 The way this technê works is illustrated in another widely held Stoic teaching, i.e., the unity of the virtues. Zeno held that virtue is practical knowledge (phronêsis) in various forms. When phronêsis deals with what is owed to others it is justice (dikaiosunê); when it deals with what should be chosen it is moderation (sôphrosunê); when it deals with what must be endured it is courage (andreia). In all of these definitions Zeno means phronêsis to be knowledge (epistêmê) (Plutarch, On moral virtue 441A). According to Sextus, the Stoics say that phronêsis, being knowledge (epistêmê) of the good and the evil, provides a technê concerning life (SVF III 598). Here we can see the ‘sage’ or fully perfected human being has a kind of insight into what is good and bad in each situation of life. In its particularity, this insight is like that of a master craftsman, who knows what is appropriate at each juncture of his practice. And like the master craftsman, the sage reacts appropriately both in the way he feels and in the way he acts.