One of the first things I was told as a fantasy writer–that anyone is told as a fantasy writer–is that you need to know the rules of your magic.
I’m not sure I’ve ever written a story where I knew the rules up front, but it is true, for the most part, I’ve worked out something resembling rules as I go, at least for longer work. Yet more and more I find myself wondering: does magic need to have rules at all, even rules that the writer works out even after the fact? Or is this a bit of received wisdom that maybe hasn’t been thoroughly questioned enough?
Magic needs limitations. You need the sense that magic can’t do everything, even if it wanted to–which it might not. Is having limitations the same as having rules, though? I’m not sure it is. Magic shouldn’t be free. There should be a cost involved–though it need not be a cost you can measure. It need not even be the person using the magic who pays the cost. I’m not sure whether this is a rule, either. Magic needs to be believable. Not consistent, necessarily–it can acted in unexpected ways. But no matter how consistent or inconsistent it is, it can never do things that make the reader say, “I don’t think so.” Because then the reader walks away, and justly so. If magic does have rules, that doesn’t mean that anyone human needs understand them. Because this is magic. Magic isn’t unbounded, but it also isn’t human. It’s the other that enters into the story, that forces your humans to deal with things beyond what humans in other sorts of stories have to deal with. Magic need not even be something humans can use or control–it need not be anything to do with us. But that’s another subject, too. If magic does have rules, they’re not the sort of rules you can work out in a spellbook or teach at a wizard’s school. They’re not as simple as knowing that if you perform certain actions, certain reactions will always occur. Magic isn’t science with better special effects. Magic definitely would never submit itself to the sort of rules that work well in gaming systems but not in novels. You can’t just roll X amount of power to get Y amount of effect. Magic is a force of nature, and forces of nature are unpredictable. If you’re fighting a wildfire or a hurricane, it’s good to study how wildfires and hurricanes have acted in the past. But each wildfire is its own event; there’s no promise that what’s protected others before will protect you now. No matter what your characters think they know about magic, the magic can change–just like gods and wind currents can.