Protagoras of Abdura was a fifth century BCE Greek sophist. He is known primarily for three claims:
  • that man is the measure of all things (which is often interpreted as a sort of radical relativism)
  • that he could make the "worse (or weaker) argument appear the better (or stronger)" using rhetoric
  • that one could not tell if the gods existed or not.

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 to place him among the best known trolls.

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 and also in postmodern politics.


Little is known of Protagoras' life with any certainty. Our main sources of information concerning Protagoras are Plato who named a dialogue for him and Theaetetus, another dialogue where his doctrines are discussed. However these mix historical account and artistic license, much in the manner of the comic plays of the period. As Protagoras died when Plato was young, it's unlikely that Plato was able to study with him.
  • Diogenes Laertius (third century CE) Lives of the Philosophers documents many early Greek philosophers' works and biographies, but over six hundred years after Protagoras' death, using unreliable materials
  • Sextus Empiricus (fl. late 2nd century CE), a skeptic of the Pyrrhonian school, wrote several books criticizing the dogmatists (non-skeptics), but was somewhat favourable to Protagoras is somewhat favorable, but perhaps because his views are closer to his own than the others. Like Diogenes, he wrote several hundred years after Protagoras' death and may not have had completely reliable sources.


Refer link en: wikipedia: Protagoras for an open content, user-editable article heavily linked to other articles

Cite link Internet Encyclopedia of Philosophy for a conventional reference