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

Man is the measure of all things.

About the gods I have no means of knowing either that they exist or that they do not exist or what they are to look at. Many things prevent my knowing. Among others, the fact that they are never seen.

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

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.

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.