I hope it is clear... that the ways in which pitches represent pitch classes, and the ways pitch classes abstract pitch, must be examined in order to describe any kind of musical sense or progression, and that if one steps back into abstracted considerations derived without respect to such concerns, an understanding of the qualities of musical uniqueness will continue to be suppressed in favor of generalizations, which at best evoke a vague sense of what a piece may be doing, perhaps in common with some other pieces, but not what one piece is doing, all by itself.

Lansky, Paul (1975). Pitch-Class Consciousness, Perspectives of New Music XIII/2 (Spring-Summer).