Arguing by question: A Toulminian reading of Cicero's account of the enthymeme

Abstract

In his Topics (§§ 54-55) Cicero discusses a type of argument which he calls enthymeme, and which he states is based on the third type of 'undemonstrated' syllogism of Stoic logic (not both p and q; but p; therefore not q). From Cicero's examples, however, it is clear that this kind of argument is meant to be regularly phrased as a rhetorical question. An analysis of this argumentative pattern according to Stephen Toulmin's model of argument structure reveals that its weak point is the unsubstantiated presupposition of some 'incompatibility' that serves as the argumentative warrant. It is argued that instead of providing appropriate argumentative backing the form of the rhetorical question is employed in order to secure acceptance of the warrant by putting strong psychological or moral pressure upon the audience by way of shifting the burden of proof or arguing ad hominem. An analysis of a selection of arguments of this kind from both Cicero's philosophical writings and his speeches further demonstrates that the persuasive force of the warrants implied can be reduced to various standard topical arguments (such as analogies, e contrario, correlations, cause-to-effect, a minore etc.), from which appropriate rebuttals may be easily derived. © 2006 Springer.