Plato

Abstract

Plato rejects Socrates’ belief that knowledge of the good is sufficient for being virtuous; he argues that human souls have a non-rational part (emotions, impulses), and that the virtues require not only knowledge, but also the correct training of the non-rational part. He rejects Socrates’ belief that virtue is sufficient for happiness. Instead he argues that the virtuous person is always happier than anyone else. He defends this view in the most difficult case, the other-regarding virtue of justice. Plato recognizes that one may plausibly argue that my justice is good for other people, but harmful to me. None the less he rejects this argument. The appropriate relation between the rational and the non-rational parts of the soul promotes both the agent’s good and the good of others; that is why the just person is happier than anyone else. Those who suppose that the just person may be worse off by being just do not understand the character of the human good.