Multi-layered harmony, polymodality, and scalar dissonance in early-century music and theoretical accounts

The paper approaches polytonality by revisiting the theorizing activity on the subject in the 1920s to 40s by proponents such as Koechlin, Milhaud, as well as casella and Bartók, which has subsequently been either dismissed or appropriated by the post-schenkerian and set-theoretical approaches developed in the second part of the century. the paper examines aspects of the debate on polytonality along two sets of theoretical tensions: (1) constructionist vs. interpretative claims about the nature of the layered harmony; and (2) exclusive vs. inclusive (or literal vs. loose) views about the implied presence of full-fledged keys. it is argued that modernistic notions of polytonality draw from a number of inclusive compositional phenomena, which actively explored compositional arrangements that engaged new listening strategies for the interaction of layers. it is also argued that detractors of polytonality—the dominant position throughout the century—often devalued and dismissed the constructionist and inclusive aspects of polytonality and adopted mostly exclusive and interpretative views. in addition to this theoretical/historical framework, the paper also proposes an analytical model called scalar dissonance (measuring the mismatch and friction between scalar layers), which is explored analytically in music of Milhaud, Bartók, Koechlin, and ravel, arguing that polytonality/modality casts a much wider net on compositional practice than traditionally granted.