Said it before, will say it again

One of the reasons, really very basic reasons, that music works, when it works, is that we have a weak notion of same and different in music.   Music is coherent due to forms of repetition, but compelling due to variety, and that play between repetition and variety is not only the very center of a composer's — and a performer's — work, but also the most important cognitive dynamic in listening to music. But no repetition in music can ever be exact, all "sames" in music being different — the very shift of some bit or stretch of music (our "material")  in time changes everything: memory is loaded, phases are shifted and locked, context is everything BUT THEN all differences are measured by grasping for similitudes even though memory is fragile and uncertain, we experience time both smoothly and in chunks, and often enough, context is not enough, if not nothing at all.  But out of this uncertainty, there are only opportunities for making more music!