Informal · II
Argumentation
argumentatio · ‘the act of bringing forward proof’
Arguments do not live in isolation. They are advanced against opposition, accepted with qualification, defeated by rebuttal. Argumentation theory is what informal logic says about all that.
Orientation
From single argument to discourse
Formal logic studies arguments as static objects: premises, a conclusion, a rule. Argumentation theory studies them as moves in a sequence. Someone advances a claim; someone else objects; a warrant is offered; the warrant is queried; a backing is supplied; a rebuttal is conceded. The argument is the trajectory of the exchange, not a single inferential step.
This reframing matters because the standards by which an argument is appraised change. A claim accepted pro tem against a weak objector is not therefore well-grounded; a valid argument that no one accepts is not therefore effective. The three pieces below — the Toulmin model, dialectic, and the rhetorical triangle — are the principal tools for studying the trajectory.
I · The richer anatomy
The Toulmin model
Stephen Toulmin's six-part diagram from The Uses of Argument (1958). The model is also introduced briefly in argument; the treatment here is focused on its use in dialogue.
- Claim
- The position being advanced — what the argument is for. Conclusion, in the bare model.
- Data (grounds)
- The facts cited in support. Premises, in the bare model.
- Warrant
- The general principle that licenses the move from data to claim. Often the unstated premise of an enthymeme.
- Backing
- Whatever justifies the warrant — the body of evidence, tradition, or theory that stands behind it.
- Qualifier
- The strength with which the claim is advanced. Presumably, plausibly, certainly.
- Rebuttal
- The conditions under which the claim would not hold. Exceptions the arguer is willing to admit.
In dialogue, the model is a checklist for what an objector can attack. Question the data, and the conclusion loses its evidential base. Question the warrant, and the data is left without a license to conclude what the arguer wants. Press on the qualifier and the rebuttal to see whether the arguer has acknowledged the limits of the position. Reasoned disagreement is what happens when each move is contested at the appropriate level.
II · The argumentative exchange
Dialectic
Dialectic is argument under adversarial conditions — one party advancing a thesis, another challenging it, and the exchange continuing until one side concedes or both reach a settled view. The word, like the practice, has moved meaning across centuries.
- GreekSocrates · Plato
- Dialectic as elenchus — the cross-examination that exposes inconsistency in an interlocutor's beliefs. Argument as the test of belief by an unsympathetic interlocutor.
- German idealistKant · Hegel
- Dialectic as a higher movement of thought, in which a thesis generates its antithesis and is overcome in a synthesis. The triadic schema is largely a Hegelian commonplace; Hegel himself rarely used the term in that schematic form.
- Twentieth-centuryToulmin · Perelman · van Eemeren
- Dialectic as a normative theory of argument: the rules of engagement that allow a genuine disagreement to be resolved on the merits.
The contemporary heir of the dialectical tradition is pragma-dialectics (van Eemeren and Grootendorst, Argumentation, Communication, and Fallacies, 1984), which gives a normative theory of a critical discussion. The theory specifies ten rules — including the right to advance any standpoint, the obligation to defend it when challenged, and the prohibition on attacking the person rather than the standpoint. Fallacies, on this view, are violations of the rules of the discussion rather than purely structural failures.
III · Persuasion and its three appeals
Rhetoric
Aristotle's Rhetoric (c. 350 BC) is the foundational text. Rhetoric is the study of how argument actually persuades, as distinct from how it ought to persuade if all parties were ideal reasoners. The three appeals below are its classical division.
Ethos
The speaker's character.
- The audience accepts the argument partly because the speaker is credible, has standing, or has been seen to argue in good faith before.
Pathos
The audience's emotion.
- The audience is moved by the argument's emotional resonance with its concerns, hopes, or fears.
Logos
The argument's logical structure.
- The audience is persuaded by the argument's reasons, evidence, and inferential adequacy.
The relation between rhetoric and logic has been contested since Plato. Plato made rhetoric the disreputable cousin — persuasion divorced from truth. Aristotle restored it as a legitimate counterpart to dialectic. The modern position, after Perelman's The New Rhetoric (1958), is that rhetoric is the practical complement of formal logic: logic establishes what an argument warrants, rhetoric whether and how an audience will accept it. A reasoner who cares only for one risks irrelevance; one who cares only for the other risks sophistry.
Closing note
The three frames, used together
The Toulmin model is the standard tool for picking apart the structure of a single argument in detail. Dialectic addresses what happens between two arguers — the rules of engagement under which the disagreement is supposed to be resolved. The rhetorical triangle is the lens for everything that contributes to persuasion beyond the argument's formal merits.
None of the three is sufficient on its own. A real treatment of a contested public argument typically calls on all three: Toulmin to lay out the structure, dialectic to assess whether the exchange has been conducted fairly, and rhetoric to register how the argument is actually landing with its audience.