Definition
Aristotle (384-322 BCE) was a Greek philosopher whose three-book treatise Rhetoric is the founding technical work of the Western rhetorical tradition. A student of Plato and tutor to Alexander the Great, Aristotle stood at the institutional centre of Greek intellectual life; his Rhetoric gave the discipline a systematic vocabulary that has remained in use for nearly 2,400 years.
Where Plato had attacked rhetoric as a deceitful knack masquerading as a real art, Aristotle accepted that persuasion is unavoidable in human affairs and set out to make it a proper technē. He defined rhetoric as 'the faculty of observing in any given case the available means of persuasion', distinguished the three branches (deliberative, forensic, epideictic), named the three modes of proof (ethos, pathos, logos), and gave the first systematic analysis of the enthymeme. Almost every later rhetorical theorist works inside Aristotle's grid.
Why it matters
How it works
Aristotle's method is descriptive and analytical rather than prescriptive. He observes that persuasion happens via three kinds of artistic proof — the speaker's character, the audience's emotion, the argument's logical force — and he catalogues each in turn. Book I sets out the framework and the three branches; Book II treats the emotions and the character of the speaker and the audience; Book III handles style and arrangement, the third and second canons in later Roman terminology.
His enduring contribution is the recognition that rhetoric reasons differently from formal logic — through enthymemes from probable premises, with audience participation — and that this is not a defect but the appropriate mode for the contingent matters about which humans deliberate. Cicero, Quintilian, the medieval trivium, the Renaissance humanists, and the 20th-century new rhetoric all build on this foundation.