"Protagoras" is a dialogue by Plato, believed to have been written in the 4th century BCE. The dialogue centers around the character of Protagoras, a renowned sophist who claims to be able to teach virtue and excellence to others. Socrates, the main character and interlocutor in the dialogue, engages with Protagoras and his followers, challenging their ideas and methods. Throughout the dialogue, Protagoras and his followers argue that virtue can be taught and that all knowledge is relative to the individual. They use a variety of rhetorical techniques and arguments to defend their position, including the famous statement, "man is the measure of all things." Socrates, however, challenges their ideas, arguing that virtue cannot be taught and that there must be some objective standard of knowledge and truth. Read in English, unabridged.