Diagramming, Argumentation Schemes and Critical Questions

Abstract

Argumentation schemes are forms of argument that model stereotypical patterns of reasoning. This paper is part of a project on the formalization of argumentation schemes. The paper shows how argumentation schemes and critical questions should be fitted into the technique of argument diagramming using the Araucaria software system. This XML-based system provides an interface through which the user can mark up a text of discourse to produce an argument diagram. We discuss several problems arising from the need to deal with enthymemes.

The formulation of the set of presumptive schemes in (Walton, 1996) was rough and ready. The variables and constants used in the schemes are quite a varied bunch, and have not been all incorporated into any single over-arching formal structure. Only the most rudimentary attempt was made to classify the schemes by a tree-structure exhibiting how some fall under others. In many cases, the organization of the premises of the scheme and the matching critical questions was obviously clumsy. For example, in some instances, it seemed that the critical question merely asked whether one of the premises was true or acceptable. Thus it looked like either the premise or the critical question was redundant. These same problems were perhaps even more evident in (1963) initial attempt to introduce a comprehensive set of schemes with matching critical questions.

Now that we have a new software system for argumentation diagramming that can accommodate argumentation schemes, many of these technical issues of how to clean up the schemes appear more pressing. Before this point they may have seemed relatively minor matters of detail to the working argumentation theorist or teacher of critical thinking. But now they demand our attention. In this presentation, some of the very most elementary of these technical questions of formalization of schemes are raised. As a means of arranging these questions, let us lay out our aims as desiderata for a theory of argumentation schemes. Such a theory should be

• rich and sufficiently exhaustive to cover a large proportion of naturally occurring argument

• simple, so that it can be taught in the classroom, and applied by students

• fine-grained, so that it can be useful employed both as a normative and evaluative system

• rigorous, and fully specified, so that it might be represented in a computational language such as XML

• clear, so that it can be integrated into traditional diagramming technique.

This is a challenging list to tackle, not least because some of these are at odds with one another: the more fine-grained our theory is, for example, the less likely it is to be at all exhaustive. Similarly, rigorous specification is crucial for computational representation, but a siginificant barrier for application to the real world. Happily, some of the aims do hang together: simplicity, for example, works to support not only computer representation, but also diagramming and classroom teaching. This then is where we are headed. Here, we briefly describe the Araucaria computer system that supports analysis of argument (and subsequent retrieval and manipulation of argument analyses), and how that software has provided a basis for formulating further developments in a theory of argumentation schemes.