Bach was integral in creating what we judge as music. He used the church modes as part of his style/basis(Ionian, Locrian, etc.). Indians(don't know if it was Aryans or those darker folk to the south) take notes(A, B, C, D, E, F, G) and divide them into fourths, unlike Bach who divided them into halves. If you're trained from a young age to discern between A 1/2 step and A 1/4 step, then you must have a distinct taste for sound that is different for us Bach's sound descendants. Then besides actual sound, there is the point of measuring and ordering that sound. Humans may evolve a thousand years from now and be able to hear higher or lower frequencies, and thus different pitches, but we also have infinite ways to place these sounds into structure. The organization of sound produces a mood. Major chords are bright and gleeful and minor chords are softer and conflicted. Genres seem to be defined by common instrumentation or perhaps philosophy(theme). I like to think that music evolves with humans. When next we reach a higher perception of things, new moods will flourish.