Tech Reports

ULCS-19-001

Representing Norms with Extended Argumentation Frameworks

Trevor Bench-Capon, Sanjay Modgil


Abstract

This paper discusses reasoning about norms using Extended Argumentation Frameworks. We start by exploring Rawl?s Theory of Justice through the use of computational argumentation. Scenarios are modelled using Action Based Alternating Transition Systems with Values, and the resulting arguments evaluated in an Extended Argumentation Framework, which permits arguments to attack attacks as well as arguments, and so provides a natural way of representing exceptions. We also offer an interpretation of the promotion of values as the fulfillment of needs, and use Maslow?s hierarchy to choose between these needs when reasoning about Rawl?s initial position. Following our consideration of how norms are justified, we consider their application. Our representation of norms in EAFs enables us to offer a new account of permissions and exceptions. We illustrate our approach with an example relating to some US Supreme Court Fourth Amendment cases.

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