Many things prevent knowledge, including the obscurity of the subject and the brevity of human life

Everyone, 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.

No 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.

Man is the measure of all things.

As to the gods, I have no means of knowing either that they exist or do not exist.

Man is the measure of all things, of the reality of those which are, and of the unreality of those which are not.

Many things prevent knowledge, including the obscurity of the subject and the brevity of human life