Conscientious and careful physicians allocate causes of disease to natural laws, while the ablest scientists go back to medicine for their first principles.
Nor was civil society founded merely to preserve the lives of its members; but that they might live well: for otherwise a state might be composed of slaves, or the animal creation... nor is it an alliance mutually to defend each other from injuries, or for a commercial intercourse. But whosoever endeavors to establish wholesome laws in a state, attends to the virtues and vices of each individual who composes it; from whence it is evident, that the first care of him who would found a city, truly deserving that name, and not nominally so, must be to have his citizens virtuous.
The soul has two parts, one rational and the other irrational. Let us now similarly divide the rational part, and let it be assumed that there are two rational faculties, one whereby we contemplate those things whose first principles are invariable, and one whereby we contemplate those things which admit of variation.
And inasmuch as the great-souled man deserves most, he must be the best of men; for the better a man is the more he deserves, and he that is best deserves most. Therefore the truly great-souled man must be a good man. Indeed greatness in each of the virtues would seem to go with greatness of soul.
People do not naturally become morally excellent or practically wise. They become so, if at all, only as the result of lifelong personal and community effort.
Emotions of any kind are produced by melody and rhythm; therefore by music a man becomes accustomed to feeling the right emotions; music has thus the power to form character, and the various kinds of music based on various modes may be distinguished by their effects on character.