Protagoras

Protagoras ( /proʊˈtæɡərəs/; Greek: Πρωταγόρας, ca. 490 BC – 420 BC) was a pre-Socratic Greek philosopher and is numbered as one of the sophists by Plato. In his dialogue Protagoras, Plato credits him with having invented the role of the professional sophist or teacher of virtue. He is also believed to have created a major controversy during ancient times through his statement that "man is the measure of all things". This idea was revolutionary for the time and contrasted with other philosophical doctrines that claimed the universe was based on something objective, outside the human influence.