I don’t know if there is no God. Certainly not the Christian god as he is often portrayed, but a deist, abstract God. Maybe something spiritual, maybe something that snapped and made that Big Bang and left after that. I don’t know, how could I know. I can doubt it, and trust me when I say that I do. But I don’t know. By definition, that makes me agnostic. I don’t call myself agnostic, though.
Agnostic, to me, holds a certain implication. That the feeling of faith, the proof even, would convert me one way or the other. That if Jesus Christ came to me, he proved his divinity, I would become a Christian. If it was just about belief, that would be true. I would believe in Jesus, I would know he was real. I would be, if you will, gnostic. But I would still call myself an atheist.
Theism, for me, is about reverence, whatever that means for the religion in question. Maybe it is following some commandments, maybe it is acceptance of some holy spirit, maybe it is ritual sacrifice or worship or prayer. Indeed, present me with a God who represents everything I believe in and asked nothing of me but that I say I was a Christian or a Buddhist or whatever it is, and I would still not do it. It is against my very nature to revere, to follow. I couldn’t, no matter the divinity presented to me.
I doubt highly it would ever come to it. But if it did, nothing would change.