Music has the power of producing a certain effect on the moral character of the soul, and if it has the power to do this, it is clear that the young must be directed to music and must be educated in it.
Anger is always concerned with individuals, ... whereas hatred is directed also against classes: we all hate any thief and any informer. Moreover, anger can be cured by time; but hatred cannot. The one aims at giving pain to its object, the other at doing him harm; the angry man wants his victim to feel; the hater does not mind whether they feel or not.
Anaximenes and Anaxagoras and Democritus say that its [the earth's] flatness is responsible for it staying still: for it does not cut the air beneath but covers it like a lid, which flat bodies evidently do: for they are hard to move even for the winds, on account of their resistance.
Now, the causes being four, it is the business of the student of nature to know about them all, and if he refers his problems back to all of them, he will assign the "why" in the way proper to his science-the matter, the form, the mover, that for the sake of which.
But nothing is yet clear on the subject of the intellect and the contemplative faculty. However, it seems to be another kind of soul, and this alone admits of being separated, as that which is eternal from that which is perishable, while it is clear from these remarks that the other parts of the soul are not separable, as some assert them to be, though it is obvious that they are conceptually distinct.
If what was said in the Ethics is true, that the happy life is the life according to virtue lived without impediment, and that virtue is a mean, then the life which is in a mean, and in a mean attainable by every one, must be the best. And the same principles of virtue and vice are characteristic of cities and of constitutions; for the constitution is in a figure the life of the city.
It is evident, then, that there is a sort of education in which parents should train their sons, not as being useful or necessary, but because it is liberal or noble.