Man is the measure of all things, of the reality of those which are, and of the unreality of those which are not.
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.
ProtagorasMan is the measure of all things, of things that are that they are, and of things that are not that they are not.
ProtagorasThere are intelligible principles inherent in the matter of every phenomenon; because matter is essentially the sum of all the seemings that it has for any and all persons.
Protagoras