Argumentation, stories and generalizations: a comment

Abstract

The underlying theory of the software program described in ‘Sense-Making Software for Criminal Investigation’ (Bex et al., 2007) complements modified Wigmorean analysis (MWA). Both adopt a qualitative rather than a quantitative approach. MWA is broadly compatible with the kind of logic involved, including abductive inference to the best explanation and the idea of defeasible argumentation. Both approaches are mainly valuable as aids to thinking, especially constructing and evaluating arguments, rather than as methods of presenting them in order to persuade. Both approaches can be applied at different stages of criminal investigation (and more broadly of legal processes), but the specific device of Wigmore charts (one part of MWA) is more useful in hypothesis testing and discarding than in hypothesis formation, which typically requires imaginative reasoning. The Anchored Narratives of Crombag et al. and MWA have similar theoretical assumptions, except that MWA gives a radically different account about the relationship between stories, generalizations and argument. The proposed program has considerable promise, but before it can be of positive practical value in police investigation, more attention needs to be given not only to the obvious dangers of using stories and generalizations in this context but also about what positive guidance can be given to mitigate these dangers. There is, however, an unresolved tension between the simplifying tendencies of formalized computer programming and the tendency of MWA to emphasize the complexities of practical inferential reasoning and argumentation in legal contexts.