Of the writers who deal with music from the point of view of the cultivated layman, Aristotle is undoubtedly the most instructive. The chapters in his Politics which treat of music in its relation to the state and to morality go much more deeply than Plato does into the grounds of the influence which musical forms exert upon temper and feeling. Moreover, Aristotle's scope is wider, not being confined to the education of the young; and his treatment is evidently a more faithful reflexion of the ordinary Greek notions and sentiment. He begins (Pol. viii. 5, p. 1340 a 38) by agreeing with Plato as to the great importance of the subject for practical politics. Musical forms, he holds, are not mere symbols (sÊmeia), acting through association, but are an actual copy or reflex of the forms of moral temper (en de tois melesin autois esti mimÊmata tÔn ÊthÔn); and this is the ground of the different moral influence exercised by different modes (harmoniai). By some of them, especially by the Mixo-lydian, we are moved to a plaintive and depressed temper (diatithesthai odyrtikÔterÔs kai synestÊkotÔs mallon); by others, such as those which are called the 'relaxed' (aneimenai), we are disposed to 'softness' of mind (malakÔterÔs tÊn dianoian). The Dorian, again, is the only one under whose influence men are in a middle and settled mood (mesÔs kai kathestÊkotÔs malista): while the Phrygian makes them excited (enthousiastikous). In a later chapter (Pol. viii. 7, p. 1342 a 32), he returns to the subject of the Phrygian. Socrates, he thinks, ought not to have left it with the Dorian, especially since he condemned the flute (aulos), which has the same character among instruments as the Phrygian among modes, both being orgiastic and emotional. The Dorian, as all agree, is the most steadfast (stasimÔtatÊ), and has most of the ethos of courage; and, as compared with other modes, it has the character which Aristotle himself regards as the universal criterion of excellence, viz. that of being the mean between opposite excesses. Aristotle, therefore, certainly understood Plato to have approved the Dorian and the Phrygian as representing the mean in respect of pitch, while other modes were either too high or too low. He goes on to defend the use of the 'relaxed' modes on the ground that they furnish a music that is still within the powers of those whose voice has failed from age, and who therefore are not able to sing the high-pitched modes (oion tois apeirÊkosi dia chronon ou rhadion adein tas syntonous harmonias, alla tas aneimenas hÊ physis hypoballei tois tÊlikoutois). In this passage the meaning of the words syntonos and aneimenos is especially clear.

In the same discussion (c. 6), Aristotle refers to the distinction between music that is ethical, music suited to action, and music that inspires religious excitement (ta men Êthika, ta de praktika, ta ho enthousiastika). The last of these kinds serves as a 'purification' (katharsis). The excitement is calmed by giving it vent; and the morbid condition of the ethos is met by music of high pitch and exceptional 'colour' (tÔn harmoniÔn parekbaseis kai tÔn melÔn ta syntona kai parakechrÔsmena).

In a different connexion (Pol. iv. 3, p. 1290 a 20), dealing with the opinion that all forms of government are ultimately reducible to two, viz. oligarchy and democracy, Aristotle compares the view of some who held that there are properly only two musical modes, Dorian and Phrygian,—the other scales being mere varieties of these two. Rather, he says, there is in each case a right form, or two right forms at most, from which the rest are declensions (parekbaseis),—on one side to 'high-pitched' and imperious oligarchies, on the other to 'relaxed' and 'soft' forms of popular government (oligarchikas men tas syntonÔteras kai despotikÔnteras, tas d' aneimenas kai malakas dÊmotikas). This is obviously the Platonic doctrine of two right keys, holding the mean between high and low.