Major Works: Truth (Alethia), On the Gods (Peritheon)
Stanford Encyclopedia of Philosophy
Concerning the gods, I have no means of knowing whether they exist or not, nor of what sort they may be, because of the obscurity of the subject, and the brevity of human life.
On the Gods
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.
Quoted in Plato's Protagoras
Man is the measure of all things.
Quoted in Plato's Theaetetus