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Descartes’s Second Meditation
Philosophy 322: Modern Philosophy
Professor Geoff Pynn
Northern Illinois University
Spring 2018
In the First Meditation , Descartes resolved to “withhold assent” from those things he has reason to doubt. In the Second Meditation , he makes an even stronger resolution: he will “put […] aside everything that admits of the least doubt, as if I had discovered it to be completely false” (17). Unless you keep this resolution in mind, some of the things he says here will be confusing. In the course of the Second Meditation , Descartes will become certain of, and hence (given the policy just mentioned) come to regard as true, the following two propositions:
I exist.
I am a thing that thinks.
He will also discuss what it is to be a thinking thing, what it is to be a body, and argue that our knowledge of bodies comes not through the senses, but through the intellect.
the cogito argument
In the Deceiving God Argument, Descartes found reason to doubt that anything in the world exists; thus given his resolution to regard everything he has reason to doubt as false, he has “per- suaded [himself] that there is absolutely nothing in the world: no sky, no earth, no mind, no bodies” (18). But then he asks: ”is it then the case that I too do not exist?” (18) Answer:
But doubtless I did exist, if I persuaded myself of something. But there is some de- ceiver or other who is supremely powerful and supremely sly and who is always delib- erately deceiving me. Then too there is no doubt that I exist, if he is deceiving me. And let him do his best at deception; he will never bring it about that I am nothing so long as I shall think that I am something. Thus, after everything has been most care- fully weighed, it must finally be established that this pronouncement “I am, I exist” is necessarily true every time I utter it or conceive it in my mind (18).
Whether or not he is being deceived, he is thinking. But if he is thinking, then he exists. So the argument goes:
(1) I am thinking (Latin: cogito , hence the name of the argument).
(2) If I am thinking, then I exist.
∴(3) I exist.
The argument is valid. Is there any reason to doubt either of the premises? If so, then Descartes must treat them as false, and so cannot accept the conclusion on their basis. Let’s grant that premise (2) can’t be doubted. What about premise (1)? Many people have thought that Descartes can’t be certain of premise (1), but only of:
(4) Thought is occurring.
Bertrand Russell states the objection clearly:
“I think” is his ultimate premise. Here the word “I” is really illegitimate; he ought to state his ultimate premise in the form “there are thoughts”. […] He nowhere proves that thoughts need a thinker, nor is there reason to believe this except in a grammat- ical sense (Russell, The History of Western Philosophy , p. 567).
If there is a deceiver creating the false thought that Descartes exists, then thought is occurring, but Descartes does not exist and hence is not thinking—after all, if the thought that Descartes exists is false , then Descartes does not exist, and so is not thinking! So if Descartes can only be certain of (4), he cannot yet derive the conclusion that he exists. Is it possible for thought to occur without a thinker? One might think not. Thoughts, it seems, have to be the thoughts of someone or other; the existence of a thought appears to imply the existence of a thinker. So we might reply to Russell’s objection as follows: if we can be certain of the existence of a thought, we can ipso facto be certain of the existence of a thinker. Still, whatever merits this response has, it does not permit Descartes to conclude with certainty that he exists. For supposing that (4) and (5) are true only licenses us to conclude (6):
(4) Thought is occurring.
(5) If thought is occurring, then a thinker exists.
∴(6) So, a thinker exists.
And (6) doesn’t imply that I exist, or that Descartes exists, but only that some thinker exists. Perhaps a clue to how Descartes himself would respond can be found in the following passage:
When someone says ‘I am thinking, therefore I am, or I exist’, he does not deduce existence from thought by means of a syllogism, but recognizes it as something self- evident by a simple intuition of the mind. This is clear from the fact that if he were deducing it by means of a syllogism, he would have to have had previous knowledge of the major premise ‘Everything which thinks is, or exists’; yet in fact he learns it from experiencing in his own case that it is impossible that he should think without existing (Second Replies, The Philosophical Writings Of Descartes , vol. II, 100).
the piece of wax
Despite the fact that he’s resolved to treat bodies as non-existent (since he has reason to doubt their existence), Descartes inserts a discussion bodies into the second half of the Second Med- itation. This doesn’t quite fit into this stage of his construction of certain foundations for his knowledge, but it makes sense given the mechanistic and rationalistic purposes of the work. Descartes has two aims in this discussion. First, to describe the nature of bodies, which he will conclude is nothing more than extension. Second, to argue—surprisingly—that our knowledge of the nature of bodies comes not through our senses, but through the mind alone. He begins by imagining a particular piece of wax, “taken quite recently from the honeycomb” and hence still smelling of honey (21). It has a particular color, shape, and size; it is hard and cold and “easy to touch” (21). Now suppose you bring it close to a fire: all of these qualities will change. It will lose its smell, change its color, shape, and size; it will become liquid and too hot to touch. And yet, Descartes says, “no one denies” that it remains the same wax. Since the wax remains, but has changed its color, shape, size, and so on, none of those qualities was essential to the wax: none of them tells us anything about the wax’s basic nature. But if none of these qualities is essential to the wax’s nature, what is essential to it?
[T]he wax itself never really was the sweetness of the honey, nor the fragrance of the flowers, nor the whiteness, nor the shape, nor the sound, but instead was a body that a short time ago manifested itself to me in these ways, and now does so in other ways. But just what precisely is this thing that I thus imagine? Let us focus our attention on this and see what remains after we have removed everything that does not belong to the wax: only that it is something extended, flexible, and mutable (21).
Descartes is saying that all that is essential to the wax’s nature is its extension in space (“flexibility” and “mutability” refer to a body’s capacity for changing its extension over time). Descartes intends for us to extend this conclusion to all bodies: for any body, the essential nature of that body is nothing more than its being extended. This conclusion relates directly to the secret purpose of the Meditations : if all it is to be a material body is to be extended, then there is no place in the material world for the substantial forms and final causes of scholastic physics, nor for qualitative properties – color, temperature, taste, smell, texture, and so on. Descartes then claims that he does not understand the wax’s nature through his imagination or sensation, “for I grasp that the wax is capable of innumerable changes [in shape], even though I am incapable of running through these innumerable changes by using my imagination” (22). Thus, he concludes, “I perceive it through the mind alone” (22). His argument is this:
(1) I know that the wax’s nature is to be flexible and mutable.
(2) I couldn’t know that the wax’s nature is to be flexible and mutable through imagination or sensation.
∴(3) So, I know the wax’s nature through my mind alone.
Descartes’s reason for premise (2) is that he couldn’t possibly imagine all of the ways in which the wax could change its shape (and he certainly he hasn’t sensed all those ways), and yet he knows
that it is capable of changing shape in an innumerable number of ways Since he knows this, but cannot know it through sense or imagination, he must know it through the mind alone. Though intriguing, note that this argument is not valid: the fact that Descartes cannot know the wax’s nature through his imagination or sensation does not imply that he understands it through the mind alone. Perhaps he needs both imagination / sensation and some additional fac- ulty of the mind to know the wax’s nature. Consider an analogous argument: you have not seen every possible shade of red, and are probably incapable of imagining every distinct shade of red, but you can understand what redness is. But clearly in order to understand what redness is, you need to have seen or imagined red things; it would be absurd to suggest otherwise. Why should we think that flexibility and mutability are any different from redness? Nonetheless, this view—that we know the nature of bodies through the mind alone—is an essential element of Descartes’s rationalism, and will be immensely important to Spinoza’s pro- gram. So regardless of whether Descartes’s argument for this claim is compelling, it’s important to understand that he accepted it.
