Music of course has physical laws and depends on them (vibrations). But there's much more...
A simple statement, a semantic etymological truth: muse, music, musical, amuse(ment)... All tied together in meaning. But as I read the current topic, I somehow have the impressing that the basic entry 'muse' (or source of inspiration) has ondergone a total twist during the last 150 years. Nothing abnormal or strange, just an observation. Maybe it has already been mentioned, but during all the centuries of musical evolution the aim was (not speaking about styles or fashion) to improve the musical performance in composition and instrumental (orchestral) rendition. Now I sometimes have the impression that we are returning to a kind of decomposing/decomposition and exploration of new (and by definition strange) sensations such as e.g. a whole asenal of violin sounds that are not inherent to (traditional) violin playing which may sound in the ears of many like some sort of 'abuse' of the instrument. More or less like the destruction on stage of electric guitares during a metal concert.
Of course discovering new possibilities is a good evolution, as long as the goal is more than just experiment for experiment's sake. (An impression that many listeners have...) We could call this phenomenon alienation (from the composer's side to his apossible audience). I suppose that's what Jerry explained. Intellectual challenge calls for emotional adaption. That would be a lot easier when beauty (depending on time, place, personality) is experienced.
Jos
Of course there is much more to music than laws governing vibration, I would think that goes without saying. It is the love of music that sustains and nourishes musicians as much as music itself. Almost every generation believes that music is getting worse and worse, nothing new there. It's best to try not to write or speak in too much generality, the intellectual/moral/spiritual/artistic/social development of human civilization and individual people is always on many levels at once. Though we are all human and share much, very much, in common, there are also vast differences in the quality of thinking, ideals, values, living habits, ways of perceiving reality and the world, etc. that makes large sweeping generalities not too useful. I do it too, we all do it, and sometimes generalities are useful because sometimes, something can be generally true. But I really think in 200 years from now, when we are all dead and gone, there will be new composers, some will be writing fantastic music and many who will be writing crap and other nonsense, and everything in between crappy and great. Just like today, yesterday and the day before.
Comparing the destruction of an electric guitar as part of a performance to using an musical instrument to make sound in ways that it was not intended for, i.e. playing the piano from the inside rather than striking the keys doesn't strike me as meaningful. The former is a childish act of rage, frustration and attention-craving spectacle, the latter is genuine musical experimentation. What is interesting is that just around the time when composers were experimenting with acoustic instruments and seeking new ways to make sounds out of violins, pianos, flutes, etc, along comes the synthesizer, then digital synths, then sample libraries and soft synths. Our timbral resources have expanded exponentially, which is a good thing to my mind.
Jerry