Plato on Morality

Plato on Morality, as summarized by Tom Griffith:

For Plato, the answer to the question 'How should we live?' was given by his friend and mentor Socrates, who, for all his protestations that he did not know anything, had an unshakable conviction that there were moral truths and moral realities. Of these truths, two were of overriding importance. The first, which found it's way into Christianity 400 years later, and has been immensely influential ever since, was that we are never justified in harming anyone (the prevailing view being that we should help our friends and harm our enemies). The second was that goodness and knowledge are the same thing, that people do wrong simply because they fail to understand what is good and what is bad. Few people these days would accept this as a moral truth, perhaps, but for Socrates and Plato it was fundamental.

Griffith, Tom. Introduction. Plato: Selections from Protagoras, Republic, Phaedrus, Gorgias. By Plato. New York: Barnes & Noble Books, 2004. 9.