Man is the measure of all things, of the reality of those which are, and of the unreality of those which are not.
ProtagorasMany things prevent knowledge, including the obscurity of the subject and the brevity of human life
ProtagorasEveryone, including the Athenians [...] are right to accept advice from anyone, since it is incumbent on everyone to share in that sort of excellence, or else there can be no city at all.
Protagoras