If music is governed completely by logic, it becomes predictable, and our ears soon realize there's no reason to continue paying attention.
If music unfolds with no pattern at all, our ears can't make sense of it, and quickly tune out, dismissing it as noise.
So, it would seem that the musical ideal is a golden mean between these two extremes: a mixture of logical progression and surprise. Set up expectations, then keep you on your toes with something your ear might have anticipated, but didn't. Certainly, what can be considered a "logical progression" varies with the acuity of the listener's ear and with the range of his previous listening experience. I know there are subtleties in the performance of a sitar raga that are beyond my discernment, and in Western classical music, I know there are people who can follow harmonic complexities that leave my ear in the dust. In this way, our differences in musical taste can be accounted for by our listening history and by the refinement of our innate sensitivities to sound.
All this is much more culture-bound than we might at first realize. Bizet's Carmen was rejected by its first audiences as obscene. The late quartets of Beethoven were deemed unintelligible. And the debut of Stranvinsky's Sacre prompted Paris concert-goers to demand an apology and return of their ticket price. Many millions of people today are in possession of ears that can relish this music without a stretch.
Hence there is a temptation for the greatest musicians of any age to compose for the century to come, to risk irrelevance in their own lifetimes by reaching beyond the standard of sophistication and complexity that their contemporaries can appreciate. There is a nobility and courage in this exercise, and without it, perhaps music would not be able to develop and grow through history. There's always the motive to make music simple, repetitive, and appealing to the commonest ear of the day. $$$. At the other end, there's the challenge of composing in a way that won't become stale or boring when we listen 100 times, but will reveal new subtleties to us each and every time we return to it. Rare geniuses have managed to create music that is appealing both on its first and its 100th exposure.
Hence we come to Pierre Boulez, whose 93rd birthday would have been today. Boulez was consciously reaching into tomorrow, both with his conducting and his composition. He was determined to create music that would be relished on its 100th listening, and less concerned with motivating us to get through the first 99. Some say you have to analyze it with your left brain before your right brain can take it in as music.
Listen to Notations - a piece relatively accessible and (I find, at times) beautiful.
La cre'ation n'existe que dans l'impre'vu rendu ne'cessaire.
Creation exists only in the unforeseen made necessary.
-- Pierre Boulez, born this day in 1925.
