with it (it contained many printer’s errors), and started work on a second edition, to be printed in Amsterdam by the famous firm of Elzevier. It appeared in January 1642, and contained a seventh set of objections from the Jesuit priest Bourdin, with Descartes’s replies, and a letter to Dinet, a former teacher of Descartes at La Flèche, who was now head of the French province of the Society of Jesus.17 In 1647 a French translation (Méditations métaphysiques touchant la première philosophie) was published: the Meditations themselves were translated by a great nobleman, the duc de Luynes, a sympathizer of the Jansenist religious movement, and the Objections and Replies by Claude Clerselier.18 Descartes himself, according to the publisher’s preface to the French edition, checked the translations (AT 9. 2–3). But there are two exceptions here. This 1647 translation did not contain the Seventh Objections or the letter to Dinet. Clerselier’s translation of these was published in the second French-language edition in 1661, but this was not revised by Descartes. Besides, Descartes did not initially wish the 1647 translation to include the exchange with Gassendi (the Fifth Objections and Replies). He consented, eventually, to its inclusion, but did not revise the translation. This edition also contained a letter by Descartes to Clerselier addressing a number of points (‘instances’) extracted from Gassendi’s Disquisitio metaphysica, published in 1641, containing his original objections, and criticisms of Descartes’s replies.19
Descartes’s approach to the problem of truth was strikingly innovative. Truth was not to be sought by mastering a range of authoritative texts, and analysing the questions to which the reading of these might give rise, with full attention to the variety of views that might be taken. What was required was an individual search, conducted along the correct methodical lines, and the correct method involved divorcing oneself from one’s inveterate tendency to turn to the senses for information about the world in which one lives. More particularly, it involved a wholesale repudiation of one’s former beliefs: not merely casual opinions but deep convictions.
It is some years now since I realized how many false opinions I had accepted as true from childhood onwards, and that, whatever I had since built on such shaky foundations, could only be highly doubtful. Hence I saw that at some stage in my life the whole structure would have to be utterly demolished, and that I should have to begin again from the bottom up if I wished to construct something lasting and unshakable in the sciences…. I have withdrawn into seclusion and shall at last be able to devote myself seriously and without encumbrance to the task of destroying all my former opinions. (p. 17)
But what need for such an unconventional approach? It puzzled many of Descartes’s contemporaries, who would have been content, where certain knowledge was unavailable, with probabilities. But Descartes was urging them to put the probable on a level with the absolutely false.20 Now, it is perfectly possible to offer a purely philosophical rationale for his approach.21 It is equally possible to seek to focus on ‘the specific question to which Descartes may have intended his doctrine of certainty as a solution’, and thus to read the Meditations more in their historical context.22 Some have read it as a response to the revival of ancient scepticism, to which Montaigne’s essay ‘Apologie de Raimond Sebond’, first published in 1580, had given a powerful expression. Montaigne’s challenge to all claims to achieve knowledge by purely human means was inspired by the ‘Pyrrhonist’ strand of scepticism represented by Sextus Empiricus (c.AD 160–210). Pyrrhonism challenges any attempt to achieve knowledge of a reality behind appearance. Snow looks white: but whether it is white or not we cannot know. Pyrrhonism makes no truth-claims itself: it does not even say: ‘We cannot achieve knowledge.’ It merely undermines everyone else’s truth-claims. Any argument can be matched by an equally convincing counter-argument. We have no criterion or mark that guarantees a perception or a proposition as true. In particular, Montaigne draws on the Pyrrhonist argument that all our knowledge is unreliable, because it is ultimately based on sense-perception, which is untrustworthy.23 (Scepticism of this kind did not necessarily imply rejection of religious belief: Montaigne presented it, rather, as a justification for religious faith.) Descartes’s presentation of sceptical arguments certainly owes much to Montaigne.24 But his ultimate aim is quite different: to use scepticism to root out not all claims to knowledge, but invalid ones, in particular the established Aristotelian philosophy for which he aimed to substitute his own mechanistic theories. (Descartes asserts that the Meditations contain all the principles of his physics (to Mersenne, 11 November 1640, AT 3. 233), but asks Mersenne to keep this quiet, to avoid alienating Aristotelian readers, who he hopes will assimilate his principles before they have realized that they make Aristotle’s untenable (28 January 1641, AT 3. 297–8).) The use of scepticism, then, is a demolition exercise designed to clear a space for the laying of new and solid foundations, not only in metaphysics but in science.25
Although Descartes retains some key Aristotelian concepts (the difference, for example, explained below, between substance and accident), he rejects the Aristotelian heritage in more ways than can even be summarized here. I shall focus on merely two aspects in this section: others will emerge in the Explanatory Notes.
First, Descartes rejects the Aristotelian conception in which bodies are seen as combinations of fundamental elements (fire, air, water, earth), themselves understood as combinations of fundamental qualities (hot, cold, wet, dry), and in which their movements are ascribed to a tendency or ‘inclination’ of the different elements to return to their place of origin (a flame moves upwards, because the element of fire belongs in the upper regions of the universe; a stone downwards, because the earth of which it is composed seeks its resting-place at the centre of the universe).26 He argues in Le Monde that a world exactly similar to the world we experience today could in theory have been formed out of homogeneous matter, credited with no qualities beyond extension (possession of length, breadth, and depth) and divisibility into parts: if different movements were produced by God in the different parts of matter, the ultimate result would be the formation of an ordered cosmos, such as the one we inhabit. (Descartes states the theory as a fiction so as to avoid the appearance of clashing with the biblical account of creation.)27 The later Principles of Philosophy restate it, but in a less polemical fashion, so as not to provoke Aristotelian ire.
Now the philosophical strategy of the Meditations enables Descartes to conclude that matter has, in fact, no basic properties but those (extension, divisibility, etc.) presupposed by the mechanistic conception.28 This strategy—this is the second point—involves showing that what we think we know through the senses is in fact unreliable, and that true knowledge must be sought independently of the senses through the understanding alone. Here Descartes clashes with a key Aristotelian thesis, summed up in the scholastic axiom (which he quotes in Part IV of the Discourse) that ‘there is nothing in the intellect which has not previously been in the senses’:29 that is, that all our concepts, even those of immaterial entities, are formed, by means of abstraction, out of sense-perceptions. (In rejecting this Aristotelian epistemology, Descartes has been seen as reviving the metaphysical approach of St Augustine.)30 Alternatively, Descartes’s break with Aristotelian scholasticism has been seen as powered by a metaphysical rather than (or as well as) a scientific programme: as a rejection of the generally accepted view that knowledge that a substance exists must precede knowledge of its essence or nature.31
There is a third possible contextual factor: the existence in 1620s Paris, perhaps amplified by the anxiety of the religious, of unbelievers, denying the existence of God and the life after death.32 (Not all unbelievers were Pyrrhonists, nor all Pyrrhonists unbelievers.) In producing a philosophy that made the existence of God and the immateriality of the soul certain, Descartes was not simply laying foundations for science: he could claim, as he does in his letter to the Sorbonne, and quite sincerely, to be serving religion by depriving unbelief of any claim to rational justification.33
All of these arguments have historical relevance and plausibility; and we can continue to seek for ever-deeper knowledge of the context of Descartes’s thought while agreeing with Jorge Secada that there is no ‘single key to the interpretation of the Cartesian philosophy’.34
It has been stressed above that the form of the ‘meditation’ is essential to Descartes’s philosophical enterprise. Descartes eschews the impersonal discourse of scholastic philosophy or of mathematics: instead, the text narrates a series of discoveries made by a figure who refers to himself in the first person—an example of what Charles Taylor has called ‘radical reflexivity’, in which one focuses not on the objects of one’s experience, but on oneself as experiencing it.35
It would be a mistake to identify this figure with the individual Descartes: when Descartes wrote the Meditations he knew already what he thought about many issues about which the ‘I’ in the text appears initially to be ignorant or in error or confused. Hence it has become conventional to refer to the ‘I’ of the text as the Meditator, and I follow this usage here.36
The reader’s task, then, is in a sense to identify with, to think along with, the Meditator.37 But Descartes knows that there must be many resistances to such an identification, to the call to abandon spontaneous attitudes. The work of breaking down this resistance devolves partly on the writing, the style. Descartes scorns one of the objectors, Gassendi, for resorting to rhetorical shifts instead of philosophical argument (Fifth Replies, p. 183). But in fact he himself resorts to rhetoric: it is an integral part of his strategy. This is not to say that he uses rhetoric where he should be using philosophical argument, or to plug gaps in his arguments; or to assert, in deconstructionist fashion, that his discourse is controlled, unbeknownst to himself, by the play of rhetorical structures, which undermine the attempts to operate with pure concepts. (Hobbes, to be sure, accuses Descartes of substituting metaphors for proof: but Descartes replies, quite fairly, that he is using metaphor to clarify not to prove (Third Objections, XIII, p. 121 ).) Rhetoric has a specific function in the Meditations, which is not dissimilar to its function in the Discourse. There, the metaphors of the journey, the building, the city, and so forth were used to justify the apparently eccentric or arrogant project of rejecting the existing structure of knowledge in order to erect a new one.38 Here metaphors and other rhetorical devices are used to unsettle the reader, to disturb his or her spontaneous convictions, first, about the world and his or her own relation in it, and secondly, about his or her own fundamental nature or self.
Thus, in the First Meditation Descartes is not simply giving a set of arguments for doubting the evidence of the senses. He is trying to induce a state of confusion and anxiety in the reader. In the unfinished dialogue La Recherche de la vérité par la lumière naturelle (The Search for Truth by Means of the Natural Light), Descartes’s spokesman says that his arguments for doubting the senses will have been successful if they appeal sufficiently to the listener’s imagination to make him afraid of them (AT 10. 513). This appeal to the passions is traditionally one of the functions of rhetoric. One of Descartes’s rhetorical devices is to incorporate an element of dialogue into the structure of the Meditation. Especially, but not only, in the First Meditation it is not always clear at once who is speaking, or how we are supposed to take what is being said. It is important, then, to sort out the different voices in the text: one, sometimes rather bluff and blustering, which offers a defence of common-sense beliefs; the other, sometimes mordantly ironic, which corrodes them with sceptical arguments. But it is also important to recognize that we cannot securely distribute them between clearly identified figures, as we can in his The Search for Truth, where Poliandre represents the average gentleman, better acquainted with life than with books, Epistémon the scholar, and Eudoxe the correct thinker. In the First Meditation the speaker has confidently prepared himself for the wholesale and fearless demolition of all his opinions. But when he comes to assess the evidence of his senses, he cannot quite rest content with the prudent maxim of never wholly trusting those who have once cheated you, as the senses have sometimes done by giving us false information. The hammer is already uplifted to smash his belief in the senses, when he suddenly loses heart and lowers it. Surely, he tells himself, there are some things I can take for granted, on the basis of sensory evidence; but then he argues himself into rejecting this reassurance. Throughout this Meditation a debate, an argumentative duel, is going on within the Meditator, between the voice of doubt and the voice of common sense: again and again, he tries to resist the assaults of doubt and remain secure in a fall-back position; again and again, this security is denied him.
Descartes’s sceptical arguments, like those of his proxy Eudoxe in The Search for Truth, appeal to the imagination. We are invited to imagine (ourselves as) the Meditator sitting by the fire in his gown; and then to consider that he might be dreaming, and imagine him in bed, dreaming he is sitting by the fire. The difference between the two states is artfully suggested by a series of antitheses. I think I am sitting: I am in fact lying down; I think I am by the fire: I am between the sheets; I think I am wrapped in my gown: I have taken off my clothes. The speaker’s nakedness (real or imagined) associates him with the poor naked wretches of madmen he has just been thinking of. The writing blurs the distinction between sleeping and waking, madness and sanity. When I am stupefied by my inability to find reliable grounds for distinguishing sleeping from waking, maybe this stupor is real, and I am in fact asleep. I try to reassure myself: look, I can move my head, I am in control, therefore awake. But the movement of the head is rendered by the Latin verb commoveo, which tends to denote a violent or agitated movement. We might imagine it as the kind of jerky, exaggerated movement one makes when one is gesturing to make a point: ‘Look, I am not asleep: I can move my head.’ But such jerky movements are also characteristic of the person struggling against sleep, ‘nodding off ‘, in fact, and this casts doubt on the Meditator’s subsequent claim that he is knowingly and deliberately stretching out his hand, which a sleeper could not do. The appeal to the imagination, and the ambiguities of the writing, thus help to convey the strictly philosophical point that all of us are liable to vivid illusions of presence that in fact have no objective foundations: that we cannot settle a philosophical doubt by simply appealing to a supposedly self-evident division between the sane and the mad, and that, if such a division exists, we cannot know, from our subjective experience, on which side of it we should fall.39
This antithetical structure can be found on a larger scale in the use of metaphors. The end of the First Meditation juxtaposes images of sleeping and waking, darkness and light. But perhaps the key metaphor here, as in the Discourse, is that of building, solidity being contrasted with precariousness. The Meditator realizes that existing knowledge is unreliable: it must be demolished, and rebuilt from the bottom up.40 Yet his search for solid ground on which to build seems doomed: doubt has pushed him into a deep whirlpool, so that he can neither touch bottom nor swim to the surface. Eventually, he finds a stable if narrow footing on the discovery of his own existence. At this point the building can commence.
At the start of the First Meditation the Meditator is setting out to fulfil a long-held ambition: to achieve certainty in the sciences.41 To this end, he decides he must abandon all his former opinions. To disprove each and every one of them would perhaps be impossible: but he decides to reject any he can find some reason for doubting. It would take for ever to examine them one by one, but he could demolish them all at once, by unsettling their foundations. Up to now, he believes, all his beliefs were founded on sense experience. What is meant here is that they involve either specific perceptions (e.g. the sun is yellow) or concepts that (according to the prevailing Aristotelian-Thomist theory of knowledge) ultimately derive, by abstraction, from such perceptions.42 But the senses are sometimes unreliable: therefore, if we reject what is open to doubt, we must reject what they seem to teach us. Various attempts to vindicate the senses’ reliability, at least to a certain extent, are tested out. These founder on the dream hypothesis: that is, given that in dreams we have vivid perceptual ‘experiences’ of non-existent objects, how can we know that our so-called waking experience is not an illusion?43 If the senses are unreliable, the Meditator wonders whether mathematical truths, at least, are immune to doubt. But two sceptical hypotheses invalidate any attempt either to rehabilitate sense-perception or to fall back on mathematical propositions as the sole field of certainty. First, the Meditator might be being deceived by God into wholesale error; secondly, if there is no God, and he himself has come into being purely by blind fate or chance, he may be so intrinsically defective as to be perpetually in error. The deep-rooted beliefs of a lifetime make these ideas hard to entertain: but in order to combat the pressure of these beliefs, the Meditator imagines an all-powerful evil spirit systematically deceiving him. The thought that this deceiver might be at work will protect the Meditator against mistakenly assenting to any false beliefs.
Not all Descartes’s initial readers saw the benefits of such a strategy. Gassendi wondered why he had to reject all his former beliefs as false: why could he not pronounce them merely uncertain, and subsequently pick out those he found to be true? Besides, he cannot really believe, as he pretends to, that his former opinions are all false, and that he is being systematically deluded by dreams or a demon. Bourdin argued that if he takes doubt to such extreme limits, he denies himself any future possibility of certainty.
This position seems hard to challenge, as the Meditator flounders in the waters of doubt at the beginning of the Second Meditation. But he then realizes that the ultra-sceptical hypothesis of the deceiving spirit paradoxically offers him one piece of certain knowledge. In order to be being deceived, he must exist. Thus, scepticism can be turned against itself. 44 The thinker’s discovery of his own existence, known traditionally as the Cogito, is one of the most debated moments in Western philosophy. How exactly does the Meditator acquire knowledge of his existence? In A Discourse on the Method, it appeared to be by an inference: ‘je pense, donc je suis’ (I am thinking, therefore I exist) (Discourse, 28, AT 6. 32). Here the inferential structure seems to be replaced by a direct intuition: ‘I can finally decide that this proposition, “I am, I exist”, whenever it is uttered by me, or conceived in the mind, is necessarily true’ (p. 18).45 But does this not require prior knowledge of a general principle, ‘Whatever thinks, exists’, which is not alluded to here? What is the relationship of the knowledge of one’s own existence to this general principle? If the former is inferred from the latter, what right has Descartes to presuppose the general principle? Descartes himself discusses the point in the Second Replies (§3, p. 92). Further clarification is provided by the ‘Conversation with Burman’ (AT 5. 147). What complicates the matter is that Descartes’s own conception of intuition includes not only truths grasped immediately, but propositions directly inferred from these (Rules for the Direction of the Mind, III, AT 10. 368–70). If the knowledge of one’s own existence is intuitive, into which of these categories of intuition does it fall? Do I grasp immediately that I exist or do I infer it from the primary intuition that I think?46
The second objection to the Cogito to be mentioned here does not, unlike the first, date back to the original Objections. It was first, apparently, put forward by the eighteenth-century German thinker Lichtenberg, who argued that Descartes had no right to assert ‘I am thinking’: at most he could say ‘there is thinking going on’.47 The objection is vigorously urged by Nietzsche.48 Descartes himself makes it quite clear that he believes he has an irreducible experience of thought as his own thought: ‘For that it is I that am doubting, understanding, wishing, is so obvious that nothing further is needed in order to explain it more clearly’ (p. 21).49 An alternative critique, developed by Kant, and restated by Husserl, holds that Descartes failed to distinguish the ego we encounter in experience and the ego presupposed as subject of knowledge but inaccessible to experience.50
The Meditator, at any rate, believes that through his thinking he has gained knowledge not only of his existence but of his nature. He compares what he now knows of himself with his former beliefs about himself, which happen, though Descartes cannily refrains from pointing this out, to be those of the orthodox Aristotelian philosophy of his time. According to these beliefs, all the functions of life (nourishment, motion, sensation, and thinking) pertain to the soul, which is imagined as a mysterious air or fire diffused through the solid body. But the deceiver hypothesis leads the Meditator to eliminate both the body and those functions ascribed to the soul (like motion and sensation) that depend on the body. Thought is all he is left with that cannot be separated from him. He can say, then, that he knows himself to be (nothing other than) a thinking thing (in other words, a mind or soul, using this last term in what he now knows to be the proper sense), and his knowledge of himself comes purely and simply from his thinking, not from sense-experience which might, for all he knows, be illusory. (As is pointed out later, this is simply a provisional state of knowledge. The Meditator will later know himself also as, in another sense, a composite of soul and body.)
During the First Meditation the Meditator became aware of the pressure of custom, that is, of lifelong beliefs. He has the same realization now: he cannot quite convince himself that he does not, after all, know bodies better than he knows himself. Hence he conducts an experiment with a piece of wax. It possesses various sensible qualities: but these are completely altered when it is heated. That he knows it is the same wax is therefore an intellectual judgement, not one based in sensation. Likewise, he realizes, recognizing moving shapes as people walking down the street is an intellectual, not a purely visual, act. In fact, exploring varieties of perceptual experience, he is getting to know not so much bodies, which after all may not exist, as his mind, which is doing the perceiving.
One result, then, the knowledge of his own existence, seems definitely acquired at the start of the Third Meditation. What distinguishes this experience of certainty is that it is a very clear and distinct perception.51 This seems to suggest that the Meditator could formulate a general rule: whatever I very clearly and distinctly perceive is true. Sense perceptions do not have this kind of clarity and distinctness (we tend to confuse ‘seeing the sun’ as a thought (‘I seem to see the sun’) with an actual perception of a hot yellow body outside us): those of mathematics do. But suppose a deceitful God is at work on him: might he not be in error even about mathematical propositions? He can know nothing until he has come to a decision on the deceitful God hypothesis.52
Descartes follows an apparently roundabout route to the existence of God. He distinguishes three categories of ideas: innate, adventitious (deriving from things outside himself), and factitious (invented by himself). Concepts like ‘thing’, ‘truth’, ‘thought’ must be innate, that is, must derive from his own nature: he did not encounter them, that is, in sense-experience, which for all he knows still is illusory. Sensations, he has always thought, are caused by bodies outside him: but these may not exist. Other ideas, like ‘siren’ or ‘hippogriff’, are invented. Essentially, he first decides that his ideas (representative thoughts) of material things might conceivably have been produced by himself. If they were in fact produced by external things, this does not prove they resemble those things.
But the Meditator finds he can distinguish different levels of reality contained in his ideas. This section needs some explanation. First, Descartes draws on the traditional Aristotelian metaphysics of substance and accident. To put it as simply as possible, accidents (e.g. ‘white’) are predicated of a subject (e.g. a jacket). That of which they are predicated, and which cannot be predicated of something else, is a substance.53 Being a jacket is not being a property of some other thing: the jacket is a thing, or substance, in its own right. In this perspective, the accident, or as Descartes prefers to call it, the ‘mode’, is less real than the substance without which it cannot exist.54 And likewise, finite and dependent substances are less real than is an infinite independent substance (supposing one exists) (Third Objections, IX, p. 117). There are, thus, degrees of reality. By the same token, our ideas must contain greater or lesser degrees of reality corresponding to those of their objects—whether or not these objects actually exist. Thus my idea of Odysseus ‘contains’ more reality than my idea of his scar or his cunning; but also more reality than my idea of, say, Stalin’s cunning. The kind of reality contained in an idea is called ‘objective’, in a sense, obviously, quite different from the modern sense.
The Meditator proceeds to argue that the principle that a cause must contain at least as much reality as its effects must apply to objective as well as to actual (what he calls ‘formal’ reality). That there is a stone here requires an explanation (someone put it there). But my idea of a stone (my seeing, or seeming to see it, say) also requires an explanation: that is, its objective reality must be accounted for by some formal reality. In this case, a good explanation for my seeing a stone (a finite substance) would be that there is a stone there (put there by someone). Or it might be that what I am seeing is not a stone but a cricket-ball: perhaps it is too dark or I am too short-sighted to perceive the shape and colour clearly. But the cricket-ball has the same degree of reality as the stone: they are both finite substances. So the causal principle still applies. On the other hand, a mode like ‘short-sightedness’ could not explain the misperception of a specific substance: it does not contain enough reality to account for the reality ‘contained’ in the perception. (Whether the substantial reality of the short-sighted person would suffice is another question: Descartes entertains the possibility that, as a finite substance, I might myself have generated all my ideas of bodies, being finite substances.) The Meditator argues, then, that the objective reality contained in his idea of God, an infinite substance, can be accounted for only by the actual (‘formal’) reality of an existing infinite substance. (The idea could not, Descartes argues repeatedly, be generated by amplification of an idea of finite substance. I have knowledge: I can conceive a being whose knowledge is without limit. But how could I form the idea of greater knowledge than I actually possess from my own limited knowledge, if that were all the knowledge in existence?)
Descartes was well aware that this was an unusual kind of argument for the existence of God. The proofs put forward by St Thomas Aquinas, say, are based for the most part on our experience of change, causation, coming to be and passing away in the physical world. But he did make the concession of offering a variant form of the causal argument, to the effect that the existence of the thinker cannot be explained save by the existence of an infinite being who created him, and indeed sustains him in being from one instant to the next. Now if an infinite being, that is, God, exists, possessing all perfections (for this is part of what Descartes understands by infinite), it is clear he must be no deceiver: for deception involves malice, an imperfection.55
In the Fourth Meditation the Meditator pursues this insight, analysing the nature of error. Error must arise not by the action of God, but from some deficiency in the creature: not an intrinsic flaw, but a misuse of the God-given powers of intellect and will. It occurs, that is, when we choose to make a judgement, which Descartes takes to be an act of will, a choice to affirm or deny that something is the case, when our understanding has no clear and distinct idea on which such a judgement can be based. If, on the other hand, the Meditator makes no affirmation or denial except where he has a clear and distinct idea, he will not fall into error. He can thus rely on the rule he formulated at the start of the Third Meditation: whatever I clearly and distinctly perceive is true.
In the Fifth Meditation he decides that he cannot conclude whether bodies exist or not before he has a clear and distinct idea of what body is. The clear and distinct idea he discovers is of continuous quantity, occupying three-dimensional space, containing various parts, of varying magnitudes, shapes, positions, moving in space over varying periods of time. In addition to this general idea, he has various particular ideas of geometrical entities. Whether or not there are any triangles in the world, he has a certain determinate idea of a triangle’s nature or essence (e.g. the sum of its angles is 180°), which he cannot, as he can with ideas he has invented, alter at will.
Now this furnishes him with another argument for the existence of God. For, since necessary existence belongs to the very concept of the supremely perfect being, he realizes that the concept itself involves the existence of the being that is its object. Thus, from the very idea of the supremely perfect being, we can reliably infer its existence. This argument, known since Kant as the ‘ontological’ proof, was invented by St Anselm (1033–1109), though Descartes seeks to distinguish his argument from Anselm’s. It is one of the most striking and perplexing arguments in the history of philosophy: various criticisms of it are discussed in the notes on the Fifth Meditation and the Objections.
In the Sixth Meditation the Meditator infers, from his clear and distinct idea of material things, that it is possible for them to exist, in the sense that God is capable of creating them. But in order to find out whether they in fact exist, he needs to review his past attitudes to the senses by which he once thought he perceived them. He thus re-traverses the ground he traversed in the Second Meditation, surveying again and in more detail his former beliefs about himself, not simply describing them, but attempting to understand their origin.
He had the sensation of having a body, which he considered as part of himself, if not his whole self; and also the sensation that this body was involved with and affected by other bodies. He registered their effect on himself by pain and pleasure. He was also aware in himself of appetites and passions, and of sensible qualities (besides extension, shape, and motion), such as hardness or heat, light and colour, smells, tastes, and sounds. By means of these he distinguished various bodies such as the sky, earth, and sea. The ideas of these qualities seemed to derive from the presence of bodies outside himself: for the ideas were not under his control and were more vivid than ideas put together by his imagination or found in his memory. Finally, he had a particular relationship to the body he called his own.
Later, he came to doubt the senses, since experience and the reasons set out in the First Meditation seemed to show they were unreliable. Now, however, he does not think they should be treated as altogether doubtful.
However, he knows that whatever he clearly and distinctly understands can be produced by God as he understands it. So if he can clearly and distinctly understand one thing without another, they must be distinct.56 And since he knows his existence purely from thought, he knows himself purely as a thinking thing. So, if he has a body, he must be distinct from it, and capable of existing without it.
But he has certain faculties (e.g. changing place), which must inhere in a substance, and cannot inhere in a thinking substance, because they have no intellectual dimension. So they must exist in a bodily substance. And the ideas he has of sensible things must be produced by a material substance. For his strong inclination to believe they are produced by actually existing physical bodies would be deceptive, if they are merely appearances produced in the absence of such bodies, and God would be responsible for the deception, which is impossible. Therefore bodies exist, even if they are not in reality exactly as our senses confusedly represent them. And he is so constituted as to believe he has a body, to which he is closely linked, because otherwise he, as a thinking substance, could not have a sensation of pain, when there is something wrong with it: he would merely be intellectually aware of the trouble. And his sensations must relate to some properties that really exist in bodies, even if they do not resemble them.57 Sensations, in fact, have the function of indicating what is beneficial or harmful to the body, and from this point of view they are generally reliable: the error is to think that they give information about the essence of bodies in themselves. The process of mind—body interaction is explained. The soul is affected not by all parts of the body, but by a particular part of the brain: whenever this part is affected in the same way by motions in the nerves it presents the same idea to the mind. Thus, an injury to the foot affects the nerves in the foot, and they transmit this experience to the brain, causing the mind to experience pain, and thus initiate action to remove the cause of the injury. When the body is out of order, this process may go wrong, but in general it works to preserve our body in being. We can thus, on the whole, rely on the senses and discard the doubts about them raised in the First Meditation. The difference between dreams and waking experience now appears very clear: waking experience has a kind of continuity, attested by the memory, very different from the disconnected experiences we have in dreams. God’s veracity enables us to rely on this distinction, and thus distinguish waking experience from the illusions of dreams.
It is impossible in an introduction like this to discuss with any adequacy the problems that over the centuries have been detected in Descartes’s argumentation, or the objections that have been raised to his very enterprise of seeking certainty through doubt. Some of them are touched on in the Explanatory Notes. However, I shall mention two here: the circle, and the relation between mind and body.
The most powerful objection to Descartes’s achievement comes in two sentences, almost casually uttered by Antoine Arnauld, author of the Fourth Objections:
I have only one final reservation: how can the author avoid arguing in a circle, when he says we know for certain that the things we clearly and distinctly perceive are true, only because God exists?
But we can only be certain God exists, because this is clearly and distinctly perceived by us. Therefore before we can be certain God exists, we must be certain, that whatever is clearly and distinctly perceived by us is true. (p. 137)
Immense efforts have been devoted both to defending Descartes against this accusation, and to refuting his defence. As Gary Hatfield very well observes, ‘we may […] arrive at different conclusions depending on whether we ask what Descartes intended to argue, as opposed to what he needed to argue to achieve his results (which is what Arnauld asked, and ultimately what we should ask as well)’.58 Many philosophers, especially analytic philosophers, agree with Hatfield that we should work out what Descartes needed to argue, or could and should have argued, because there is a widespread perception that his actual reply is inadequate.
That reply runs as follows:
That I did not argue in a circle when I said that we can be certain that what we clearly and distinctly perceive is true, only if God exists, and we can be certain that God exists, only because we clearly perceive it, is already made sufficiently clear in the Second Replies, §§3–4, where I distinguished between what we clearly perceive in actual fact and what we remember we once clearly perceived. For first of all, we are certain that God exists, since we reflect on the reasons by which his existence is proved; but subsequently it is sufficient for us to remember that we have clearly perceived something, in order to be certain it is true; and this would not be sufficient, unless we knew that God exists and does not deceive us. (p. 158)
Descartes had already replied along the same lines to a similar, but more limited, objection in the second set (Second Replies, §3, p. 92). Following Ferdinand Alquié, we can summarize the two major problems with this reply as follows:
1. Descartes seems to imply that the guarantee of the divine veracity is required only for remembered perceptions, not current ones—but elsewhere he seems to require current perceptions also to be validated in this way;
2. The memory of past perceptions is only a memory like other memories, so how can it be validated by the appeal to the divine veracity, any more than any other kind of memory.?59
Many efforts have been made to find a more satisfactory answer.60 The debate will doubtless continue.
As it will on the nature of ‘Cartesian dualism’. First, it looks as if Descartes has to explain how two utterly different substances, one thinking and non-extended, the other extended and non-thinking, can interact, as his theory seems to require. Descartes does not seem to have been greatly worried by this: he was content to observe that experience shows it takes place, that we have a basic notion of our soul and body as interacting.61 Other philosophers were less easily satisfied, and propounded alternative solutions. Malebranche and others developed what is commonly called an ‘occasionalist’ theory: this holds that, say, a physical event, like the collision between one’s foot and a stone, does not, properly speaking, cause an event in the mind (the sensation of pain); nor does a mental event, my decision to stand up, cause movements in my limbs. Rather, God has established laws, according to which when, for example, contact between bodies takes place, certain sensations occur in the mind, and when a given volition occurs in the mind, certain processes occur in the nerves and the muscles by which the volition is accomplished. The causal efficacy is thus in the laws, and hence ultimately God’s will, rather than the physical or mental events as such. Leibniz formulated an alternative theory of ‘pre-established harmony’. Just as two clocks can be set up so as always to keep time together, likewise God has ordained that a certain sequence of bodily events takes place in parallel with a certain sequence of events in the mind. Spinoza adopted a more radical solution: soul and body are not two distinct substances, but two attributes of the one infinite substance that is all that exists. What we call distinguish as bodily and mental processes are two aspects of the movement of this single substance: a thought-process can be thought of as the expression of a process going on in the body, but no interaction between the two attributes takes place.62
Whether or not Descartes was arguing in a circle is a vital question for students of his philosophy, but it does not engage our deepest convictions about the kind of creatures we are. But the relation between mind and body does. Among philosophers, the view that the mind is an immaterial substance distinct from the body, and capable of existing without it, is, to put it mildly, unfashionable. But in the larger intellectual community, and indeed among some philosophers, it is often perceived as objectionable: as complicit with a pernicious and ultimately repressive devaluation of our physical and this-worldly existence (and perhaps, if it is accepted that the hierarchical distinction between mind and body has, historically, been mapped onto the hierarchical distinction male—female, with the maintenance of gender inequality).63 His denial of souls to animals has been viewed as legitimating a purely instrumental attitude to them, indifferent to the suffering it fails to recognize.64
Be that as it may, the clarification of Descartes’s doctrine remains an enduring interest, and recent analyses have been effectively directed against an oversimplified understanding of it.65 Descartes’s reduction of the ‘self’ to a thinking thing has to be understood as tactical and provisional: it is geared specifically to the discovery of epistemological certitude. Human life in general, however, involves experiences and actions in which soul and body function in unison. It is fair to say, though, that for a full understanding of Descartes’s conception of mind—body relationships we must go beyond the Meditations to later works, the letters to Princess Elisabeth and the treatise on The Passions of the Soul.66 As regards the ideological implications of Descartes’s doctrine, it is difficult to read them off from specific philosophical positions, or to map doctrines onto ideological tendencies, as if materialism were inherently progressive and dualism intrinsically reactionary. These are matters requiring contextual and historical analysis. But one of the surprises that may lie in wait for readers of the Objections, if they are not already acquainted with the medieval Aristotelian tradition, is the realization that Descartes’s distinction between mind and body was perceived by contemporaries, not as reassuring or uplifting, but as downright strange. The physical dimension of thought and experience was not something scholastic philosophers and theologians needed to have revealed by audacious and heterodox innovators like Spinoza. They took it for granted.
They might have been surprised, however, by a new way of doing philosophy: one that respected no authorities beyond the thinker’s own cognitive powers, that dispensed, in particular, with the reading of canonical texts. But, in fact, though sometimes puzzled by the content of Descartes’s arguments, and sometimes convinced his whole approach is wrong, the Objectors do not appear especially scandalized by it. Yet Descartes has often been seen as inaugurating a ‘completely new manner of philosophizing which seeks its ultimate foundations in the subjective’.67 Along with Husserl, Martin Heidegger has influentially propounded this view: Descartes, he contends, is chiefly responsible for the development of a new concept of the subject as coextensive with the human I, and as driven by the quest for power over the entire earth.68 This view of the ‘Cartesian subject’ has also helped to reinforce some of the ideological objections noted above in connection with dualism. Or, again, the ‘Cartesian subject’ has been targeted by exponents of psychoanalysis, who challenge the conception of an ego identifying itself with consciousness. But it is, arguably, misleading to read Descartes retrospectively through a concept of ‘subject’ projected onto rather than discovered in his work.69
Certainly, in philosophy Descartes helped to set the agenda for at least the following century: the work of Spinoza, Malebranche, and Leibniz offered quite diverse solutions to problems deemed to be unresolved in his conception of mind and matter as separate substances, capable of interaction; Locke reasserted the claims of empiricism against him; Hume those of scepticism. Hume in turn provoked Kant into seeking his own solution to the problem addressed by Descartes of justifying scientific knowledge while allowing room for the human free will on which Descartes laid so much stress. One key effect of his philosophy was to undermine the Aristotelian view that in knowledge the mind, so to speak, becomes one with its object, assimilating its ‘form’ or nature without its matter. On this showing truth consists in a match or conformity between the intellect and the thing (‘adæquatio rei et intellectus’). This conception of truth survives even in a philosopher like Gassendi, who was no Aristotelian (see Fifth Objections, IV. 3, p. 176). Descartes’s theory of truth as correspondence is apparently identical: it consists in the conformity of thought to the object (to Mersenne, 16 October 1639, AT 2. 597). But he holds that we have no knowledge of what is outside ourselves except via the ideas we have in ourselves: and therefore our judgements cannot be immediately matched against things. The conformity of the idea to its object is evaluated not in relation to the thing to which the idea relates, but by means of a clarification of the idea itself (to Gibieuf, 19 January 1642, AT 3. 474). How we know our ideas correspond to reality became a major problem for those subsequent philosophers who accepted Descartes’s formulation of the problem of knowledge, but not his solution.
If, perhaps, the influence of Kant or Hegel helped to diminish the presence of Descartes in nineteenth-century thought, he certainly made a comeback in European philosophy of the twentieth century. Though criticizing him in detail, Husserl claims Descartes as an inspiration for his phenomenology, as the very title of his Cartesian Meditations makes clear.70 In Being and Nothingness Sartre adapts the notion of the Cogito to the purposes of his own phenomenology.71 Emmanuel Levinas, whose work has been profoundly influential on contemporary philosophy in the ‘continental’ tradition, shows a profound engagement with the Meditations.72 Philosophy, like every other activity, has its fashions, but, to judge by the history of the three-and-a-half centuries since their appearance, the Meditations are unlikely to lose their position in the front rank of European philosophical texts.