Protagoras is one of the early dialogues of Plato, where the celebrated philosopher Socrates and the sophist Protagoras are involved in a discussion. The dialogue takes place in the house of Callias, the host of Protagoras during his stay in Athens. The theme of the dialogue is the learnability of virtue.
This dialogue provides an overview of the key concepts of Socratic ethics. Socrates meets the eminent sophist Protagoras, who explains to him that his job is "teaching virtue". By this he means that the essence of his art is to be able to teach any person how he can achieve to lead a successful life.
The dialogue Protagoras is focused largely on the notion of virtue. It is important to know that what the ancient Greeks meant by 'virtue' not entirely coincides with the definition we now give. Virtue (Greek: arete), among other connotations, meant something like 'excellence', the right temperament and courage. It would be a misconception to think of good only in the sense of moral virtue. Virtue may also relate to the good qualities of things, objects and forms of behaviour that have no direct relationship to moral virtue. This also explains the difference between Socrates' idea of virtue and that of Protagoras. If virtue can be learned as if it were a collection of doctrines or moral rules, then it is obvious that it could form the basis of an education. This is consistent with the view of Protagoras in the dialogue. Socrates takes a different approach. He argues that virtue is not easily taught by social conditioning, and can only be acquired with great difficulty. At the end of the dialogue, Socrates gets the upper hand in the debate and it is established that virtue is a form of knowledge. Yet it remains unclear what that knowledge (episteme) really is or how this virtue can be acquired.