An integrated theory of causal stories and evidential arguments

14^th April 2015, 13:00 Ashton Lecture Theater
Dr Floris Bex
Department of Information and Computing Science
University of Utrecht
The Netherlands

Abstract

The process of proof in legal cases is about using the evidence to establish the facts of a case. It has been argued that both arguments and stories are needed in order to do justice to all the relevant reasoning mechanisms in the process of proof. Stories – coherent causal sequences of events – are needed to organise the complex mass of facts in a case into one or more hypotheses about 'what happened' in the case. Arguments - defeasible evidential inferences based on evidence - can then be used to support or attack the individual facts in these hypothetical stories.

In this talk, I will discuss the integrated formal approach to reasoning in the process of proof, in which arguments and stories can be used in conjunction as well as interchangeably. I will show how 'deductive' and 'abductive' reasoning with causal and evidential rules can be incorporated in a common framework for structured argumentation. This allows for the construction and comparison of causal stories, evidential arguments and mixed causal-evidential structures, and grounds the combination of arguments and stories in well-known dialectical argumentation semantics.