Abstract: The knowledge argument aims to refute physicalism, the view that the world is entirely physical. The argument first establishes the existence of facts (or truths or information) about consciousness that are not a priori deducible from the complete physical truth, and then infers the falsity of physicalism from this lack of deducibility. Frank Jackson (1982, 1986) gave the argument its classic formulation. But now he rejects the argument (Jackson 1998b, 2003, chapter 3 of this volume). On his view, it relies on a false conception of sensory experience, which should be replaced with representationalism (also known as intentionalism), the view that phenomenal states are just representational states. And he argues that mental representation is physically explicable

Abstract: David Lewis (1983, 1988) and Laurence Nemirow (1980, 1990) claim that knowing what an experience is like is knowing-how, not knowing-that. They identify this know-how with the abilities to remember, imagine, and recognize experiences, and Lewis labels their view ‘the Ability Hypothesis’. The Ability Hypothesis has intrinsic interest. But Lewis and Nemirow devised it specifically to block certain anti-physicalist arguments due to Thomas Nagel (1974, 1986) and Frank Jackson (1982, 1986). Does it?

Abstract: What is the nature of consciousness? How is consciousness related to brain processes? This volume collects thirteen new papers on these topics: twelve by leading and respected philosophers and one by a leading color-vision scientist. All focus on consciousness in the "phenomenal" sense: on what it's like to have an experience. Consciousness has long been regarded as the biggest stumbling block for physicalism, the view that the mind is physical. The controversy has gained focus over the last few decades, and phenomenal knowledge and phenomenal concepts--knowledge of consciousness and the associated concepts--have come to play increasingly prominent roles in this debate. Consider Frank Jackson's famous case of Mary, the super-scientist who learns all the physical information while confined in a black-and-white room. According to Jackson, if physicalism is true, then Mary's physical knowledge should allow her to deduce what it's like to see in color. Yet it seems intuitively clear that she learns something when she leaves the room. But then how can consciousness be physical? Arguably, whether this sort of reasoning is sound depends on how phenomenal concepts and phenomenal knowledge are construed. For example, some argue that the Mary case reveals something about phenomenal concepts but has no implications for the nature of consciousness itself. Are responses along these lines adequate? Or does the problem arise again at the level of phenomenal concepts? The papers in this volume engage with the latest developments in this debate. The authors' perspectives range widely. For example, Daniel Dennett argues that anti-physicalist arguments such as the knowledge argument are simply confused; David Papineau grants that such arguments at least reveal important features of phenomenal concepts; and David Chalmers defends the anti-physicalist arguments, arguing that the "phenomenal concept strategy" cannot succeed

Abstract: Phenomenal knowledge usually comes from experience. But it
need not. For example, one could know what it’s like to see red without
seeing red—indeed, without having any color experiences. Daniel Dennett
(2007) and Pete Mandik (forthcoming) argue that this and related
considerations undermine the knowledge argument against physicalism.
If they are right, then this is not only a problem for anti‐physicalists. Their
argument threatens to undermine any version of phenomenal realism—
the view that there are phenomenal properties, or qualia, that are not
conceptually reducible to physical or functional properties. I will argue
that this threat is illusory. Explaining why will clarify what is and is not at issue in discussions of the knowledge argument and phenomenal realism. This will strengthen the case for physically and functionally irreducible qualia.

Abstract: Frank Jackson first presented the Knowledge Argument (henceforth KA) in "Epiphenomenal Qualia" 1982). The KA is an argument against physicalism, the doctrine that (very roughly put) everything is physical. The general thrust of the KA is that physicalism errs by misconstruing or denying the existence of the subjective features of experience. Physicalists have given numerous responses, and the debate continues about whether the KA ultimately succeeds in refuting any or all forms of physicalism. Jackson himself has recently

Abstract: The knowledge argument aims to refute physicalism, the doctrine that the world is entirely physical. Physicalism (also known as materialism) is widely accepted in contemporary philosophy. But some doubt that phenomenal consciousness

Abstract: One of the most persuasive objections to the identity thesis

Abstract: The book under review is a collection of thirteen essays on the nature phenomenal concepts and the ways in which phenomenal concepts figure in debates over physicalism. Phenomenal concepts are of special interest in a number of ways. First, they refer to phenomenal experiences, and the qualitative character of those experiences (aka “qualia”) whose metaphysical status is hotly debated. There are recent arguments, originating in Descartes’ famous conceivability argument, that purport to show that phenomenal experience is irreducibly non-physical. Second, phenomenal concepts are widely thought to be special and unique among concepts. Both the anti-physicalist arguments and physicalist replies to these arguments turn on views about the nature of phenomenal concepts. In this review I survey the many ways in which the essays in this volume are engaged (pro or con) with anti-physicalist arguments and the role phenomenal concepts play in these arguments.

Abstract: The explicit aim of Daniel Dennett’s new paper ‘What RoboMary Knows’ is to show that Mary (the hypothetical colour-blind neuroscientist) will necessarily be able to come to know what it is like to see in colour, if she fully understands all the physical facts about colour vision. I believe we can establish that Dennett’s line of reasoning is flawed, but the flaw is not as simple as an equivocation on ‘knows’. Rather, it goes to the heart of functionalism and hinges on whether or not Dennett is correct to claim that there is ‘no fact of the matter’ about what subjective experience consists in.

Abstract: Frank Jackson argued, in an astronomically frequently cited paper on 'Epiphenomenal qualia'[Jackson 1982 that materialism must be mistaken. His argument is called the knowledge argument. Over the years since he published that paper, he gradually came to the conviction that the conclusion of the knowledge argument must be mistaken. Yet he long remained totally unconvinced by any of the very numerous published attempts to explain where his knowledge argument had gone astray. Eventually, Jackson did publish a diagnosis of the reasons why, he now thinks, his knowledge argument against materialism fails to prove the falsity of materialism [Jackson 2005. He argues that you can block the knowledge argument against materialism - but only if you tie yourself to a dubious doctrine called representationalism. We argue that the knowledge argument fails as a refutation of either representational or nonrepresentational materialism. It does, however, furnish both materialists and dualists with a successful argument for the existence of distinctively first-person modes of acquaintance with mental states. Jackson's argument does not refute materialism: but it does bring to the surface significant features of thought and experience, which many dualists have sensed, and most materialists have missed

Abstract: Jackson's black-and-white Mary teaches us that the propositional content of perception cannot be fully expressed in language

Abstract: *[[This paper is largely based on material in other papers. The first three sections and the appendix are drawn with minor modifications from Chalmers 2002c (which explores issues about phenomenal concepts and beliefs in much more depth, mostly independently of questions about materialism). The main ideas of the last three sections are drawn from Chalmers 1996, 1999, and 2002a, although with considerable revision and elaboration. ]]

Abstract: According to the knowledge argument, physicalism fails because when physically omniscient Mary first sees red, her gain in phenomenal knowledge involves a gain in factual knowledge. Thus not all facts are physical facts. According to the ability hypothesis, the knowledge argument fails because Mary only acquires abilities to imagine, remember and recognise redness, and not new factual knowledge. I argue that reducing Mary’s new knowledge to abilities does not affect the issue of whether she also learns factually: I show that gaining specific new phenomenal knowledge is required for acquiring abilities of the relevant kind. Phenomenal knowledge being basic to abilities, and not vice versa, it is left an open question whether someone who acquires such abilities also learns something factual. The answer depends on whether the new phenomenal knowledge involved is factual. But this is the same question we wanted to settle when first considering the knowledge argument. The ability hypothesis, therefore, has offered us no dialectical progress with the knowledge argument, and is best forgotten.

Abstract: An important theme running through D.H. Mellor’s work is his realism, or as I shall call it, his objectivism: the idea that reality as such is how it is, regardless of the way we represent it, and that philosophical error often arises from confusing aspects of our subjective representation of the world with aspects of the world itself. Thus central to Mellor’s work on time has been the claim that the temporal A-series (previously called ‘tense’) is unreal while the B-series (the series of ‘dates’) is real. The A-series is something which is a product of our representation of the world, but not a feature of reality itself. And in other, less central, areas of his work, this kind of theme has been repeated: ‘Objective decision making’ (1980) argues that the right way to understand decision theory is as a theory of what is the objectively correct decision, the one that will actually as a matter of fact achieve your intended goal, rather than the one that is justified purely in terms of what you believe, regardless of whether the belief is true or false. ‘I and now’ (1989) argues against a substantial subjective conception of the self, using analogies between subjective and objective ways of thinking about time and subjective and objective ways of thinking about the self. And in the paper which shall be the focus of my attention here, ‘Nothing like experience’ (1992), Mellor..

Abstract: The central attempt of this paper is to explain the underlying intuitions of Frank Jackson’s “Knowledge Argument” that the epistemic gap between phenomenal knowledge and physical knowledge points towards a corresponding ontological gap. The first step of my analysis is the claim that qualia are epistemically special because the acquisition of the phenomenal concept of a quale x requires the experience of x. Arguing what is so special about phenomenal concepts and pointing at the inherence-relation with the qualia they pick out, I give compelling reasons for the existence of ontologically distinct entities. Finally I conclude that phenomenal knowledge is caused by phenomenal properties and the instantiation of these properties is a specific phenomenal fact, which can not be mediated by any form of descriptive information. So it will be shown that phenomenal knowledge must count as the possession of very special information necessarily couched in subjective, phenomenal conceptions

Abstract: The definitive statement of the Knowledge Argument was formulated by Frank Jackson, in a paper entitled “Epiphenomenal Qualia” that appeared in The Philosophical Quarterly in 1982. Arguments in the same spirit had appeared earlier (Broad 1925, Robinson 1982), but Jackson’s argument is most often compared with Thomas Nagel’s argument in “What is it Like to be a Bat?” (1974). Jackson, however, takes pains to distinguish his argument from Nagel’s. This entry will follow standard practice in focusing on Jackson’s argument, though I will also describe the main points of alleged similarity and dissimilarity between these two arguments

Abstract: Frank Jackson has argued that, in principle, all mental truths are deducible from all physical science truths: 'deducibility'. Jackson's defence of deducibility relies upon the method for producing naturalistic definitions of mental states championed in the analytical functionalism of himself, David Lewis, and others. Two arguments are presented. The first contends that the particular naturalistic definitions of analytical functionalism fail because they do not take account of the extraordinary kind of bodily animation displayed by human beings, which I argue is necessary to (at least one kind of) mentality; machines lacking (at least this one kind of) mentality can satisfy the naturalistic definitions of analytical functionalism. So Jackson's defence of deducibility fails as it stands. The second argument contends that no naturalistic conceptual analysis of the mental can be adequate, because understanding (certain) mental concepts requires a special kind of affective reaction here named 'personal response', while understanding naturalistic concepts does not require this- therefore no naturalistic analysis can ever capture our common-sense mental concepts. The upshot is that Jackson's defence of deducibility cannot be repaired. No defence of deducibility will work which relies upon the possibility of naturalistic conceptual analyses of mentality

Abstract: I argue on linguistic grounds that when Mary comes to know what it's like to see a red thing, she comes to know a certain inexpressible truth about the character of her own experience. This affords a "no concept" reply to the knowledge argument. The reason the Knowledge Argument has proven so intractable may be that we believe that an inexpressible concept and an expressible concept cannot have the same referent.

Abstract: The subjectivity of the mental consists in the idea that there are features of our mental states that are perspectival in that they are accessible only from the first-person point of view. This is held to be a problem for materialist theories of mind, since such theories contend that there is nothing about the mind that cannot be fully described from a third-person (objective) point of view. Lycan suggests a notion of “phenomenal information” that is held to be perspectival in the relevant sense but also perfectly objective, since it is explicated in terms of the computational roles of higher-order mental representations. I argue that his project fails because phenomenal information is accessible to observers, and hence it fails to be perspectival in the required sense. That sense demands that there be aspects of our conscious experiences that cannot be intersubjectively compared

Abstract: I much appreciated Elizabeth Schier's paper on Frank Jackson's knowledge argument, published in the January 2008 issue of Journal of Consciousness Studies (Schier, 2008) -- in part, I confess, because of resonances with my gestalt argument for free will (Hodgson, 2001; 2002; 2005; 2007a,b). I would like to offer two comments on this paper

Abstract: Frank Jackson formulated his knowledge argument as an argument for dualism. In this paper I show how the argument can be modified to also establish the irreducibility of the secondary qualities to the properties of physical theory, and ultimately

Abstract: In this paper I argue that Frank Jackson

Abstract: In this paper I present a new argument against internalist theories of practical reason. My argument is inpired by Frank Jackson's celebrated Knowledge Argument. I ask what will happen when an agent experiences pain for the first time. Such an agent, I argue, will gain new normative knowledge that internalism cannot explain. This argument presents a similar difficulty for other subjectivist and constructivist theories of practical reason and value. I end by suggesting that some debates in meta-ethics and in the philosophy of mind might be more closely intertwined than philosophers in either area would like to believe

Abstract: This paper offers a new solution to the knowledge argument. Both a priori and a posteriori physicalists reject the claim that Mary does not know all the facts, but they do so for different reasons. While the former think that Mary gains no new knowledge of any fact, the latter think that Mary gains new knowledge of an old fact. This paper argues that on a broad understanding of what counts as physical, it is consistent with physicalism that Mary does not know all the physical facts, and that on a narrow understanding, it is consistent with physicalism that Mary knows all the physical facts, but not all the facts. Either way, Mary gains new knowledge of a new fact that is not non-physical. The resultant view

Abstract: The arguments presented in this comprehensive collection have important implications for the philosophy of mind and the study of consciousness.

Abstract: In two recent publications I argued against Nemirow and Lewis that there is distinctive, irreducibly phenomenal and perspectival information of the sort alleged by Jackson; but I gave an account of such information that is entirely compatible with a materialist view of human subjects. Hershfield argues that the latter account is inadequate, in that it fails to support the claim that the information it characterizes is irreducibly phenomenal or perspectival. I reply that Hershfield's conclusion does not follow from his argument's premises

Abstract: Someday there will be no more articles written about the

Abstract: Deviant phenomenal knowledge is knowing what it’s like to have experiences of, e.g., red without actually having had experiences of red. Such a knower is a deviant. Some physicalists have argued and some anti-physicalists have denied that the possibility of deviants undermines anti-physicalism and the Knowledge Argument. The current paper presents new arguments defending the deviant-based attacks on anti-physicalism. Central to my arguments are considerations concerning the psychosemantic underpinnings of deviant phenomenal knowledge. I argue that physicalists are in a superior position to account for the conditions in virtue of which states of deviants constitute representations of phenomenal facts

Abstract: The knowledge argument is an argument against physicalism that was first formulated by Frank Jackson in 1982. While Jackson no longer endorses it, it is still regarded as one of the most important arguments in the philosophy of mind. Physicalism is the metaphysical thesis that, roughly speaking, everything in this world—including tables, galaxies, cheese cakes, cars, atoms, and even our sensations— are ultimately physical. The knowledge argument attempts to undermine this thesis by appealing to the following simple imaginary scenario: Mary is confined to a black-and-white room, is educated through black-and-white books and through lectures relayed on black-and white television. In this way she learns everything there is to know about the physical nature of the world. She knows all the physical facts about us and our environment, in a wide sense of ‘physical’ which includes everything in completed physics, chemistry, and neurophysiology, and all there is to know about the causal and relational facts consequent upon all this, including of course functional roles. (Jackson 1986, p. 291) The knowledge argument says that if physicalism is true, Mary knows everything in this world. However, it seems obvious that her knowledge is not yet complete. Suppose that..

Abstract: Paul Churchland argues that Frank Jackson

Abstract: Frank Jackson endorses epiphenomenalism because he thinks that his knowledge argument undermines physicalism. One of the most interesting criticisms of Jackson’s position is what I call the ‘inconsistency objection’. The inconsistency objection says that Jackson’s position is untenable because epiphenomenalism undermines the knowledge argument. The inconsistency objection has been defended by various philosophers independently, including Michael Watkins, Fredrik Stjernberg, and Neil Campbell. Surprisingly enough, while Jackson himself admits explicitly that the inconsistency objection is ‘the most powerful reply to the knowledge argument’ he knows of, it has never been discussed critically. The aim of this paper is to evaluate the objection and to identify and consider its implications. The objection is alleged to be based on a causal theory of knowledge. I argue that the objection fails by showing that any causal theory of knowledge is such that it is either false or does not support the inconsistency objection. In order to defend my argument, I offer a hypothesis concerning phenomenal knowledge

Abstract: The Knowledge argument based on the grey Mary thought experiment cannot be claimed as a basis for rejecting physicalism. First, because it is flawed, being so formulated as to predetermine the outcome of the thought experiment in favour of a refutation of physicalism. Second, because, once this is recognised, it becomes clear that there is one - and only one - account of the qualia-physical relationship that will permit physicalism to survive the thought experiment itself. It is suggested that the position in question is worthy of further consideration as a reasonable candidate theory for a physicalist account of qualia

Abstract: The Knowledge Argument is misconstructed. Knowing that it is ‘just obvious’ that Mary will learn something new on leaving her black and white room, we nevertheless assume she can acquire a complete knowledge of the physical inside it – thereby predetermining the outcome of the thought experiment in favour of a refutation of physicalism. If we reformulate the argument to leave the question of what she can learn in the room open, it becomes clear, not only that physicalism can survive the Knowledge Argument, but also that there is only one perspective on the relationship between qualia and the physical that will permit it to do so. If physicalism is true, this perspective must be the correct view of the qualia-physical relationship – the solution to the mind-body problem, a conclusion supported by its ability to resolve a number of associated difficulties, including Kripke’s problem for proposed identities and Chalmers’ Hard Problem

Abstract: One diagnosis of what is wrong with the Knowledge Argument rests on the Ability Hypothesis. This couples an ability analysis of knowing what an experience is like together with a denial that phenomenal propositions exist. I argue against both components. I consider three arguments against the existence of phenomenal propositions and find them wanting. Nevertheless I deny that knowing phenomenal propositions is part of knowing what an experience is like. I provide a hybrid account of knowing what an experience is like which is the coherent expression of a single idea: knowing what an experience is like is knowing what it would be like to have the phenomenal content of the experience as the content of an experience one is currently having. I explain how my conclusions indicate that the focus of discussion should be on the alleged explanatory gap between phenomenal facts and physical facts and not on the Knowledge Argument. The latter is a poor expression of the difficulty Physicalists face

Abstract: This paper examines some consequences of the (quasi-)epiphenomenalism implied by a property dualistic view of phenomenal consciousness. The focus is upon the variation of phenomenal content over time. A thought-experiment is constructed to support two claims. The weaker claim exhibits an incompatibility which arises in certain logically possible situations between a conscious subject’s epistemic norms and the requirement that one be aware of one’s conscious experience. This could be interpreted as providing some epistemic grounds for the postulation of bridging laws between the physical/functional and phenomenal domains. The stronger claim has it that the ontology of property dualism is not properly able to account for the certainty I have of being phenomenally conscious. The problem is viewed as resulting from the neglect of the intensional context involved in a proper representation of the argument for property dualism. It is argued that only a transcendental move can do justice to this certainty I have.

Abstract: This paper develops a response to the knowledge argument against physicalism. The response is both austere, in that it does not concede the existence of non-physical information (much less non-physical facts), and natural, in that it acknowledges the alethic character of phenomenal knowledge and learning. I argue that such a response has all the advantages and none of the disadvantages of existing objections to the knowledge argument. Throughout, the goal is to develop a response that is polemically effective in addition to theoretically sound

Abstract: Someone who knew everything about the world’s physical nature could, apparently, suffer from ignorance about various aspects of conscious experience. Someone who knew everything about the world’s physical and mental nature could, apparently, suffer from moral ignorance. Does it follow that there are ways the world is, over and above the way it is physically or psychophysically? This paper defends a negative answer, based on a distinction between knowing the fact that p and knowing that p. This distinction is made intelligible by reference to criterial connections between the possession of moral or phenomenal knowledge, and the satisfaction of cognitively neutral conditions of desire and experiential history. The existence of such connections in the moral case makes for an efficient dissolution of the so-called moral problem

Abstract: In a now famous thought experiment, Frank jackson asked us t0 imagine an omniscient scientist, Mary, who is coniincd in a black-and-white room and then released into the world 0f color (jackson 1982; jackson 1986; cf. Braddon—Mitch<-:11 and Jackson 1996). Assuming that she is omniscicnt in respect of all physical facts—roughiy, all the facts available to physics and all the facts that they in turn Hx or determine-physicalism would suggest that there is no new fact Mary can discover after emancipation; physicalism holds that all facts are physical in the relevant sense (for a fuller statement scc Pettit 1993; jackson 1998). Yet we cannot help but feel that coming out of that room would be an occasion of dramatic enlightenment and, in particular, an occasion for learning facts to do with how red or yellow or blue 100ks or, as it is usually said, with what it is like t0 sec red or yellow or blue. Many in the black-and—whit<—: room knew all the physical facts about the world, where these may be taken to include three sorts of color facts: objcctual facts, as to what surface colors different objects have, assuming as I shall do throughout—that colors are properties of objects; intentional facts, as to which colors different objects 0r apparent objects are represented as having in the subjc-:ct’s experience, rightly or wrongly; and nonintentional facts, about what such color experiences are like in their effects on subiccts—wh<—:ther they are comforting, or arousing, or whatever. But, according to the argument, Mary didn’t know how any color looks or, equivalently, what color experience is like in itself, not just in its effects O1'1 subjects. This particular nonintentional fact about the quality of color c-zxpc-2ri<—:ncc-—this phenomenal fact, as it is often describcd—she did not..

Abstract: I defend Frank Jackson's knowledge argument against physicalism in the philosophy of mind from a criticism that has been advanced by Laurence Nemirow and David Lewis. According to their criticism, what Mary lacked when she was in her black and white room was a set of abilities; she did not know how to recognize or imagine certain types of experience from a first-person perspective. Her subsequent discovery of what it is like to experience redness amounts to no more than her acquisition of these abilities. The physicalist can admit this, since it does not commit one to the view that there are any facts of which Mary was ignorant (in spite of her exhaustive knowledge of truths about the physical world). I argue against this view, on the grounds that the knowledge of what an experience is like cannot be equated with the possession of any set of abilities

Abstract: Recently a number of authors have responded to the knowl-edge argument by suggesting that Mary could learn about new physi-cal facts upon release (Flanagan, 1992; Mandik, 2001; Stoljar, 2001; Van Gulick, 1985). A key step in achieving this is a demonstration that there are facts that can be known via colour experience that cannot be learnt scientifically. In this paper I develop an account of scientific and visual knowledge on which there is a difference between the knowledge provided by science and that provided by vision

Abstract: Chalmers' hard problem confuses within and without-system information. This can be seen in his case of Mary. This neurophysiologist of colour vision raised in a black and white room in an age of a completed neuroscience in spite of her knowing everything about colour vision lacks colour experience. I demonstrate with a counter-example involving Milton, an economist in an age of completed economics, that Chalmers mixes up scientific accountability and accessibility of information processing. There is a profound conceptual difference between the external understanding of information processing in the brain and the internal understanding that participates in it -- as can be illustrated in Aristotles' illusion

Abstract: Mary is confined to a black-and-white room, is educated through black-and-white books and through lectures relayed on black-and white television. In this way she learns everything there is to know about the physical nature of the world. She knows all the physical facts about us and our environment, in a wide sense of 'physical' which includes everything in completed physics, chemistry, and neurophysiology, and all there is to know about the causal and relational facts consequent upon all this, including of course functional roles. If physicalism is true, she knows all there is to know. For to suppose otherwise is to suppose that there is more to know than every physical fact, and that is just what physicalis..

Abstract: The so called "Knowledge Argument" of Frank Jackson (1982, 1986) ¹ claims to show that there is something about the human mind that must inevitably escape the grasp of physical science: "There are truths about . . . people ( . . . ) which escape the physicalist story" (Jackson, 1986). In effect, materialism is false, and science, as opposed to metaphysics, cannot hope to attain to an understanding of consciousness

Abstract: Outline by Section: INTRODUCTION HUSSERL'S TRANSCENDENTAL POSITION Brentano's Notion of Intentionality Frege's Notion of Sinn Husserl's Transcendental Position Intentional Relations are not Causal. Realism is Wrong, Objects must be Meaningful Psychological States are Empirical. Meanings cannot be In-Themselves, but always for an Ego SEARLE'S THEORY OF INTENTIONALITY CONFRONTATION OF SEARLE'S THEORY WITH THE FOUR THESES Searle Intentionalizes or Trivializes Causation Searle is still a Realist Visual Experience is a Thing-In-Itself Intentional States Presented as Stopping Points CONCLUSION

Abstract: In 'Jackson on physical information and qualia'(1984) Terry Horgan defended physicalism against Frank Jackson's Knowledge Argument by raising what later has been called the 'mode of presentation reply'- arguingthatthe Knowledge Argumentis fallacious because itsubtly equivocates on two different readings of 'physical information'. In 'Mary, Mary, quite contrary' (2000) however, George Graham and Terry Horgan maintain that none of the replies against Jackson has yet been successful, not even Horgan's own 1984 rejoinder.Tosubstantiate their claim, they present an allegedly improved version of the Knowledge Argument, the 'Mary Mary Argument' whose default moral is property-dualism. In section 1, I will set the scene by making some clarifying remarks regarding Jackson's original argument. In section 2, I will consider several objections to the most promising physicalist rejoinder to the Knowledge Argument, the mode of presentation reply. In section 3 I will discuss the Mary Mary Argument and propose the indexical account of consciousness that, as it happens, is based on Horgan's own 1984 account as a possible solution. Finally,in section 4, I will argue that to the extent that the Mary Mary Argument exceeds the force of Jackson's original challenge it coincides with Joe Levine's Explanatory Gap Argument

Abstract: Perry, in this lucid, deep, and entertaining book (based on his 1999 Jean Nicod lectures), supposes that type-identity physicalism is antecedently plausible, and that rejecting this thesis requires good reason (this is