Conrad Grebel College, Univ. of Waterloo, Waterloo, ON N2L 3G6, Canada
The tradition rules of voice-leading in Western music are elucidated using empirically established perceptual principles. Six core principles are shown to account for the majority of traditional rules of voice-leading given in music theory texts. The pertinent principles include the principle of dissonant spread, the principle of tonal fusion, the pitch proximity principle, and the pitch comodulation principle. These principles are treated as axioms in a formal system from which the traditional rules of voice-leading are derived. All of the major rules of voice-leading are derived---including such arcane rules as avoid doubling the leading-tone, and when approaching an octave by similar motion, ensure that one part moves by diatonic step. In the process of the derivation, several novel rules arise that are not found in treatises on voice-leading. For these novel rules, computer-based score analysis show that composers do indeed write in a manner consistent with these additional rules.