Toward Justifying Actions with Logically and Socially Acceptable Reasons

Abstract

This paper formalizes argument-based reasoning for actions supported by believable reasons in terms of nonmonotonic consequences and desirable reasons in terms of Pareto optimality and maximizing social welfare functions. Our unified approach gives a four-layer practical argumentation framework structured with a propositional modal language with defaults and defeasible inference rules associated with practical reasoning. We show that the unified argument-based reasoning justifies an argument whose conclusion is supported by Pareto optimal, social welfare maximizing and nonmonotonic consequence reasons. Our formalization contributes to extend argument-based reasoning so that it can formally combine reasoning about logical believability and social desirability by benefiting from economic notions.