With regard to the censorship of stories, Socrates (or Plato) seems above all concerned with what we expose our children to. What intelligent parents don’t regulate what their children read, watch, listen to, etc.? But once this becomes a matter of public legislation, we stir up a hornet’s nest. And outlawing certain types of music, musical instruments, food, and so on, does appear extreme. Yet I have always suspected that Plato’s main purpose with all of this is to get us to see that aesthetic worlds aren’t morally or politically neutral. . . .
Beyond mere survival, for human beings to flourish, they need the virtues. Actually, this is a tautology: human flourishing just is living a virtuous life. As Socrates argues at the end of Book 1, a pruning knife needs its “virtue,” that is, sharpness, to be a good pruning knife. So too, he adds, human beings need the virtues to live the good life. But which virtues are the virtues? In Book 4, Socrates tells us that they are wisdom, courage, temperance, and justice—what St. Ambrose would later call the virtutes cardinales. We can discuss whether this is a complete list, but, rightly understood, I don’t see how anyone can deny that the cardinal virtues are essential for a good human life.
However, just as no one teaches himself his mother tongue, no one trains himself in virtue. We are trained in virtue by others. Not only, then, do we need a community to survive, we also need it, as I mentioned earlier, to flourish. Ideally, training in virtue occurs in the family. But families need environments that are friendly to this training in virtue, even reinforcing it where appropriate. In other words, virtue shouldn’t be merely a private matter but a public and political one. Socrates gets this. You might say that he gets it all too well. It’s the reason for the censorship, the closed social classes, and the banishment of the mimetic poets. These are among the measures Socrates proposes to make the city a well-ordered city.
Joseph G. Trabbic, In Defense of Plato’s Republic