We can't put 100% confidence in the claim that Santa Claus doesn't exist either, yet we say he doesn't because it'd be extraordinary for him to exist and we have no evidence to suggest he does.
That is not an "end of knowledge" style pronouncement, merely shorthand to avoid having to tack an "as far as we know" onto every single statement we make. Because we can known next to nothing with certainty. I don't know I'm speaking to a person and not an automaton for example, nor do I know I'm not a brain in a vat. It'd be very tedious if I had to caveat everything I said, however.
That is not an "end of knowledge" style pronouncement, merely shorthand to avoid having to tack an "as far as we know" onto every single statement we make. Because we can known next to nothing with certainty. I don't know I'm speaking to a person and not an automaton for example, nor do I know I'm not a brain in a vat. It'd be very tedious if I had to caveat everything I said, however.