A theist can't empirically prove that God exists but he believes in God because no one can allegedly disprove God's existence. By his logic, you must believe in anything you can't disprove. That means all things are real until disproved--including the tooth fairy, the Loch Ness Monster, Santa Claus, the Flying Spaghetti Monster, etc.

I have found it an amusing strategy, when asked whether I am an atheist, to point out that the questioner is also an atheist when considering Zeus, Apollo, Amon Ra, Mithras, Baal, Thor, Wotan, the Golden Calf and the Flying Spaghetti Monster. I just go one god further.