Simon Blackburn’s supervenience argument—focusing on the mysterious “ban on mixed worlds”—is still subject to a variety of conflicting interpretations. In this paper, I hope to provide a defense of the argument that clarifies both the argument and the objections it must overcome. Many of the extant objections, I will argue, fail to engage the argument in its true form. And to counter the more compelling objections, it will be necessary to bring in additional argumentation that Blackburn himself does not clearly (...) provide. One important upshot of this discussion is that moral realism is not the only target of the argument: it raises trouble for a variety of metaethical views wed to realist-friendly construals of moral evaluation. Rightly understood, this argument not only survives the prominent responses, but turns out to be more powerful than his critics and Blackburn himself have recognized. (shrink)

It is widely accepted that the ethical supervenes on the natural, where this is roughly the claim that it is impossible for two circumstances to be identical in all natural respects, but different in their ethical respects. This chapter refines and defends the traditional thought that this fact poses a significant challenge to ethical non-naturalism, a view on which ethical properties are fundamentally different in kind from natural properties. The challenge can be encapsulated in three core claims which the chapter (...) defends: that a defensible non-naturalism is committed to the supervenience of the ethical, that this commits the non-naturalist to a brute necessary connection between properties of distinct kinds, and that commitment to such brute connections counts against the non-naturalist’s view. Each of these claims has recently been challenged. Against Nicholas Sturgeon’s recent doubts about the dialectical force of supervenience, this chapter defends a supervenience thesis as deserving to be common ground among ethical realists. It is then argued that attempts to explain supervenience on behalf of the non-naturalist either fail as explanations, generate near-identical explanatory burdens elsewhere, or appeal to commitments that are inconsistent with core motivations for non-naturalism. The chapter concludes that, suitably refined, the traditional argument against non-naturalism from supervenience is alive and well. (shrink)

This chapter argues that the best way for a non-naturalist to explain why the normative supervenes on the natural is to claim that, while there are some sui generis normative properties whose essences cannot be fully specified in non-normative terms and do not specify any non-normative sufficient conditions for their instantiation, there are certain hybrid normative properties whose essences specify both naturalistic sufficient conditions for their own instantiation and sufficient conditions for the instantiation of certain sui generis normative properties. This (...) is the only metaphysical explanation for supervenience on offer, the chapter argues, that can both clearly maintain the pre-theoretical commitments of non-naturalism, and provide a metaphysical explanation not just for supervenience, but for all metaphysical necessities involving natural and normative properties. (shrink)

In 1971, Simon Blackburn worked out an argument against moral realism appealing to the supervenience of the moral realm on the natural realm.1 He has since revised the argument, in part to take account of objections,2 but the basic structure remains intact. While commentators3 seem to agree that the argument is not successful, they have not agreed upon what goes wrong. I believe this is because no attempt has been made to see what happens when Blackburn's argument is addressed to (...) particular varieties of moral realism. As I see it, we must look to these various brands if we want to understand just where the concept of supervenience can be usefully employed. (shrink)

It is widely accepted that the ethical supervenes on the natural, where this is roughly the claim that it is impossible for two circumstances to be identical in all natural respects, but different in their ethical respects. This chapter refines and defends the traditional thought that this fact poses a significant challenge to ethical non-naturalism, a view on which ethical properties are fundamentally different in kind from natural properties. The challenge can be encapsulated in three core claims which the chapter (...) defends: that a defensible non-naturalism is committed to the supervenience of the ethical, that this commits the non-naturalist to a brute necessary connection between properties of distinct kinds, and that commitment to such brute connections counts against the non-naturalist’s view. Each of these claims has recently been challenged. Against Nicholas Sturgeon’s recent doubts about the dialectical force of supervenience, this chapter defends a supervenience thesis as deserving to be common ground among ethical realists. It is then argued that attempts to explain supervenience on behalf of the non-naturalist either fail as explanations, generate near-identical explanatory burdens elsewhere, or appeal to commitments that are inconsistent with core motivations for non-naturalism. The chapter concludes that, suitably refined, the traditional argument against nonnaturalism from supervenience is alive and well. (shrink)