Protagoras was the most celebrated of the sophists, teachers who charged fees to teach rhetoric and the art of winning debates. A friend of Pericles, he became known for the idea that the human being is the measure of all things. Plato criticized him harshly, but he was a pioneer in thinking about truth and values from human experience.
Core ideas
The human being is the measure of all things: truth depends on who perceives it
About the gods it is impossible to know whether they exist or not
On any subject there are arguments on both sides, and both can be defended
The tradition: Sophist
Sophists were traveling teachers who taught oratory and politics, often doubting absolute truths. Protagoras is the most famous and the most respected of them.
