Remember his famous remark that “man is the measure of all things, of the things that are, that they are, of the things that are not, that they are not.”5 In this brief statement we have the roots of an ancient and, to many, disturbing philosophical tradition: relativism. This is how Plato understood Protagoras: he was saying that each man judges what is true for him, but no one is in a position to judge what is true for anyone else.
