Logic

Is it possible for something that is said to be logically impossible, to be physically possible? That is, what is the "proof" that logical impossibilities cannot actually exist (if there is any such 'proof')?

Comments

By "X is logically possible," I think most philosophers mean something like "X could exist (or could have existed) or could obtain (or could have obtained) in the broadest sense of 'could', i.e., 'could' without restriction or qualification." This sense of 'could' is supposed to be compatible with 'does', so the claim that you do exist is compatible with the claim that you could exist. In fact (to get to your question), the first claim obviously implies the second claim: any X exists (or obtains) only if X could exist (or obtain). It just makes no sense to say that something is true that couldn't have been true. That's the best "proof" I think I can give.

Now, some analytic philosophers calling themselves "dialetheists" say that some logical contradictions -- some propositions of the form P & not-P -- are true. But they're not properly described as saying that some logical impossibilities are true or could be true; rather, they say that not all contradictions are logical impossibilities in the first place.

Again, logical possibility is usually taken to be the broadest or weakest kind of possibility, with physical possibility being a narrower or stronger kind of possibility: Everything physically possible is logically possible, but the converse needn't hold.

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