As I’ve said before, it’s very difficult to be a true and honest atheist. Most unbelievers actually hold to some form of agnosticism. And within’ that framework where God is distant, the supernatural can sometimes crop up right around the corner.
Chesterton recounts this curious story to illustrate the point:
Superstition recurs in all ages, and especially in rationalistic ages. I remember defending the religious tradition against a whole luncheon table of distinguished agnostics; and before the end of our conversation every one of them had procured from his pocket, or exhibited on his watch-chain, some charm or talisman from which he admitted that he was never separated. I was the only person present who had neglected to provide himself with a fetish.
Superstition recurs in a rationalist age because it rests on something which, if not identical with rationalism, is not unconnected with skepticism. It is at least very closely connected with agnosticism. It rests on something that is really a very human and intelligible sentiment, like the local invocations of the numen in popular paganism. But it is an agnostic sentiment, for it rests on two feelings: first that we do not really know the laws of the universe; and second that they may be very different to all we call reason. Such men realize the real truth that enormous things do often turn upon tiny things. When a whisper comes, from tradition or what not, that one particular tiny thing is the key or clue, something deep and not altogether senseless in human nature tells them that it is not unlikely.
-G.K. Chesterton, The Everlasting Man, p.130
Indeed, the desire for something transcendent is hardwired within us. I suspect it takes as much effort to supress as for one not called to celibacy to supress his sexual desires. The tiny whisper, the small key, the rumour of a clue, our minds latch onto these things because we feel (and know) deep down that they just might be true.