"What about the manner of the style and the speech?" I said. "Don't they follow the disposition of the soul?"
"Of course."
"And the rest follow the style?"
"Yes."
"Hence, good speech, good harmony, good grace, and good rhythm accompany good disposition, not the folly that we endearingly call 'good disposition,' but that understanding truly trained to a good and fair disposition."
"That's entirely certain," he said.
"Mustn't the young pursue them everywhere if they are to do their own work?"
"Indeed they must be pursued."
"Surely painting is full of them, as are all crafts of this sort; weaving is full of them, and so are embroidery, housebuilding, and also all the crafts that produce the other furnishings; so, furthermore, is the nature of bodies and the rest of what grows. In all of them there is grace or gracelessness. And gracelessness, clumsiness, inharmoniousness, are akin to bad speech and bad disposition, while their opposites are akin to, and imitations of, the opposite—moderate and good disposition."
"Entirely so," he said.
"Must we, then, supervise only the poets and compel them to impress the image of the good disposition on their poems or not to make them among us? Or must we also supervise the other craftsmen and prevent them from impressing this bad disposition, a licentious, illiberal, and graceless one, either on images of animals or on houses or on anything else that their craft produces? And the incapable craftsman we mustn't permit to practice his craft among us, so that our guardians won't be reared on images of vice, as it were on bad grass, every day cropping and grazing on a great deal little by little from many places, and unawares put together some one big bad thing in their soul? Mustn't we, rather, look for those craftsmen whose good natural endowments make them able to track down the nature of what is fine and graceful, so that the young, dwelling as it were in a healthy place, will be benefited by everything; and from that place something of the fine works will strike their vision or their hearing, like a breeze bringing health from good places; and beginning in childhood, it will, without their awareness, with the fair speech lead them to likeness and friendship as well as accord?"
"In this way," he said, "they'd have by far the finest rearing."
"So, Glaucon," I said, "isn't this why the rearing in music is most sovereign? Because rhythm and harmony most of all insinuate themselves into the inmost part of the soul and most vigorously lay hold of it in bringing grace with them; and they make a man graceful if he is correctly reared, if not, the opposite. Furthermore, it is sovereign because the man properly reared on rhythm and harmony would have the sharpest sense for what's been left out and what isn't a fine product of craft or what isn't a fine product of nature. And, due to his having the right kind of dislikes, he would praise the fine things; and, taking pleasure in them and receiving them into his soul, he would be reared on them and become a gentleman. He would blame and hate the ugly in the right way while he's still young, before he's able to grasp reasonable speech. And when reasonable speech comes, the man who's reared in this way would take most delight in it, recognizing it on account of its being akin?"
"In my opinion, at least," he said, "it's for such reasons that there's rearing in music. "
(The Republic, Book III, 400d, Translation Allan Bloom, Bold type and underline applied by James Thomas Angelidis)