Vive la différence? Structural diversity as a challenge for metanormative theories

Abstract

The vast majority of philosophers working on the problem of decision-making under normative uncertainty assume that normative theories can disagree in content but not in structure—i.e., that they all provide assessments of options on an interval or ratio scale, or that some provide only ordinal assessments while others provide cardinal ones. This paper argues that this assumption is false. There is a wide range of possible structural variations across normative theories, including the possibility of theories employing non-standard value scales (like infinite or infinitesimal value), comparability of imperfect duties and impossible outcomes, coexistence of cardinal and ordinal assessments within a single theory, conflicting definitions of choice-set dependent considerations, and choice functions involving incomparability, option-set dependence, or intransitivities. This “problem of structural diversity” challenges extant approaches to metanormative theories, which typically involve the aggregation of the assessments of multiple normative theories into a single assessment that tells the agent what to do. It is argued that the best way to cope with this challenge is to use a “multi-stage” aggregation procedure, in which sets of theories that share the same optimal aggregation rule are aggregated together, then the results of these partial aggregations are themselves aggregated with theories that have different optimal aggregation rules. – AI-generated abstract.