John Anthony Blair

I argue that argumentation is not to be identified with (attempted) rational persuasion, because although rational persuasion appears to consist of arguments, some uses of arguments are not attempts at rational persuasion. However, the use of arguments in argumentative communication to try to persuade is one kind of attempt at rational persuasion. What makes it rational is that its informing ideal is to persuade on the basis of adequate grounds, grounds that make it reasonable and rational to accept the claim at issue.

The question, “What norms are appropriate for the evaluation of the probative merits of visual arguments?” underlies the investigation of this paper. The notions of argument and of multimodal visual argument employed in the study are explained. Then four multimodal visual arguments are analyzed and their probative merits assessed. It turns out to be possible to judge these qualities using the same criteria that apply to verbally expressed arguments. Since the sample is small and not claimed to be representative, this finding can at best be regarded as suggestive for the probative assessment of multimodal visual arguments in general.