Modelling dialogues in court using a gradual argumentation model: a case study

Abstract

This paper presents a formal model of dialogues in court using a gradual argumentation model. The gradual argumentation model provides computations for the strengths of arguments in an argumentation framework and the degrees of justification of arguments in a gradual argumentation semantic. In dialogues in court the adjudicator plays a neutral or active role to decide about burdens and standards of proof in the common law system or in the civil law system. The notions of strength and degree of justification are applied to define the corresponding standards of proof which are suggested as the measurements to assess the burden of production in the argumentation phase and the burden of persuasion in the decision phase. With application of the gradual argumentation model, this paper studies a formal model of dialogues in court. Specifically several new moves for the adjudicator are given within an updated communication language, protocol rules are defined for the adjudicator in accordance with the updated communication language are defined, a new notion of Record of commitments (RC) for the adjudicator is added in order to record qualified commitments, and the adjudicator's options in the decision phase are discussed. This paper tests the new model through a criminal case study.