Identity Thesis for Language and Music:

All formal differences between language and music are a consequence of differences in their fundamental building blocks (arbitrary pairings of sound and meaning in the case of language; pitch-classes and pitch-class combinations in the case of music). In all other respects, language and music are identical.

In particular, we argue, developing but also extending earlier proposals by Lerdahl and Jackendoff (1983), that music, like language, contains a syntactic component in which headed structures are built by iterated, recursive, binary Merge. This is the component that Lerdahl and Jackendoff called Prolongational Reduction, which represents hierarchical patterns of tension and relaxation in tonal harmony. We further argue that the distinct component that Lerdahl and Jackendoff called Time Span Reduction is a musical prosodic component (a point anticipated by Lerdahl and Jackendoff themselves) -- whose interface with the syntactic component is strikingly similar to the comparable interface between syntactic and prosodic structure in language.

Though our discussion takes Lerdahl and Jackendoff's work as a starting point and touchstone throughout, our proposals also constitute a significant realignment of their model -- necessary in order to reveal similarities between musical and linguistic structure that were not evident in their presentation. This realignment also reflects a distinction in goals between our proposal and theirs. Their work took as its starting point the question "Given a piece of music in a particular musical idiom I, what laws govern the class of analyses that a listener assigns to it in I?" Our proposals arise from a related but distinct question, more typical of generative linguistic work: "What general laws define the class of possible pieces in I?" That is, what is the grammar of I?

Our realignment of Lerdahl and Jackendoff's proposals in light of the Identity Thesis allows us to ask questions not taken up in their work. For example, does Internal Merge (i.e. syntactic movement) apply in the construction of musical syntactic structure, in addition to External Merge? We argue that the phenomenon of cadence is an instance of exactly this: head-movement from the penultimate constituent of a musical passage (the dominant) to the final tonic chord.

Finally, we argue that the output of musical syntax feeds a Tonal-Harmonic Component whose formal relation to the music syntax strongly resembles the relation between linguistic syntax and the semantic system that interacts with it -- and is subject to a Principle of Full Interpretation with respect to that component.