The aim of this paper is to assess the relationship between anti-physicalist arguments in the philosophy of mind and anti-naturalist arguments in metaethics, and to show how the literature on the mind-body problem can inform metaethics. Among the questions we will consider are: (1) whether a moral parallel of the knowledge argument can be constructed to create trouble for naturalists, (2) the relationship between such a "Moral Knowledge Argument" and the familiar Open Question Argument, and (3) how naturalists can respond (...) to the Moral Twin Earth argument. We will give particular attention to recent arguments in the philosophy of mind that aim to show that anti-physicalist arguments can be defused by acknowledging a distinctive kind of conceptual dualism between the phenomenal and the physical. This tactic for evading anti-physicalist arguments has come to be known as the Phenomenal Concept Strategy. We will propose a metaethical version of this strategy, which we shall call the `Moral Concept Strategy'. We suggest that the Moral Concept Strategy offers the most promising way out of these anti-naturalist arguments, though significant challenges remain. (shrink)

In a series of articles, Terry Horgan and Mark Timmons have argued that Richard Boyd’s defence of moral realism, utilizing a causal theory of reference, fails. Horgan and Timmons construct a twin Earth-style thought experiment which, they claim, generates intuitions inconsistent with the realist account. In their thought experiment, the use of (allegedly) moral terms at a world is causally regulated by some property distinct from that regulating their use here on Earth; nevertheless, Horgan and Timmons claim, it is intuitive (...) that the inhabitants of this world disagree with us in their moral claims. Since any disagreement would be merely verbal were the alleged moral facts identical to or constituted by different natural facts, the identity or constitution claim must be false. I argue that their argument fails. Horgan and Timmons’ thought experiment is underdescribed; when we fill out the details, I claim, we shall see that the challenge to moral realism fades away. I sketch two possible interpretations of the (apparently) moral claims of the inhabitants of moral Twin Earth. On one interpretation, they fail to disagree with us because they actually agree with us; on the other, they fail to disagree with us because they are not moralizers at all. Which interpretation is true, I argue, will depend on the facts that explain the differences between us and the inhabitants of moral twin Earth. (shrink)

In order to rebut G. E. Moore’s open question argument, ethical naturalists adopt a theory of direct reference for our moral terms. T. Horgan and M. Timmons have argued that this theory cannot be applied to moral terms, on the ground that it clashes with competent speakers’ linguistic intuitions. While Putnam’s Twin Earth thought experiment shows that our linguistic intuitions confirm the theory of direct reference, as applied to ‘water’, Horgan and Timmons devise a parallel thought experiment about moral terms, (...) in order to show that this theory runs against our linguistic intuitions about such terms. My claim is that the Horgan–Timmons argument does not work. I concede that their thought experiment is a good way to test the applicability of the theory of direct reference to moral terms, and argue that the upshot of their experiment is not what they claim it is: our linguistic intuitions about Moral Twin Earth are parallel to, not different from, our intuitions about Twin Earth. (shrink)

Horgan and Timmons have argued that our intuitions about the semantics of non-moral language and moral language differ, and that while twin-earth semantic intuitions generate one result in Putnam´s twater case, moral twin-earth fails to generate comparable results for moral terms. Horgan and Timmon´s conclude from this that the semantic norms governing the use of natural kind terms differ from the semantic norms governing the use of moral terms. I will argue that Horgan and Timmons’ intuitive moral twin-earth argument fails (...) to derail the new moral realism. Further, I will discuss Boyd’s semantic theory and raise problems for it that do not rely on the use of moral twin-earth. (shrink)

Terence Horgan and Mark Timmons's ' moral twin earth argument' raises doubts about the naturalistic realist's ability to make sense of genuine disagreement. I offer three arguments the realist's behalf. First, I argue that the example at the heart of their argument is underdescribed; when fully developed, it loses its intuitive force. Second, I suggest that taking the stipulations of the Horgan-Timmons example seriously gives us reason to revise our initial judgments. Third, I propose combining naturalistic realism about moral judgments (...) with expressivism about the last ought before action in order to preserve the conflict between moralists and twin -moralists. (shrink)

What considerations place genuine constraints on an adequate semantics for normative and evaluative expressions? Linguists recognize facts about ordinary uses of such expressions and competent speakers’ judgments about which uses are appropriate. The contemporary literature reflects the widespread assumption that linguists don’t rely upon an additional source of data—competent speakers’ judgments about possible disagreement with hypothetical speech communities. We have several good reasons to think that such judgments are not probative for semantic theorizing. Therefore, we should accord these judgments no (...) probative value for the development of a semantics for our moral terms. Such judgments can no longer be presumed to put pressure on theories according to which our moral expressions share a semantics with ordinary, descriptive terms. Many rivals to pure, Descriptivist theories count among their advantages the ability to accommodate these judgments. If these judgments have no probative value, such theories lose an important source of support. (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)

Terry Horgan and Mark Timmons’s “Moral Twin Earth” thought experiment allegedly undercuts virtually any form of naturalist moral realism. I argue that a neo-Aristotelian conception of moral properties defeats Moral Twin Earth. Developing themes in the work of Peter Geach, Philippa Foot, and Rosalind Hursthouse, I sketch an Aristotelian moral semantics that is unique in construing terms like ‘right’ and ‘good’ exclusively as attributive adjectives that denote relational properties. On this view, moral goodness is a relational property predicated of those (...) human beings that satisfy kind-relative criteria of goodness; i.e., morally good human beings are good qua human being. The reference of moral terms is therefore fixed by the natural properties of human beings. This account ensures that moral facts cannot differ across worlds in which the relevant natural facts do not differ and thus defeats Moral Twin Earth. (shrink)

Hilary Putnam's Twin Earth thought experiment has come to have an enormous impact on contemporary philosophical thought. But while most of the discussion has taken place within the context of the philosophy of mind and language, Terence Horgan and Mark Timmons (H8cT) have defended the intriguing suggestion that a variation on the original thought experiment has important consequences for ethics.' In a series of papers, they' ve developed the idea of a Moral Twin Earth and have argued that its significance (...) is that it has the resources to undermine naturalistic versions of moral realism.' H8t T don't hold back in their assessment. "Moral Twin.. (shrink)

J. L. Mackie argued that if there were objective moral properties or facts, then the supervenience relation linking the nonmoral to the moral would be metaphysically queer. Moral realists reply that objective supervenience relations are ubiquitous according to contemporary versions of metaphysical naturalism and, hence, that there is nothing especially queer about moral supervenience. In this paper we revive Mackie's challenge to moral realism. We argue: (i) that objective supervenience relations of any kind, moral or otherwise, should be explainable rather (...) than sui generis; (ii) that this explanatory burden can be successfully met vis-à-vis the supervenience of the mental upon the physical, and in other related cases; and (iii) that the burden cannot be met for (putative) objective moral supervenience relations. (shrink)

(1992). TROUBLES FOR NEW WAVE MORAL SEMANTICS: THE ‘OPEN QUESTION ARGUMENT’ REVIVED. Philosophical Papers: Vol. 21, No. 3, pp. 153-175. doi: 10.1080/05568649209506380.

This article explores the theory of natural kind essentialism, as developed by Putnam and Kripke. It defends the theory against certain criticisms, but also suggests that it should not be treated as universally true. Rather, it comes down to how different people use language, offering reasons why some people's idiolects might behave in an essentialist way while others behave in the contrary way, but explaining how we can all still communicate perfectly well despite this.

This precis explains that _Philosophical naturalism contains three parts. Part I examines arguments for physicalism and maintains I) that all causally relevant special science properties must be realized by physical ones, and II) that all special science laws must reduce to physical ones, apart from the significant category of special laws that result from selection processes. Part II defends a teleological theory of representation and an identity theory of consciousness. Part III defends reliabilism and applies it to inductive scepticism and (...) also defends a fictionalist account of mathematics. (shrink)

The prospects for moral realism and ethical naturalism have been important parts of recent debates within metaethics. As a first approximation, moral realism is the claim that there are facts or truths about moral matters that are objective in the sense that they obtain independently of the moral beliefs or attitudes of appraisers. Ethical naturalism is the claim that moral properties of people, actions, and institutions are natural, rather than occult or supernatural, features of the world. Though these metaethical debates (...) remain unsettled, several people, myself included, have tried to defend the plausibility of both moral realism and ethical naturalism. I, among others, have appealed to recent work in the philosophy of language—in particular, to so-called theories of “direct reference” —to defend ethical naturalism against a variety of semantic worries, including G. E. Moore's “open question argument.” In response to these arguments, critics have expressed doubts about the compatibility of moral realism and direct reference. In this essay, I explain these doubts, and then sketch the beginnings of an answer—but understanding both the doubts and my answer requires some intellectual background. (shrink)

According to many philosophers, the notion of belief is constitutively normative ; Shah ; Shah and Velleman (); Gibbard (); Wedgwood ). In a series of widely discussed papers, Terence Horgan and Mark Timmons have developed an ingenious ‘Moral Twin Earth’ argument against ‘Cornell Realist’ metaethical views which hold that moral terms have synthetic natural definitions in the manner of natural kind terms. In this paper we shall suggest that an adaptation of the Moral Twin Earth argument to the doxastic (...) case – Doxastic Twin Earth – provides new evidence for the normativity of belief. (shrink)

In his 2013 Theoria article, “Unreliable Intuitions: A New Reply to the Moral Twin-Earth Argument,” Jorn Sonderholm attempts to undermine our moral twin earth argument against Richard Boyd's moral semantics by debunking the semantic intuitions that are prompted by reflection on the thought experiment featured in the MTE argument. We divide our reply into three main sections. In section 1, we briefly review Boyd's moral semantics and our MTE argument against this view. In section 2, we set forth what we (...) take to be Sonderholm's master debunking argument, along with his proposed Boydian explanation of the semantic intuitions he seeks to debunk. Then in section 3, we mount our defence of the semantic intuitions under scrutiny, arguing on abductive grounds that, contrary to Sonderholm, the semantic intuitions generated by reflection on MTE scenarios are to be trusted in evaluating the plausibility of Boydian moral semantics. Section 4 is our summary and conclusion. (shrink)

In "Milk, Honey, and the Good Life on Moral Twin Earth", David Copp explores some ways in which a defender of synthetic moral naturalism might attempt to get around our Moral Twin Earth argument. Copp nicely brings out the force of our argument, not only through his exposition of it, but through his attempt to defeat it, since his efforts, we think, only help to make manifest the deep difficulties the Moral Twin Earth argument poses for the synthetic moral naturalist.