Usually when people talk about magic in novels, they also talk about rules. What limitations are there on magic? Who can perform it and when? Under what circumstances? What can’t magic control? Do you have to be born with magical abilities or can anyone learn?
Most people agree that your system of magic needs some rules; otherwise your main character would never be in any real danger. But N.K. Jemisin’s post at io9 takes the opposite view. It’s magic–why do we need to explain it?
“Because this is magic we’re talking about. It’s supposed to go places science can’t, defy logic, wink at technology, fill us all with the sensawunda that comes of gazing upon a fictional world and seeing something truly different from our own. In most cultures of the world, magic is intimately connected with beliefs regarding life and death – things no one understands, and few expect to. Magic is the motile force of God, or gods. It’s the breath of the earth, the non-meat by-product of existence, that thing that happens when a tree falls in the forest and there’s no one around to hear it. Magic is the mysteries, into which not everyone is so lucky, or unlucky, as to be initiated. It can be affected by belief, the whims of the unseen, harsh language. And it is not. Supposed. To make. Sense. In fact, I think it’s coolest when it doesn’t.”
My first reaction was, admittedly, a bit of pearl-clutching. “Of course magic needs to make sense! How else will we understand your world? How else will there be tension?”
But I don’t think Jemisin’s saying that creating a magical world is akin to playing wizards as a kid. (“Zap! I got you!” “No you didn’t, I’m wearing an invisible shield that protects me from spells!” “Well my spell destroys invisible shields!”) I think the point is more about over-explaining magical systems. At some level, the audience just has to buy the fact that magic exists and that it works a certain way. In Harry Potter, every wizard has a wand that’s specially tied to him. Although JK Rowling goes into a little background on what makes a wand, we don’t get pages of the history of wand-making and what exactly ties a wizard to his particular wand. Harry goes to Ollivanders, tries a few wands, and eventually get to his. Rowling doesn’t need to stop the action to explain why wizards have wands outside of “they help perform magic.” At some level, the reader just has to buy that wizards need wands.
That said, I don’t think you can just throw magic on the page and assume it’s all okay. You still need some limitations and a level of consistency. In Doctor Who, the Doctor carries a sonic screwdriver that can pretty much fix/adjust/open/etc. anything. Except a natural substance like wood. Having a limitation like that means that the Doctor can’t just go around screwdriver-ing everything; it would make for a fairly boring episode. There’s always the threat that his magical device won’t be able to help him out of a jam.
Also, I think it’s good for a writer to have worked out their magical system in detail. It doesn’t have to go on the page, but it’s good for you to know in advance so you can heighten tension and get your characters out of binds in a way that’s still exciting for the reader.