Cristian Constantinescu

This chapter explores the implications of moral vagueness (namely, the vagueness of moral predicates) for non-naturalist metaethical theories like those recently championed by Shafer-Landau, Parfit, and others. It characterizes non-naturalism in terms of its commitment to seven theses: Cognitivism, Correspondence, Atomism, Objectivism, Supervenience, Non-reductivism, and Rationalism. It starts by offering a number of reasons for thinking that moral predicates are vague in the same way in which “red,” “tall,” and “heap” are said to be. It then argues that the moral non-naturalist seeking to countenance moral vagueness faces a dilemma: are moral properties vague, or perfectly sharp? On either horn of the dilemma, serious problems arise for some of the central tenets of non-naturalism: vague properties seem to threaten Objectivism, Supervenience, and Non-reductivism; on the other hand, sharp properties raise problems for Supervenience and Rationalism. The difficulties on each horn of the dilemma are real, and while they may not be insuperable, they do, at the very least, drastically limit the things non-naturalists can consistently say about moral properties, facts, and reasons.

This chapter explores the implications of moral vagueness for non-naturalist metaethical theories like those recently championed by Shafer-Landau, Parfit, and others. It characterizes non-naturalism in terms of its commitment to seven theses: Cognitivism, Correspondence, Atomism, Objectivism, Supervenience, Non-reductivism, and Rationalism. It starts by offering a number of reasons for thinking that moral predicates are vague in the same way in which “red,” “tall,” and “heap” are said to be. It then argues that the moral non-naturalist seeking to countenance moral vagueness faces a dilemma: are moral properties vague, or perfectly sharp? On either horn of the dilemma, serious problems arise for some of the central tenets of non-naturalism: vague properties seem to threaten Objectivism, Supervenience, and Non-reductivism; on the other hand, sharp properties raise problems for Supervenience and Rationalism. The difficulties on each horn of the dilemma are real, and while they may not be insuperable, they do, at the very least, drastically limit the things non-naturalists can consistently say about moral properties, facts, and reasons.

The paper examines two competing accounts of value incomparability presented in the recent literature. According to the standard account, developed most famously by Joseph Raz, incomparability means determinate failure of the three classic value relations (better than, worse than, and equally good): two value-bearers are incomparable with respect to a value V if and only if (i) it is false that x is better than y with respect to V, (ii) it is false that x is worse than y with respect to V, and (iii) it is false that x and y are equally good with respect to V. Most philosophers have followed Raz in adopting this account of incomparability. Recently, however, John Broome has advocated an alternative view, on which value incomparability is explained not in terms of determinate failure of the trichotomy of value relations, but in terms of vagueness, or indeterminacy. The paper aims to further Broome’s view in two ways. Firstly, it seeks to supply some independent reasons for thinking that the phenomenon of value incomparability is indeed a matter of the indeterminacy inherent in our comparative predicates. Secondly, it attempts to defend Broome’s account by warding off several objections that worry him, due mainly to Ruth Chang and Erik Carlson.