Decision Theory, Action Guidance, and Moral Uncertainty

Abstract

Proponents of decision-theoretic models of rational choice contend that maximizing expected moral choice-worthiness can resolve moral uncertainty and provide practical action guidance. However, standard decision theory fails to be action-guiding in contexts of moral uncertainty because its normative prescriptions are unknowable to actual decision-makers. For a decision procedure to guide action, an agent must be capable of knowing which act the procedure prescribes from a first-person perspective. In decision-theoretic calculations under moral uncertainty, an action’s appropriateness often hinges on minuscule differences in an agent’s subjective credences regarding non-zero-probability moral theories that assign extreme or arbitrary disvalues. Real human agents cannot introspectively differentiate between such infinitesimal credal values, rendering the prescribed choice indeterminate from their perspective. Proposed remedies—such as adopting imprecise credences, relying on epistemic probabilities or behavioral criteria, truncating minuscule probabilities via discounting, or utilizing minimax decision rules—either generate severe theoretical inconsistencies, lead to paralyzing fanaticism, or fail to resolve the underlying ambiguity. Consequently, decision-theoretic principles cannot serve as a reliable guide for action under moral uncertainty or provide a shortcut for resolving dilemmas in practical ethics. – AI-generated abstract.