"Rules of simultaneous ensemble constraint can't be assumed a priori to be the kinds of rules or rest on the same foundations as rules for constraint on succession. They may well be similar, but they may well not be similar also. It seems to me that ensemble constraints must first be understood in their own terms, within musical cultures individually and comparitively, looking to what appear to be basic principles in each in light of the others, I would call such a study "comparative counterpoint."
Harold Powers, "Language Models and Musical Analysis", p.39.