PROTAGORAS, pro-tag'6-ras, Greek soph ist: b. Abdera, Thrace, about 480; d. about 410 s.c. He studied the old Ionian philosophy paying especial attention to Heraclitus and he was the first to assume the title of &list, and to teach for pay, a practice which, Plato in forms us, proved very remunerative. He taught principally at Athens. When, about 443, a num ber of Athenians left the to join in found ing the new colony of Thu, Protagoras was appointed by Pericles to accompany them and subsequently drew up a constitution for the Thurians. Before returning to Athens he lived for some time in Sicily, where he acquired great fame. He returned to Athens before 430. In 411 he was brought before the Aeropagus for beginning one of his works ((Concerning the Gods') with the words, "Respecting the gods, I am unable to know whether they exist or do not exist, was banished for atheism, and per ished at sea. He was the author of a large number of works, all of which are lost. The two most important of them were the ones al ready mentioned, and another entitled One of the dialogues of Plato (q.v.) bears the title 'Protagoras,' and yields some information regarding his mode of teaching. His famous apophthegm, aveprorospirpor (man is the mea sure of all things) has become the eternal pos session of philosophy and can never lose its significance. Man from his subjective impres sions can, he said, decide what things are, and what things are not. Hence he taught Science was impossible and Opinion everything. This was what in modern philosophy corre sponds to Sensualism. For these views he was controverted by Socrates and the Socratic school. He is also credited with being the first grammarian to have systemized grammar and to have been the originator of a classification of the parts of speech, tenses and moods.
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