Gorgias (late 5th century BC)

The most important of the fifth-century bc Greek Sophists after Protagoras, Gorgias was a famous rhetorician, a major influence on the development of artistic prose and a gifted dabbler in philosophy. His display speeches, Encomium of Helen of Troy and Defence of Palamedes, are masterpieces of the art of making a weak case seem strong, and brilliant exercises in symmetrical and antithetical sentence structure. Of philosophical importance is his treatise On Not-Being, or On the Nature of Things, an elaborate reversal of the metaphysical argument of Parmenides, showing: (1) that nothing exists; (2) that if anything exists, it cannot be known; and (3) if anything can be known, it cannot be communicated. This nihilistic tour de force is probably a caricature rather than a serious statement of a philosophical position. Gorgias is a master of the persuasive use of logos (discourse), understood both as eloquence and as argumentative skill.