The speculations described so far constitute, in many ways, the most important part of the history of Greek philosophy because all of the most fundamental problems of Western philosophy turned up here for the first time. One also finds here the formation of a great many concepts that have continued to dominate Western philosophy and science to the present day. Anthropology and relativism
In the middle of the 5th century bc, Greek thinking took a somewhat different turn through the advent of the Sophists. The name is derived from the verb sophizesthai, “making a profession of being inventive and clever,” and aptly described the Sophists, who, in contrast to the philosophers mentioned so far, charged fees for their instruction. Philosophically they were, in a way, the leaders of a rebellion against the preceding development, which increasingly had resulted in the belief that the real world is quite different from the phenomenal world. “What is the sense of such speculations?” they asked, since no one lives in these so-called real worlds. This is the meaning of the pronouncement of Protagoras of Abdera (c. 490–c. 420 bc) that “man is the measure of all things, of those which are that they are and of those which are not that they are not.” For human beings the world is what it appears to them to be, not something else; Protagoras illustrated his point by saying that it makes no sense to tell a person that it is really warm when he is shivering with cold because for him it is cold—for him, the cold exists, is there.
His younger contemporary Gorgias of Leontini (flourished 5th century bc), famous for his treatise on the art of oratory, made fun of the philosophers in his book Peri tou mē ontos ē peri physeōs (“On That Which Is Not; or, On Nature”), in which—referring to the “truly existing world,” also called “the nature of things”—he tried to prove (1) that nothing exists, (2) that if something existed, one could have no knowledge of it, and (3) that if nevertheless somebody knew something existed, he could not communicate his knowledge to others.
The Sophists were not only skeptical of what had by then become a philosophical tradition but also of other traditions. On the basis of the observation that different nations have different rules of conduct even in regard to things considered most sacred—such as the relations between the sexes, marriage, and burial—they concluded that most rules of conduct are conventions. What is really important is to be successful in life and to gain influence over others. This they promised to teach. Gorgias was proud of the fact that, having no knowledge of medicine, he was more successful in persuading a patient to undergo a necessary operation than his brother, a physician, who knew when an operation was necessary. The older Sophists, however, were far from openly preaching immoralism. They, nevertheless, gradually came under suspicion because of their sly ways of arguing. One of the later Sophists, Thrasymachus of Chalcedon (flourished 5th century bc), was bold enough to declare openly that “right is what is beneficial for the stronger or better one”—that is, for the one able to win the power to bend others to his will. The seminal thinkers of Greek philosophy Socrates
Socrates (c. 470–399 bc) was also widely considered to be a Sophist, though he did not teach for money and his aims were entirely different from theirs. Although there is a late tradition according to which Pythagoras invented the word philosopher, it was certainly through Socrates—who insisted that he possessed no wisdom but was striving for it—that the term came into general use and was later applied to all earlier serious thinkers. In fact, all of the records of Socrates’ life and activity left by his numerous adherents and disciples indicate that he never tried to teach anything directly. But he constantly engaged in conversations with everybody—old and young, high and low—trying to bring into the open by his questions the inconsistencies in their opinions and actions. His whole way of life rested on two unshakable premises: (1) the principle never to do wrong nor to participate, even indirectly, in any wrongdoing and (2) the conviction that nobody who really knows what is good and right could act against it. He demonstrated his adherence to the first principle on various occasions and under different regimes. When, after the Battle of Arginusae (406 bc), the majority of the Athenian popular assembly demanded death without trial for the admirals, Socrates, who on that day happened to be president of the assembly (an office changing daily), refused to put the proposal to a vote because he believed it was wrong to condemn anyone without a fair trial. He refused even though the people threatened him, shouting that it would be terrible if the sovereign people could not do as they pleased.
When, after the overthrow of democracy in Athens in 404 bc, the so-called Thirty Tyrants, who tried to involve everybody in their wrongdoing, ordered him to arrest an innocent citizen whose money they coveted, he simply disobeyed. This he did despite the fact that such disobedience was even more dangerous than disobeying the sovereign people had been at the time of unrestricted democracy. Likewise, in the time of the democracy, he pointed out by his questions the inconsistency of allowing oneself to be swayed by the oratory of a good speaker instead of first inquiring into his capability as a statesman, whereas in private life a sensible citizen would not listen to the oratory of a quack but would try to find the best doctor. When, after the overthrow of democracy, the Thirty Tyrants had many people arbitrarily executed, Socrates asked everybody whether a man was a good shepherd who diminished the number of sheep instead of increasing it; and he did not cease his questioning when Critias, the leader of the Thirty Tyrants, warned him to take heed not to diminish the number of sheep by his own—Socrates’—person. But the most fundamental inconsistency that he tried to demonstrate everywhere was that most people by their actions show that what they consider good, wonderful, and beautiful in others—such as, for instance, doing right at great danger to oneself—they do not consider good for themselves, and what they consider good for themselves they despise and condemn in others. Although these stands won him the fervent admiration of many, especially among the youth, they also caused great resentment among leading politicians, whose inconsistencies and failings were exposed. Although Socrates had survived unharmed through the regime of the Thirty Tyrants—partly because it did not last long and partly because he was supported by some close relatives of their leader, Critias—it was under the restored democracy that he was accused of impiety and of corrupting the youth and finally condemned to death, largely also in consequence of his intransigent attitude during the trial.
After Socrates’ death his influence became a dominating one through the greater part of the history of Greek and Roman philosophy down to the end of antiquity, and it has been significant ever since. Many of his adherents—Plato first among them, but also including the historian Xenophon (431–c. 350 bc)—tried to preserve his philosophical method by writing Socratic dialogues. Some founded schools or sects that perpetuated themselves over long periods of time: Eucleides of Megara (c. 430–c. 360 bc) emphasized the theoretical aspects of Socrates’ thought (see Megarian school), and Antisthenes (c. 445–c. 365 bc) stressed the independence of the true philosopher from material wants. The latter, through his disciple Diogenes of Sinope (died c. 320 bc), who carried voluntary poverty to the extreme and emphasized freedom from all conventions, became the founder of the sect of the Cynics. Aristippus of Cyrene (c. 435–366 bc), traditional founder of the Cyrenaic school, stressed independence from material goods in a somewhat different way, declaring that there is no reason why a philosopher should not enjoy material goods as long as he is completely indifferent to their loss. Although Aristippus renounced his son because he led a dissolute life, the school that he founded (through his daughter and his grandson) was hedonistic, holding pleasure to be the only good. Plato