Nigel J. T. Thomas.
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[Published in Minds and Machines (13 #3) 2003 pp. 449-452]
For some reason I never received the printer's proofs for this review before it was published. As a consequence, several typographical errors occur in the version published in Minds and Machines, and one of them is serious. Several lines of my original text (about 140 words) were lost from one paragraph. What is worse, it appears that the paragraph was then copy edited so that it is no longer obvious that text is missing, except for the fact that the argument no longer makes any sense! In this online version, text, punctuation etc. that I have found to be missing or incorrectly printed in the published version appears in dark green. What appears here is what I originally wrote, and what I intended to say.
At my instigation, the journal has now published an erratum, giving the correct version of the mangled paragraph [Minds and Machines (14 #2) 2004 p. 279].
So far as I can recall, I never got asked to sign away the copyright on this review (usually that happens when you get the proofs). Nevertheless, copyright is probably claimed by Kluwer Academic Publishers. - N.J.T.T.
This book is a follow-up to Tye's influential earlier work Ten Problems of Consciousness (1995), which offered a physicalist account of phenomenal (or qualitative) consciousness, arguing that it can be fully and satisfactorily explained in terms of mental representations. Tye's particular version of this theory (representationalism) holds that our conscious experiences consist in those mental representations that are Poised (to influence our beliefs and desires), and have Abstract, Nonconceptual, Intentional Content (from which Tye coins the acronym PANIC). The eight loosely connected essays in Consciousness, Color, and Content (some new, and some previously published) elaborate and amend aspects of the theory of the earlier book, and defend it from various objections that have been or might be made, either to representationalism or to reductive theories of consciousness in general.
Perhaps I should confess at the outset that I am very sympathetic to certain aspects of Tye's view, but find other aspects utterly wrong-headed. In particular, I believe that Tye's "tracking" theory of intentional content (seemingly a form of "causal" or "correlational" theory (Cummins 1989), wherein functional states are held to have content inasmuch as their occurrence is correlated, under appropriate conditions, with the occurrence of whatever they represent) is both unworkable (Cummins 1989, 1997), and an unsuitable foundation for his representationalist account of consciousness. However, given a radically different theory of representation, much of what Tye says about phenomenal consciousness might well turn out to be true. But the book does not dwell upon the theory of intentional representation, so it would not be appropriate to enter into a detailed critique of Tye's view of it here, still less to set it against my own theories of representation and phenomenal consciousness (Thomas 1999, 2001). However, the fact that I see Tye sometimes as a powerful ally and sometimes as a dangerous opponent inevitably colors my attitudes toward different parts of this book.
Certain chapters, however, merely rehash certain "classic" thought-experiment arguments of recent philosophy of mind, attempting to show that, despite initial appearances, they pose no threat to physicalism in general, or representationalism in particular: chapter 1 on the knowledge argument (Mary the incarcerated color expert); chapter 5 on the inverted spectrum (which goes back to Locke, although Tye is particularly concerned with Sydney Shoemaker's take on it); and chapter 6 on swampman and inverted Earth. I have no great quarrel with the general direction of Tye's thinking in these chapters, but I deprecate the genre. The original thought experiments, and perhaps the first two or three rounds of objections, objections to objections, and so on, may have offered valuable insights, but that stage is long past. They have become fodder for the publish-or-perish academic philosophy industry, and the resulting scholasticism can achieve little beyond persuading other cognitive scientists that listening to the philosophers is a waste of time. No consensus is discernable, and every finely honed argument soon meets its equally clever rebuttal. Although Tye handles this sort of stuff better than most, and one cannot help but admire his skill in juggling what has become extremely complex material, reading these chapters did not leave me feeling I understood the underlying substantive issues any better.
Admittedly, the problem introduced at the beginning of chapter 6, is a relatively novel compound of some old elements: Tye notes that the most obvious riposte to Block's (1990) inverted Earth argument against representationalism (itself a product of miscegenation between the inverted spectrum and Putnam's Twin Earth) entails the very counterintuitive conclusion that a spontaneously created physical duplicate of me (swampman) would not have phenomenal consciousness. Tye's ultimate solution to this problem, at the end of the chapter, seems fairly convincing. The trouble is with the dozen or so pages in between, wherein Tye defends a different response to the inverted Earth argument in tedious detail, before pointing out a fairly obvious flaw in the scenario and moving on to the relatively quick exposition of his actual solution. This chapter would have been much better at about half the length.
Chapters 3, 4, 7 and 8 are more constructive in intent, and, I found, much more readable and enlightening. Chapter 4, is still concerned with rebutting various objections that have been or might be made to representationalism, mostly to do with various optical effects, afterimages, illusions and the like. However, these objections are still relatively fresh, so the substantive issues have not yet been obscured in a fog of philosophical nit picking. I found Tye's rebuttals, generally, clear and prima facie convincing.
Chapter 8 applies the PANIC perspective to the question of how far down the phylogenetic scale consciousness occurs. I would not say Tye's answers are entirely compelling (he tentatively concludes that caterpillars are not conscious, but bees are, although, lacking metarepresentation, they do not suffer from any pains they may feel), but the chapter is an interesting exploration of the uses to which a theory of the nature consciousness can be put. Without such a theory we have nothing but vague and conflicting intuitions to tell us which of our fellow creatures might be fellow conscious beings.
For a full understanding of the PANIC criteria, that supposedly set conscious mental representations apart from the non-conscious herd, you will need to turn to Tye's earlier (1995) account. They are briefly explained in chapter 3, but the main focus of this keystone chapter is on two positive, and I think powerful, arguments for representationalism: Tye argues that it provides the only plausible account both of the intentionality of phenomenal discourse, and of the widely acknowledged transparency of consciousness: the way the qualities of perceptual experience seem to belong not to experience itself, but to the objects being perceived. Tye's view, as I understand it, is that experience seems this way because it is this way: the quality of greenness we experience when we look at, say, grass, exists not in our minds but in the grass itself, and to experience green is to mentally represent (in a PANICy way) the greenness that is out there.
Although this seems to square with common sense, it goes against a deeply entrenched scientific and philosophical consensus (going back to Galileo), by locating the qualities of experience, such as colors, out in the world rather than in the mind. Tye thus devotes chapter 7 to a lucid defense of this "color objectivism" against both some time worn objections, and some based on recent science. He would surely not claim to have settled all the complex issues here (indeed, he has recently had more to say - Bradley & Tye, 2001), but he is not alone, today, in pressing such a view (e.g. Hilbert, 1987; Byrne & Hilbert, 1997; Ross, 2001). Tye is aware, however, that representationalism requires objectivism about all types of experiential qualities, not just colors (e.g. pains, he suggests, will need to be thought of "qualities of bodily disturbances"), and here the work is hardly begun. Representationalism may be set to trigger a substantial research program in quality-objectivist metaphysics.
But if phenomenal experiences are to be explained in terms of mental representations, and if (as Tye, with the mainstream of cognitive science, assumes) mental representations are (token) identical to brain states, which are, of course, physical states, then, as a form of mind-brain identity theory, Tye's representationalism faces the notorious "hard problem" or "explanatory gap", vividly presented by authors such as Chalmers (1996) and Levine (1983). Tye himself sums up the issue neatly in a conditional statement:
if experiences are indeed fully physical, in the traditional sense (. . .), then an explanation is needed, but has not yet been found, for why the relevant physical states and qualities feel on the inside as they do (p. 23)
The quest for that elusive explanation has so far defeated the best efforts of philosophers and cognitive scientists. Some are still hopefully seeking, but their efforts look increasingly quixotic; others, such as McGinn (1991) argue that the explanation may be forever beyond our reach; yet others, such as Chalmers, think that the quest has failed because the antecedent of the conditional is false, because experiences are not "fully physical, in the traditional sense". In chapter 2, "The Explanatory Gap as a Cognitive Illusion," Tye argues that they are all barking up the wrong tree. The conditional statement itself is false. Experiences are brain states, but no explanation of how such states can have an "inside feel" is necessary.
This chapter is surely the most difficult and the most brilliant of the book, as Tye employs all his very considerable ingenuity and technical command (Kripkean semantic theory plays a prominent role) to try to persuade us of this deeply implausible thesis. The argument, very roughly, is that the "explanatory gap" problem is only really problematic when interpreted as a demand to demonstrate that our phenomenal concepts are a priori co-referential with our "third-person" concepts of our brain states. However, because of the very different sorts of epistemic access we have to the two classes of concept, this is a conceptually incoherent demand; and we should not be concerned by our inability to answer incoherent questions. I was greatly impressed, but quite unconvinced. I cannot say I am exactly sure where the very involved argument goes wrong (although the blithe and thinly explicated axiom that our phenomenal concepts are introspectively based certainly worried me: introspection is a notoriously slippery, perhaps itself quite incoherent, concept (Lyons 1986)), but one thing I do know: I still want an answer! My puzzlement about how brain states could be qualitative experiences is not at all assuaged. (My own view is that although experiences are representational, intentional mental representations are not brain states. However, reconciling this view with physicalism (Thomas, 1999) is far beyond the scope of this review.)
Some form of representationalism probably provides the best hope for achieving a physicalist theory of phenomenal consciousness, and this book, taken together with Tye (1995), probably provides the best account of representationalism yet available. It is thus well worth reading. Be prepared, however, for some tough sledding.
Block, N. (1990), 'Inverted Earth', in J. Tomberlin, ed., Philosophical Perspectives 4, Northridge, CA: Ridgeview.
Bradley, P. & Tye, M. (2001), 'Of Color, Kestrels, Caterpillars, and Leaves', Journal of Philosophy 98, pp. 469-487.
Byrne, A. & Hilbert, D. R. (1997), 'Colors and Reflectances', in A. Byrne & D. R. Hilbert, eds., Readings on Color, Vol. 1, Cambridge, MA: MIT Press.
Chalmers, D. J. (1996), The Conscious Mind, Oxford: Oxford University Press.
Cummins, R. (1989), Meaning and Mental Representation. Cambridge, MA: MIT Press.
Cummins, R. (1997), 'The LOT of the Causal Theory of Mental Content', Journal of Philosophy 94, pp. 535-542.
Hilbert, D. R. (1987), Color and Color Perception, Stanford CA: Center for the Study of Language and Information.
Levine, J. (1983), 'Materialism and Qualia: The Explanatory Gap', Pacific Philosophical Quarterly 64, pp. 354-361.
Lyons, W. (1986), The Disappearance of Introspection, Cambridge, MA: MIT Press.
McGinn, C. (1991), The Problem of Consciousness, Oxford: Blackwell.
Ross, P. W. (2001), 'The Location Problem for Color Subjectivism', Consciousness and Cognition 10, pp. 4258.
Thomas, N. J. T. (1999), 'Are Theories of Imagery Theories of Imagination? An Active Perception Approach to Conscious Mental Content', Cognitive Science 23, pp. 207-245.
Thomas, N. J. T. (2001), 'Color Realism: Toward a Solution to the "Hard Problem"', Consciousness and Cognition 10, pp. 140-145.
Tye, M. (1995), Ten Problems of Consciousness: A Representational Theory of the Phenomenal Mind, Cambridge, MA: MIT Press.
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