The choice of souls was in most cases based on their own experience of a previous life... Knowledge easily acquired is that which the enduing self had in an earlier life, so that it flows back easily.
Poets do not compose their poems with knowledge, but by some inborn talent and by inspiration, like seers and prophets who also say many fine things without any understanding of what they say.
Because, unlike courage and wisdom, which made our state brave and wise by being present in a particular part of it, discipline operates by being diffused throughout the whole of it. It produces a concord between its strongest and weakest and middle elements, whether you define them by the standard of good sense, or of strength, or of numbers or money or the like. And so we are quite justified in regarding discipline as this sort of natural harmony and agreement between higher and lower about which of them is to rule in state and individual.
A sensible man will remember that the eyes may be confused in two ways - by a change from light to darkness or from darkness to light; and he will recognize that the same thing happens to the soul.