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The purpose of this article is to illustrate the application of Modified Wigmorean Analysis to reasoning in fact-finding by international criminal tribunals, using selected aspects of the ICTR case of Muvunyi as the central example. This case study should show that Modified Wigmorean Analysis can be applied to this kind of material, that it is capable of illuminating what was in fact argued in justification by the Court and what might have been argued more cogently. Furthermore, we suggest that the method is not as difficult as might appear at first sight, in that some first year American law students have produced analyses of this and other ICTR cases to a reasonably high standard. This case study illustrates the uses and limitations of Modified Wigmorean Analysis and its particular application to witness credibility on which this and some other ICTR cases have largely turned.

In their respective papers, Gordon1 and Walton2 have addressed many of the concerns raised in my initial paper on visualization tools and argument schemes.3 Gordon’s simplified description of Carneades graphs effectively demonstrates that mastery of the mathematical theory on which the system is based is not necessary for its use. Walton has developed subquestions for each of the six critical questions for his scheme for Argument from Expert Opinion that satisfy the conditions for the admission of expert evidence and provide criteria for testing its probative value. The more detailed scheme provides a valuable heuristic device for lawyers, law students, and others concerned with the uses and limitations of expert evidence in legal contexts. Those papers also make it possible to refine and clarify the concerns that remain.

Visualization tools and argument schemes, such as those described by Thomas Gordon and Douglas Walton,1 have been developed by a community of scholars interested in argumentation theory and artificial intelligence, primarily theorists in logic, argumentation and information science (collectively the ‘argument theory’ or ‘AT’ community). The visualization tools provide excellent vehicles for teaching critical thinking skills and make it possible to depict the relationships and functions of the propositions in an argument in a form that facilitates analysis. The argumentation schemes provide a mechanism for stating stereotypical arguments in a standardized format that makes it possible to critique and determine their dialectical validity. The ongoing development of argument schemes and visualization tools may also hold promise for those seeking to develop artificial intelligence systems. By establishing standardized templates for varied arguments, argument schemes may provide a vehicle through which the arguments can be used and manipulated in artificial intelligence systems. The classification of the types of propositions in an argument, e.g. premises, assumptions, exceptions, etc., and development of symbol systems for depicting both the relationships and the functions of propositions in an argument may make it possible to create computer programs that may enable artificial intelligence systems to generate and depict the products of their analysis in an Araucariaor Carneades-like format. The AT community has long been interested in whether and how its tools might be used to facilitate the understanding and solution of legal problems.2 The AT community’s interest in evidential reasoning to resolve disputed questions of fact in legal contexts is more recent.3 The visualization tools and argument schemes that have been developed since that time have been designed primarily

In this chapter, we discuss the Wigmore chart method, which was originally developed to systematise arguments about disputed questions of fact, but which has also been used, in a modified form, to construct, represent and assess historical arguments in a range of other contexts. Building on the previous chapter, we consider here an application of Modified Wigmorean Analysis to an argument developed by Assyriologist Mark Geller for the claim that the Sumerian language survived in cuneiform for at least three centuries longer than historians had previously recognised (Anderson 2003; Geller (1994) 2003). The original exchange runs to almost 100 pages; the argument is summarised here, and the detailed analysis can be accessed at material-evidence.net.

This extensively revised second edition is a rigorous introduction to the construction and criticism of arguments about questions of fact, and to the marshalling and evaluation of evidence at all stages of litigation. It covers the principles underlying the logic of proof; the uses and dangers of story-telling; standards for decision and the relationship between probabilities and proof; the chart method and other methods of analyzing and ordering evidence in fact-investigation, in preparing for trial, and in connection with other important decisions in legal processes and in criminal investigation and intelligence analysis. Most of the chapters in this new edition have been rewritten; the treatment of fact investigation, probabilities and narrative has been extended; and new examples and exercises have been added. Designed as a flexible tool for undergraduate and postgraduate courses on evidence and proof, students, practitioners and teachers alike will find this book challenging but rewarding.