When puzzling events happen in life — things that simply can't be explained, or at least can't be explained simply — people often put them down to fate. It's as though ascribing our troubles to fate somehow relieves us of the need to understand them. But what is fate, really? At best it's a difficult concept to grasp, much less explain in words. That may be why so many evocations of fate can be heard in music, a medium in which words are optional.