Assumptive Sequent-Based Argumentation

Abstract

In many expert and everyday reasoning contexts it is very useful to reason on the basis of defeasible assumptions. For instance, if the information at hand is incomplete we often use plausible assumptions, or if the information is conflicting we interpret it as consistently as possible. In this paper sequent-based argumentation, a form of logical argumentation in which arguments are represented by a sequent, is extended to incorporate defeasible assumptions. The resulting assumptive framework is general, in that several other approaches to reasoning with assumptions from the literature can adequately be represented in it. Moreover, assumptive sequent-based argumentation has many desirable properties. It will be shown that assumptive sequent-based argumentation can easily be extended to a prioritized setting, it satisfies rationality postulates and reasoning with maximally consistent subsets can be represented in it