The biggest cop-out in a fantasy story is when the author (in the form of one of the characters) has something happen as a result of some magic spell or item of power and when the illogic begins to rain down just says “It’s magic, it doesn’t need any reason.” Well, I’m here to say that it does. EVERYTHING in a story needs a reason, logic, and purpose.

I’ve said it before, that in the context of any story magic is simply a power like any other that can be tapped. It has its own attributes and rules, just like electricity and gravity. It is up to the writer to determine what these rules are. None of the characters might know what those rules are, or they might word them in more esoteric or poetic forms, but that backdrop of logic needs to be there nonetheless.

For instance. If magic is treated as a power to be tapped, then one needs a source of magical power for one’s spells, the wizard will fatigue over time, and it requires some effort to control such forces. One good distraction while a wizard is in the middle of a powerful spell and you have a new plot complication. In fact by keeping a certain amount of logic to your magic, you have the benefit of built-in limits for your characters and villains, plot developments that fall straight out of that backdrop, and all without the need for being arbitrary.

Surprising the reader with unusual things and unexpected surprises is one thing- and a very good thing- but when you start being arbitrary without any reason other than “I wrote myself into a hole” the reader will see it and start throwing rotten fruit at you. So even with magic, you need logic, something self-consistent that at least the author knows of.