A system for defeasible argumentation, with defeasible priorities

Abstract

Inspired by legal reasoning, this paper presents an argument-based system for defeasible reasoning, with a logic-programming-like language, and based on Dung's argumentation-theoretic approach to the semantics of logic programming. The language of the system has both weak and explicit negation, and conflicts between arguments are decided with the help of priorities on the rules. These priorities are not fixed, but are themselves defeasibly derived as conclusions within the system.