On the aesthetic education of the young

From Book III of The Republic, by Plato (circa 375 BCE, translation by F. M. Cornford). Socrates is speaking with Glaucon:
One thing, however, is easily settled, namely that grace and seemliness of form and movement go with good rhythm; ungracefulness and unseemliness with bad.
Naturally.
And again, good or bad rhythm and also tunefulness or discord in music go with the quality of the poetry; for they will be modelled after its form, if, as we have said, metre and music must be adapted to the se