A Theory of Marginal Ethics

Åsbjørn Melkevik

Table of Contents


This paper argues for a marginal revolution in ethics, following the marginal revolution that marked the beginning of neoclassical economics. Ethics is situational in the sense that it is concerned with increments of values. We are not choosing between all the liberty or all the equality in the world. We are choosing between increments of, say, liberty or equality. This paper therefore introduces the bases of a theory of marginal ethics : (1) we should prefer cardinal to ordinal scales, (2) values should be assessed through their marginal rate of substitution, (3) we should reject the idea of absolute or intrinsic value, (4) something is just when the last feasible desideratum attached to it at the margin is satisfied. The objective of this approach is to permit us to better rank desiderata, which are conceptualized at the margin, and to introduce in the field of ethics some notions from mainstream economic theory.


  • 1. Can ethics follow the marginal revolution from economics ?
  • 2. Whether we should favour cardinal or ordinal scales
  • 3. Taking seriously the law of diminishing marginal utility in ethics
  • 4. How can we determine the just price of a bottle of wine ?
  • 5. We need a revolution in ethics – enter marginal ethics


JEL Codes : B13, A12, A13

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