Man is the measure of all things, of the reality of those which are, and of the unreality of those which are not.
ProtagorasConcerning the gods, I have no means of knowing either that they exist or that they do not exist, nor what sort of form they may have; there are many reasons why knowledge on this subject is not possible, owing to the lack of evidence and the shortness of human life.
ProtagorasMany things prevent knowledge, including the obscurity of the subject and the brevity of human life
ProtagorasNo intelligent man believes that anybody ever willingly errs or willingly does base and evil deeds; they are well aware that all who do base and evil things do them unwillingly.
Protagoras