Following the order of time, we come next to the passage in the Republic (p. 398), where Socrates is endeavouring to determine the kinds of music to be admitted for the use of his future 'guardians,' in accordance with the general principles which are to govern their education. First among these principles is the condemnation of all undue expression of grief. 'What modes of music (harmoniai),' he asks, are plaintive (thrÊnÔdeis)?' 'The Mixo-lydian,' Glaucon replies, 'and the Syntono-lydian, and such-like.' These accordingly Socrates excludes. 'But again, drunkenness and slothfulness are no less forbidden to the guardians; which of the modes are soft and convivial (malakai te kai sympotikai)?' 'Ionian,' says Glaucon, 'and Lydian, those which are called slack (chalarai).' 'Which then remain?' 'Seemingly Dorian and Phrygian.' 'I do not know the modes,' says Socrates, 'but leave me one that will imitate the tones and accents of a brave man enduring danger or distress, fighting with constancy against fortune: and also one fitted for the work of peace, for prayer heard by the gods, for the successful persuasion or exhortation of men, and generally for the sober enjoyment of ease and prosperity.' Two such modes, one for Courage and one for Temperance, are declared by Glaucon to be found in the Dorian and the Phrygian. In the Laches (p. 188) there is a passing reference in which a similar view is expressed. Plato is speaking of the character of a brave man as being metaphorically a 'harmony,' by which his life is made consonant to reason—'a Dorian harmony,' he adds—playing upon the musical sense of the word—'not an Ionian, certainly not a Phrygian or a Lydian, but that one which only is truly Hellenic' (atechnÔs DÔristi, all' ouk Iasti, oiomai de oude Phrygisti oude Lydisti, all' hÊ per monÊ HellÊnikÊ estin harmonia). The exclusion of Phrygian may be due to the fact that the virtue discussed in the Laches is courage; but it is in agreement with Aristotle's opinion. The absence of Aeolian from both the Platonic passages seems to show that it had gone out of use in his time (but cp. p. 11).

The point of view from which Plato professes to determine the right modes to be used in his ideal education appears clearly in the passage of the Republic. The modes first rejected are those which are high in pitch. The Syntono-lydian or 'high-strung Lydian' is shown by its name to be of this class. The Mixo-lydian is similar, as we shall see from Aristotle and other writers. The second group which he condemns is that of the 'slack' or low-pitched. Thus it is on the profoundly Hellenic principle of choosing the mean between opposite extremes that he approves of the Dorian and Phrygian pitch. The application of this principle was not a new one, for it had been already laid down by Pratinas: mÊte syntonon diÔke mÊte tan aneimenan.

The three chapters which Aristotle devotes to a discussion of the use of music in the state (Politics viii. cc. 5-7), and in which he reviews and criticises the Platonic treatment of the same subject, will be found entirely to bear out the view now taken. It is also supported by the commentary of Plutarch, in his dialogue on Music (cc. 15-17), of which we shall have something to say hereafter. Meanwhile, following the chronological order of our authorities, we come next to the fragment of Heraclides Ponticus already mentioned (Athen. xiv. p. 624 c-626 a).