A Theory of Moral Reasoning

We propose a framework for modeling the influence of normative considerations on decision-making and social interaction. Our key insight is that axiomatic models like those used in cooperative game theory can be reinterpreted as theories of moral reasoning and norm formation which describe the principles agents use to reason about the normative properties of a set of feasible outcomes in a choice set or game. We show how to choose axioms to represent different theories of moral reasoning, ranging from simple, abstract moral rules to radically context-dependent moral psychology. Then, under a given theory, we use the axioms to generate an "injunctive norm" which defines an agreed-upon ranking of feasible outcomes from most to least normatively appealing. Paired with a norm-dependent utility specification, this framework provides a powerful tool for modeling the influence of morality on decision-making. We show how the framework relates to the literature on social preferences, and why a theory of moral reasoning rooted in moral psychology is better able to account for the context-dependent nature of decision-making than a simpler theory rooted in moral rules