The conclusion of Descartes’ Fourth Meditation purports to further his answers to the doubt laid out at the beginning of the Meditations. How can I know that what I perceive is accurate? What if I am being deceived, as in a dream? After moving, rather suspiciously, from his own existence to that of God, he has now to transition from a world that may be wholly composed of ideas to one with some external reality. After examining the role of the will and the intellect in forming judgments about the certainty of things, he summarizes his argument from proceeding meditation:
[W]henever in passing judgment I so keep my will under control that it confines itself to items clearly and distinctly represented to it by the intellect, it certainly cannot come about that I should make a mistake; since every clear and distinct perception is something, and therefore cannot come from nothing , but necessarily derives from God — God, the supremely perfect being whose nature is incompatible with deception. It is therefore undoubtedly true. (Meditations, 62)
While it is necessary to the task he has set himself that he should in some such way transition from a position of complete doubt toward being able to assert with some degree of certainty that something exists, and especially that we should be able to know something about those things which exist, this argument hardly seems an improvement on those unexamined opinions Descartes’ claimed to have held before setting about writing the Meditations, except in being more clearly expressed. What is his argument here, and how might it prove a more sure and certain foundation for pursuing the truth of things in the world?
The argument goes something like this: 1) God exists and is supremely perfect. Deception is wicked, and therefore an imperfection. God would therefore not deceive his creatures (53). 2) However, I have sometimes erred in my judgment of the truth of things; how is that possible when God, who created me and everything else, did not deceive me? There must, besides God, also be some kind of nothingness, which shares in none of the perfections of God; I, as a finite creature, exist in some intermediate state between perfection and nothingness, and can therefore lack understanding (54). 3) Even so, to the extent that I lack the supreme perfections, I am not necessarily in error, but merely ignorant. I am only in error when my will, which has a greater range then my intellect, makes judgments about things of which I am partly ignorant. 4) Because what I perceive is a mixture of nothingness, in which I am ignorant of much, and reality, of which God, who would not deceive me, is the supreme perfection, my ideas are true insomuch as they are clear and distinct, and in doubt insomuch as they are vague and confused. 5) Therefore, as in the above quotation, in order to not be deceived I would trust only those ideas that are clear and distinct, and doubt all ideas that are in some way confused.
Much depends upon distinguishing “clear and distinct” ideas from their opposites. What, then, does this formulation mean? At first I might expect that the most distinct things would be those I perceive with my senses, such as a fire or tree or piece of wax, even if these things are subject to change. They are also, however, held in some doubt, for they could be dreams or holograms or the invention of an evil genie. But even if they are as they appear, that very changeability throws doubt on what they in fact are, as when Descartes holds the wax to the fire and all its attributes change as it begins to melt, until only “extension” is left as something clear and distinct (33). Clarity in Descartes’ usage seems to be more a kind of logical necessity, and distinctness as something like the potential to be articulated precisely by the non-imaginative function of the intellect. Thus the most compelling examples of these kinds of ideas are mathematical. It is not necessary to examine the properties of a triangle, but once one has begun to do so certain things follow, especially relationships of equality and inequality, that are necessary to all such figures in all circumstances in a way that coolness or yellowness are not necessary to wax.
The weakest assertion is, perhaps, the fourth: that if something is clear and distinct it must be of God, and if otherwise, at least partly of nothingness, “since every clear and distinct perception is something, and therefore cannot come from nothing, but necessarily derives from God.” A good deal, not only here, but throughout the Meditations, depends on what kind of being I suppose God to be. This God must not only be the height of all perfections, but also the only altogether real thing, even among ideas, so that for something to be “something” in any sense, even something as an idea, it must “necessarily derive from God.” Derive in what sense? In such a way that God is responsible for those ideas, so that if it were wrong he would be a deceiver. In such a way, perhaps, that, once seen, it appears necessarily and certainly true, perhaps, as with arithmetic truths. If it were wrong to say that two and three make five, then there must be something, not only lacking, but deeply distorted about the human intellect. Since God is the measure of reality, and he created humans, he would have had to intend that we be deceived for there to be such a distortion.
The most certain thing, then, is presumably the existence of a supremely perfect God from which everything else derives its being, quite before I have any cause to rely upon my natural powers of reasoning, since the accuracy of those powers is predicated upon just such a being — and not of any kind whatever, but such that its’ perfections are recognizable by my reason. Presumably. Actually, it is certain that this God exists because I have an idea of him in my mind that cannot possibly be produced by myself because it contains perfections that I do not myself possess, and “I manifestly understand that there is more reality in infinite than in finite substance, and therefore the perception of the infinite must be in some way prior to the finite” (45). In other words, I know that my idea of God is true because I clearly and distinctly perceive it to be so. I also know that whatever I so perceive is true because my idea of God is true. Finally, in the Fifth Meditation, I know that my idea of God is true because I clearly and distinctly perceive that existence is part of the essence of any supremely perfect being, and what I so perceive is true, because God would not deceive me, being thus perfect (66).
It turns out, then, that I exist because I have a clear idea of myself as existing, and God exists for a similar reason. Meanwhile, I can trust these ideas concerning myself and God because the God of whom I have a clear and distinct idea would not deceive me. Then, after that has been established I can prove that God exists, because I have a clear idea of him as necessarily existing. Really convincing there, Descartes.
The more I (the writer, not the Descartes proxy) try to lay out what, exactly, the arguments of the Meditations are, the more strongly I am convinced that he cannot possibly be sincere in his intentions as described in the introductory letter. They seem in some way ironic and subversive, but also slippery like a greased eel and circular like an ouroboros. The only argument that actually seems to be one is that of the separation of material from intellectual reality, and, by extension that those ideas that are more directly perceived by the intellect without the aid of the imagination or senses are more likely to be true.
Some of that affect is due to Descartes’ incessant use of first person statements that can only be proved or disproved by the reader’s own experience. The I ends up being, at the same time, Descartes in his chair by the fire, and the reader, either as himself or, more often, imagining himself as Descartes. It implicitly invites the reader to see for himself how distinctly and clearly he perceives the idea of a being possessing all possible perfections and necessarily existing in a way that standard proofs do not. It’s easy enough to suppose that someone else has a very clear idea of something that is unclear to me, as when geometers make use of the certainty of certain proposition, and the same might be said of theologians’ treatment of the idea of God. It’s quite another thing, however, to try to find such clarity in oneself, and perhaps Descartes is relying on that.
Nevertheless, Descartes’ insistence upon the reality of clearly perceived ideas seems in some way genuine, even if his reasoning isn’t. The distinction, for instance, between the affect that a physical phenomenon has upon my senses and the physical state that creates that affect is quite compelling, as well as that between ideas that are clear and distinct to the intellect and those that seem certain to the senses, but turn out to be changeable or deceptive. His argument that, supposing our clear ideas of things to be true, the cause of error lies in the will affirming those things about which the intellect is unclear is both compelling in itself as a reason to believe mathematical reason over sensory experience, but also suggests a definition of error that is uncomfortably similar to that of faith.
The “more sure and certain foundation” that suggests itself would be to, first, suppose that one’s own intellectual processes are primary over other modes of experience. Then, one would make a sharp distinction between one’s intellections as logical certainties and those which are based upon appearances, and in the case of the latter to distinguish phenomenon as they are experienced for the sake of physical preservation (“hot” or “green” or “pleasant,” for instance) from those same phenomenon as they may exist in themselves, which are probably quite different from the sensations they produce. They are more certain of the self and the intellect at the expense of any certainty about the world as known to our senses.