Argument Strength in Probabilistic Argumentation Using Confirmation Theory

Anthony Hunter

Abstract: It is common for people to remark that a particular argument is a strong (or weak) argument. Having a handle on the relative strengths of arguments can help in deciding on which arguments to consider, and on which to present to others in a discussion. In computational models of argument, there is a need for a deeper understanding of argument strength. Our approach in this paper is to draw on confirmation theory for quantifying argument strength, and harness this in a framework based on probabilistic argumentation. We show how we can calculate strength based on the structure of the argument involving defeasible rules. The insights appear transferable to a variety of other structured argumentation systems.