Quote Originally Posted by Gez View Post
The best approach I've seen is that magic can be either exploited or explained, but not both.

Suppose you can generate fireballs at will. Your scientist friend comes up with a lot of ways to examine and analyze what's happening. Finally he discovers that all along it was just spontaneous explosions of swamp gas, a complete coincidence. Now you can't generate fireballs at will anymore. Thanks, scientist friend.
I don't see how explaining a phenomenon stops you from using it as you did before. People didn't randomly stop being able to make fire when it was discovered that it's the bonding of carbon and oxygen and not a classical element.