Case law in extended argumentation frameworks

Abstract

In this paper we discuss how recent developments in argumentation frameworks, most notably Extended Argumentation Frameworks, can inform the representation of a body of case law using abstract argumentation techniques. This builds on previous work which has first used abstract Argumentation Frameworks, and then Value based Argumentation Frameworks for this purpose.Extended Argumentation Frameworks augment Argumentation Frameworks to not only allow arguments to be attacked, but also attacks to be attacked. This allows argumentation based reasoning about information normally assumed to be metalevel to the object level domain of argumentation, including argumentation over preferences, values and the audience based ranking of values promoted by arguments. The Extended Argumentation Frameworks can then be rewritten as standard Argumentation Frameworks, so that cases, and values and their rankings relevant to the cases, can be reasoned about using standard dialogue games for Argumentation Frameworks. In this way precedents can be represented as collections of arguments and dialogues using these arguments. Now, when confronted with a new case, these dialogues may be used to identify ways of deploying the arguments in the new case so as to reach a favourable position.