A political treatise attributed to the fourth-century B.C. reflects the attitude that had developed in Athens in the later fifth century. “If all men were to gather in a heap the customs which they hold to be good and noble, and if they were next to select from it the customs which they hold to be base and vile, nothing would be left over.”[2] Once such a view has found capable defenders, the custom-basis of social organization begins to give way, and institutions venerable with age are ruthlessly subpœnaed to appear before the bar of reason. Men begin to contrast “Nature” with custom, somewhat to the disadvantage of the latter. Even the most basic of Greek institutions is questioned: “The Deity,” says a fourth-century Athenian Rousseau, “made all men free; Nature has enslaved no man.”[3] Botsford speaks of “the powerful influence of fourth-century socialism on the intellectual class.”[4] Euripides and Aristophanes are full of talk about a movement for the emancipation of women.[5] Law and government are examined: Anarcharsis’ comparison of the law to a spider’s web, which catches small flies and lets the big ones escape, now finds sympathetic comprehension; and men arise, like Callicles and Thrasymachus, who frankly consider government as a convenient instrument of mass-exploitation. IV The Sophists The cultural representatives of this individualistic development were the Sophists. These men were university professors without a university and without the professorial title. They appeared in response to a demand for higher instruction on the part of the young men of the leisure class; and within a generation they became the most powerful intellectual force in Greece. There had been philosophers, questioners, before them; but these early philosophers had questioned nature rather than man or the state. The Sophists were the first group of men in Greece to overcome the natural tendency to acquiesce in the given order of things. They were proud men,--humility is a vice that never found root in Greece,--and they had a buoyant confidence in the newly discovered power of human intelligence. They assumed, in harmony with the spirit of all Greek achievement, that in the development and extension of knowledge lay the road to a sane and significant life, individual and communal; and in the quest for knowledge they were resolved to scrutinize unawed all institutions, prejudices, customs, morals. Protagoras professed to respect conventions,[6] and pronounced conventions and institutions the source of man’s superiority to the beast; but his famous principle, that “man is the measure of all things,” was a quiet hint that morals are a matter of taste, that we call a man “good” when his conduct is advantageous to us, and “bad” when his conduct threatens to make for our own loss. To the Sophists virtue consisted, not in obedience to unjudged rules and customs, but in the efficient performance of whatever one set out to do. They would have