In the Apology Socrates criticizes people for their inverted values by saying, "Virtue does not come from wealth, but it is through virtue that wealth and everything else, private and public, become good for men" (30B). For Socrates virtue is, first and foremost, something which does dominate the whole pattern of one's life, to be identified with knowledge--knowledge of what is really good and bad for oneself. But what does he suppose this identification is? In Plato's early dialogues Socrates never tries to examine virtue as a whole but inquires into specific recognized virtues separately. In the Protagoras, however, Socrates' subject is virtue as such, and the relationship of five virtues (justice, temperance, piety, courage, wisdom) to it and to each other, yet moreover in the Meno, considered to be a typical transitional dialogue, he first asks the question of what virtue is, not what a particular virtue is. In this essay I made an attempt to examine the main argument of the Protagoras to clarify Socrates' position regarding the unity of the virtues. I argued that Socrates assumes there that the names for the individual virtues all have the same meaning as well as the same reference, that they all refer to a single thing, the knowledge of good and bad. Perhaps the difficulty with this account of his assumption is that common sense is outraged if a particular virtue is used beyond its common meaning, to refer to all of virtue, and if anyone who has one virtue must have all of virtue. But if I am correct in arguing that for Socrates, words get their meaning through their reference, no gap being found between the two, we can ascribe the strong thesis of the unity of the virtues to him. Socrates, who always sticks to logic, will outrage common sense. However, once the identity of virtue and knowledge has been established, a further question arises: is knowledge sufficient for being a virtuous person and acting virtuously, or is a man who possesses knowledge often ruled not by it but by passion or any other emotional factor? This is the subject Socrates attempts to investigate in the final section of the Protagoras. Instead of discussing Socrates' denial of akrasia, I drew attention to the fact that Socrates makes no reification of a desire for the good, and when he regards virtue as knowledge of the good, that good is not prima facie goods but something valuable which is intrinsic to human life. To get an understanding of it, then, entails the task of examining one's own life, and vice versa. Without reflecting what is good no desire could take definite form. In Socrates' view since judgment precedes desire, the good life must have reflection as an integral part of its goodness. But the point here is that there must be some self capable of contemplating one's own life. Thus Socrates distinguishes "himself" from "his own things" (Ap. 36C). He connects virtue above all with self-knowledge, that is, being "himself".