Semantics for a theory of defeasible reasoning

In this paper, we establish a formal semantics for Pollock's [ 23] theory of defeasible reasoning. As a notion of argument or argumentation has never been formalised in this theory, it is important that such a formal account be introduced to couple with the algorithmic description of the theory. In particular, it makes Pollock's theory become more comparable to other related frameworks as shown in the paper. In also enforces a well-defined semantical account for Pollock's theory of defeasible reasoning based on the argumentation-theoretic approach proposed by Dung and Bondarenko et al. [ 1,5]. Our formalisation thus enables further studies to the meta-theoretic properties of Pollock's defeasible reasoning system.