“I think therefore I am” is not the most fundamental claim we can make about the nature of knowledge (an epistemological claim). Why not? “I think therefore I am” depends critically on “therefore”—that is, it depends on logic, specifically on the law of non-contradiction.
The law of non-contradiction says that two contradictory positions cannot both be true in the same way at the same time. I cannot exist (in order to assert my existence) and simultaneously not exist. And of course we all accept that law. But notice—we believe in the law of non-contradiction; we don’t know it. And we can’t logically claim that we absolutely know it, because any claim to the truth of the law of non-contradiction depends on… the law of non-contradiction. To claim that the law of non-contradiction is certain is to reason in a circle.
But note what follows: Because we can’t prove that logic is true, we could “think” but not “exist”! Thus we can’t even claim to know with certainty that we exist. To do so is to invoke a law of logic that, however obvious it seems, we must take on faith.
Our most fundamental knowledge is of logic—specifically, the law of non-contradiction—and even that we must take on faith.Michael Egnor, “How do you know you are not the only human who ever existed?” at Mind Matters News
We must believe that the universe is a certain sort of universe for logic to make sense to us.
Physicist rejects free will — and thus fails logic. If we accepted his argument for materialism, we would have to stop believing in it—a curious, self-refuting result.
Interview with a woman (or women) formerly called Susan Blackmore. A professor of psychology argues that there is no continuity between our present selves and our past selves.