Tonal Function

in music, the tonal significance of an individual degree of a scale. The concept of tonal functions has been most fully elaborated for chords (harmonic functions) and defines the role of chords in a tonal organization.

There are two types of general chordal functions: stability, or state of rest, and instability, or movement. In the major and minor tonal system, stability is a function of the tonic chord, which defines the center of a tonality. There are two unstable functions: the dominant and subdominant. Dominant and subdominant chords are built on tones that are acoustically very closely related to the root of the tonic and which are a fifth above the root and a fifth below, respectively, hence the logical opposition of the functions of the dominant and subdominant, an opposition that is intensified by their contrasting tonal structures. The tritone interval that lies between the root of the subdominant and the third tone of the dominant (the leading tone of the key) intensifies the tendency of the chords to gravitate toward the root and third of the tonic chord. The workings of harmonic functions are seen most clearly in cadences.

The premises of a theory of harmonic functions are contained in the works of J.-P. Rameau, M. Hauptmann, and A. von Oettingen. N. A. Rimsky-Korsakov developed the notion of a “group” comprising the tonic, subdominant, and dominant in his work Textbook of Harmony.

A developed theory of harmonic functions was advanced in the late 19th century by H. Riemann. According to Riemann, all chords in a given key represent transformations of three “functionally” different chords: the tonic, dominant, and subdominant. The Soviet theoretician B. L. lavorskii proposed an original conception of tonal functions that involves “moments of gravitation.” An important contribution toward a theoretical development was made by the Soviet musicologist Iu. N. Tiulin. The theory of harmonic functions is most frequently used in the analysis of harmony in the music of the mid-18th to the early 20th century.