Let’s just bring this back to the original post, shall we?
There are two threads going on at the same time here:
[1] Why is Western music divided into 12 notes per octave?
[2] Why don’t people like serial music (Schoenberg, in particular)?
These are really very, very different questions. If I may:
[1] Why is Western music divided into 12 notes per octave?
Mathematically speaking, 12 notes per octave is the best mix of smallish-number-of-divisions-per-octave and interesting-enough-to-approximate-natural-overtone-intervals. Please read as much of this as you can. Essentially, the next best division after twelve occurs at 41. That’s just too much for us to be comfortable with, as listeners or performers.
Sure, you can have less than 12, but you get very few intervals that are reasonably close to small integer ratios. And, there’s less to work with, melodically.
GorillaMan, try as you might, you won’t be able to convince me that 12 notes per octave is arbitrary.
[2] Why don’t people like serial music (Schoenberg, in particular)?
It’s not because there are 12 tones per octave. Anyone ever hear of a little tune called The Well-Tempered Clavier?
No, it’s because he’s abandoned the concept of tonality. Gone are the relationships of tonic-dominant. Gone are the carefully-crafted modulations and whistleable tunes of the past.
Schoenberg’s music is all about mathematical beauty. If you like looking at fractals and pondering the nature of pi, you’ll find interest in well-written serial music such as his. It’s much more cosmic and cerebral than a polka. Essentially, it’s because the masses can’t dance to it or request it at wedding parties that snooty brainy types like it.