Have you ever crossed your fingers for something you really, really wanted?
Most of us probably have. The gesture is said to have originated with early Christianity, as a secret signal between believers. You don’t have to see it as religious, though, to do it when you’re hoping for good luck. You don’t even — and here’s the interesting part — have to believe it that it works.
I mean, really. What good does it do to have your middle finger hooked over your index finger? That won’t affect the outcome of anything, and we generally know it. Yet we do it anyway. Just like we knock on wood and put rabbits’ feet on our keychains and make wishes before we blow out the candles on our birthday cakes. And those are only the tip of the iceberg: for every such practice we remember today, there are dozens that have been discarded from earlier times.
The colloquial term for such things is “superstition.” Folklorists are more likely to call them “folk beliefs,” in order to get away from the bad old habit of contrasting superstition with (true) religion. (A habit which, of course, relegated the religions of many non-white peoples to the category of foolish superstition.) These are fascinating to study for a variety of reasons. First, their origins are often obscure; there may be no apparent explanation for them, or there may be several, one or more of which is an after-the-fact invention — a process which becomes interesting in its own right. Second, they tell us a lot about a society: its symbols, its hopes, its fears. Third, as the above examples show, they can persist as a cultural practice even when their original motivation is gone. We may call them folk beliefs, but that doesn’t mean people always believe in them.
The term works because at its core, a superstition is usually based on the idea that A has a supernatural influence on B. Crossing one’s fingers makes the sign of the Cross, so it’s a shorthand for prayer; you’re asking God to look with favor on the subject at hand. Of course, when you look at superstitions in that light, the range of things that could fall under that label becomes huge. In fact, it covers a wide swath of fantasy — because after all, the genre is all about things having a supernatural influence. In The Lord of the Rings, wearing the One Ring corrupts you because it was made by a corrupt power. Obsidian hurts the white walkers in George R. R. Martin’s series A Song of Ice and Fire because it’s made by volcanoes and also known as dragonglass, and fire is their bane. Resurrecting someone in Dungeons & Dragons requires a diamond worth at least 25,000 gold pieces, because getting a life back necessitates the sacrifice of something valuable. (Actuaries take note: 25,000 gp is the value of a sentient humanoid life in D&D worlds.)
And yet, I’m going to immediately contradict myself by saying that I sometimes think we don’t have enough superstition in fantasy. Where are the random little beliefs the characters hold, the associations they make between things, the actions they don’t really believe in but practice anyway because that’s just what you do? When these things show up, it’s usually because they’re important. If dragonglass was considered really good for hunting sea-serpents off the coast of Westeros, nobody would ever mention it, because sea-serpents are irrelevant to the story. Narrative efficiency says we shouldn’t spend words on things that don’t actually matter.
But there’s a point at which that sort of efficiency ceases to be a virtue. We’ve all probably read a fantasy where every single legend that gets mentioned a) conveys valuable information about the plot and b) is perfectly accurate in every respect. In those stories, legends cease to be a part of the world; they turn into a half-hearted disguise for the Hand of the Author, infodumping for the hero’s benefit. Similarly, if the only folk beliefs turn out to be 100% utilitarian, then they stop being the sort of thing found in human cultures all over the world, and start being blatant pieces of narrative machinery. In case of trouble, break glass, use superstition.
I’m not saying I want long digressions into things that don’t matter to the story. But the nifty thing about superstitions is, they don’t need long digressions. You don’t have to tell your reader the history of early Christianity in order to explain why your heroine is crossing her fingers; you just have to say she does it for luck. She covers her eyes when someone mentions a dead friend. She throws a handful of dirt into the air before embarking on a long journey. Why?
Because that’s just what you do.