In dealing with the lighter thing called mythology, I have said little about the most disputable aspect of it; the extent to which such invocation of the spirits of the sea or the elements can indeed call spirits from the vasty deep; or rather (as the Shakespearean scoffer put it) whether the spirits come when they are called. I believe that I am right in thinking that this problem, practical as it sounds, did not play a dominant part in the poetical business of mythology. But I think it even more obvious, on the evidence, that things of that sort have sometimes appeared, even if they were only appearances. But when we come to the world of superstition, in a more subtle sense, there is a shade of difference; a deepening and a darkening shade. Doubtless most popular superstition is as frivolous as any popular mythology. Men do not believe as a dogma that God would throw a thunderbolt at them for walking under a ladder; more often they amuse themselves with the not very laborious exercise of walking round it. There is no more in it than what I have already adumbrated; a sort of airy agnosticism about the possibilities of so strange a world. But there is another sort of superstition that does definitely look for results; what might be called a realistic superstition. And with that the question of whether spirits do answer or do appear becomes much more serious. As I have said, it seems to me pretty certain that they sometimes do; but about that there is a distinction that has been the beginning of much evil in the world.