 The main theme of this dialogue is the role of knowledge in the virtue under discussion. A dialogue of definition, the Charmides takes up the subject of sophrosune, a word that does not have a clear equivalent in English. It is the virtue of having a morally healthy soul, undamaged by wrongdoing, and nourished by knowledge or wisdom. Sophrosune produces the ability to resist the temptation to act violently in satisfaction of desires, the temptation that, in Plato’s scheme of things, characteristically leads tyrants to disaster. But sophrosune is not the same as self-control (enkrateia), which presupposes a division in the soul into a part that controls and a part that is controlled. 