Raymond Smullyan is name that is probably familiar to a lot of readers of this blog. In addition to being a mathematician and philosopher, he is known for being a master of using brainteasers and other puzzles to illuminate sometimes deep ideas in logic, especially Godel’s theorems. He is perhaps best known for his knight/knave puzzles. Those are the ones where knights always tell the truth and knaves always lie. Remember those?
Anyway, I’ve recently been browsing through his book 5000 BC and other Philosophical Fantasies. In one section he has a series of short vignettes containing anecdotes, jokes, puzzles and paradoxes. I especially liked this one:
Speaking of proofs of the existence of God, the funniest one I have ever seen was in a term paper handed in by a freshman. “God must exist because he wouldn’t be so mean as to make me believe he exists if he really doesn’t!” Is this argument really so much worse than the ontological proofs of the existence of God provided by Anselm and Descartes, among others?