Why is diatonic function of a chord important in music theory?
A diatonic function, in tonal music theory, is the specific, recognized role of each note and chord in relation to the [diatonic] key. Three general and inseparable essential features of harmonic function in tonal music are: * Position within a gamut [the available collection] of notes determines a note’s function * Each note within the gamut is a generator and collector of other notes in the gamut, in other words both the root and its chord exercise function, and * Exercise and identification of function depends on musical behavior or structure. A fourth feature is the ambiguity that arises from the use of the same terms to describe functions across all temporal spans of a hierarchical structure from the surface to the deepest level, and that the longer term or deeper functions act as a center for shorter higher level ones and that the functions of each tend to counteract each other. Pandiatonic music is diatonic music without the use of diatonic functions.
