Diagrams

The canonical form of an argument describes that argument as it is conceived by its author, insofar as it identifies the propositions the argument's author has employed in constructing an evidential case in support of some claim. By identifying an argument's propositional components – its premise(s) and conclusion – a canonical form delineates that argument's macrostructure. Canonical forms, however, provide no information about an author's conception of how the premises of her argument are relevant to, or how they ground, her conclusion. The specific evidential relations that obtain between an argument's propositional parts constitute that argument's microstructure. So canonical forms are silent on microstructural matters. In the following three chapters, we'll develop a method of argument diagraming that will allow us to display graphically both the macrostructure and the microstructure of arguments as those arguments are conceived by their authors.

We'll begin with five brief methodological comments about the general practice of argument diagraming. First, this practice is an extension of our overriding concern, in this text, with listening to authors. For our purposes, an argument diagram is, first and foremost, a visual description of the structure of an argument as it is conceived by its author. To be sure, one can construct diagrams of one's own arguments, either to explain to others or to clarify in one's own mind the microstructure of those arguments.