Add this site to your Home Screen by opening it in Safari, tapping and selecting "Add to home screen"

Our panel of 88 professional philosophers has responded to

Question of the day

I don't think there's a deep puzzle here, as I hope I can explain.

The kind of possibility that stems from uncertainty is usually called "epistemic possibility," often signaled in English by "may" or "might," as in "There may [or might] be life on other planets." We're far from certain that there isn't life on other planets, so there may [for all we know] be life on other planets: life on other planets is an epistemic possibility for us. There are other kinds of possibility, such as metaphysical possibility, but I think the general point I'll make applies to all of them.

To deny possibility in this sense, to say that some state of affairs S isn't epistemically possible for someone, is roughly to say that he/she is certain that S doesn't obtain, or at least he/she knows that S doesn't obtain (if knowledge doesn't require certainty). So I'd say that, right now, my own non-existence is epistemically impossible for me, because I know (indeed, I'm certain) that I exist, for the reason Descartes gives in the second of his Meditations. By contrast, my non-existence is epistemically possible for someone who's never met or heard of me: for all that person knows, I don't exist.

Importantly, to say that my own non-existence is epistemically impossible for me is not to say that there's an epistemic possibility that I know doesn't obtain. Rather, it's to say that my own non-existence isn't an epistemic possibility, for me, in the first place. I deny that I might, for all I know, not exist right now. I can deny my own non-existence without having to regard it as an epistemic possibility, i.e., as something that might obtain.

I hope that helps.