In the fifth century, the term referred mainly to people who were known for their knowledge (for example, Socrates, the seven sages) and those who earned money by teaching advanced pupils (for example, Protagoras, Prodicus) and seemed to be a somewhat neutral term, although sometimes used with pejorative overtones by those who disapproved of the new ideas of the so-called “Sophistic Enlightenment”. The first step in understanding Protagoras is to define the general category of “sophist,” a term often applied to Protagoras in antiquity. His treatment of Protagoras is somewhat favorable, but since his purpose is to prove the superiority of Pyrrhonism to all other philosophies,we cannot trust him to be “objective” in a modern sense moreover, like Diogenes, he wrote several hundred years after Protagoras’ death and may not have had completely reliable sources. late 2nd century C.E.): Sextus Empiricus was a skeptic of the Pyrrhonian school. Sextus wrote several books criticizing the dogmatists (non-skeptics). Unfortunately, his work was compiled over six hundred years after Protagoras’ death and is an uncritical compilation of materials from a wide variety of sources, some reliable, some not, and many hopelessly garbled. Diogenes Laertius (third century C.E.): Diogenes’ Lives of the Philosophers is probably our single most extensive source for many early Greek philosophers’ works and biographies.Moreover, Protagoras died when Plato was quite young and Plato may have depended on not entirely reliable second-hand evidence for his understanding of Protagoras. Plato’s dialogues, however, are a mixture of historical account and artistic license, much in the manner of the comic plays of the period. Plato (427-347 B.C.E.): Protagoras is a leading character in Plato’s dialogue Protagoras and Protagoras’ doctrines are discussed extensively in Plato’s Theaetetus.Our main sources of information concerning Protagoras are: Surprising little is known of Protagoras’ life with any certainty. Social Consequences and Immediate Followers.He emphasized how human subjectivity determines the way we understand, or even construct, our world, a position which is still an essential part of the modern philosophic tradition. Along with the other Older Sophists and Socrates, Protagoras was part of a shift in philosophical focus from the earlier Presocratic tradition of natural philosophy to an interest in human philosophy.
Historically, it was in response to Protagoras and his fellow sophists that Plato began the search for transcendent forms or knowledge which could somehow anchor moral judgment. Protagoras’ notion that judgments and knowledge are in some way relative to the person judging or knowing has been very influential, and is still widely discussed in contemporary philosophy. Protagoras’ influence on the history of philosophy has been significant. While some ancient sources claim that these positions led to his having been tried for impiety in Athens and his books burned, these stories may well have been later legends. Protagoras is known primarily for three claims (1) that man is the measure of all things (which is often interpreted as a sort of radical relativism) (2) that he could make the “worse (or weaker) argument appear the better (or stronger)” and (3) that one could not tell if the gods existed or not. Protagoras of Abdera was one of several fifth century Greek thinkers (including also Gorgias, Hippias, and Prodicus) collectively known as the Older Sophists, a group of traveling teachers or intellectuals who were experts in rhetoric (the science of oratory) and related subjects.