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)

A brief account of Putnam's Twin Earth thought experiment and its significance, written for a general audience. Sadly, I can't include Helen De Cruz's drawing of it - check out the beautiful book!

Horgan and Timmons, with their Moral Twin Earth arguments, argue that the new moral realism falls prey to either objectionable relativism or referential indeterminacy. The Moral Twin Earth thought experiment on which the arguments are based relies in crucial ways on the use of intuitions. First, it builds on Putnam’s well-known Twin Earth example and the conclusions drawn from that about the meaning of kind names. Further, it relies on the intuition that were Earthers (...) and Twin Earthers to meet, they would be able to have genuine moral disagreements. I will argue that the similarities with Putnam’s thought experiment are questionable and so the reliance on Putnam-like intuitions is questionable. I will then further argue that even if we accept the intuitions that Horgan and Timmons rely on, the anti-realist conclusion is not warranted due to there being more to the meaning of kind terms than the argument assumes. Once we develop the meaning of kind terms further we can acknowledge both that Earthers and Twin Earthers refer to different properties with their moral terms, and that in spite of that they can have a substantive disagreement due to a shared meaning component. (shrink)

Robert Stalnaker; XVI*—Twin Earth Revisited, Proceedings of the Aristotelian Society, Volume 93, Issue 1, 1 June 1993, Pages 297–312, https://doi.org/10.1093/ar.

In this paper I argue against Twin-Earth externalism. The mistake that Twin Earth arguments rest on is the failure to appreciate the force of the following dilemma. Some features of things around us do matter for the purposes of conceptual classification, and others do not. The most plausible way to draw this distinction is to see whether a certain feature enters the cognitive perspective of the experiencing subject in relation to the kind in question or not. (...) If it does, we can trace conceptual differences to internal differences. If it doesn’t, we do not have a case of conceptual difference. Neither case supports Twin Earth externalism. (shrink)

A presentation and analysis of the twin-earth thought experiments.

This volume will acquaint novice philosophers with one of the most important debates in twentieth-century philosophy, and will provide seasoned readers with a ...

In this dissertation, I attempt to provide some new evidence in favour of the claim that meaning is normative—specifically, for the claim that semantic judgments or ascriptions of meaning are action-guiding. I attempt to achieve this by developing an analogue of the Moral Twin Earth argument advanced by Horgan and Timmons which I call the ‘Meaning Twin Earth’ argument. In the course of the dissertation, I outline Kripke’s 1982 sceptical argument for the thesis that there are (...) no meaning facts in virtue of which ascriptions of meaning are true or false and highlight how the claim that meaning is normative is necessary for that argument to succeed with the kind of generality that Kripke intends. I then explain how one of Kripke’s main arguments against dispositionalist accounts of meaning can be viewed as a kind of open question argument. This argument is ultimately a failure, but nonetheless, I argue that the argument can be revised in a way that does pose a genuine threat to dispositionalist accounts of meaning by using an analogue of Horgan and Timmons’ Moral Twin Earth argument. I claim that a Meaning Twin Earth scenario yields linguistic intuitions that, in my view, are best explained by invoking the claim that meaning is normative. These intuitions constitute evidence against both reductive dispositionalism and anti-normativism about meaning. I forestall several potential objections to the Meaning Twin Earth argument drawn from Plunkett and Sundell, Copp, Merli, and Baker. In closing, I consider two broad options for a normativist account of semantic judgment: an expressivist form and a rationalist form. I argue that, provisionally, McDowell’s rationalist version of factualism about meaning faces a less serious challenge than Gibbard’s expressivist alternative. (shrink)

Mark Timmons and Terry Horgan have argued that the new moral realism, which rests on the causal theory of reference, is untenable. While I do agree that the new moral realism is untenable, I do not think that Timmons and Horgan have succeeded in showing that it is. I will lay out the case for new moral realism and Horgan and Timmons’ argument against it, and then argue that their argument fails. Further, I will discuss Boyd’s semantic theory as well (...) as attempts to improve upon it, raise serious problems for these semantic accounts, and suggest an alternative view that accounts for our use of moral terms. (shrink)

It is widely believed that Twin-Earth-style thought experiments show that the contents of a person's thoughts fail to supervene on her intrinsic properties. Several recent philosophers have made the further claim that Twin-Earth-style thought experiments produce metaphysically necessary conditions for the possession of certain concepts. I argue that the latter view is false, and produce counterexamples to several proposed conditions. My thesis is of particular interest because it undermines some attempts to show that externalism is incompatible (...) with privileged access. (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)

Robert Stalnaker; XVI*—Twin Earth Revisited, Proceedings of the Aristotelian Society, Volume 93, Issue 1, 1 June 1993, Pages 297–312, https://doi.org/10.1093/ar.

Jonathan Weinberg (2007) has argued that we should not appeal to intuition as evidence because it cannot be externally corroborated. This paper argues for the normative claim that Weinberg’s demand for external corroboration is misguided. The idea is that Weinberg goes wrong in treating philosophical appeal to intuition analogous to the appeal to evidence in the sciences. Traditional practice is defended against Weinberg’s critique with the argument that some intuitions are true simply in virtue of being intuited by the majority (...) of people. The argument proceeds by way of examining a paradigm case, Putnam’s Twin Earth. (shrink)

This paper presents a framework for analysing perceptual Twin Earth thought experiments. Visual content normally has an analogue character, and it is argued in this paper that this sets certain constraints on the extent to which Twin Earth thought experiments can be successful. The argumentation in the paper is developed by using examples from visual spatial content. It is argued that visual spatial content can only be “twin-earthed” in a very limited way. Whereas the metrics (...) of space can be twin-earthed, visual experience has a structure that means that it can only be the vehicle for representing entities with geometrical structures. (shrink)

In this paper I revisit an important response to the Moral Twin Earth (MTE) challenge: The Common Functional Role strategy (CFR). I argue that CFR is open to a revenge problem. MTE-cases allegedly show that two linguistic communities can be in genuine disagreement even when they are regulated by distinct families of properties. CFR provides a way to reconcile the intuition that the two communities are in genuine disagreement with the claim that the use of moral terms by (...) both communities is causally regulated by different families of properties. This is done by identifying a functional role that those families of properties both fulfill. Still, even if CFR is successful, its proponents need to face a serious revenge problem. Roughly, it could be that the families of properties that regulate each community are equally perfect realizers of the relevant higher-order functional state. I suggest that the proponent of CFR faces a dilemma: either CFR has controversial implications about first-order moral theory, or CFR needs to be coupled with substantive and parochial empirical/metaphysical assumptions to avoid those implications. (shrink)

A key objection to naturalistic versions of moral realism is that the (meta)semantics to which they are committed yields incorrect semantic verdicts about so-called Moral Twin Earth cases. Recently, it has been proposed that the Moral Twin Earth challenge can be answered by adopting a neo-Aristotelian semantics for moral expressions. In this paper, I argue that this proposal fails. First, however attractive the central claims of neo-Aristotelianism are, they do not for us have the status of (...) analytic constraints on the use of ethical expressions, as they must if they are to block Moral Twin Earth counterexamples. Second, even when the neo-Aristotelian’s claims are taken as non-negotiable analytic constraints, the semantics faces a dilemma: if characteristic human functioning is understood in an ethically neutral way, the semantics yields an incorrect intension for ‘good human.’ If human functioning is understood in an ethically partisan way, the semantics fails to avoid problematic Moral Twin Earth counterexamples. (shrink)

"Twin earth" examples have motivated a number of proposals for the lexicography of kind terms in natural languages. It is argued that these proposals create unacceptable difficulties for the analysis of de dicto propositional attitudes. A conservative solution of the twin earth problems is then proposed according to which they reflect pragmatic features of language use rather than semantic features of lexical content.

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)

Terence Horgan and Mark Timmons have written a number of articles where they use their Moral Twin Earth thought experiment to attack the new moral realism. The new moral realism is based on advances made in the philosophy of language that allows us to introduce synthetic definitions of moral terms. The Moral Twin Earth thought experiment relies in crucial ways on the use of intuitions. Specifically, it relies on the intuitions that were Earthers and Twin (...) Earthers to meet, they would be able to have genuine moral disagreements. Horgan and Timmons rely on that intuition when they argue that the meaning of the relevant terms on Earth and Twin Earth must be the same. I will argue that we can accept that Earthers and Twin Earthers can have genuine moral disagreement while at the same time claim that the terms they use have different referents and so different semantic meaning. That is, having genuine disagreements does not require that the semantic meaning or the reference of the terms used in the debate being the same. (shrink)

This paper presents two cases demonstrating that theories allowing the environment to partially determine the content of moral concepts provide incorrect truth-conditions for moral terms. While typical Moral Twin Earth cases seek to establish that these theories fail to account formoral disagreement, neither case here essentially involves interpersonal disagreement. Both involve a single person retaining moral beliefs despite recognizing actual or potential mismatches with the purportedly content-determining facts. This lets opponents of such theories grant objections that standard Moral (...) Twin Earth cases fail to demonstrate disagreement, and argue more straightforwardly that they generate implausible truth-conditions for moral claims. (shrink)

A popular form of virtue epistemology—defended by such figures as Ernest Sosa, Linda Zagzebski and John Greco—holds that knowledge can be exclusively understood in virtue-theoretic terms. In particular, it holds that there isn't any need for an additional epistemic condition to deal with the problem posed by knowledge-undermining epistemic luck. It is argued that the sustainability of such a proposal is called into question by the possibility of epistemic twin earth cases. In particular, it is argued that such (...) cases demonstrate the need for virtue-theoretic accounts of knowledge to appeal to an independent epistemic condition which excludes knowledge-undermining epistemic luck. (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 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)

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)

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. (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)

In a 1911 research manuscript, Husserl puts forth an idea that resembles Putnam’s Twin Earth thought experiment presented in the 1970s. In this paper, I study Husserl’s “Twin Earth” passage and assess various readings of it to determine whether Husserl is better understood as an internalist or an externalist. I define internalism as the view that content depends solely on internal factors to the subject, whereas I distinguish between two versions of externalism: weak externalism, according to (...) which content can also depend on other subjects’ conceptions, and strong externalism, which maintains that content can also depend on the real world. Only strong externalism maintains what McGinn calls “the philosophical significance of externalism” because it entails realism about the world. I argue that Husserl is better understood as an externalist when it comes to the “Twin Earth” passage, but the more precise question regarding weak and strong externalism requires further evidence. This additional evidence concerns Husserl’s concepts of the identity of sense (Sinnesidentität) and worldly meaning (weltlicher Sinn). In evaluating externalist Husserl interpretations, I classify Smith’s externalist interpretation as weak, whereas I take Crowell’s externalist interpretation to be ambivalent. Crowell’s excellent but somewhat embryonic interpretation leaves the dependence relation between content and the real world ambiguous. I clarify this relation by assessing McGinn’s argument for the philosophical significance of externalism from the Husserlian viewpoint. Although this study is historical, it also serves a systematic purpose because the externalist interpretation of Husserl calls into question central issues in phenomenology and externalism. (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)

Liberals about perceptual contents claim that perceptual experiences can represent kinds and specific, familiar individuals as such; they also claim that the representation of an individual or kind as such by a perceptual experience will be reflected in the phenomenal character of that experience. Conservatives always deny the latter and sometimes also the former claim. I argue that neither liberals nor conservatives have adequately appreciated how the content internalism/externalism debate bears on their views. I show that perceptual content internalism entails (...) conservativism when conjoined with one other, extremely plausible premise. Hence, liberals are committed to perceptual contents externalism, yet they have failed to fully address the consequences that this has for their view. Moreover, the argument is easily adapted to perceptual experiences of Twin Earthable properties, like colour and shape. I use this last result to show why existing conservative arguments that appeal to Twin Earth plausibly overgeneralize. (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)

This paper offers a simple response to the Moral Twin Earth (MTE) objection to Naturalist Moral Realism (NMR). NMR typically relies on an externalist metasemantics such as a causal theory of reference. The MTE objection is that such a theory predicts that terms like ‘good’ and ‘right’ have a different reference in certain twin communities where it’s intuitively clear that the twins are talking about the same thing when using ‘good’. I argue that Boyd’s causal regulation theory, (...) the original target of the MTE objection, was never vulnerable to this objection. The theory contains an epistemic constraint on reference which implies that either the property that causally regulates uses of ‘good’ isn’t different for the twin communities or, in scenarios where the reference is different, the communities diverge in ways where it’s not intuitively clear that ‘good’ has the same reference for them. (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)

Following the influential thought experiments by Hilary Putnam and others, philosophers of language have for the most part adopted semantic externalism concerning natural kind terms. In this article, we present results from three experiments on the reference of natural kind terms. Our results confirm some standard externalist assumptions, but are in conflict with others: Ordinary speakers take both appearance and underlying nature to be central in their categorization judgments. Moreover, our results indicate that speakers’ categorization judgments are gradual, and proportional (...) to the degree of similarity between new samples and familiar, “standard” samples. These findings pose problems for traditional theories, both externalist and internalist. (shrink)

The Linguistic Account of Thought holds that thought is the meaning of declarative sentences. According to Linguistic Internalism, two languages can share sentential meanings and hence express the same thought. According to Linguistic Particularism, thought content is relative to languages and is not shared. We can contrast these two accounts of thought with a third: the intension of a thought is a common disciplinary use of differing meaningful claims, and the extension of a thought is the collection of sentences or (...) symbols that share a disciplinary use---a view inspired by Patanjali's Yoga, Linguistic Externalism. Having noted that the Linguistic Account of Thought is the defining feature of the Western tradition, underwriting the European philosophical tradition and work in Indology, I consider whether the competing accounts of thought can be tested. I note that the Moral Twin Earth thought experiment by Horgan and Timmons, assumes Linguistic Internalism and attempts to test competing accounts of moral semantics for their capacity to facilitate cross cultural communication on morals across different languages. I propose testing competing accounts of thought to the same end on Planet Ethics: here the moral semantics of a language simply is its national moral theory. So the literal meaning of “good” for Nation Kant would be “a will determined by the categorical imperative,” but for Nation Expressivism Kant it would an internalist semantics that allows speakers to express their minds. Nation Plato is ruled by a philosopher king, and "good" there means "the form of the forms," and for Nation Positive Utilitarians it means "maximal happiness" while for the Negative Utilitarians it means "minimal suffering." The scenario also contains with in it the Thems: they have their own Them language tied to their own moral tradition, but they also participate in the linguistic culture of their adopted homes. Can the citizens of Planet Ethics have a conversation about morals, and can they avoid Anti Thematism? I note that the two Linguistic Accounts of Thought cannot explain how moral conversations occur across languages on Planet Ethics. Each culture will try to use its own language as a frame to understand others, who will be incomprehensible in so far as they depart from the assumed linguistic frame: each culture will view itself as having the moral frame work. Worse, the linguistic accounts of thought render right answers to moral questions analytically true, and criticisms of the dominant moral theory a contradiction in terms. A community who cannot get along with each other can separate and make separate moral communities, each with its own national ethos and corresponding moral semantics, but then they will not be able to conceptualize their prior disagreement especially if both new languages are departures from the earlier shared moral semantics. Also, the Thems will be viewed with suspicion for not wholly and univocally supporting the national ethos of their adopted homes. Linguistic externalism has no problem accounting for moral discourse here or in allowing for intra cultural moral criticism: the common philosophical use of the diverse philosophical sentences is the common proposition on which speakers of the various languages can agree or disagree to. On Planet Ethics it becomes clear there is "right" moral semantics: all will do as well as each other. Whereas the Linguistic Account of Thought leads to an inflationary approach to linguistic meaning, the linguistic externalist option is deflationary with respect to linguistic meaning. Finally I note that the linguistic approach to thought underwrites Indological investigations into Indian ethics and I consider two Davidson inspired tweaks to save the linguistic approach. The upshot is that Orthodox Indologists, in practice, adopt the procedure that Davidson recommends for understanding malopropers, such as Archie Bunker. In short, Orthodox Indologists, in being wedded to the linguistic approach to thought, treat Indian philosophers like malapropers who can't speak Sanskrit, like Bunker cannot speak English without erring. All can be avoided by Linguistic Externalism. This means that the conceptual content of moral vocabulary is not their linguistic meaning, but their philosophical purpose. (shrink)

The Moral Twin Earth challenge to ethical naturalism threatens to undermine an otherwise promising metaethical view by showing that typical, naturalist-friendly theories of reference determination predict diverging reference in Twin Earth scenarios, making it difficult to account for substantive moral disagreement. Several theorists have recently invoked David Lewis’s doctrine of reference magnetism as a solution, claiming that a highly elite moral property—a moral “joint in nature”—could secure shared reference between ourselves and our twins on Twin (...) Earth, despite our diverging usages of moral terms. This paper argues that this move has significant methodological implications: namely, it entails that a certain sort of simplicity is truth-conducive. Consequently, when applied to moral theories, this gives certain views, specifically monist ones like utilitarianism and contractualism, an advantage over their more complicated rivals, forms of pluralism and particularism. Thus, ethical naturalists cannot invoke reference magnetism without a substantial impact on first-order theorizing. (shrink)

A crucial disanalogy between Twin Earth and Inverted Earth undermines qualia‐internalism. A recent transplant to Inverted Earth has been equipped with color‐inverting contact lenses, so that she is unable to see the colors of objects whereas a recent transplant to Twin Earth can see twater. It is implausible to think that time alone could rectify this perceptual shortcoming – that the passage of time could alter the contents of her visual perceptions or the meaning (...) of her color terms. Thus, the thought experiment does not refute the close tie between phenomenology and representation in the case of color. (shrink)

A crucial disanalogy between Twin Earth and Inverted Earth undermines qualia‐internalism. A recent transplant to Inverted Earth has been equipped with color‐inverting contact lenses, so that she is unable to see the colors of objects whereas a recent transplant to Twin Earth can see twater. It is implausible to think that time alone could rectify this perceptual shortcoming – that the passage of time could alter the contents of her visual perceptions or the meaning (...) of her color terms. Thus, the thought experiment does not refute the close tie between phenomenology and representation in the case of color. (shrink)

What is it to be a woman? What is it to be a man? We start by laying out desiderata for an analysis of 'woman' and 'man': descriptively, it should link these gender categories to sex biology without reducing them to sex biology, and politically, it should help us explain and combat traditional sexism while also allowing us to make sense of the activist view that gendering should be consensual. Using a Putnam-style 'Twin Earth' example, we argue that (...) none of the existing analyses in the feminist literature succeeds in meeting all of our desiderata. Finally, we propose a positive account that we believe can satisfy all the desiderata outlined. According to our theory, the genders 'woman' and 'man' are individuated not by their contemporary connections to sex biology, but by their historical continuity with classes that were originally closely connected to sex biology. (shrink)

Terence Horgan and Mark Timmons? Moral Twin Earth thought experiment shows that realist ethical naturalism entails a kind of conceptual relativism about moral predicates. This conceptual relativism implies, further, that Earthlings and Twin Earthlings do not express substantive disagreement with one another. Because this latter implication clashes with considered linguistic intuitions, Horgan and Timmons conclude that we should reject realist ethical naturalism. Against this, several critics recommend that realists ?bite the bullet? with respect to Moral Twin (...) Earth: despite our intuitions, we should accept that the speakers do not disagree. These critics argue that the intuitions elicited by the thought experiment are either the result of a failure on the part of readers to appreciate hidden details of the Moral Twin Earth case, or else they are mere artifacts of readers? epistemic limitations. In this paper, I show that the Moral Twin Earth argument prevails against this line of attack. (shrink)

This paper is structured as follows. First, it offers a brief presentation of the Twin Earth thought experiment. Second, it offers an interpretation of Putnam'santi-realism. Third, it argues for the incompatibility of anti-realism and the semantic role of extension that Twin Earth is supposed to establish.

Terry Horgan and Mark Timmons have recently presented a series of papers in which they argue against what has come to be called the ‘new wave’ moral realism and moral semantics of David Brink, Richard Boyd, Peter Railton, and a number of other philosophers. The central idea behind Horgan and Timmons’s criticism of these ‘new wave’ theories has been extended by Sean Holland to include the sort of realism that drops out of response-dependent accounts that make use of an analogy (...) between moral properties and secondary qualities. This paper argues that Holland’s extension depends crucially on the fact that his target is a direct response-dependent account of moral value. His argument does not work against such accounts of more basic normative notions such as ‘harm’ or ‘benefit’. And these more basic notions may then serve as the basic normative building blocks for an indirectly response-dependent moral theory. (shrink)