 A disciple of Aristotle, Aristoxenus (fl. 4th century BCE) argues that harmonics should not be concerned with an explanation of musical phenomena in mathematical terms, but rather describe musical structures through the analysis of musical elements as objects of perception. For example, Aristoxenus distinguishes between the speaking and singing voice, the former being characterized by a continuous movement across pitch space, the latter by intervallic movement from one pitch to another (Elementa Harmonica, book I, 9–10). On the basis of this distinction, he provides a definition of note (phthongos) as any pitch on which the voice rests and that has a position in a given melodic line (Elementa Harmonica, book I, 9–10; for a detailed discussion of Aristoxenus as a music theorist, see Mathiesen 1999: 294–344).