"I have no cold proof of the non-existence of the Olympian Gods or the Gods of Valhalla or Satan, Beelzebub, Moloch, etc. To prove non-existence is almost always impossible. What I maintian [sic] in all these cases, as in that of the Christian God, is that there is no positive evidence of their existence. Suppose I were to say that I believe there is a China tea-pot circling round the sun half-way between the Earth and Mars. You would think my belief absurd even if I said that it afforded me much spiritual comfort, but you would be quite unable to prove that there is no such teapot."