Q&A: Descartes’ Cogito Proof
Descartes’ Cogito Proof
Question
Hello Rabbi,
I’m currently reading your book Truth and Unstable (excellent so far), and I’m now on page 100, where you raise the objection to Descartes’ cogito argument by saying that there is no necessity to claim “I think,” since the opposite of “I think” is simply “not to think,” and therefore it is not necessary that I think. But doesn’t that still leave the argument valid when I am thinking, or when I think that I am not thinking (and only then)?
Another question: isn’t it possible to reject Descartes’ argument from a different direction, namely because of the evil deceiver—that is, maybe it is he who causes me to perceive myself as existing and as thinking? Maybe in fact everything is an illusion (and true, there is a “someone” who completes the illusion, but that “someone” too is only an illusion of the evil deceiver, and in fact the world is empty and does not exist at all)?
Answer
Yes, but then it is no longer necessary, because in principle a person who never thinks could exist.
The question of the evil deceiver cannot attack logic. Beyond that, the question is: whom is the deceiver deceiving? Whom is he causing to think that he is thinking?
Discussion on Answer
You have to distinguish between a plausible argument and a proof. If you are looking for plausibility, there is no need for the cogito. Everyone understands that he exists even without proofs. Descartes tried to present an argument that compels us with certainty to reach that conclusion. What I argued is that there is no certainty here. You keep coming back and saying that there is a high probability, and nobody disputes that he thinks from time to time. Indeed, that is true. By the same token, there is a high probability that I exist. I haven’t met anyone who disputes that either.
I asked you the question: whom is the deceiver deceiving? If I do not exist (as you want to claim), then the deception does not exist, because there is no one being deceived. And consequently there is no reason to assume that there is an evil deceiver. Therefore, either way, I exist. Which was to be shown.
I don’t want to claim anything. I’m just asking in order to understand.
I didn’t understand your answer that the evil deceiver cannot attack “logic.” What did you mean by the term “logic”?
If you raise a claim against logic, you destroy the very possibility of discourse altogether (because it takes place within logic). Yes, a claim about an evil deceiver against logic is nothing but an oxymoron. That itself is Descartes’ cogito argument: even if you think that an evil deceiver is deceiving you, you are still thinking, and from that it follows that you exist and that there is thought (= logic).
Likewise, the evil deceiver cannot be a reason to deny my existence, because then he has no one to deceive.
That is—since Descartes tried to ground reality on something that cannot be doubted, and since hypothetically (although in my life I’ve never met a person who does not think at all—it seems that every human being thinks on some level) it is possible to doubt this—has he lost the proof?
As for the second part of the question:
Why can’t the evil deceiver attack logic?? Isn’t that his whole claim—that perhaps the answer to 1+1 is being dictated to me by the evil deceiver?