THE SOPHIST TRADITION — PROTAGORAS AND GORGIAS

Core Argument

The sophists argue that knowledge is relative to the knower and that justice is a convention imposed by the stronger on the weaker, not a discoverable fact about the world. Protagoras holds that man is the measure of all things: what appears true to a person is true for that person, and no external standard arbitrates between conflicting perceptions. Gorgias advances a more radical position in On Non-Being, arguing that nothing exists, that if anything did exist it could not be known, and that if it could be known it could not be communicated. Together, these positions dissolve the possibility of objective philosophical inquiry.

Context

The sophists were paid teachers of rhetoric and argument in fifth-century Athens, employed to prepare young men for public life in the law courts and assembly. Their success rested on the claim that any position could be argued persuasively. Plato's dialogues, particularly the Gorgias, the Protagoras, and the Sophist, are sustained attempts to refute them on their own terms. Thrasymachus in Book I of The Republic is Plato's composite figure for the tradition's political consequences: justice is whatever the strong say it is.

Lineage

Reader's Note

Most sophist texts survive only in fragments and through Plato's hostile reconstructions. Sprague's collection is the most complete source. Plato's Gorgias and Protagoras are the most accessible entry points, with the caveat that they are written by a committed opponent. De Romilly's "The Great Sophists in Periclean Athens" (Oxford, 1992) provides useful historical context.

Author

Protagoras of Abdera (c. 490–420 BCE) and Gorgias of Leontini (c. 483–375 BCE) were the two most prominent figures of the Sophist movement — professional teachers of rhetoric and practical wisdom who traveled the Greek world charging fees for instruction at a time when no such profession had previously existed. Protagoras, the older and more influential, was associated with Pericles and the intellectual circle of democratic Athens; he reportedly wrote laws for the Athenian colony of Thurii. Gorgias was primarily a rhetorician and diplomat, sent as ambassador from Leontini to Athens in 427 BCE, whose dazzling oratorical style made him famous across Greece. Their surviving works are fragmentary and in part preserved only through hostile sources: Plato's dialogues Protagoras, Gorgias, Meno, and Sophist are the primary ancient accounts of their positions, filtered through a sustained philosophical polemic. The Sophists represent the position that the Platonic enterprise was specifically constructed to refute: the claim that knowledge is relative, that justice is convention, and that rhetoric — the art of persuasion — is the highest practical skill.

Historical Impact

The Sophists created the discipline of rhetoric as a teachable art, and their rhetorical curriculum — the systematic training of argument, style, and persuasion — passed through Isocrates and Cicero into the Roman educational tradition, where it organized the trivium (grammar, rhetoric, dialectic) that structured European education through the medieval period and beyond. Protagoras's homo mensura thesis — that man is the measure of all things — established the terms of the debate between relativism and objectivism in ethics and epistemology that has never concluded. In the modern period, pragmatism (William James, John Dewey) and later poststructuralism (Derrida, Lyotard) both claimed the Sophistic tradition as a precursor — the view that truth is perspectival, that knowledge is inseparable from power, and that the construction of argument is as important as its content. Nietzsche's rehabilitation of the Sophists in Philosophy in the Tragic Age of the Greeks as more honest than their Platonic critics was a turning point in the reception history. Gorgias's account of logos in the Encomium of Helen — that speech is a great ruler, accomplishing the most divine works with the smallest and most invisible body — anticipates the twentieth-century philosophy of language's account of the performative and world-constituting power of discourse.

Reception History

For most of Western history the Sophists were known almost entirely through Plato's polemical portraits — caricatures of intellectual charlatanism deployed to define philosophy against its corrupted double. The first major rehabilitation came from Hegel, who in the Lectures on the History of Philosophy presented the Sophists as philosophically necessary — the historical stage at which thought turned toward the human subject and away from cosmological speculation, making Socratic ethics possible. George Grote's Plato and the Other Companions of Sokrates (1865) went further, arguing that Plato's portraits were systematically unfair and that the Sophists were genuine contributors to democratic culture. The twentieth century produced the standard scholarly account in Kerferd's The Sophistic Movement (1981) and Guthrie's The Sophists (1971): serious thinkers who addressed genuine philosophical questions about language, knowledge, and political life. The debate about Protagoras's homo mensura continues: the 'restricted' reading holds that the thesis applies only to perceptual appearances (wind is cold to me, warm to you); the 'unrestricted' reading extends it to all claims including moral and political ones. Gorgias's On Non-Being is similarly contested: some read it as a serious reductio of Eleatic logic, others as deliberate rhetorical display.

Key Passages

Scholarly Works

Lectures

Further Reading