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1 Daniel C. Dennett Tufts University Third draft, December 4, 2006 Descartes's Argument from Design It is not at all impossible for a philosopher to be driven to a conviction by an argument that has never been consciously articulated, an argument the philosopher would have difficulty recognizing and might even disavow. Indeed, philosophers typically work backwards, casting about for suitably presentable arguments to support propositions they find irresistible for reasons to which they have only imperfect access. Tacitly recognizing this, there has been a distinguished tradition of second-guessing among interpreters, who try to impose “better” arguments on their authors than those authors ever dreamt of. A classic case is Jaako Hintikka’s “Cogito, ergo sum: Inference or Performance?” (1962), which argues that contrary to what Descartes himself seemed to be asserting in both the Discourse on Method and the Meditations, the force of the cogito lies in the performatory aspect of saying “I exist.” The obviousness lies in “the existential inconsistency of the sentence ‘I don’t exist’ and therefore the existential self- verifiability of ‘I exist’” rather than on any deduction of sum from cogito. Descartes certainly never formulated the argument from pragmatic self-contradiction that Hintikka adduces, but it may indeed have fueled his confidence in the supreme self-evidence of sum. (Hintikka surmises that this is something Descartes may have “realized, albeit dimly” (p25). And more important than this hard-to-ascertain biographical fact about Descartes, Hintikka’s analysis may help explain why we today find cogito, ergo sum strangely compelling even though we cannot agree on a sound interpretation of it. I want to explore a similarly subliminal argument in Descartes’s Third Meditation, which has always posed a problem for beginning students and their professors, but rather the opposite problem: what Descartes says there is not compelling at all. Descartes offers a notoriously unconvincing argument for the existence of God, based on nothing more than the fact that he, Descartes, has the particular idea of God that he has. This strikes most readers as a desperate move, forced on Descartes by the very success of his skeptical housecleaning, which has left him with precious little in the way of raw materials from which to construct an argument. Having just impressed us with his Olympian standards of systematic skepticism, he spoils the effect by endorsing a principle he seems to pull out of thin air: "in order for a given idea to contain such and such objective reality, it must surely derive it from some cause which contains at least as much formal reality as there is objective reality in the idea." (AT VII, 41). This principle does not seem obvious to our "natural light". In fact, although commentators have written extensively about Descartes's concept of objective reality, they generally don't even try to explain how this causal principle could seem obvious to Descartes. How on earth could Descartes be persuaded by this transparently contrived and 2 unconvincing exercise in scholasticism? I will suggest that whatever the merits of Descartes’s explicit argument in the Third Meditation, beneath the surface there is a very interesting--but ultimately flawed--argument for the existence of God that has at least this virtue: a confused appreciation of it could well have convinced Descartes, even if in the end it is unsound. This is Descartes’s almost unspoken Argument from Design. (As we shall see, he does articulate all the pieces of the argument, without ever putting them together explicitly.) 1. The explicit argument First let's review how the explicit argument in the Third Meditation actually runs. The conclusion carried over from the Second Meditation is not just that he, the res cogitans, exists, but that his ideas, "in so far as they are simply modes of thinking, do exist within me--of that I am certain." (AT VII, 35) Then, after raising the issue of whether or not he can be certain of those of his ideas that are entirely "clear and distinct," and deciding that in order to establish this he must first prove God's existence, and that God is not a deceiver, he turns to his first argument for the existence of God--with both hands tied behind his back, one might say. The complete inventory of his available premises is this: he exists, and his ideas, as modes of thinking, exist. That's all. From this he must construct a proof of God's existence. So, not surprisingly, he turns to his ideas, to see what can be made of them. They come in different varieties, he notes, and "Of course, if I considered just the ideas themselves simply as modes of my thought, without referring them to anything else, they could scarcely give me any material for error." (AT38) Some of these ideas seem to be innate, others adventitious (coming from outside--via the senses, presumably) and still others seem to be invented by him. So long as he is merely talking of how these ideas seem to him, he is not "referring them to anything else" but just describing their properties simply as modes of his thought. "Insofar as the ideas are considered simply as modes of thought, there is no recognizable inequality among them; they all appear [my emphasis] to come from within me in the same fashion. But in so far as different ideas are considered as [my emphasis] images which represent different things, it is clear that they differ widely." (AT40) He is still not "referring them to anything else", but noting their differences in what they represent--or, one might better say, apparently represent--just to keep it clear that no commitment to external things has been made. In this regard, ideas differ widely; ideas representing substances, for instance, "are something more and, so to speak, contain more objective reality" than the ideas of accidents. And, he goes on to add, his idea of God has more objective reality than those ideas "by which finite substances are exhibited." (AT VII, 40) His idea of God, more precisely his idea of a supreme God, eternal, infinite, immutable, omniscient, omnipotent and the creator of all things that exist apart from him "certainly" has in it more objective reality than the ideas that represent finite substances. 3 The term "objective reality" is generally regarded as an unfortunate label for the distinction Descartes apparently had in mind. As Antony Kenny notes, "'Objective reality,' which for Descartes signified something mental, has come by a quirk of history to be synonymous with 'extramental existence.'" (1968, p.132) But even after we have set this awkwardness aside, the concept is apt to strike us as dubious. Suppose I have the idea of a sloop, a one-masted sailboat with two sails. Does the idea of a two-masted sailboat contain more objective reality than that idea? Does the idea of the fastest sloop in the world contain more objective reality? Does the idea of a solid gold sloop larger than the sun and capable of exceeding the speed of light contain more objective reality? The manifest differences between these ideas are indeed readily accessible to Descartes, and to us, independently of whether they in fact refer to or represent anything real independent of themselves, but if this is how one distinguishes the objective reality of ideas, it is a dubious distinction indeed, especially when one sees how Descartes proposes to exploit it: "Now it is manifest by the natural light that there must be at least as much reality in the efficient and total cause as in the effect of that cause." And "it follows from this both that something cannot arise from nothing, and also that what is more perfect--that is, contains in itself more reality--cannot arise from what is less perfect." And, he goes on, this is "transparently true not only in the case of effects which possess what the philosophers call actual or formal reality, but also in the case of ideas, where one is considering only what they call objective reality." But in order for a given idea to contain such and such objective reality, it must surely derive it from some cause which contains at least as much formal reality as there is objective reality in the idea. (AT VII, 41) . . . But what is my conclusion to be? If the objective reality of any of my ideas turns out to be so great that I am sure the same reality does not reside in me, either formally or eminently, and hence that I myself cannot be its cause, it will necessarily follow that I am not alone in the world, but that some other thing which is the cause of this idea also exists. (AT VII, 42) In the general run of his ideas he finds "nothing in them so great or excellent as to make it seem impossible" that it originated in himself. But his idea of God is different; it has attributes "such that, the more carefully I concentrate on them, the less possible it seems that they could have originated from me alone. So from what has been said it must be concluded that God necessarily exists." (AT 45) Later he summarizes: The whole force of the argument lies in this: I recognize that it would be impossible for me to exist with the kind of nature I have--that is, having within me the idea of God-- were it not the case that God really existed. (AT 52) Even to his contemporaries, this argument was unpersuasive. Why did Descartes think his idea of God was so impressive? Why, for instance, could he not have made it up himself, cobbled out of the negations of the ordinary ideas of mortality, (limited) power, knowledge, and goodness? Descartes offers various responses to this challenge, which I confess I find utterly 4 unconvincing. He makes it clear that he thinks his idea of God is different from other complex ideas that can indeed be constructed from various more modest ideas, but the grounds he gives strike me--and many others, including some of his contemporaries--as ad hoc and, at the very least, lacking the sort of overwhelming certainty that ought to reside in any constructive move that follows on the heels of the methodical skepticism of the first two Meditations. It really does not seem to require infinite intellectual competence to frame the idea of an infinite, perfect, omnipotent Being--any more than to frame the idea of a perfect sailboat or a golden mountain. In Descartes's "First Set of Replies" to his critics--to Caterus, in fact--he responds with an interesting analogy: Thus if someone possesses in his intellect the idea of a machine of a highly intricate design, it is perfectly fair to ask what is the cause of this idea. And it will not be an adequate reply to say that the idea is not anything outside the intellect and hence that it cannot be caused but can merely be conceived. For the precise question being raised is what is the cause of its being conceived. Nor will it suffice to say that the intellect itself is the cause of the idea, in so far as it is the cause of its own operations; for what is at issue is not this, but the cause of the objective intricacy which is in the idea [my emphasis]. . . and what applies to the objective intricacy belonging to this idea also applies to the objective reality belonging to the idea of God. Now admittedly there could be various causes of the intricacy contained in the idea of the machine. Perhaps the cause was a real machine of this design which was seen on some previous occasion, thus producing an idea resembling the original. Or the cause might be an extensive knowledge of mechanics in the intellect of the person concerned, or perhaps a very subtle intelligence which enabled him to invent the idea [my emphasis] without any previous knowledge. But notice that all the intricacy which is to be found merely objectively in the idea must necessarily be found, either formally or eminently, in its cause, whatever this turns out to be. And the same must apply to the objective reality in the idea of God. (AT 104) Let me paraphrase, anachronistically, what Descartes is asserting here: if someone is found in possession of the blueprints for a highly intricate machine, then that person must either be a great engineer and the author of those blueprints, or that person must have copied– plagiarized–the design from an existing machine--or from somebody else’s blueprints. You don’t get highly intricate design–Intelligent Design!--for free. Although this machine analogy does not occur in the main text of the Meditations, Descartes does allude to it in his introductory Synopsis, so we can conclude that he had it in mind if not from the outset, at least from the time the Meditations went to press. He pushes the analogy further in his reply to Caterus: if someone possesses the idea of a machine, and contained in the idea is every imaginable intricacy of design, then the correct inference is plainly that this idea originally came from some cause in which every imaginable intricacy really did exist, even though the intricacy now has only objective existence in the idea. By the same token, since we have within us the idea of God, and contained in the idea is every perfection that can be thought of, the absolutely evident inference is that this idea depends on some cause in which all this perfection is indeed to be found, namely a really existing God." (AT 105) 5 In his Principles of Philosophy published two years later, Descartes repeats this passage almost word for word, so it is not an aberration or a fluke. And in this subsequent version he uses a phrase that perfectly captures an apparent ambiguity in his thinking: "Furthermore, we cannot have within us the idea or image of anything without there being somewhere, either within us or outside us, an original which contains in reality all the perfections belonging to the idea [my emphasis]." (AT VIIIA, 12 [I, p.199]) Are these perfections represented by the idea, or perfections of the idea's representation? What does it mean for a perfection to belong to an idea? 2. Wonderful ideas of wonderful things Here Descartes might be charged with making a curious mistake: confusing an idea of a wonderful thing with a wonderful idea of a wonderful thing. The distinction can be illustrated by noting a familiar problem facing novelists and other artists who wish to portray genius. Suppose you want to write a novel about a great poet. The instructor in your creative writing class keeps admonishing you "show, don't tell" and in this instance the way to follow the advice is to exhibit some of the hero's great poems. But that means you'll have to write some great poetry! Novelists have responded in different ways to this challenge: Vladimir Nabokov, in Pale Fire, (1962) tells the story of a great poet, John Shade, and the novel takes the form of a rambling commentary by Shade’s executor, one Charles Kinbote, of Shade’s masterpiece, Pale Fire, “a poem in heroic couplets, of nine hundred ninety-nine lines, divided into four cantos”– which Nabokov duly presents in its entirety. Nabokov has indeed composed a wonderful poem, embedded in a wonderful novel, a tour de force that makes Nabokov a world champion of “show, don’t tell.” Ian MacEwan, in his recent novel Saturday (2005), solves the same problem with less bravura: his young poet, Daisy Perowne, is given lines lifted (with grateful attribution) from excellent poems by Craig Raine (see Acknowledgements, p290). Philosophers will be amused by another instance of the same strategy in the recent film, Closer, in which Julia Roberts plays a brilliant art photographer. When the action calls for scenes in the art gallery exhibiting her wonderful work, the works on the walls are some of the photographic portraits of philosophers taken by the British photographer Steve Pyke. (The unforgettable photo of Elizabeth Anscombe and Peter Geach appears in several shots, and Philippa Foot’s portrait makes a brief, out-of-focus appearance.) Alternatively, when confronting your own inability to compose some great poetry (and your unwillingness to borrow from others), you can give up and just tell the reader how ravishingly beautiful the poems were, how deep, how elegant, how intricate, and you may support these claims with anecdotes about how the poems made strong men weep, brought jaded critics to their feet, and inspired the lives of all who read them. In short, you can represent the hero's poems as wonderful, but without having to come up with any particularly wonderful representations of them yourself. Child's play. This, too, is a strategy–a dodge, really–with many familiar variations. Consider, for instance, the standard cartoonist's trick of portraying genius scientists at a blackboard covered with a thicket of equations which we are to understand to be 6 brilliant and deep, when in fact what is written on the blackboard is pseudo-impressive gobbledygook. That's another cheap way of representing something as wonderful and intricate without having to come up with a wonderful and intricate representation of it. The huge difference between a wonderful representation of a wonderful thing, and a mere representation of a wonderful thing was brought home to me most dramatically at an exhibit at the Powerhouse Museum of Science and Design in Sydney Australia some years ago. On display in the same hall were (1) Charles Babbage’s Difference Engine, one of the brilliant fore-runners of the computer and a tour de force of brass-instrument engineering, and (2) various artists’ sculptures meant to evoke, symbolize, celebrate . . . . the genius of technology. The latter were as full of gee-whiz mechanical details–gears, wires, dials, test tubes, circuit boards, rocket engine cowlings and the like–as the Difference Engine, but the parts were just glued together haphazardly, “for effect,” well-intentioned but ludicrous hodge-podges that did not belong in the same building with Babbage’s creation. In this contrast, we now have a worthy candidate for Descartes’s curious concept of objective reality as referring somehow to the excellence of the idea, rather than just the excellence of the object of the idea. Second-rate ideas of God or any other wonderful thing, like the second-rate representations of scientific genius created by those sculptors, would not rate high in objective reality. This is definitely not the standard interpretation. (See, e.g., Kenny, 1968, p.132; Wilson, 1978, pp.105-6; Chappell, 1986; Normore, 1986.) It is possible however to read one of Descartes’s definitions of objective reality as supporting such a view: "By this I mean the being of the thing which is represented by an idea, in so far as this exists in the idea [my emphasis]. In the same way we can talk of 'objective 'perfection' 'objective intricacy' and so on." (AT VII, 160) And in his reply to Gassendi, Descartes compares his idea of God with a work of artistic genius: "Suppose there is a painting in which I observe so much skill that I judge that it could only have been painted by Apelles, and I say that the inimitable technique is like a kind of mark which Apelles stamped on all his pictures to distinguish them from others. The question you raise is just like asking, in this case, 'What is the form of this mark, and how is the stamping carried out?' (AT VII, 372 [p.256])1 If we don't interpret objective reality as a mark of excellence in the design of the idea, Descartes's principle of causation loses all its persuasiveness. There is just no reason at all to think that a second-rate representation of something magnificent needs a fancier cause than a second-rate representation of something modest. The suspicion is, however, that even when we grant him some such reading, Descartes is just wrong about his idea of God. It seems a rather ordinary idea of an undeniably wonderful thing, rather than, as he thinks, a wonderful idea of a wonderful thing--an idea so wonderful he himself could not be its cause. It is not that there couldn't be a wonderful idea of God, but just that the idea Descartes tells us about doesn't seem to bear the mark of genius. Where is the "intricacy," where is the wonderfulness? We can get a better perspective on this if we indulge in some alternative fantasies. 1 Kenny briefly considers and rejects this reading of objective reality: "If I think about an ingenious machine, then my idea has the property of objective ingeniousness (AT VIII, 11, HR I, 226). But of course it may lack the property of formal ingeniousness: it may be a vague and inaccurate idea of a machine whose workings I do not understand. Perhaps Descartes did not sufficiently reflect on this possibility when he discussed our idea of God." (p. 132) 7 3. The marks of genius Suppose we discovered a five-year-old child who, without any special education, spoke spontaneously in perfect sonnets. Now that would be a great marvel indeed, crying out for explanation. Or suppose we found a race of people who apparently had an innate knowledge and understanding of Maxwell's Equations. It would be stunning to discover such wonderful ideas already fully formed and understood. And if when we asked for an explanation, we were told, simply, that they inherited this talent from their parents, we would not be satisfied. How did their parents acquire this innate talent? What makes these ideas wonderful is not their basic ingredients--their expressions are composed of ordinary words and symbols in every normal person's vocabulary--but the excellent design of their construction. It takes genius to come up with the particular designs found in (good) sonnets or in (good) scientific equations, and if the imagined children seemed manifestly to lack the genius to have authored the ideas, some prior author would have to be located. (One is reminded here of the tragic folly of “facilitated communication” in which severely disabled children are deemed to be composing meaningful and heart-wrenching messages thanks to the helping hands of their handlers. There is much controversy–though I don’t believe there should be—regarding whether the children themselves are the authors, but there is no disagreement about the underlying premise: someone of some intelligence is composing these messages; they are not random juxtapositions of letters. In Descartes’s terms, there has to be as much formal reality in the cause as objective reality in the effect.) What, then, would be a similarly wonderful idea of God? It could be an idea of poetic or artistic power and beauty--of the sort that many great religious artists have claimed to derive from divine inspiration.2 Or, presumably, it could be an idea of great scientific power. Some great scientific ideas have the sort of intricacy Descartes mentions in his discussion of the idea of a machine. Maxwell's Equations, for instance, 1 . δE = curl B - 4πj, δE = -curl E c2 δt δt div E = 4πρ, div B = 0 have the sort of impressive surface intricacy that make them just the thing for the cartoonist to put on the blackboard. But other great scientific ideas are famously simple: E = mc2 Now there are two ways of having this idea in your mind: just as a sort of icon, a talisman or good luck charm that doesn't have to be understood--that's the second-rate way most of us have the idea in our minds--or alternatively, we could understand it deeply, and be able to use it, to see its implications, to exploit it in the development of further scientific theories. If we have 23. One should bear in mind Descartes's tale of the dream that inspired his project. 8 the idea of E = mc2 in our minds in the latter way, I propose that we might say that the idea has, for us, great objective reality. 4. The presumed productivity of Descartes’s idea of God But now we can see for the first time that Descartes did have grounds for believing that his idea of God, for all its apparent simplicity, was a wonderful idea of a wonderful thing, an idea of tremendous objective reality, for he did believe, after all, that he had used that very idea and no other as the sole foundation for his theory of . . . Le Monde--the World! Descartes propounded the original TOE, (Theory Of Everything), a prototypical Grand Unified Theory, in which everything was to be explained (and predicted, deductively): from the orbits of the planets and the nature of light to the tides, from volcanoes to magnets, why water forms into spherical drops, how fire is struck from flint, and much, much more. Descartes’s theory was almost all dead wrong, of course, but what would you expect from a theory derived, more or less as Descartes insisted it was, from the solitary idea of an omnipotent, omniscient God? The fact remains that it was a huge theory, full of intricacy, remarkably self-consistent, often fiendishly persuasive even in today's hindsight. Any idea that could generate such a stunning intellectual edifice would be a prodigiously fecund idea, and if the edifice were true in all particulars (as Descartes thought his edifice was), the fact that such an idea was to be found in a mind would be something aching for explanation. So now we can explain what puzzled us at the outset: how could a great thinker like Descartes find his own idea of God so wonderful that he himself could not be its author? It is because his idea is not just made of lots of good parts (ideas available to everybody), and not because his idea is of a wonderful thing–God; it is because his idea is (he thought) a stunningly well-designed engine of scientific discovery. Like Babbage’s Difference Engine, it wasn’t just intricate, it worked. 5. The flaw in Descartes’s Argument from Design Where on earth could Descartes have come across such a wonderful idea? Here comes the Big Step3--the only cause that could explain such a prodigious effect is God.4 3 Gassendi, as usual, had particularly acute insights into Descartes's presuppositions here, and introduces his remarks by saying "But this is a very big step to take, and we must stop you here for a while . . . and goes on to consider "effects produced by some skill. Although a house gets all its reality from the builder, the builder does not have this reality in himself--he simply takes it from some other source and passes it on to the house. 4 In his Second Set of Replies, Descartes says: "You suggest that I may have derived the idea which gives me my representation of God from preconceived notions of the mind, from books, conversations with friends etc., and not from my mind alone. But there is no force in this suggestion. If I ask these other people (from whom I have allegedly got this idea) whether they derive it from themselves or from someone else, the argument proceeds in the same way as it does if I ask the same question of myself; my conclusions will always be that the original source of the idea is God. (AT VII, 136) 9 Now this argument is just a special case of the Argument from Design, a special case forced on Descartes by his starting point. "Look round the world" the fictional Cleanthes urges, in Hume's Dialogues Concerning Natural Religion (1779) "You will find it to be nothing but one great machine, subdivided into an infinite number of lesser machines . . . . All these various machines, and even their most minute parts, are adjusted to each other with an accuracy, which ravishes into admiration all mean, who have ever contemplated them." But at the beginning of the Third Meditation, Descartes has no external world to contemplate; if he is to find an impressive design from which to infer a Designer a posteriori, it will have to be an impressively designed idea. There is no doubt that Descartes considered the argument in the Third Meditation to be an a posteriori argument from effect to cause (See, e.g, AT VII, 167). When defending his second, a priori argument (his version of Anselm's Ontological Argument in the Fifth Meditation), he says: "there are only two ways of proving the existence of God, one by means of his effects, and the other by means of his nature or essence; and since I expounded the first method to the best of my ability in the Third Meditation, I thought that I should include the second method later on." (AT VII, 120). The principle of inference he cites to defend the Big Step is the ancient idea of nihil ex nihilo--nothing can come from nothing. The fact that 'there is nothing in the effect which was not previously in the cause, either in a similar or in a higher form,' is a primary notion which is as clear as any that we have; it is just the same as the common notion' Nothing comes from nothing.'(AT VII, 135) This principle may indeed be "as clear as any that we have," but we now know that it is a mistake to rely on it in the way that Descartes does. This comes out more clearly in John Locke's appeal to the same principle in his own argument for the existence of an intelligent God (Essay Concerning Human Understanding, Book IV, ch. 10, parag. 10). If then there must be something eternal, let us see what sort of Being it must be. And to that, it is very obvious to Reason, that it must necessarily be a cogitative Being. For it is as impossible to conceive, that ever bare incogitative Matter should produce a thinking intelligent Being, as that nothing should of it self produce Matter. Let us suppose any parcel of Matter eternal, great or small, we shall find it, in it self, able to produce nothing. . . . . Matter then, by its own Strength, cannot produce in it self so much as Motion: the Motion it has, must also be from Eternity, or else be produced, and added to Matter by some other Being more powerful than Matter. . . . But let us suppose Motion eternal too: yet Matter, incogitative Matter and Motion, whatever changes it might produce of Figure and Bulk, could never produce Thought: Knowledge will still be as far beyond the Power of Motion and Matter to produce, as Matter is beyond the Power of nothing or nonentity to produce. And I appeal to everyone's own Thoughts, whether he cannot as easily conceive Matter produced by nothing, as Thought produced by pure Matter, when before there was no such thing as Thought, or an intelligent Being existing. . . . So if we will suppose nothing first, or eternal: Matter can never begin to be: If we suppose bare Matter, 10 without Motion, eternal: Motion can never begin to be: If we suppose only Matter and Motion first, or eternal: Thought can never begin to be. For it is impossible to conceive that Matter either with or without Motion could have originally in and from it self Sense, Perception and Knowledge, as is evident from hence, that then Sense, Perception, and Knowledge must be a property eternally inseparable from Matter and every Particle of it. The trouble, as Darwin showed us, is that it is conceivable, in spite of what Locke says, that Thought should be born of mere Matter and Motion, and the same objection applies to the phantom argument I have located in Descartes. Until Darwin came along, Descartes had a pretty compelling reason for believing in God. He had found some Intelligent Design within the confines of his own mind, and you don’t get Intelligent Design for free. Something pretty special has to account for it. What Descartes could not have imagined–or, like Hume, could not have taken seriously if he did imagine it–is the hypothesis that all this wonderfulness, all this design, can have a non-divine ultimate cause: evolution by natural selection. So my conclusion is that while Descartes's argument in the Third Meditation is best seen as a special case of the Argument from Design, like the more often discussed versions of it, it mistakes a failure of imagination for an insight into necessity. Darwin corrected that failure of imagination, pulling the rug out from under all forms of the Argument from Design. This leaves Descartes's second argument, in the Fifth Meditation, for another day. 11 References Chappell, V., "The Theory of Ideas," in A. O. Rorty, ed., Essays on Descartes' Meditations, Berkeley: Univ. of Calif. Press, pp.175-98. Kenny, A., 1968, Descartes: a Study of his Philosophy, New York: Random House. Hintikka, Jaako, 1962, “Cogito, ergo sum: Inference or Performance?” Phil. Review, 1962, 71, pp3-32. Normore, C., 1986, "Meaning and Objective Being: Descartes and his Sources," in A. O. Rorty, ed., Essays on Descartes' Meditations, Berkeley: Univ. of Calif. Press, pp.223-41. Wilson, M. D., 1978, Descartes, London: Routledge & Kegan Paul.
