Tarsney, Christian (forthcoming). Vive la Différence? Structural Diversity as a Challenge for Metanormative Theories. Ethics.
Decision-making under normative uncertainty requires an agent to aggregate the assessments of options given by rival normative theories into a single assessment that tells her what to do in light of her uncertainty. But what if the assessments of rival theories differ not just in their content but in their structure -- e.g., some are merely ordinal while others are cardinal? This paper describes and evaluates three general approaches to this "problem of structural diversity": structural enrichment, structural depletion, and multi-stage aggregation. All three approaches have notable drawbacks, but I tentatively defend multi-stage aggregation as least bad of the three.
As readers of EAF, you're hopefully already familiar with the ideas around various forms of normative uncertainty and that it can't be resolved simply by coming up with a simple "conversion" between different ethical systems because they may be incomparable because they are of different "types", e.g. you can't just "average" over the differences between deontological and consequentialist ethical systems because there may be no coherent basis for comparison. In this paper, Tarsney explores some possible but ultimately inadequate solutions.
The most interesting part of the paper to me are sections 2 and 3, where he attempts to give an account of what "structure" means as it is relevant to uncertainty about normativity, and I think many will like section 4 as it provides an overview of resolutions previously considered.
You can find the full-text up on the PhilPapers archive.