How does Descartes try to extricate himself from the sceptical doubts that he has raised? Does he succeed? [All page references and quotations from the Meditations are taken from the 1995 Everyman edition] In the Meditations, Descartes embarks upon what Bernard Williams has called the project of ‘Pure Enquiry’ to discover certain, indubitable foundations for knowledge. By subjecting everything to doubt Descartes hoped to discover whatever was immune to it. In order to best understand how and why Descartes builds his epistemological system up from his foundations in the way that he does, it is helpful to gain an understanding of the intellectual background of the 17th century that provided the motivation for his work. We can discern three distinct influences on Descartes, three conflicting world-views that fought for prominence in his day. The first was what remained of the mediaeval scholastic philosophy, largely based on Aristotelian science and Christian theology.
Descartes had been taught according to this outlook during his time at the Jesuit college La Flech and it had an important influence on his work, as we shall see later. The second was the scepticism that had made a sudden impact on the intellectual world, mainly as a reaction to the scholastic outlook. This scepticism was strongly influenced by the work of the Pyrrhonians as handed down from antiquity by Sextus Empiricus, which claimed that, as there is never a reason to believe p that is better than a reason not to believe p, we should forget about trying to discover the nature of reality and live by appearance alone. This attitude was best exemplified in the work of Michel de Montaigne, who mockingly dismissed the attempts of theologians and scientists to understand the nature of God and the universe respectively. Descartes felt the force of sceptical arguments and, while not being sceptically disposed himself, came to believe that scepticism towards knowledge was the best way to discover what is certain: by applying sceptical doubt to all our beliefs, we can discover which of them are indubitable, and thus form an adequate foundation for knowledge. The third world-view resulted largely from the work of the new scientists; Galileo, Copernicus, Bacon et al. Science had finally begun to assert itself and shake off its dated Aristotelian prejudices.
Coherent theories about the world and its place in the universe were being constructed and many of those who were aware of this work became very optimistic about the influence it could have. Descartes was a child of the scientific revolution, but felt that until sceptical concerns were dealt with, science would always have to contend with Montaigne and his cronies, standing on the sidelines and laughing at science’s pretenses to knowledge. Descartes’ project, then, was to use the tools of the sceptic to disprove the sceptical thesis by discovering certain knowledge that could subsequently be used as the foundation of a new science, in which knowledge about the external world was as certain as knowledge about mathematics. It was also to hammer the last nail into the coffin of scholasticism, but also, arguably, to show that God still had a vital rle to play in the discovery of knowledge. Meditation One describes Descartes’ method of doubt.
By its conclusion, Descartes has seemingly subjected all of his beliefs to the strongest and most hyberbolic of doubts. He invokes the nightmarish notion of an all-powerful, malign demon who could be deceiving him in the realm of sensory experience, in his very understanding of matter and even in the simplest cases of mathematical or logical truths. The doubts may be obscure, but this is the strength of the method – the weakness of criteria for what makes a doubt reasonable means that almost anything can count as a doubt, and therefore whatever withstands doubt must be something epistemologically formidable. In Meditation Two, Descartes hits upon the indubitable principle he has been seeking. He exists, at least when he thinks he exists.
The cogito (Descartes’ proof of his own existence) has been the source of a great deal of discussion ever since Descartes first formulated it in the 1637 Discourse on Method, and, I believe, a great deal of misinterpretation (quite possibly as a result of Descartes’ repeated contradictions of his own position in subsequent writings). Many commentators have fallen prey to the tempting interpretation of the cogito as either syllogism or enthymeme. This view holds that Descartes asserts that he is thinking, that he believes it axiomatic that ‘whatever thinks must exist’ and therefore that he logically concludes that he exists. This view, it seems to me, is wrong. It should be stated on no occasion, in the Meditations, does Descartes write ‘I am thinking, therefore I am’, nor anything directly equivalent.
Rather, he says: “Doubtless, then, that I existand, let him deceive me as he may, he can never bring it about that I am nothing, so long as I shall be conscious that I am something. So that it must, in fine, be maintained, all things being maturely and carefully considered, that this proposition I am, I exist, is necessarily true each time it is expressed by me or conceived in my mind.” (p. 80). The point here is that it is impossible to doubt the truth of the proposition ‘I exist’ when one utters it. It is an indubitable proposition, and one that will necessarily be presupposed in every attack of the sceptic. Descartes is not yet entitled to use syllogisms as the possibility of the malign demon is still very much alive.
As an aside, Descartes himself denies that the cogito is a syllogism, although it should be mentioned that in some of the Replies to Objections he seems to assert that it is in fact a syllogism. Finally, in the Regulae ad directionem ingenii, Descartes denies the usefulness of syllogisms as a means to knowledge. I believe that, given Descartes’ project, it is fair to grant him that the cogito deserves the status he bestows upon it. For can there be anything more certain than something that is so forceful and so powerful that every time it is presented to our mind we are forced to assent to it? What Descartes did here was to jiggle about the way philosophy normally approaches the construction of knowledge structures. By starting with self-knowledge, he elevates the subjective above the objective and forces his epistemology to rest upon the knowledge he has of his own self (and inadvertently sets the tone for the next 300 years of philosophy). This leaves him with a problem.
He can know his own existence, that he is a thinking thing and the contents of his consciousness, but how can any of this ever lead to any knowledge of anything outside of himself? The answer is that, by itself, it can’t. Descartes, in the third Meditation, attempts to prove the existence of God, defined as a being with all perfections. This proof is to be derived from his idea of a God, defined as a being with all perfections. So far, so good – Descartes examines the contents of his consciousness and discovers within it this idea, and we can allow him this. At this point, however, he introduces a whole series of scholastic principles concerning different modes of causation and reality without proper justification: “For, without doubt, those [ideas considered as images, as opposed to modes of consciousness] that represent substances are something more, and contain in themselves, so to speak, more objective reality, that is, participate by representation in higher degrees of being or perfection than those that represent only modes or accidents; and again the idea by which I conceive a Godhas certainly in it more objective reality than those ideas by which finite substances are represented. 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 its effect; for whence can the effect draw its reality if not from its cause? And how could the cause communicate to it this reality unless it possessed it in itself?” Whence do these principles draw their indubitability? Even if we grant that it is contrary to natural reason that an effect can have greater ‘reality’ than its cause, that the concepts of modes and substances are coherent with Descartes’ method, let alone possess the properties that he ascribes to them, then surely we can still bring the malign demon into play? Is it not possible that this all- powerful demon could bring it about that Descartes has a notion of a being with all possible perfections that he calls God? No, says Descartes, because the notion (representing something perfect) would then have more objective reality than the demon (as something evil and thus imperfect) has formal reality, and ‘it is manifest by the natural light’ that this is not possible. But why not? Maybe the demon has just made it seem impossible, and it seems that Descartes has no answer to this.
Further problems remain. Cosmological arguments for God invoking the notion of causation have always had to contend with the problem of the cause of God. For if all events (or ideas) are caused ultimately by God, then what about God Himself? Why should He be exempt from this rule? The standard response to this is to claim that God, being omnipotent, causes Himself. One of the chief perfections that Descartes attributes to God is that of ‘self-existence’, that is, that His existence depends on nothing else but itself. But if we examine this idea, it seems a little confused. If God is the efficient cause of God then we are forced to ask how something that does not yet exist can cause anything. If God is the formal cause of God, i.e. it is part of the intrinsic nature of God that he exists – which seems more likely – then it seems that we have merely a reformulation of the ontological argument for God’s existence from Meditation 5.
It seems that Descartes may have anticipated the wealth of criticism that the causal proof of God would inspire, and so, after explaining how human error and a benevolent, non-deceiving God are compatible in Meditation Four, he produced in Meditation Five a version of the mediaeval ontological argument for God’s existence. Unlike the causal argument, the ontological argument doesn’t involve the covert import of any new principles. It simply purports to show that, from an analysis of his own idea of God, Descartes can show that He necessarily exists. The reasoning goes like this: I have ideas of things which have true and immutable natures. If I perceive clearly and distinctly that a property belongs to an idea’s true and immutable nature, then it does actually belong to that nature. I perceive clearly and distinctly that God’s true and immutable nature is that of a being with all perfections.
Further, I perceive clearly and distinctly that existence is a perfection and non-existence a non- perfection. Thus existence belongs to God’s true and immutable nature. God exists. One of the interesting things about this argument is that, at first sight, it does not seem to depend in any way upon anything that has been proved hitherto. It is an application of pure logic, an analysis of what we mean when we say ‘God’ and a inference from that analysis. Descartes explicitly says that an idea’s true and immutable nature does not in any way depend upon his thinking it, and thus upon his existence.
Once he has perceived clearly and distinctly that an idea’s true and immutable nature consists in such-and-such, that is the case whether or not he thinks it is, or even if he exists or not. Descartes in fact recognises the primacy of the ontological argument: “although all the conclusions of the preceding Meditations were false, the existence of God would pass with me for a truth at least as certain as I ever judged any truth of mathematics to be.” If this is true, which it seems to be, then this argument is only as trustworthy as the faculties which enabled us to construct it, which are the same faculties that enable us to know mathematical truths, and so it seems worthwhile to ask how, under Descartes’ theory, we come to know mathematical truths. Descartes claims we perceive them clearly and distinctly. How do we know that what we perceive clearly and distinctly is true? Because God, being perfect, is no deceiver, and would not let it be the case that we could ever perceive something clearly and distinctly without it being the case. It seems then, that this proof of God, relying on the veracity of clear and distinct ideas, relies on the certain knowledge that a non-deceiving God exists. We have another proof of God, the causal proof as described in Meditation three. But apart from the patent futility of using one proof of p to construct another proof of p, on examining the causal proof of God further, we find that it, too, relies upon a methodology that can only be relied upon if the divine guarantee is present, for if this guarantee is not present, then, as I mentioned above, how can we be sure that the all-powerful demon is not exercising his malignant influence? This, of course, is the infamous Cartesian circle, first identified by Arnauld in the Fourth Objections and discussed ever since. Many philosophers have tried to get Descartes off the hook in various ways, some by denying that there is a circle and some by admitting the circularity but denying its significance. I will here briefly evaluate a few of their arguments. Some commentators have taken a passage from Descartes’ reply to the Second set of Objections (Mersenne’s) to indicate that Descartes is only actually interested in the psychological significance of fundamental truths.
The passage is as fo …