The Sophist Protagoras in Plato’s Dialogues, His Biography and Fragments of His Works

"What does Protagoras mean when he says that man is the measure of all things? Does this only refer to perceptions, or does he mean that man can measure his own moral principles?

Did the teachings of the Sophists corrupt the youth of Athens?

Why did the many Athenian jurors trying Socrates believe he was a Sophist?

Why did Aristophanes accuse Socrates of being a sophist?

There are so few fragments of the works of Protagoras that survive that we have reflected on all the fragments we could find."