Lives and Opinions of Eminent Philosophers

​Protagoras was the son of Artemon, or, as Apollodorus and Dinon in the fifth book of his Persian History say, of Maeandrius; he was an Abderite, as Pontic Heraclides says in his work On Laws, who also says that he wrote laws for the Thurians; but according to Eupolis in the Flatterers, he was a Teian; for he says: "Within is Protagoras the Teian." He and Prodicus of Ceos collected contributions by giving public readings of their discourses; and Plato in the Protagoras says that Prodicus had a deep voice. Protagoras was a pupil of Democritus. He was also called Wisdom, as Favorinus says in his Miscellaneous History.

​He was the first to assert that there are two arguments opposed to each other concerning every subject; and with these he also used to conduct cross-examinations, being the first to do so. Moreover, he also began in somewhere the following manner: "Man is the measure of all things, of the things that are that they are, and of the things that are not that they are not." And he used to say that the soul is nothing other than the senses, as Plato too says in the Theaetetus, and that all things are true. Elsewhere, too, he began in this manner: "Concerning the gods, I am unable to know either that they are or that they are not; for there are many things that prevent knowledge, the obscurity of the matter and the life of man being short."

​Because of this beginning of his treatise, he was expelled by the Athenians; and they burned his books in the marketplace, having gathered them from each of their owners by means of a public herald. This man was the first to charge a fee of one hundred minae; he was the first to distinguish the parts of time, to expound the power of the opportune moment, to establish verbal contests, and to introduce sophisms to practitioners of forensics; and abandoning the thought, he argued against the bare name, and gave birth to the present superficial tribe of disputants; wherefore Timon too says concerning him: "And Protagoras, that mongrel, well versed in disputing."

​He was also the first to set in motion the Socratic form of discourse. And he was the first to argue against the thesis of Antisthenes which attempts to prove that it is impossible to contradict, as Plato says in the Euthydemus. He was also the first to point out the methods of attack against philosophical theses, as Artemidorus the dialectician says in his Against Chrysippus. And he was the first to invent the so-called porter's pad, upon which they carry burdens, as Aristotle says in his On Education; for he was a porter, as Epicurus also says somewhere. And in this way he was taken up by Democritus, having been observed binding wood together. He was also the first to divide speech into four parts: wish, question, answer, and command;

(others, however, say into seven: narrative, question, answer, command, report, wish, and address), which he also called the roots of speech. But Alcidamas says that there are four kinds of speech: affirmation, denial, question, and address. The first of his works that he read publicly was that On the Gods, whose opening we cited above; he read it at Athens in the house of Euripides, or, as some say, in that of Megacleides; others say in the Lyceum, with his pupil Archagoras, the son of Theodotus, lending him his voice. He was accused by Pythodorus the son of Polyzelus, one of the Four Hundred; but Aristotle says it was by Euathlus.

​The following of his books are extant: The Art of Disputation; On Wrestling; On the Sciences; On the State; On Ambition; On the Virtues; On the Original State of Things; On the Things in Hades; On the Errors of Mankind; Precepts; Lawsuit Concerning a Fee, Contradictions, Books I and II. These are his books. Plato has also written a dialogue against him. Philochorus says that while he was sailing to Sicily, his ship sank; and that Euripides hints at this in his Ixion. Some say that he died on a journey, having lived nearly ninety years;

​but Apollodorus says seventy, and that he was a sophist for forty years, and flourished during the eighty-fourth Olympiad. There is also an epigram of our own on him, runs as follows: "Of thee too, Protagoras, I have heard the tale, that going once from Athens, an old man on a journey, thou didst die; for the city of Cecrops resolved that thou shouldst flee; but while thou didst escape Pallas' town, thou didst not escape Pluto." It is said that once, when he demanded his fee from his pupil Euathlus, and the latter replied, "But I have not yet won a victory," he said: "Nay, but if I win, because I have won, I must receive it; and if thou winnest, because thou [hast won]." There was also another Protagoras, an astronomer, on whom Euphorion also wrote a dirge; and a third who was a Stoic philosopher.