Episode of "Through the Wormhole" was about "what is nothing?" Point was made that once we give something a name, it's something, thus "nothing" is something called nothing. So doesn't God exist once we name it, give it personality and attributes, etc.? The wormhole doc explained how a true and perfect nothing is scientifically impossible. There's always something in any point in space. So how much does God have to encompass before we agree it exists in at least some way? We murder for God, die for God, how much more "real" does God need to be?
So then Santa is real too.
The standard of evidence required to prove a gods existence is immediately more than any personal anecdote, witness testimony, ancient book or reported miracle none of which can be considered extraordinarily reliable.
Every conceivable argument, every imaginable piece of evidence for god is not without some fatal flaw or more likely explanation which precludes it from being used as definitive proof. Note:
There is, however, a simple answer to this question: God is what it would take to convince an atheist. An omniscient god would know the exact standard of evidence required to convince any atheist of its existence and, being omnipotent, it would also be able to immediately produce this evidence. If it wanted to, a god could conceivably change the brain chemistry of any individual in order to compel them to believe. It could even restructure the entire universe in such a way as to make non-belief impossible.
In short, a god actually proving its own existence is what would convince any atheist of said gods existence.
Of course, that presumes such a god wants you to know or cares if you know or not.
Exactly. If there is a god, he doesn't give a shit about gismys or me or you. That's be like a lion in africa caring about a tardigrade in the rain forest.