Evaluating Corroborative Evidence
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How should we evaluate an argument in which two witnesses independently testify to some claim? In fact what would happen is that the testimony of the second witness would be taken to corroborate that of the first to some extent, thereby boosting up the plausibility of the first argument from testimony. But does that commit the fallacy of double counting, because the second testimony is already taken as independent evidence supporting the claim? Perhaps the corroboration effect should be considered illogical, since each premise should be seen as representing a separate reason in a convergent argument for accepting the claim as plausible. In this paper, we tackle the problem using argumentation schemes and argument diagramming. We examine a number of examples, and come up with two hypotheses that offer methods of analyzing and evaluating this kind of evidence.
KeywordsExpert opinion evidence Argumentation scheme Plausible reasoning Undercutting Fallacy of double counting Circumstantial evidence Corroborative witness testimony
- Goddu, G.C. 2003. Against the “Ordinary Summing” test for convergence. Informal Logic 23(3): 215–236.Google Scholar
- Redmayne, Mike. 2000. A corroboration approach to recovered memories’. Law Quarterly Review, 116, 147–155.Google Scholar
- Reed, C.A., and T.J. Norman. 2003. Argumentation machines. Dordrecht, Holland: Kluwer.Google Scholar
- Reed, C., and G. Rowe. 2004. Araucaria: software for argument analysis, diagramming and representation. International Journal on Artificial Intelligence Tools 13(4): 961–980. (Available at http://araucaria.computing.dundee.ac.uk/).
- Walton, D. (1984). Logical dialogue-games and fallacies. Lanham, Maryland: University Press of America. (Available free at http://io.uwinnipeg.ca/~walton/books/LDG84bk.pdf).
- Walton, D. 1997. Appeal to expert opinion. University Park, PA: Penn State University Press.Google Scholar
- Walton, D. 2005. Argumentation methods for artificial intelligence in law. Berlin: Springer (Lecture Notes in Artificial Intelligence Series).Google Scholar
- Walton, D., and T.F. Gordon. 2005. Critical questions in computational models of legal argument. In International Workshop on Argumentation in Artificial Intelligence and Law, ed. Paul E. Dunne and Trevor Bench-Capon, 103–111. Nijmegen: Wolf Legal Publishers. (Available on web page http://io.uwinnipeg.ca/~walton/books/LDG84bk.pdf).
- Wigmore, J. H. 1913. The principles of judicial proof as given by logic, psychology and general experience and illustrated in judicial trials. Boston: Little, Brown and Company.Google Scholar