At the start of the 20th century the question of whether life could be explained in purely me- chanical terms was as hotly debated as the mind-body problem is today. Two factions opposed each other: Biological mechanists claimed that the properties characteristic of living organisms (metabolism, perception, goal-directed behavior, procreation, morphogenesis) could be ex- plained mechanistically, in the way the behavior of a clock can be explained by the properties and the arrangement of its cogs, springs, and weights. Substantial vitalists, (...) on the other hand, maintained that the explanation envisaged by the mechanists was impossible and that one had to postulate a special nonphysical substance in order to explain life. (shrink)

Proponents of the explanatory gap claim that consciousness is a mystery. No one has ever given an account of how a physical thing could be identical to a phenomenal one. We fully understand the identity between water and H2O but the identity between pain and the firing of C-fibers is inconceivable. Mark Johnston [Journal of philosophy (1997), 564–583] suggests that if water is constituted by H2O, not identical to it, then the explanatory gap becomes a pseudo-problem. This is because all (...) “manifest kinds”—those identified in experience—are on a par in not being identical to their physical bases, so that the special problem of the inconceivability of ‘pain = the firing of C-fibers’ vanishes. Moreover, the substitute relation, constitution, raises no explanatory difficulties: pain can be constituted by its physical base, as can water. The thesis of this paper is that the EG does not disappear when we substitute constitution for identity. I examine four arguments for the EG, and show that none of them is undermined by the move from constitution to identity. (shrink)

The explanatory gap . Consciousness is a mystery. No one has ever given an account, even a highly speculative, hypothetical, and incomplete account of how a physical thing could have phenomenal states. (Nagel, 1974, Levine, 1983) Suppose that consciousness is identical to a property of the brain, say activity in the pyramidal cells of layer 5 of the cortex involving reverberatory circuits from cortical layer 6 to the thalamus and back to layers 4 and 6,as Crick and Koch have suggested (...) for visual consciousness. (See Crick (1994).) Still, that identity itself calls out for explanation! Proponents of an explanatory gap disagree about whether the gap is permanent. Some (e.g. Nagel, 1974) say that we are like the scientifically naive person who is told that matter = energy, but does not have the concepts required to make sense of the idea. If we can acquire these concepts, the gap is closable. Others say the gap is uncloseable because of our cognitive limitations. (McGinn, 1991) Still others say that the gap is a consequence of the fundamental nature of consciousness. (shrink)

It will not have escaped notice that the defendant in this afternoon.

I argue that the explanatory gap is generated by factors consistent with the view that qualia are physical properties. I begin by considering the most plausible current approach to this issue based on recent work by Valerie Hardcastle and Clyde Hardin. Although their account of the source of the explanatory gap and our potential to close it is attractive, I argue that it is too speculative and philosophically problematic. I then argue that the explanatory gap should not concern physicalists because (...) it makes excessive demands on physical theory. (shrink)

Can phenomenal consciousness be given a reductive natural explanation? Exponents of an.

Confronted with the apparent explanatory gap between physical processes and consciousness, there are many possible reactions. Some deny that any explanatory gap exists at all. Some hold that there is an explanatory gap for now, but that it will eventually be closed. Some hold that the explanatory gap corresponds to an ontological gap in nature.

_tableau_ can be given a full and satisfying explanation, while others cannot. We can explain in a full and satisfying way why the water in the mug is identical with H2O, why its liquidity is identical with a state of its molecular bonds, and why its heat is identical with its molecules being in motion. But we cannot explain in the same way why the neural processes which Joe undergoes when he looks at the mug are such as to make (...) the mug look green, and not red. The latter explanations have gaps. (shrink)

Chalmers has provided a dilemmatic master argument against all forms of the phenomenal concept strategy. This paper explores a position that evades Chalmers's argument, dubbed Type Bb: it is for Type B physicalists who embrace horn b of Chalmers's dilemma. The discussion concludes that Chalmers fails to show any incoherence in the position of a Type B physicalist who depends on the phenomenal concept strategy.

This paper is a defence of Terence Horgan’s claim that any genuinely physicalist position must distinguish itself from (what has been traditionally known as) emergentism. I argue that physicalism is necessarily reductive in character -- it must either give a reductive account of apparently non-physical entities, or a reductive explanation of why there are non-physical entities. I argue that many recent ‘nonreductive’ physicalists do not do this, and that because of this they cannot adequately distinguish their view from emergentism. The (...) conclusion is that this is the real challenge posed by Joseph Levine’s ‘explanatory gap’ argument: if physicalists cannot close the explanatory gap in Levine’s preferred way, they must find some other way to do it. Otherwise their view is indistinguishable from emergentism. (shrink)

J. G. Taylor advances an empirically testable local neural network model to understand the neural correlates of phenomenal experience. Taylor's model is better able to explain the presence (i.e., persistence, latency, and seamlessness) and unity of phenomenal consciousness which support the idea that consciousness is coherent, undivided, and centered. However, Taylor fails to offer a satisfactory explanation of the nonlinear relationship between local and global neural systems. In addition, the ontological assumptions that PE is immediate, intrinsic, and incorrigible limit an (...) understanding of the different experiential forms consciousness takes during neurobehavioral development. Recent studies suggest that neurobehavioral development is discontinuous and that judgment emerges under conditions of uncertainty to render feeling and perception in equivalent terms of energy and behavior. Approaching the problem of phenomenal experience from a developmental perspective may help resolve the paradox of feeling infinitely close as well as distant from one's self. (shrink)

This paper considers the so-called explanatory gap between brain activity and conscious experience. A number of different, though closely related, explanatory gaps are distinguished and a monistic account of conscious experience, a version of Herbert Feigl's "dual-access theory," is advocated as a solution to the problems they are taken to pose for physicalist accounts of mind. Although dual-access theory is a version of the mind-body identity thesis, it in no way "eliminates" conscious experience; rather, it provides a parsimonious and explanatorily (...) fruitful theory of the consciousness-body relation which faithfully preserves the nature of conscious experience while going quite far in "bridging" the various explanatory gaps distinguished below. (shrink)

According to many philosophers, there is an explanatory gap between physical truths and phenomenal truths. Someone could know all the physical truths about the world, and in particular, all the physical information about the brain and the neurophysiology of vision, and still not know what it is like to see red (Jackson 1982, 1986). According to a similar example, someone could know all the physical truths about bats and still not know what it is like to be a bat (Nagel (...) 1974). We can conceive of an individual that is physically identical to me, molecule per molecule, but does not have any phenomenally conscious state whatsoever (Chalmers 1996). Some philosophers have argued that the explanatory gap shows that we cannot explain consciousness in physical terms (Levine 2001), or even that phenomenal consciousness is not physical and therefore physicalism is false (Chalmers 1996, 2002). (shrink)

One of the most important arguments against physicalism is the so-called conceivability argument. Intuitively, this argument claims that since certain statements concerning the separation of the physical and the phenomenal are conceivable, they are possible. This inference from conceivability to possibility has been challenged in numerous ways. One of these ways is the so-called phenomenal concept strategy, which has become one of the main strategies against the conceivability argument. David Chalmers says it “is perhaps the most attractive option for a (...) physicalist to take in responding to the problem of consciousness”.2 Certainly, in the recent years, a multitude of proposals of that sort have been proposed and developed.3 However, Chalmers (2006) has recently argued that no version of the phenomenal concept strategy can succeed. In what follows, I will examine his argument for that conclusion, and I will argue that it is not sound. I will conclude that he has not posed any serious problem for the phenomenal concept strategy to succeed.. (shrink)

Consciousness often presents itself as a problem for materialists because no matter which physical explanation we consider, there seems to remain something about conscious experience that hasn't been fully explained. This gives rise to an apparent explanatory gap. The explanatory gulf between the physical and the conscious is reflected in the broader population, in which dualistic intuitions abound. Drawing on recent empirical evidence, this essay presents a dual-process cognitive model of consciousness attribution. This dual-process model, we suggest, provides an important (...) part of the explanation for why dualism is so attractive and the explanatory gap so vexing. (shrink)

The claim that there is an explanatory gap between physical and phenomenal properties is perhaps the leading current challenge to materialist views about the mind. Tye tries to block this challenge, not by providing an explanation to bridge the gap but by denying that phenomenalphysical identities introduce an explanatory gap. Since an explanatory gap exists only if there is something unexplained that needs explaining, and something needs explaining only if it can be explained (whether or not it lies within the (...) power of human-beings to explain it), there is no gap. (Tye ????, p. ???) Tyes strategy differs crucially from the claim that identities never stand in need of explanation because they constitute ultimate explanations; for he allows that identities such as water = H?O are explainable. Unlike WATER and H?O, which are descriptive concepts, phenomenal concepts are perspectival and hence irreducible to descriptive concepts, according to Tye. The fact that something picked out by a perspectival concept is identical to something picked out by a non-perspectival concept cannot be explained.1 So, he concludes, phenomenalphysical identities need not be explained. (shrink)

This paper investigates the status of the purported explanatory gap between pain phenomena and natural science, when the “gap” is thought to exist due to the special properties of experience designated by “qualia” or “the pain quale” in the case of pain experiences. The paper questions the existence of such a property in the case of pain by: (1) looking at the history of the conception of pain; (2) raising questions from empirical research and theory in the psychology of (...) pain; (3) considering evidence from the neurophysiological systems of pain; (4) investigating the possible biological role or roles of pain; and (5) considering methodological questions of the comparable status of the results of the sciences of pain in contrast to certain intuitions underpinning “the explanatory gap” in the case of pain. Skepticism concerning the crucial underlying intuitions seems justified by these considerations. (shrink)

Levine (1997) claims that Locating Consciousness (1995) does not seriously address the problem of the explanatory gap; instead it merely provides lots of data. Here I argue that, contrary to the intuitions of some philosophers, the best remedy for our gaps in explanation and understanding is in fact through empirical investigation.

Discussions of the mind-body problem often refer to an.

A robot that is functionally indistinguishable from us may or may not be a mindless Zombie. There will never be any way to know, yet its functional principles will be as close as we can ever get to explaining the mind.

Presents the author’s view of the best current positions on certain core philosophical and psychological problems. These positions together suggest a traditional nihilist perspective modified by evolutionary psychology and other contemporary thinking that accepts limitations on our understanding (rather than the conclusive non-existence of certain explanations), the psychological (if not absolute) reality of values, free will and other phenomena and our desire to live as best we can. The positions presented are: (1) the origin of the universe cannot be understood, (...) (2) morality has no absolute rational foundation, (3) some people have unquestioned beliefs they view as absolute, (4) we don’t really have free will but can act as if we do, (5) brains are conscious but we don’t know how, (6) we live by relative values, biological dispositions, upbringing, habit and choice and (7) we don’t know how much we can modify ourselves, what makes us happy or what we value. (shrink)

According to the self-representational theory of consciousness – self- representationalism for short – a mental state is phenomenally conscious when, and only when, it represents itself in the right way. In this paper, I consider how self- representationalism might address the alleged explanatory gap between phenomenal consciousness and physical properties. I open with a presentation of self- representationalism and the case for it (§1). I then present what I take to be the most promising self-representational approach to the explanatory gap (...) (§2). That approach is threatened, however, by an objection to self-representationalism, due to Levine, which I call the just more representation objection (§3). I close with a discussion of how the self-representationalist might approach the objection (§4). (shrink)

Conscious experience presents a deep puzzle. On the one hand, a fairly robust materialism must be true in order to explain how it is that conscious events causally interact with non-conscious, physical events. On the other hand, we cannot explain how physical phenomena give rise to conscious experience. In this wide-ranging study, Joseph Levine explores both sides of the mind-body dilemma, presenting the first book-length treatment of his highly influential ideas on the "explanatory gap," the fact that we can't explain (...) the nature of phenomenal experience in terms of its physical realization. He presents a careful argument that there is such a gap, and, after providing intriguing analyses of virtually all existing theories of consciousness, shows that recent attempts to close it fall short of the mark. Levine concludes that in the foreseeable future consciousness will remain a mystery. (shrink)

Contrary to certain rumours, the mind-body problem is alive and well. So argues Joseph Levine in Purple Haze: The Puzzle of Consciousness . The main argument is simple enough. Considerations of causal efficacy require us to accept that subjective experiential, or 'phenomenal', properties are realized in basic non-mental, probably physical properties. But no amount of knowledge of those physical properties will allow us conclusively to deduce facts about the existence and nature of phenomenal properties. This failure of deducibility constitutes an (...) explanatory problem - an explanatory gap - but does not imply the existence of immaterial mental properties. Levine introduced this notion of the explanatory gap almost two decades ago. Purple Haze allows Levine to situate the explanatory gap in a broader philosophical context. He engages with those who hold that the explanatory gap is best understood as implying anti-materialist metaphysical conclusions. But he also seeks to distance himself from contemporary naturalistic philosophical theorizing about consciousness by arguing that reductive and eliminative theories of consciousness all fail. Levine's work is best seen as an attempt to firmly establish a definite status for the mind-body problem, i.e. that the mind-body problem is a real, substantive epistemological problem but emphatically not a metaphysical one. Because Levine's work is tightly focused upon contemporary Anglophone analytic philosophy of mind, there is little discussion of the broader conceptual background to the mind-body problem. My aim here is to place Levine's work in a broader conceptual context. In particular, I focus on the relationship between consciousness and intentionality in the belief that doing so will allow us better to understand and evaluate Levine's arguments and their place in contemporary theorizing about mentality and consciousness. (shrink)

This book brings together an international group of neuroscientists and philosophers who are investigating how the content of subjective experience is...

The contributions to this book are original articles, representing a cross-section of current philosophical work on consciousness and thereby allowing students and readers from other disciplines to acquaint themselves with the very latest debate, so that they can then pursue their own research interests more effectively. The volume includes a bibliography on consciousness in philosophy, cognitive science and brain research, covering the last 25 years and consisting of over 1000 entries in 18 thematic sections, compiled by David Chalmers and Thomas (...) Metzinger. (shrink)

Wittgenstein demystified the notion of ''observational self-knowledge''. He dislodged the long-standing conception that we have privileged access to our impressions, sensations and feelings through introspection, and more precisely eliminated knowing as the kind of awareness that normally characterizes our first-person present-tense psychological statements. He was not thereby questioning our awareness of our emotions or sensations, but debunking the notion that we come to that awareness via any epistemic route. This makes the spontaneous linguistic articulation of our sensations and impressions nondescriptive. (...) Not descriptions, but expressions that seem more akin to behaviour than to language. I suggest that Wittgenstein uncovered a new species of speech acts. Far from the prearranged consecration of words into performatives, utterances are deeds through their very spontaneity. This gives language a new aura: the aura of the reflex action. I argue, against Peter Hacker, that spontaneous utterances have the categorial status of deeds. This has no reductive consequences in that I do not suggest that one category is reduced to another, but that the boundary between them is porous. This explodes the myth of an explanatory gap between the traditionally distinct categories of saying (or thinking) and doing, or of mind and body. (shrink)

The explanatory gap and theknowledge argument are rooted in the conflationof propositional and phenomenal knowledge. Thebasic knowledge argument is based on theconsideration that ``physical information'' aboutthe nervous system is unable to provide theknowledge of a ``color experience'' (Jackson,1982). The implication is that physicalism isincomplete or false because it leaves somethingunexplained. The problem with Jackson'sargument is that physical information has theform of highly symbolic propositional knowledgewhereas phenomenal knowledge consists in innateneurophysiological processes. In addition totheir fundamental epistemological differences,clinical, anatomical, pathological and brainimaging (...) studies demonstrate that phenomenal andpropositional knowledge are fundamentallydifferent neurobiological processes. Propositional knowledge is phylogeneticallynew, highly symbolic, culturally acquired,exclusively human and expressible in differentnatural and artificial languages. By contrast,phenomenal knowledge (i.e.: knowingwhat-it-is-like to see a color) consists inqualitative experiences and phenomenal conceptsthat provide an internal, language-independentreference to the properties of objects and theneeds of the organism. Language andpropositional knowledge are exclusively humanattributes implemented in specific regions ofthe dominant hemisphere. This contrastssharply with the phylogenicallysensory areas that are common to animals andhumans, which implement qualitativeexperiences. Experiences are hard-wiredneurobiological processes that can neither betransmitted nor re-created through thesymbolism of propositions. Thus, I concludethat the fallacy in the explanatory gap and inthe knowledge argument is a fallacy ofequivocation that results from ignoringfundamental neurobiological differences betweenphenomenal and propositional knowledge. (shrink)

The American Philosophical Association Newsletter on Philosophy and Computers. Harman.

I argue that O'Regan & Noë's (O&N's) theory is in a no better position than any other theory to solve the “hard problem” of consciousness. Getting rid of the explanatory gap by exchanging sensorimotor contingencies for neural representations is an illusion.

On the first page of The Problem of Consciousness (1991), Colin McGinn asks "How is it possible for conscious states to depend on brain states? How can technicolour phenomenology arise from soggy grey matter?" Many philosophers feel that questions like these pose an unanswerable challenge to physicalism. They argue that there is no way of bridging the "explanatory gap" between the material brain and the lived world of conscious experience (Levine, 1983), and that physicalism about the mind can therefore provide (...) no answer to the "hard problem" of why brains give rise to consciousness (Chalmers, 1996). (shrink)

A widely accepted theory holds that emotional experiences occur mainly in a part of the human brain called the amygdala. A different theory asserts that color sensation is located in a small subpart of the visual cortex called V4. If these theories are correct, or even approximately correct, then they are remarkable advances toward a scientific explanation of human conscious experience. Yet even understanding the claims of such theories.

Cognitive science is shamelessly materialistic. It maintains that human beings are nothing more than complex physical systems, ultimately and completely explicable in mechanistic terms. But this conception of humanity does not ?t well with common sense. To think of the creatures we spend much of our day loving, hating, admiring, resenting, comparing ourselves to, trying to understand, blaming, and thanking -- to think of them as mere mechanisms seems at best counterintuitive and unhelpful. More often it may strike us as (...) ludicrous, or even abhorrent. We are. (shrink)

It is argued that the explanatory gap argument, according to which it is fundamentally impossible to explain qualitative mental states in a physicalist theory of mind, is unsound. The main argument in favour of the explanatory gap is presented, which argues that an identity statement of mind and brain has no explanatory force, in contrast to "normal" scientific identity statements. Then it is shown that "normal" scientific identity statements also do not conform to the demands set by the proponent of (...) the explanatory gap. Rather than accept all such gaps, it is argued that we should deny the explanatory gap in a physicalist theory of mind. (shrink)

One popular materialist response to the explanatory gap identifies phenomenal concepts with type-demonstrative concepts. This kind of response, however, faces a serious challenge: that our phenomenal concepts seem to provide a richer characterization of their referents than just the demonstrative characterization of 'that quality'. In this paper, I develop a materialist account that beefs up the contents of phenomenal concepts while retaining the idea that these contents contain demonstrative elements. I illustrate this account by focusing on our phenomenal concepts of (...) phenomenal colour. The phenomenal colours stand in a similarity space relative to one another in virtue of being complex qualities—qualities that contain saturation, lightness, and various aspects of hue as component elements. Our phenomenal concepts, in turn, provide a demonstrative characterization of each of these component elements as well as a description of how much of that element is present in a given phenomenal colour. The result is an account where phenomenal concepts contain demonstrative elements and yet provide a significantly richer characterization of the intrinsic nature of their referents than just 'that quality'. (shrink)

This paper examines a paradigm case of allegedly successful reductive explanation, viz. the explanation of the fact that water boils at 100°C based on facts about H2O. The case figures prominently in Joseph Levine’s explanatory gap argument against physicalism. The paper studies the way the argument evolved in the writings of Levine, focusing especially on the question how the reductive explanation of boiling water figures in the argument. It will turn out that there are two versions of the explanatory gap (...) argument to be found in Levine’s writings. The earlier version relies heavily on conceptual analysis and construes reductive explanation as a process of deduction. The later version makes do without conceptual analysis and understands reductive explanations as based on theoretic reductions that are justified by explanatory power. Along the way will be shown that the bridge principles — which are being neglected in the explanatory gap literature — play a crucial role in the explanatory gap argument. (shrink)

The contemporary epistemic status of mental health disciplines does not allow the cross validation of mental disorders among various genetic markers, biochemical pathway or mechanisms, and clinical assessments in neuroscience explanations. We attempt to provide a meta-empirical analysis of the contemporary status of the cross-disciplinary issues existing between neuro-biology and psychopathology. Our case studies take as an established medical mode an example cross validation between biological sciences and clinical cardiology in the case of myocardial infarction. This is then contrasted with (...) the incoherence between neuroscience and psychiatry in the case of bipolar disorders. We examine some methodological problems arising from the neuro-imaging studies, specifically the experimental paradigm introduced by the team of Wayne Drevets. Several theoretical objections are raised: temporal discordance, state independence, and queries about the reliability and specificity, and failure of convergent validity of the inter-disciplinary attempt. Both modern neuroscience and clinical psychology taken as separate fields have failed to reveal the explanatory mechanisms underlying mental disorders. The data acquired inside the mono-disciplinary matrices of neurobiology and psychopathology are deeply insufficient concerning their validity, reliability, and utility. Further, there haven’t been developed any effective trans-disciplinary connections between them. It raises the requirement for development of explanatory significant multi-disciplinary “meta-language” in psychiatry (Berrios, 2006, 2008). We attempt to provide a novel conceptual model for an integrative dialogue between psychiatry and neuroscience that actually includes criteria for cross-validation of the common used psychiatric categories and the different assessment methods. The major goal of our proactive program is the foundation of complementary “bridging” connections of neuroscience and psychopathology which may stabilize the cognitive meta-structure of the mental health knowledge. This entails bringing into synergy the disparate discourses of clinical psychology and neuroscience. One possible model accomplishment of this goal would be the synergistic (or at least compatible) integration of the knowledge under trans-disciplinary convergent cross-validation of the commonly used methods and notions. (shrink)

A number of philosophers have recently argued that (i) consciousness properties are identical with some set of physical or functional properties and that (ii) we can explain away the frequently felt puzzlement about this claim as a delusion or confusion generated by our different ways of apprehending or thinking about consciousness. This paper examines David Papineau’s influential version of this view. According to Papineau, the difference between our “phenomenal” and “material” concepts of consciousness produces an instinctive but erroneous intuition that (...) these concepts can’t co-refer. I claim that this account fails. To begin with, it is arguable that we are mystified about physicalism even when the account predicts that we shouldn’t be. Further, and worse, the account predicts that an “intuition of distinctness” will arise in cases where it clearly does not. In conclusion, I make some remarks on the prospects for, constraints on, and (physicalist) alternatives to, a successful defence of the claim (ii). (shrink)

An exploration is given of neural network features now being uncovered in cortical processing which begins to go a little way to help bridge the ''Explanatory Gap'' between phenomenal consciousness and correlated brain activity. A survey of properties suggested as being possessed by phenomenal consciousness leads to a set of criteria to be required of the correlated neural activity. Various neural styles of processing are reviewed and those fitting the criteria are selected for further analysis. One particular processing style, in (...) which semiautonomous and long-lasting cortical activity ''bubbles'' are created by input, is selected as being the most appropriate. Further experimental criteria are used to help narrow the possible neural styles involved. This leads to a class of neural models underpinning phenomenal consciousness and to a related set of testable predictions. (shrink)

The thesis that there is a troublesome explanatory gap between the phenomenal aspects of experiences and the underlying physical and functional states is given a number of different interpretations. It is shown that, on each of these interpretations, the thesis is false. In supposing otherwise, philosophers have fallen prey to a cognitive illusion, induced largely by a failure to recognize the special character of phenomenal concepts.

A major part of the mind–body problem is to explain why a given set of physical processes should give rise to qualia of one sort rather than another. Colour hues are the usual example considered here, and there is a lively debate between, for example, Hardin, Levine, Jackson, Clark and Chalmers as to whether the results of colour vision science can provide convincing explanations of why colours actually look the way they do. This paper examines carefully the type of explanation (...) that is needed here, and it is concluded that it does not have to be reductive to be effective. What needs to be explained more than anything is why inverted hue scenarios are more intuitive than other sensory inversions: and the issue of physicalism versus dualism is only of marginal relevance here. (shrink)

The explanatory gap refers to the lack of concepts for understanding “how it is that . . . a state of consciousness comes about as a result of irritating nervous tissue.” By assuming that there are colours in the outside world, Block needlessly widens this gap and Lycan and Kitcher simply fail to see the gap. When such assumptions are abandoned, an unnecessary and incomprehensible constraint disappears. It then becomes clear that the brain can use its own neural language for (...) representing aspects of the outside world. While this may not close the gap, it becomes clearer where we need new concepts. (shrink)

Russell (1912) and others have argued that the real nature of colour is transparentto us in colour vision. It's nature is fully revealed to us and no further knowledgeis theoretically possible. This is the doctrine of revelation. Two-dimensionalFourier analyses of coloured checkerboards have shown that apparently simple,monadic, colours can be based on quite different physical mechanisms. Experimentswith the McCollough effect on different types of checkerboards have shown thatidentical colours can have energy at the quite different orientations of Fourierharmonic components but (...) no energy at the edges of the checkerboards, thusrefuting revelation. It is concluded that this effect is not explained by a superveniencedispositional account of colour as proposed by McGinn (1996). It was argued that theMcCollough effect in checkerboards was an example of a local mind/body reduction(Kim 1993), by which the different characteristics of identical colours falsifies revelation. This reduction being based on both physical and neurological mechanisms led to a clear explanation of the perceive phenomenal effects and thus laid a small bridge over the explanatory gap. (shrink)