The Inverted Spectrum

As Gert says, the basic claim of representationism is that the phenomenal character of an experience supervenes on its representational content. Restricted to color experience, representationism may be put as follows.

This chapter examines the spectrum inversion hypothesis as an argument against certain kinds of account of what it’s like to be conscious of color. The hypothesis aims to provide a counterexample to accounts of what it’s like to be conscious of color in non-qualitative terms, as well as to accounts of what it’s like to be conscious of color in terms of the representational content of conscious visual states (which, according to some philosophers, is in turn given an account in (...) non-qualitative terms). I explain the hypothesis’s reasoning in sections 1 and 2. I then take up background issues: since the counterexample provided by the hypothesis is typically given as a possibility rather than an actuality, I briefly discuss the kind of possibility involved in section 3, and the methodologies used to evaluate the plausibility of possibilities in section 4. In section 5, I describe some general considerations that are commonly used against the spectrum inversion hypothesis. I take up attempts to support the hypothesis with findings from color science in section 6. I end with comments skeptical of both the motivation for the spectrum inversion hypothesis and the methodology used to support it. (shrink)

The study of color expanded rapidly in the 20th century. With this expansion came fragmentation, as philosophers, physicists, physiologists, psychologists, and others explored the subject in vastly different ways. There are at least two ways in which the study of color became contentious. The first was with regard to the definitional question: what is color? The second was with the location question: are colors inside the head or out in the world? In this chapter, we summarize the most prominent answers (...) that color scientists and philosophers gave to the definitional and location questions in the 20th century. We identify some of the different points at which their work intersected, as well as the most prominent schisms between them. One overarching theme of the chapter is the surprising proliferation of different views on color. Whereas some assume that progress in science must take the form of convergence, the 20th century history of color exhibited a marked divergence in views. This chapter leaves it an open question whether an ultimate unification of views is possible, or whether the only thing that ties together the study of “color” is the shared inheritance of a word. (shrink)

We all have different “tastes” for different tastes: some of us have a sweet tooth, while others prefer more subtle flavors; some crave spicy foods, while others cannot stand them. As Bourdieu and others have pointed out, these varying judgments seem to be more than mere preferences; often they reflect (and partially constitute) differences of class and culture. But I want to suggest that we’ve possibly overlooked another important source of these divergent gastronomic evaluations, other than hierarchy and caste: mere (...) interpersonal variability with respect to brute gustatory sensations. After all, we all know about “supertasters and cilantro-haters”; how likely is it, though, that the interpersonal heterogeneity of gustatory sensation is limited to this one dimension? In this paper, I make the case that we should take this possibility more seriously, and offer some thoughts on how we might start getting a better handle on the nature and scope of interpersonal gustatory variability—including by suggesting some diagnostics that can help us get at (what I call) some of the “non-flavor dimensions” of our gustatory experience. I conclude by developing some implications for the prospects of an “alimentary aesthetics”: namely, that—should our gustatory experiences turn out to be quite heterogeneous—then they do not seem well-suited to serve as the basic ingredients of bona fide aesthetic judgment about food and drink. (shrink)

The objective of this paper is to defend the non-reductive thesis of phenomenal consciousness. This paper will give an overview of the arguments for the non-reductive explanation of phenomenal consciousness and justify why the reductionist approach is implausible in the context of explaining phenomenal subjective experience. The debate between reductionist and non-reductionist on the project of demystifying and mystifying phenomenal consciousness is driven by two fundamental assumptions-1) Reductive-Naturalistic Objectivism, 2) Phenomenal Realism. There are several arguments for the irreducibility of phenomenal (...) consciousness; this paper will focus on the inverted spectrum argument, knowledge argument, and the conceivability argument. (shrink)

This paper revisits some classic thought experiments in which experiences are detached from their characteristic causal roles, and explores what these thought experiments tell us about qualia epiphenomenalism, i.e., the view that qualia are epiphenomenal properties. It argues that qualia epiphenomenalism is true just in case it is possible for experiences of the same type to have entirely different causal powers. This is done with the help of new conceptual tools regarding the concept of an epiphenomenal property. One conclusion is (...) that it is not obvious if qualia epiphenomenalism is false; and it is also not obvious what should make us believe that it is false—or for that matter, true. Connections between qualia epiphenomenalism, physicalism, and non-physicalist property dualism are further explored. (shrink)

Proponents of the hard problem of consciousness argue that the zombie and inverted spectrum thought experiments demonstrate that consciousness cannot be physical. They present scenarios designed to demonstrate that it is conceivable that a physical replica of someone can have radically different or no conscious experiences, that such an experience-less replica is possible and therefore that materialism is false. I will argue that once one understands the limitations that the physics of this world puts on cognitive systems, zombies and the (...) inverted spectrum are not conceivable. (shrink)

By considering another version of the Inverted Earth thought experiment in which the protagonist is informed that she is implanted with inverting lenses behind her eyes, I argue that the thought experiment doesn’t successfully pose a challenge to representationalism because after many years, the protagonist’s visual experience of the sky of Inverted Earth would simply represent it as blue.

The sensorimotor theory of perception and consciousness is frequently presented as a variety of anti-representationalist cognitive science, and there is thus a temptation to suppose that those who take representation as bedrock should reject the approach. This paper argues that the sensorimotor approach is compatible with representationalism, and moreover that representationalism about phenomenal qualities, such as that advocated by Tye, would be more complete and less vulnerable to criticism if it incorporated the sensorimotor account of conscious feel. The paper concludes (...) by arguing that the project of naturalizing phenomenal qualities would nonetheless be better served by abandoning ‘representation’ talk altogether, a move that would require only a small modification of existing representationalist accounts. (shrink)

Physicalism is incompatible with what is known as the possibility of zombies, that is, the possibility of a world physically like ours, but in which there are no conscious experiences. But it is compatible with what is known as the possibility of ghosts, that is, the possibility of a world which is physically like ours, but in which there are additional nonphysical entities. In this paper we argue that a revision to the traditional definition of physicalism designed to accommodate the (...) possibility of ghosts inadvertently accommodates what is known as the possibility of inverted spectra, that is, the possibility of a world which is physically like ours, but in which colour experience is inverted. This consequence is unwelcome, because it is widely agreed that the possibility of inverted spectra is incompatible with physicalism. We argue for a revised definition of physicalism which resolves this problem. We then use our definition to argue that physicalism is not compatible with what is known as the possibility of blockers, that is, the possibility of a world which is physically like ours, but in which additional nonphysical entities have prevented the existence of conscious experience. This undermines Stephan Leuenberger's attempt to defend physicalism from arguments which purport to establish the possibility of zombies. (shrink)

This is terribly hard, Thouless, I'm sorry. I have thought over all this for years. … It is now as if we had ploughed furrows in different parts of a field. There is a lot left to do. Judging from their writings, most contemporary analytic philosophers have not been persuaded that “the inverted spectrum problem” is – as Wittgenstein maintained – really a conceptual puzzle calling for dissolution, rather than a straight problem calling for a solution. In this paper, I (...) present Wittgenstein's view as clearly and persuasively as I can, contrasting it with the views of Sidney Shoemaker and Ned Block, two of his more prominent critics. I conclude with a look at Frank Jackson's well-known Knowledge Argument, which, if successful, would demonstrate the futility of looking for a physicalist solution to the inverted spectrum and related philosophical problems. My goal is to combat what I take to be the common and unfortunate failure – among both physicalistically inclined philosophers, including Shoemaker and Block, and anti-physicalists, such as Jackson – to appreciate the force of Wittgenstein's arguments. (shrink)

Following the well known inverted spectrum argument by John Locke we examine the necessity of the first person experience in creating scientific knowledge, in particular, in physics. It is found that Locke’s argument is irrelevant for creating objective knowledge as the necessary things we need to do physics are: ability to perform measurements in terms of comparing certain quantities, ability to create theoretical ideas (in dependence inter alia on cultural principles, changing in the course of history), and the brain structure (...) enabling the former two. (shrink)

In this paper we advocate the thesis that qualia are tropes (or qualitons), and not (universal) properties. The main advantage of the thesis is that we can accept both the Wittgensteinian and Sellarsian assault on the given and the claim that only subjective and private states can do justice to the qualitative character of experience. We hint that if we take qualia to be tropes, we dissolve the problem of inverted qualia. We develop an account of sensory concept acquisition that (...) takes the presence of qualia as an enabling condition for learning. We argue that qualia taken to be qualitons are part of our mechanism of sensory concept acquisition. (shrink)

Michael Tye’s considered position on visual experience combines representationalism with externalism about color, so when considering spectrum inversion, he needs a principled reason to claim that a person with inverted color vision is seeing things incorrectly. Tye’s responses to the problem of the inverted spectrum ( 2000 , in: Consciousness, color, and content, The MIT Press, Cambridge, MA and 2002a , in: Chalmers (ed.) Philosophy of mind: classical and contemporary readings, Oxford University Press, Oxford) rely on a teleological approach to (...) the evolution of vision to secure the grounds upon which people with normal color vision can be justly called ‘right’ and those with inverted color vision can be called ‘wrong’. I demonstrate that since the inverted spectrum thought experiment requires that both sorts of vision be behaviorally indistinguishable, no biologically acceptable concept of teleology will allow Tye to draw the distinction he needs. (shrink)

Even if spectrum inversion of various sorts is possible, spectrum inversion without a difference in representation is not. So spectrum inversion does not pose a challenge for the intentionalist thesis that, necessarily, within a given sense modality, if two experiences are alike with respect to content, they are also alike with respect to their phenomenal character. On the contrary, reflection on variants of standard cases of spectrum inversion provides a strong argument for intentionalism. Depending on one’s views about the possibility (...) of spectrum inversion, the impossibility of spectrum inversion without a difference in representation can also be used as an argument against a variety of reductive theories of mental representation. (shrink)

What, according to Locke, are ideas? I argue that Locke does not give an account of the nature of ideas. In the Essay, the question is simply set to one side, as recommended by the “Historical, plain Method” that Locke employs. This is exemplified by his characterization of ‘ideas’ in E I.i.8, and the discussion of the inverted spectrum hypothesis in E II.xxxii. In this respect, Locke's attitude towards the nature of ideas in the Essay is reminiscent of Boyle's diffident (...) attitude towards the nature of matter. In posthumously published work, however, Locke suggests that the enquiry into the nature of ideas is one of the things that the enquiry into the extent of human knowledge undertaken in the Essay actually shows to lie beyond the “compass of human understanding”. In this respect, Locke's attitude towards the nature of ideas is reminiscent of Sydenham's attitude towards the nature of diseases. (shrink)

Intentionalism debates seek to uncover the relationship between the qualitative aspects of experience—phenomenal character—and the intentionality of the mind. They have been at or near center stage in the philosophy of mind for more than two decades, and in my view need to be reexamined. There are two core distinct intentionalism debates that are rarely distinguished (Sect. 1). Additionally, the characterization of spectrum inversion as involving inverted qualities and constant intentional content is mistaken (Sect. 3). These confusions can be witnessed (...) from an often-ignored and lonely perspective, that of the sense-datum theorist, and in particular of the projectivist (Sect. 2). In my view we have been so wary of sense-datum theory in recent years that we have failed to see that, even if false, it may permit perspectives on intentionalism issues difficult to occupy from other views. (shrink)

The doctrine of physicalism can be roughly spelled out simply as the claim that the physical state of the world determines the total state of the world. However, since there are many forms of determination, a somewhat more precise characterization is needed. One obvious problem with the simple formulation is that the traditional doctrine of epiphenomenalism holds that the mental is determined by the physical (and epiphenomenalists need not assert that there are any properties except mental and physical ones, so (...) one can freely add to epiphenomenalism the claim that everything is determined by the physical state of the world). However, the orthodox view, which seems obviously correct, is that physicalists would and should balk at the claim that epiphenomenalism is a form of physicalism. The philosophical zombie thought experiment vividly reveals exactly why epiphenomenalism is not a version of physicalism. According to traditional epiphenomenalism the determination relation in question is causation, and causal relations do not hold with full necessity. They hold with at most nomological necessity. Thus there is a possible world, w, in which the causal laws (or, if one prefers a more Humean approach, where the cosmic regularities) are different in such a way that the physical states which in the actual world cause mental states either cause no mental states at all in w (the zombie option) or cause aberrant mental states (the inverted spectrum option). Why should the physicalist care about this ‘mere possibility’? Because it shows that the mental can vary independently of the physical and there can be no better demonstration of ontological distinctness 1 than independent variation. Therefore, physicalism requires that the sort of determination at issue must exhibit maximum modal force; it must be absolutely impossible for the mental to vary without attendant, determining physical variation (let us label this relation ‘logical determination’). I think the best way to state physicalism which meets this constraint is in terms of what are called minimal physical duplicates (MPDs) of possible worlds (an approach pioneered by David Lewis, see Lewis (1983b); see also Jackson (1998) and Chalmers and Jackson (2001)).. (shrink)

The claim that behaviourally undetectable inverted spectra are possible has been endorsed by many physicalists. I explain why this starting point rules out standard forms of scientific explanation for qualia. The modern ‘phenomenal concept strategy’ is an updated way of defending problematic intuitions like these, but I show that it cannot help to recover standard scientific explanation. I argue that Chalmers is right: we should accept the falsity of physicalism if we accept this problematic starting point. I further argue that (...) accepting this starting point amounts to at least implicitly endorsing certain theoretical claims about the nature of introspection. I therefore suggest that we allow ourselves to be guided, in our quest to understand qualia, by whatever independently plausible theories of introspection we have. I propose that we adopt a more moderate definition of qualia, as those introspectible properties which cannot be fully specified simply by specifying the non-controversially introspectible ‘propositional attitude’ mental states (including seeing x, experiencing x, and so on, where x is a specification of a potentially public state of affairs). Qualia thus defined may well fit plausible, naturalisable accounts of introspection. If so, such accounts have the potential to explain, rather than explain away, the problematic intuitions discussed earlier; an approach that should allow integration of our understanding of qualia with the rest of science. (shrink)

In ‘Wittgenstein and Qualia’ Ned Block argues for the existence of inverted spectra and those ineffable things, qualia. The essence of his discussion is a would-be proof, presented through a series of pictures, of the possible existence of an inverted spectrum. His argument appeals to some remarks by Wittgenstein which, Block holds, commit the former to a certain ‘dangerous scenario’ wherein inverted spectra, and consequently qualia live and breath. I hold that a key premise of this proof is incoherent. Furthermore, (...) Block’s dangerous scenario does not follow from Wittgenstein’s innocent one, as Block believes it does, but rather is in conflict with it. (shrink)

In this paper, I shall evaluate a strategy recently used to try to demonstrate the impossibility of behaviorally undetectable spectrum inversion. After showing that the impossibility proof proves too much, I shall identify where it goes wrong. In turn, I shall explain why someone attracted to functionalist and representationalist assumptions might rightly remain agnostic about the possibility of inversion.

It is possible for a person and their environment to be physically identical each day and yet the representational content of their beliefs about color are inverted. Each day they utter the same words, ‘Wow! The colors of everything have switched again today.’ In uttering these words, they express a different proposition each day. This supports the view held by Reichenbach and Carnap that when it comes to representations of colored objects, relations of similarity and difference are fundamental. There are (...) no such things as colors like ‘redness’ and ‘greenness’ apart from the particular things we call red and green. (shrink)

Inverted spectrum and absent-qualia arguments have at least shown that giving the functional role of a qualitative state is challenging, as it is arguable that the same functional organization among one's inputs, outputs, and mental states can be preserved despite having one's qualia radically altered or eliminated. Sydney Shoemaker has proposed a promising strategy for the functionalist: defining a given qualitative state as being disposed to cause a belief that one is in such a state. Such beliefs would be different (...) or not obtain should the qualitative state be altered or absent—showing that the qualitative state is in fact functionally relevant. I will argue that this approach, and a similar one by David Chalmers, face a difficulty in accounting for qualia at a fine grain, particularly those that do not readily fit our linguistic concepts and/or occur in peripheral awareness. I then show how the problem can be solved by incorporating certain conditional statements into functional definitions of qualia, and by relying on two theoretical resources I will discuss: qualitative beliefs with nonlinguistic content and QSMs (qualia-structuring mental phenomena). (shrink)

The principle of functional invariance states that it is a natural law that conscious beings with the same functional organization have the same quality of conscious experience. A group of arguments in support of this principle are rejected, on the grounds that they establish at most only the weaker intra-subjective principle that any two stages in the life of a single conscious being that duplicate one another in terms of functional organization also duplicate one another in terms of quality of (...) phenomenal experience. (shrink)

Most philosophers who have endorsed the idea that there is such a thing as phenomenal content—content that supervenes on phenomenal character—have also endorsed what I call Standard Russellianism. According to Standard Russellianism, phenomenal content is Russellian in nature, and the properties represented by perceptual experiences are mind-independent physical properties. In agreement with Sydney Shoemaker [Shoemaker, S. (1994). Philosophy and Phenomenological Research, 54 249–314], I argue that Standard Russellianism is incompatible with the possibility of spectrum inversion without illusion. One defense of (...) (...) Standard Russellianism is to hold that spectrum inversion without illusion is conceivable but not in fact possible. I argue that this response fails. As a consequence, either phenomenal content is not Russellian, or experiences do not represent mind-independent physical properties. (shrink)

Intentionalism holds that two experiences differ in their representational content if and only if they differ in phenomenal character. It is generally held that Intentionalism cannot allow for the possibility of spectrum inversion without systematic error, unless it abandons the idea that, for example, the qualitative character of color experience is inherited from the qualitative character of colors. The paper argues that the conjunction of all three -- the possibility of spectrum inversion, Intentionalism, and the inheritance thesis -- can be (...) consistently, and plausibly, accepted. (shrink)

Philosophical and scientific defenses of Indirect Realism and counterarguments to the attacks of qualiaphobes.

endorsed one kind of inverted spectrum hypothesis and rejected another. This paper argues that the kind of inverted spectrum hypothesis that Wittgenstein endorsed is the thin end of the wedge that precludes a Wittgensteinian critique of the kind of inverted spectrum hypothesis he rejected. The danger of the dangerous kind is that it provides an argument for qualia, where qualia are contents of experiential states which cannot be fully captured in natural language. I will pinpoint the difference between the innocuous (...) and dangerous scenarios that matters for the argument for qualia, give arguments in favor of the coherence and possibility of the dangerous scenario, and try to show that some standard arguments against inverted spectra are ineffective against the version of the dangerous scenario I will be advocating. The leading idea of the paper is that an argument for qualia based on spectrum inversion does not require that the inversion be behaviorally indistinguishable. At one crucial point, I will rely on a less controversial version of an argument I gave in Block. Wittgenstein's views provide a convenient starting point for a paper that is much more about qualia than about Wittgenstein. (shrink)

To the familiar idea of an undetectable spectrum inversion some have added the idea of inverted earth. This new combination of ideas is even harder to make coherent, particularly as it applies to a supposed inversion of black and white counteracted by an environmental switch of these. Black and white exhibit asymmetries in their connections with illumination, shadow and visibility, which rule out their being reversed. And since the most saturated yellow is light and the most saturated blue dark, yellow (...) and blue could not be reversed unless light and dark could be. The difficulties suggest some more general morals for how to think of the role of 'qualia' in colour perception. (shrink)

Funkcinës psichiniø savybiø analizës atveriama jø materialiojo ákûnijimo ávairovës galimybë verèia materialistiná monizmà sàmonës filosofijoje formuluoti ne psichiniø ir fiziniø savybiø tapatumo, bet pirmøjø pareities nuo antrøjø tezæ. Pareities sàvoka sàmonës filosofijoje iðreiðkia minimalius reikalavimus fizikalistinëms teorijoms – paneigus pareities fizikalizmà bûtø paneigtos ir stipresnës fizikalizmoversijos. Straipsnyje tyrinëjama fizikalizmo kritika paremta vadinamuoju kokybiø perkeitimo galimybës argumentu. Parodoma, kad, viena vertus, toks argumentas negali bûti atremtas nuorodomis áempirinius duomenis, nes svarstoma hipotetinë situacija numano jos empiriná nestebimumà; kita vertus, jei svarstoma situacija (...) ið tikrøjø yra galima, tai kokybinës psichinës charakteristikos niekaip nërasusaistytos funkciðkai ar fiziologiðkai apraðomais ryðiais, vadinasi, antireduktyvistinæ iðvadà galima grástisvarstant ne tik atvejus, kai kokybës perkeistos, bet ir kai jø apskritai nëra.Pagrindiniai þodþiai: sàmonës filosofija, fizikalizmas, funkcionalizmas, pareitis, perkeistos kokybës. (shrink)

Can the physicalist consistently hold that representational content is all there is to sensory experience and yet that two perceivers could have inverted phenomenal spectra? Yes, if he holds that the phenomenal properties the inverts experience are dummy properties, not instantiated in the physical objects being perceived nor in the perceivers.

Philosophers have devoted a great deal of discussion to the question of whether an inverted spectrum thought experiment refutes functionalism. (For a review of the inverted spectrum and its many philosophical applications, see Byrne, 2004.) If Ho?man is correct the matter can be swiftly and conclusively settled, without appeal to any empirical data about color vision (or anything else). Assuming only that color experiences and functional relations can be mathematically represented, a simple mathematical result.

Qualia internalism is the thesis that qualia are intrinsic to their subjects: the experiences of intrinsic duplicates have the same qualia. Content externalism is the thesis that mental representation is an extrinsic matter, partly depending on what happens outside the head. 1 Intentionalism comes in strong and weak forms. In its weakest formulation, it is the thesis that representationally identical experiences of subjects have the same qualia. 2.

The possibility of spectrum inversion has been debated since it was raised by Locke and is still discussed because of its implications for functionalist theories of conscious experience . This paper provides a mathematical formulation of the question of spectrum inversion and proves that such inversions, and indeed bijective scramblings of color in general, are logically possible. Symmetries in the structure of color space are, for purposes of the proof, irrelevant. The proof entails that conscious experiences are not identical with (...) functional relations. It leaves open the empirical possibility that functional relations might, at least in part, be causally responsible for generating conscious experiences. Functionalists can propose causal accounts that meet the normal standards for scientific theories, including numerical precision and novel prediction; they cannot, however, claim that, because functional relationships and conscious experiences are identical, any attempt to construct such causal theories entails a category error. (shrink)

There has been much written in recent years about whether a pair of subjects could have visual experiences that represented the colors of objects in their environment in precisely the same way, despite differing significantly in what it was like to undergo them, differing that is, in their qualitative character. The possibility of spectrum inversion has been so much debated1 in large part because of the threat that it would pose to the more general doctrine of Intentionalism, according to which (...) the representational content of an experience fixes what it. (shrink)

In November 2003, the University of Fribourg hosted a symposium on the ontology of colors. The invited participants included Justin Broackes, Alex Byrne, David Chalmers, Larry Hardin, Joe Levine and Barry Maund. The points of view presented by the participants in their thought-provoking papers were highly divergent. The presentation of each paper was followed by a long and intense discussion. Despite the divergence of the views proposed, the discussion during the symposium was highly focused. Several specific issues came up repeatedly (...) in the debate and illuminated the puzzle about the nature of colors in a thought provoking way from different angles. We include these papers in our brief description in the present introduction to present to the reader all the different viewpoints that have nourished the debate throughout the symposium. We are glad to be able to include one further invited paper by Jonathan Cohen in the present volume. In an attempt to transfer some of the atmosphere of the meeting to the reader and in order to make this collection still more stimulating we invited each participant to contribute comments on the other papers. (shrink)

Sydney Shoemaker offers an account of color perception that attempts to do justice, within a functionalist framework, to the commonsense view that colors are properties of ordinary objects, to the existence of qualia, and to the possibility of spectrum inversions. Shoemaker posits phenomenal properties as dispositional properties of colored objects that explain how there can be intersubjective variation in the experience of a particular color. I argue that his account does not in fact allow for the description of a spectrum (...) inversion scenario, and that it cannot sustain a functionalist relationship between an object's color and its phenomenal properties. Functionalists must, however, come to terms with Shoemaker's recognition that intersubjective spectrum shifts are possible. (shrink)

Chalmers has argued for a form of property dualism on the basis of the concept of a zombie , and the concept of the inverted spectrum. He asserts that these concepts show that the facts about consciousness, such as experience or qualia, are really further facts about our world, over and above the physical facts. He claims that they are the hard part of the mind-body issue. He also claims that consciousness is a fundamental feature of the world like mass, (...) charge, etc. He says that consciousness does not logically supervene on the physical and all current attempts to assert an identity between consciousness and the physical are just as non-reductive as his dualism. They are simply correlations and are part of the problem of the explanatory gap. In this paper, three examples of strong identities between a sensation or a quale and a physiological process are presented, which overcome these problems. They explain the identity in an a priori manner and they show that consciousness or sensations logically supervene on the physical , in that it is logically impossible to have P and not to have Q. In each case, the sensation was predicted and entailed by the physical. The inverted spectrum problem for consciousness is overcome and explained by a striking asymmetry in colour space. It is concluded that as some physical properties realize some sensations or qualia that human zombies are not metaphysically possible and the explanatory gap is bridged in these cases. Thus, the hard problem is overcome in these instances. (shrink)

In this paper I examine whether representationalism can account for various thought experiments about colour inversions. Representationalism is, at minimum, the view that, necessarily, if two experiences have the same representational content then they have the same phenomenal character. I argue that representationalism ought to be rejected if one holds externalist views about experiential content and one holds traditional exter- nalist views about the nature of the content of propositional attitudes. Thus, colour inver- sion scenarios are more damaging to externalist (...) representationalist views than have been previously thought. More specifically, I argue that representationalists who endorse externalism about experiential content either have to become internalists about the content of propositional attitudes or they have to adopt a novel variety of externalism about the content of propositional attitudes. This novel type of propositional attitude externalism is investigated. It can be seen that adopting it forces one to reject Putnam. (shrink)