The New Rhetoric

In the mid-20th century, rhetoric underwent one of its most significant theoretical renovations. Working independently in Belgium and England, a Belgian philosopher-jurist and a British philosopher each concluded that formal logic — the dominant model of reasoning in modern philosophy — was inadequate to the reality of how arguments actually work. Their response was to return to Aristotle's Rhetoric and Topics and rebuild, on more rigorous foundations, a theory of the arguments that real people actually make. The result was the New Rhetoric — a framework that transformed how scholars, lawyers, and communication theorists think about persuasion and argument.

The Problem with Formal Logic

Formal deductive logic — the tradition running from Aristotle's syllogistics through Frege, Russell, and modern mathematical logic — evaluates arguments by the relationship between their form and the truth-values of their premises. A valid argument is one where, if the premises are true, the conclusion must be true. This is powerful for mathematics and some domains of science. But it describes almost none of the arguments that actually matter in law, politics, ethics, and everyday life.

Most real arguments proceed from premises that are probable rather than certain, involve value judgments rather than purely factual claims, and are addressed to particular audiences whose agreement must be earned rather than compelled. Formal logic has nothing useful to say about such arguments — and the positivist philosophy of the early 20th century, which dismissed as "meaningless" all claims that couldn't be verified empirically, effectively declared the entire domain of practical and ethical reasoning irrational.

Both Perelman and Toulmin found this dismissal philosophically untenable and practically dangerous. The response of each was to develop a theory of the actual structures of reasonable argument — argumentation theory.

Perelman and Olbrechts-Tyteca: Audience and Adherence

Chaïm Perelman (1912–1984) and his collaborator Lucie Olbrechts-Tyteca (1899–1987) began their project in the late 1940s with a simple but radical premise: instead of asking what makes an argument logically valid, ask what makes an argument effective — what leads an audience to adhere to a conclusion. Their magnum opus, La Nouvelle Rhétorique: Traité de l'Argumentation (1958, translated as The New Rhetoric in 1969), is one of the most comprehensive accounts of argument types and strategies ever written.

The Universal and Particular Audience

Perelman's central conceptual innovation is the distinction between the particular audience and the universal audience. The particular audience is the specific group of people one is actually addressing; the universal audience is an idealized construction of all reasonable people — the standard against which arguments can be evaluated for their rational cogency rather than just their persuasive success.

This distinction allows Perelman to maintain that some arguments are genuinely better than others (those that would persuade the universal audience) without resorting to formal logic as the only standard of evaluation. It also preserves rhetoric's essential feature: argument is always addressed to someone, always contextual, never purely abstract.

Starting Points and Argument Schemes

Perelman and Olbrechts-Tyteca devoted the bulk of their treatise to cataloguing the starting points of argument (values, hierarchies, presumptions, facts) and the techniques of argumentation — a taxonomy that rivals Aristotle's own in comprehensiveness. Their argument schemes include quasi-logical arguments (resembling formal logic but operating rhetorically), arguments based on the structure of reality (causation, analogy), and arguments that establish or dissociate the structure of reality.

Stephen Toulmin: The Layout of Arguments

Stephen Toulmin (1922–2009) approached the problem from a different angle. Where Perelman analyzed the social and rhetorical dimensions of argument, Toulmin focused on its logical structure — the actual anatomy of an argument as it moves from evidence to conclusion.

His The Uses of Argument (1958) proposed what has become known as the Toulmin model — arguably the most widely used analytical framework in argumentation theory, rhetoric, debate pedagogy, and communication education:

The Influence of the New Rhetoric

The New Rhetoric's influence has been pervasive and cross-disciplinary. In law, Perelman's work provided a philosophical foundation for legal argumentation that formal logic could not supply — his account of the role of precedent, analogy, and value hierarchy in legal reasoning remains influential in jurisprudence and legal education. In communication and debate studies, the Toulmin model is probably the most widely taught analytical framework for argument structure. In philosophy, the New Rhetoric helped establish informal logic as a legitimate academic discipline.

Frans van Eemeren and Pragma-Dialectics

The New Rhetoric spawned a rich subsequent tradition in argumentation theory. The most systematic is pragma-dialectics, developed by Frans van Eemeren and Rob Grootendorst at the University of Amsterdam. Pragma-dialectics combines linguistic analysis with normative argumentation theory to define the rules of a critical discussion — the ideal procedure for resolving disagreements through argument. Its concept of the argumentum ad hominem (and other fallacies) as violations of discussion rules rather than logical errors has been particularly influential.