Man is the measure of all things.

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.

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

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 things that are that they are, and of things that are not that they are not.

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.

There 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.