Expressivism, Constructivism, and the Supervenience of Moral Properties
Philosophy and Religion
One of the most familiar arguments for expressivist metaethics is the claim that the rival theory, moral realism, cannot provide a satisfying explanation of why moral properties supervene on natural properties. Non-cognitivism, however, has its own problems explaining supervenience. Expressivists try to establish supervenience either by second-order disapproval of type-inconsistent moral evaluations or by pragmatic considerations. But disapproval of inconsistency is merely a contingent attitude that people happen to have; and pragmatic justification does not allow for appraisers to take their own moral attitudes seriously enough. What has been overlooked is a third alternative. The metaethical theory that can best account for supervenience is neither realist nor non-cognitivist but an objectivist version of constructivism. On the constructivist theory, right and wrong are determined by the principles that people would (hypothetically) consent to under ideal conditions. Type-consistency is a required feature of any principles regulating our conduct, if they are to be freely agreed to by ideally rational people.
Meyers, C. D.
(2012). Expressivism, Constructivism, and the Supervenience of Moral Properties. Philosophical Explorations, 15(1), 17-31.
Available at: http://aquila.usm.edu/fac_pubs/12045