To escape the power of the unknown, to prove to yourself that you don't believe in it, you accept its spells. Like an avowed atheist who sees the Devil at night, you reason: He certainly doesn't exist; this is therefore an illusion, perhaps a result of indigestion. But the Devil is sure that he exists, and believes in his upside-down theology. What, then, will frighten him? You make the sign of the cross, and he vanishes in a puff of brimstone.