a) there's an infinite amount of things that can't be proven/disproven and this includes all sorts of human imagination. We should focus on things that we can actually prove or disprove. The source of a god is human imagination, so you can't even prove that any god exists because you just don't know what it is (iow what exactly you're trying to prove).

b) This being a fundamental question proves scientific curiosity. We wouldn't have achieved current technology if not for scientific curiosity.