24 Facts About Protagoras

Protagoras is numbered as one of the sophists by Plato.

Protagoras argued that believing that others' opinions about the world are valid and must be respected, even if our own experience of truth is different, is necessary for a community to base itself and its decisions on open, democratic debate.

Protagoras was born in Abdera, Thrace, opposite the island of Thasos.

Democritus realized that Protagoras had tied the load together with such perfect geometric accuracy that he must be a mathematical prodigy.

Protagoras became well known in Athens and even became a friend of Pericles.

In Protagoras Plato wrote that, before a gathering of Socrates, Prodicus, and Hippias, Protagoras stated that he was old enough to be the father of any of them.

Protagoras was skeptical about the application of theoretical mathematics to the natural world; he did not believe they were really worth studying at all.

Nonetheless, mathematics was considered to be by some a very viable form of art, and Protagoras says on the arts, "art without practice and practice without art are nothing".

Protagoras was known as a teacher who addressed subjects connected to virtue and political life.

Protagoras especially was involved in the question of whether virtue could be taught, a commonplace issue of fifth century BC Greece, that has been related to modern readers through Plato's dialogue.

Rather than educators who offered specific, practical training in rhetoric or public speaking, Protagoras attempted to formulate a reasoned understanding, on a very general level, of a wide range of human phenomena, including language and education.

Diogenes Laertius reports that Protagoras devised a taxonomy of speech acts, such as assertion, question, answer, command, etc.

Aristotle says that Protagoras worked on the classification and proper use of grammatical gender.

The titles of his books, such as Technique of Eristics, prove that Protagoras was a teacher of rhetoric and argumentation.

Eusebius quoting Aristocles of Messene says that Protagoras was a member of a line of philosophy that began with Xenophanes and culminated in Pyrrhonism.

Protagoras said that on any matter, there are two arguments opposed to one another.

Protagoras is credited with the philosophy of relativism, which he discussed in his lost work, Truth.

Protagoras appears to have meant that each individual is the measure of how things are perceived by that individual.

The truth, according to Protagoras, is relative, and differs according to each individual.

Plato ascribes relativism to Protagoras and uses his character Socrates as a foil for his own commitment to objective and transcendent realities and values.

Protagoras was a proponent of either agnosticism or, as Tim Whitmarsh claims, atheism, on the grounds that since he held that if something is not able to be known it does not exist.

The classicist John Burnet doubts this account as both Diogenes Laertius and Cicero wrote hundreds of years later and as no such persecution of Protagoras is mentioned by contemporaries who make extensive references to this philosopher.

Burnet notes that even if some copies of the Protagoras books were burned, enough of them survived to be known and discussed in the following century.

Nonetheless, very few fragments from Protagoras have survived, although he is known to have written several different works: Antilogiae and Truth.