Descartes claims to have shown two things:
I agreed with him about the first point but expressed reservations about the second.
Descartes argues that his knowledge of his own existence is unlike knowledge derived from the senses. To understand this, we should first review why he doesn’t think we can be certain about what we know on the basis of the senses.
I cannot know for certain what I think I see, hear, taste, feel, or smell because I cannot tell the difference between really seeing, hearing, tasting, feeling, or smelling and only dreaming that I see, hear, taste, feel or smell. Nor can I tell the difference between really sensing things and being deceived about what I sense by an evil genius.
It’s possible that I’m asleep and dreaming now. It’s also possible that an evil genius is deceiving me. What’s more, I cannot tell the difference between really being here and one of those other possibilities. I seem to see the computer screen, hear the music, smell the coffee, taste the coffee (unfortunately: bleah), and feel the keyboard, but that is not enough to make me certain that I really am here. If I were dreaming or being deceived, I would seem to have exactly the same experiences. Unless I can tell the difference between the real experiences and the false ones, I can’t be certain that I’m having the real ones and, thus, that I’m really here.
Remember, it’s the possibility of being mistaken that is crucial. Descartes doesn’t have to show that there really is an evil genius any more than he has to show that I’m really asleep. He just has to show that I don’t know for certain what I think I know on the basis of the senses.
Things are different with my belief in my own existence.
Suppose I am dreaming that I exist. Well, then I exist. After all, I’m the one having the dream.
Or suppose an evil genius tried to deceive me, tricking me into thinking that I don’t exist. If he succeeded, who would be fooled? Me! And I could figure this out. So there’s a contradiction in supposing that the evil genius could deceive me about my own existence. I would be the one who was deceived, after all.
On the other hand, if I’m neither asleep nor deceived, I can also be certain that I exist. For starters, I have no reason to doubt that I exist. But suppose I asked. I would find that the question “do I exist?” has a built in answer. If I’m asking the question, then I must exist. Non-existent things don’t ask questions.
The argument is quite similar to one made by Saint Augustine. Augustine’s version is on the handout.
I agree with Descartes that we really are immune from being deceived about our own existence. But Descartes has bigger fish to fry. As the title makes clear, he’s trying to demonstrate that the soul is distinct from the body.** Look on the title page, not the cover.
He announced in the part we read that he has discovered that he is “precisely nothing but a thinking thing; that is, a mind, or intellect, or understanding, or reason” and that he is “not that concatenation of members we call the human body” (p. 19, AT 27).†† The link is to the Oxford English Dictionary. It’s the most comprehensive dictionary of English. It’s especially useful when you’re reading something old because it traces the history of a term’s meaning.
The most difficult part of our session involved wrangling with the question of whether Descartes had fried his fish, that is, did he show that he can reach any certain conclusions about the nature of the self, mind, or soul? (Let’s treat those words as meaning the same thing).
Let’s start with the argument about the impossibility of being deceived. If I have a thought, say “I wonder if I exist?”, then I know that I exist. But what did I really learn about myself from that? Did I learn that my mind is something distinct from my body? I know that I exist because it’s built into the question: “I wonder …” already identifies me as the one doing the wondering. It doesn’t tell us much other than that I’m insulated from a kind of error.
Would it help if we stripped that part out? Suppose we said something like “somebody wonders if Michael Green exists.” But if that’s what we’re starting with, we couldn’t draw any conclusions about whether I exist or not. That would be like inferring that I exist because Summer had a thought about a lion.
I had thought that Descartes could get some mileage out of the following sort of argument.
The idea is that I have to be the kind of thing that I could certainly know exists. And the First Meditation showed that a human body could not be that kind of thing.
But Galen criticized this argument.‡‡ In fact, he thought it was so bad that Descartes couldn’t have made it! He said that if that argument were valid, the following argument would be valid too.
But, as we literally saw, that argument is not valid. I did know that something was in my pocket and I did not know whether I had a quarter in there. Yet I pulled not one but two quarters out of my pocket, right before your very eyes. So the conclusion does not follow from the premises.
I don’t know how to answer Galen’s point in a way that is favorable to Descartes. In fact, having spent the afternoon looking at books about Descartes, I see that no one knows how to do that. Actually, it’s worse than that. Different scholars have answers, but they’re all long, complicated, and, tellingly, different from one another. So I think it’s safe to say that Galen has identified a problem with Descartes’s argument.
If you look at the Synopsis, you see that Descartes himself claimed that some parts of what he wanted to say about the nature of the mind are proven in the Second Meditation and others have to wait for the Sixth Meditation (pp. 8–9, AT 12–14). So maybe we shouldn’t expect to find a complete argument in the Second Meditation and, if we find that the arguments given there don’t support Descartes’s conclusions, that just means we have to keep reading until we get to the end.
We won’t discuss the Sixth Meditation in class, so we won’t track this down. I can tell you two things based on my own research.
First, it isn’t easy to understand how the argument in the Sixth Meditation is significantly different from the one in the Second Meditation. Don’t take my word for it, see for yourself: it’s on p. 51, AT 78.
Second, those scholars who have claimed to find what is different in the Sixth Meditation have to do a lot of work in order to explain the difference and, as I said earlier, they disagree with one another. That doesn’t mean they’re all wrong, of course. But it does mean that the answer is not terrifically clear.
So what should we make of this? I think we should conclude that the arguments in the Second Meditation do not establish much about the nature of the self. That doesn’t mean that Descartes did not establish much about the nature of the self. Perhaps he did so elsewhere. It just means that our questions about the Second Meditation are genuine ones and not simply the result of our misunderstanding him.