Nearly 30 years ago, Terry Horgan and Mark Timmons published a now- popular article that combines Hilary Putnam’s Twin Earth scenario with G.E. Moore’s open question argument in an effort to show that moral naturalism – the view that moral facts are at bottom ordinary, natural facts of some sort – is probably false. Responses to Horgan and Timmons’s “revised open question argument” have been legion, but surprisingly, no one has attempted to test the core assumption upon which the argument (...) is based; namely, that competent language users univocally treat natural kind-terms as rigid designators. Here, I present evidence that the intuitions of competent English speakers are not as univocal as Horgan and Timmons need them to be to ground their argument against moral naturalism. I also briefly sketch a way that the moral naturalist can respond even if competent language speakers do treat natural-kind terms in the way that Horgan and Timmons suggest. (shrink)

The purpose of this paper is to conceptualize and explore what I shall call the Common Subject Problem for ethics. The problem is that there seems to be no good answer to what property everyone who makes moral claims could be talking and thinking about. The Common Subject Problem is not a new problem; on the contrary, I will argue that it is one of the central animating concerns in the history of both metaethics and normative theory. But despite its (...) importance, the Common Subject Problem is essentially invisible on many contemporary ways of carving up the problems of metaethics and normative ethical theory.My aim, therefore, is to make progress – in part by naming the problem, but also by beginning to sketch out the contours of what gives the problem its force, by distinguishing between different paths of response to the problem and assessing some of their chief merits, and finally, by distinguishing the Common Subject Problem from another problem with which it has come to be conflated. This nearby problem is the Moral Twin Earth Problem. Whereas the Common Subject Problem is a problem about what property ‘wrong’ could refer to, the Moral Twin Earth Problem is a problem about how ‘wrong’ could refer to it.The upshot of the paper, therefore, is to rescue one of the historically significant problems in normative ethics and metaethics – a problem that is essentially about normative semantics – from the illusion that has persisted over the last twenty years that it is really, somehow, a problem about metasemantics. Once we have reclaimed this problem, we can see that it could still be a problem even if there are no distinctively metasemantic problems in metaethics at all, that it is a problem faced by a wider variety of views, and that the space of possible solutions is much wider and more interesting for normative theory, moral psychology, and moral epistemology. (shrink)

A number of philosophers defend naturalistic moral realism by appeal to an externalist semantics for moral predicates. The application of semantic externalism to moral predicates has been attacked by Terence Horgan and Mark Timmons in a series of papers that make use of their “ Moral Twin Earth ” thought experiment. In response, several defenders of naturalistic moral realism have claimed that the Moral Twin Earth thought experiment is misleading and yields distorted and inaccurate semantic intuitions. If they are right, (...) the intuitions generated by Moral Twin Earth cannot be appealed to in arguments against externalist moral semantics. The most developed case against the Moral Twin Earth argument that follows this strategy is found in a paper by Stephen Laurence, Eric Margolis and Angus Dawson. Here I argue that their attack on the Moral Twin Earth thought experiment fails. Laurence, Margolis and Dawson have not shown that we have reason to distrust the semantic intuitions it generates. (shrink)

At the beginning of the twentieth century, G. E. Moore’s open question argument convinced many philosophers that moral statements were not equivalent to statements made using non- moral or descriptive terms. For any non- moral description of an object or object it seemed that competent speakers could without confusion doubt that the action or object was appropriately characterized using moral terms such as ‘good’ or ‘right’. The question of whether the action or object so described was good or right was (...) always open, even to competent speakers. In the absence of any systematic theory to explain the possibility of synthetic as opposed to analytic identities, many were convinced this demonstrated that moral properties could not be identified with any natural properties. Thus Moore and others concluded that moral properties such as goodness were irreducible sui generis properties, not identical to natural. (shrink)

This dissertation is a critique of synthetic ethical naturalism (SEN). SEN is a view in metaethics that comprises three key theses: first, there are moral properties and facts that are independent of the beliefs and attitudes of moral appraisers (moral realism); second, moral properties and facts are identical to (or constituted only by) natural properties and facts (ethical naturalism); and third, sentences used to assert identity or constitution relations between moral and natural properties are expressions of synthetic, a posteriori necessities. (...) The last of these theses, which distinguishes SEN from other forms of ethical naturalism, is supported by a fourth: the semantic contents of the central moral predicates such as 'morally right' and 'morally good' are fixed in part by features external to the minds of speakers (moral semantic externalism). Chapter 1 introduces SEN and discusses the most common motivations for accepting it. The next three chapters discuss the influential "Moral Twin Earth" argument against moral semantic externalism. In Chapter 2, I defend this argument from the charge that the thought experiment upon which it depends is defective. In Chapters 3 and 4, I consider two attempts to amend SEN so as to render it immune to the Moral Twin Earth argument. I show that each of these proposed amendments amounts to an abandonment of SEN. Chapter Five explores Richard Boyd's proposal that moral goodness is a "homeostatic property cluster." If true, Boyd's hypothesis could be used to support several metaphysical, epistemological, and semantic claims made on behalf of SEN. I advance three arguments against this account of moral goodness. In the sixth chapter, I argue that moral facts are not needed in the best a posteriori explanations of our moral beliefs and moral sensibility. Because of this, those who accept a metaphysical naturalism ought to deny the existence of such facts or else accept skepticism about moral knowledge. In Chapter 7, I consider a counterargument on behalf of SEN to the effect that moral facts are needed in order to explain the predictive success of our best moral theories. I show that this argument fails. (shrink)