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

- Protagoras

Man is the measure of all things.

- Protagoras

There are two sides to every question.

- Protagoras

Concerning 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…

- Protagoras

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 knowin…

- Protagoras

Everyone, including the Athenians [...] are right to accept advice from anyone, since it is incumbent on everyone to share in that sort of excellence…

- Protagoras

There are intelligible principles inherent in the matter of every phenomenon; because matter is essentially the sum of all the seemings that it has f…

- Protagoras

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

- Protagoras

Man is the measure of all things, of things that are that they are, and of things that are not that they are not.

- Protagoras