“Sophist” refers to a number of intellectuals in the 5th century BC representing a school of thought arising out of an intellectual impasse reached between the Ionian and Italian pre-Socratic philosophers.
A number of Greek thinkers realized that even the greatest minds could find little, if any, agreement on big metaphysical questions and issues. This led to an engagement with other (often practical) areas involving influence, persuasion, popularity, and power. Two schools of thought arose within this milieu: the Sophists and the Cynics.
The sophists are sometimes viewed as the first great champions of rhetoric. They taught for money a variety of intellectual skills with the most valuable being rhetorical argument. These skills were intended to give learners a great advantage over others within public life. The most famous of the sophists were Protagoras of Abdera (481-411 BC), Prodicus of Ceos (465-395 BC), Hippias of Elis (443-399 BC), and Thrasymachus of Chalcedon (d. 399 BC).
Protagoras is best remembered for his relativism, and the phrase that “man is the measure of all things.” He was a traveling teacher and lecturer, and earned his living from these occupations. He taught oratory, public speaking, grammar, and poetry, and known for the high fees he charged for his services. Protagoras claimed that he could make the worse (or weaker) argument appear the better (or stronger). Theologically, he held that one could not tell if the gods existed, likely making him an agnostic or perhaps an atheist. Prodicus, a student and disciple of Protagoras, became famous for the study of language and for his teachings on word usage. He accumulated some wealth from teaching, but was accused of being an atheist for his views on the gods and the origin of religion. The gods, to him, were little more than personifications of natural objects in the world. Hippias, criticized by Plato (429-348 BC) for his arrogance, traveled around Athens and through Greek towns where he lectured people on mathematics, astronomy, poetry, grammar, and history. He purportedly invented natural law as the foundation of morality, the quadratrix, and a system of mnemonics. Thrasymachus was a noted teacher of rhetoric and a speechwriter in Athens. He believed that moral values are socially constructed and thus little more than reflections of the interests of particular political communities.
Although some of the concerns of the Sophists fit within the wider philosophical tradition they are still deemed of a somewhat fringe status when compared to other Greek philosophers. This is because Plato immortalized them in his dialogues negatively and as incompetent fools. Plato’s depictions are likely unfair but historians possess a severe shortage of independent evidences to counter them in any detail. Plato did not like their views, particularly relativism, and believed that teaching intellectual skills for money degraded philosophy by turning it into a commodity. He criticized their reputation lying in only what others would pay them rather than earning respect for their own sake.