My brother, an atheist like me, posed to me this humorous thought experiment, and I thought it was worth playing the game and posting it here:
God - the bearded white guy who looks a lot like me (he wears more robes than I do) - turns up on Earth, having decided to prove his omnipotence once and for all.
He turns up everywhere you go, in all your recent photos, and in all the morning shows. He agrees to meet Mr Obama, and he is recorded by numerous news cameras as having said that he disapproves of Ms Gillard's living in sin. (God declines to visit Alan Jones due to allegations of repressed homosexuality.) When your Grandma says "grace" at the Xmas dinner table, and she finishes with "Thank the Lord", God appears and says "No worries, love".
God goes through MRIs, Xrays and CAT scans, as well as standing on a set of scales. All systems indicate that he is THE REAL GOD.
You are a critical thinker, and now God has well and truly been proven to exist - he's eating your Doritos as we speak! Do you continue to deny the possibility of God, or do you resign yourself to the FACT that he exists and start giving Him the praise that He deserves?
Interesting! Okay first we have to establish a few things:
1. This God is Abrahamic God.
2. It would seem from this description that the bible is the true world of God.
3. This God really wants praise.
I guess, if he really could prove himself to be God, then I would not be able to say any longer that "no God exists". But here's the problem: How could we determine the true identity of a God anyhow? What test could there possibly be to truly determine that this guy, beard and all, is the one true God, straight from the ceiling of the Sistine Chapel, and not just a member of a sufficiently advanced race of interstellar alien? We haven't set up a series of experiments designed to test for "God-ness" so the experiments would have to be pretty special indeed.
In order for me to be truly satisfied that there is a God, let alone that this Charlton Hestonesque character is that said God, he'd need to be able to convince me that he was the creator of the universe, and I think the only thing he could do would be to do just that: create the universe, in front of my eyes. It would be like the universe's most amazing magic act! Then again, I would remain skeptical as to the authenticity of this creation, and besides I would probably be destroyed, ripped apart atom by atom, as the new universe emerged.
I guess, assuming there were an experiment that was flawlessly designed to detect God-ness, and if he passed, then I would see no reason not to admit he exists. However, if the God you describe is the God of the bible, as described in the bible, I wouldn't worship him either, but instead might want to sit down with him and tell him where he's gone/going wrong with the world.
I guess the real question is, does God like Doritos?