Remove ads - become a member


published on 02 September 2009

Protagoras of Abdera (c.485-415 BCE) is considered the greatest of the Sophists of ancient Greece.  A Sophist was a teacher of rhetoric, politics, and logic who served as a private tutor to the youth of the upper classes. As Greece, particularly Athens, was extremely litigious, a knowledge of the art of public speaking was highly valued as a means of defending oneself in court or prosecuting someone else. There were no professional lawyers in ancient Greece and, therefore, it was up to the individual involved in a case of law to hire a professional speech writer and then be able to deliver that speech eloquently. According to ancient writers, Protagoras chiefly made his living by coaching wealthy youth in the art of rhetoric for use in the courtroom. A great deal of what we know of Protagoras' life and teachings comes from two of Plato's dialogues, the Protagoras and the Theaetetus. He is best known for his claim that, "Of all things the measure is Man, of the things that are, that they are, and of the things that are not, that they are not" or, in other words, that everything is relative to individual experience, judgement, and interpretation. This claim, it is thought, was of particular use in court where a prosecutor or defendant could employ relativistic reasoning to win a case.

In philosophy, `relativism' is the belief that there is no final, objective truth, and Protagoras may be regarded as the first known relativist in Western culture. Plato, of course, believed in an objective standard of truth which everyone needs to apprehend and acknowledge in order to live a full life. He was, therefore, at great odds with the philosophy of Protagoras. Professor Forrest E. Baird writes, "Plato takes Protagoras to mean that each person, not humanity as a whole, is the measure of all things and so attacks Protagoras's relativism" (43). It may be, however, that Protagoras was simply making use of ideas first espoused by the earlier Greek philosopher Xenophanes (c. 570-478 BCE) who emphasized the limitations of human knowledge. Xenophanes writes, "No man knows or ever will know the truth about the gods and about everything I speak of; for even if one chanced to say the complete truth, yet oneself knows it not but seeming is wrought over all things" (DK21B38). Xenophanes is here saying that, owing to the subjective nature of human interpretation and understanding, even if an individual were to uncover the truth about the gods, one would not be able to realize that truth because `seeming', our subjective understanding, clouds and distorts such a possibility. Protagoras seems to be saying something much along the same lines when he writes, "About the gods, I am not able to know whether they exist or do not exist, nor what they are like in form; for the factors preventing knowledge are many: the obscurity of the subject and the shortness of human life" (Baird, 44). This line also mirrors another of Xenophanes' thoughts concerning knowledge of the gods in which the elder philosopher claimed that one could only approach such knowledge through seeking after it and, even then, would only be able to apprehend a shadow. Protagoras' famous relativism, then, could have originally been a simple empirical observation concerning the human condition and not `relativism' at all in that he may never have claimed `truth' or the `gods' did not exist, merely that there is no way of objectively defining what those things might be. Everyone, according to Protagoras, will interpret the truth individually, and this has been understood to mean that if someone claims there is no God, then there is no God for that person. While Plato asserts that this is what Protagoras believed and taught, it cannot be stated with certainty as only fragments of Protagoras' work have survived.

Whatever motivation or inspiration Protagoras may have been working from, his ideas were antithetical to Plato's, and the latter has done much to make him appear foolish. In his dialogue of the Theaetetus, Plato has the character of Socrates say,

[Protagoras] says, doesn't he, that what is believed by each person is so for him who believes it?...Well, gratifying as it is to be told that what each of us believes is true, I am surprised that he does not begin his Truth by saying that of all things the measure is the pig, or the dog-faced baboon...If what each man believes to be true through sensation is true for him - then how, my friend, was Protagoras so wise that he should consider himself worthy to teach others and for huge fees? And how are we so ignorant that we should go to school to him if each of us is the measure of his own wisdom?(161B).

While it seems clear that Protagoras did hold to this relativistic philosophy, it is not known whether he made his money teaching these concepts as philosophical truths. It is likely, again, that he used his paradigm of an individual alone being able to apprehend separate truths and realities to teach his students how to win court cases by `making the worse appear to be the better cause' (as Plato phrases it in his Apology).

Protagoras was considered at least an agnostic and, perhaps, an atheist based upon his teachings and his claim concerning the existence of the gods. He was charged and convicted of impiety by the court of Athens and drowned while fleeing to Sicily in 415 BCE. His 'Man is the Measure' claim has been cited by many through the ages as the first and best statement of human relativism, and he has also been hailed as an early 'humanist' and 'free thinker'. His relativism so bothered Plato that the latter devoted an enormous amount of time and effort in his writings to refuting the idea that anything can be true as long as it is believed to be true by the individual. Plato's theory of Forms (that what we see and call 'true' is but a reflection of a higher Truth) is a direct response to Protagoras' earlier relativistic claim, in that Plato was trying to prove there had to be some standard of truth by which one could objectively recognize what was right and what was wrong. Plato's body of work may, in fact, be read as one long refutation of Protagoras' famous assertion.


Note: The DK citation regarding Xenophanes is in reference to the Diels-Krantz catalogue of The Fragments of the Pre-Socratic Philosophers.

About the Author

Joshua J. Mark
A freelance writer and part-time Professor of Philosophy at Marist College, New York, Joshua J. Mark has lived in Greece and Germany and traveled through Egypt. He teaches ancient history, writing, literature, and philosophy.

Share This

Cite this work


Remove ads - become a member
Add Event


Visual Timeline
  • c. 500 BCE
    Life of the Chinese Sophist/Philosopher Teng Shih (probable date of death 522 or 502 BCE).
  • c. 485 BCE - c. 415 BCE
    Life time of Protagoras of Abdera.
  • 440 BCE
    The sophist Protagoras of Abdera, claiming 'man is the measure of all things', visits Athens.
  • 403 BCE
    Plato turns away from politics toward philosophy.

AHE Greeting Cards @Etsy


Remove ads - become a member

Protagoras Books



Remove ads - become a member


Our latest articles delivered to your inbox, once a week:


Remove ads - become a member