Douglas Adams. Hitchhiker's guide to the galaxy (№ 52053)

"I refuse to prove that I exist, says God, for proof denies faith, and without faith I am nothing."
"But - he meets People - Babel fish gives you with the head, isn't it? She could not evolve by chance. It proves you exist and therefore by your own words - you don't exist. Quod erat demonstrandum."
"Oh, saith God. - To me it never occurred," and he disappears in a poof of logic.
"Nothing is easier," says Man, and for an encore proves that white is black, then the next crosswalk hit by a car.