Proceedings of the Annual Meeting of the Cognitive Science Society

We explore the use of argumentation for justifying claims reached by plausible reasoning methods in domains where knowledge is incomplete, uncertain, or inconsistent. We present elements of a formal theory of argumentation that includes two senses of argument, argument as supporting explanation and argument as dialectical process. W e describe a partial implementation of the theory, a program that generates argument structures that organize relevant, available, plausible support for both a claim and its negation. Then we describe a theory of argument as dialectical process, where the format of a two-sided argument is used to intertwine the strengths and weaknesses of support for competing claims, so arguments can be refuted and directly compared.