It is probably best not to think too much about this--in fact I shouldn't even be writing this post, I should be finishing my set of bagatelles for solo guitar! But sometimes how mysterious composition is just hits me afresh. Think of it: every time you write a new piece you want to create something new. But at the same time, you know you can't. It is not the case that everything has been done. Theorists and critics have been claiming that for almost five hundred years and they are always wrong. Every decent composer comes up with something new. And every time we are astonished at how it is related to what has come before. True, a lot of experimental music in the last century appeared to be entirely novel, but if you look closely, you will probably notice that the entirely novel bits are not terribly musical. So composers are hung up in this dilemma. But the answer is not to think about it, instead to turn off that discursive, analytical part of your mind and just let it free-wheel.
Often it is the simplicity that astonishes us. How did so-and-so come up with that amazingly simple idea? My favorite example of this is Mozart:
Tonic--dominant--tonic. It would be very difficult indeed to write an opening phrase simpler than that one. But he spins a great piece out of it. Most composers, in sheer frustration, end up writing something that is needlessly complex to hide the fact that they haven't come up with something simpler! Paradoxical, I know, but compare it to writing. Most bad writing is bad because it is too long, too complex and too confused. Right? It takes more effort to boil down your thoughts into a simpler, clearer form. It is the same with composition. Let's imagine a very difficult exercise in composition: write a movement for string quartet. The melody has to be nothing but falling fifths in half notes and the other three strings just accompany with repeated chords in eighth notes. Yeah, right! However, one composer did just that:
...and it happens to be one of the best quartets he ever wrote! I'll leave you to ponder the mystery of how he managed that while I go off and work on my bagatelles...