In The Uses of Argument, Stephen Toulmin proposed a model for the layout of arguments: claim, data, warrant, qualifier, rebuttal, backing. Since then, Toulmin’s model has been appropriated, adapted and extended by researchers in speech communications, philosophy and artificial intelligence. This book assembles the best contemporary reflection in these fields, extending or challenging Toulmin’s ideas in ways that make fresh contributions to the theory of analysing and evaluating arguments.

In Roman rhetoric, contrarium was variably considered either a figure of speech or an argument. The paper examines the logical pattern of this type of argument, which according to Cicero is based on a third Stoic indemonstrable syllogism: $$ \neg ({\hbox{p}} \wedge {\hbox{q}});<$> <$>{\hbox{p}} \to \neg {\hbox{q}}{\hbox{.}} $$ The persuasiveness of this type of argument, however, vitally depends on the validity of the alleged ‹incompatibility’ forming its major premiss. Yet this appears to be the argument’s weak point, as the ‹incompatibilities’ (...) employed generally hold for the most part only, and are reducible to topical argument schemes. This is why in practical usage such arguments are most often phrased as rhetorical questions, the persuasive force of which, enhanced by certain strategical maneuverings and fallacies, makes the audience swallow the argument. (shrink)

Since Mates’ seminal Stoic Logic there has been uncertainty and debate about how to treat the term anapodeiktos when used of Stoic syllogisms. This paper argues that the customary translation of anapodeiktos by ‘indemonstrable’ is accurate, and it explains why this is so. At the heart of the explanation is an argument that, contrary to what is commonly assumed, indemonstrability is rooted in the generic account of the Stoic epistemic notion of demonstration. Some minor insights into Stoic logic ensue.