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(Extracted from Lehar (2000) The Function of Conscious Experience)
Of all the branches of human knowledge, philosophy might be expected to be the best inoculated against the na´ve realist error, since the issue of the epistemology of conscious experience is a central focus of philosophy. However modern philosophy is just as rife with na´ve realists as are modern psychology and neuroscience. As in psychology there is a recurring pattern of the occasional visionary who points out the fallacy of the na´ve view, interspersed with long periods of enthusiastic support for the latest na´ve inspired view, although again the issue is generally not addressed directly but only peripherally, as it is hidden in the details of various theories. Jaegwon Kim (1998) traces the origins of the mind-body identity theory to C. D. Broad (1925) and Herbert Feigl (1958). Broad, according to Kim, was the original exponent of this theory, although Feigl was more influential. But a careful analysis of Broad's theory reveals the residual na´ve realism of his critical realist philosophy. Broad argues that our mind is the object of our introspection, just as physical things are the objects of our perceptions. However Broad does not recognize the perception of external objects to be introspection, but `inspection' (i.e. exteroception). He denies that `sense data' such as the perceived shape and color of a perceived object can be counted as states of our mind, because "if this were so, the colour could not pervade the external place" (Broad 1925 p. 177). This confusion of external and internal entities lead to endless confusion in Broad's concept of perception.
Feigl (1958) on the other hand does present a cogent case for the identity of mind and brain in its entirety, and Feigel even cites Bertrand Russell and Wolfgang K÷hler among those who preceded him in this belief. On isomorphism Feigl explains (1958, p. 79) "the states of direct experience - are identical with certain (presumably configurational) aspects of neural processes - [so that] what is had in experience - is identical with - what the science of neurophysiology describes - as processes in the central nervous system, perhaps especially in the cerebral cortex." He then systematically lists and refutes all of the common objections to mind-brain identity. Feigl concludes (1958 p. 41) that "our arguments have -disproved- the Cartesian contention that the mental is non-spatial. To put it very strongly, mental events as directly experienced and phenomenally described are spatial." Similar compelling arguments are presented by Boring (1933) and Smart (1959). This then should have put the final nail in the coffin of na´ve realism. But it was not long before identity theory was attacked on two fronts, which Kim (1998) calls the multiple realizations argument (Putnam 1968, 1975), and the anomalous monist argument (Davidson 1970, 1980).
Putnam objects that mental states can and do have vastly diverse physical or biological realizations in different species and structures. For example both humans and mollusks presumably experience pain, but that experience is mediated by entirely different neural mechanisms. Therefore no mental state can be identified with any single physical or biological state. Turning the argument the other way around, therefore seems to suggest that if pain that we experience as humans could potentially be implemented in a number of different ways, then there is little we can say about the neurophysiological correlate of our experienced pain. This supposedly absolves the philosopher of the need to worry about neurophysiology at all, and permits us to treat the phenomenal and the physiological as two separate domains. In fact Putnam claims that mental kinds and properties are functional kinds of a higher level of abstraction than physicochemical or biological kinds, and that therefore mental or cognitive properties are a distinctive domain to be investigated independently of their physical / biological interpretations. That mental properties are realized or implemented in physical properties, although, Putnam insists, they are neither identical to, nor are they reducible to them. But although this argument may have some validity when applied to basic constituent qualia such as color and pain, it does not apply to the dimensionality of the perceptual representation or its information content, i.e. the manner in which those qualia are arranged or structured to represent external reality. For whatever the neurophysiological mechanism underlying spatial perception, the principle of isomorphism suggests that it must be a spatial mechanism of three spatial dimensions, because its spatial nature is clearly evident phenomenologically. Now there are multiple possible realizations of a spatial representation, so the mere fact of the spatiality of phenomenal experience cannot of itself select between different spatial realizations. However phenomenology can exclude the possibility of non-spatial representations to account for the spatial nature of perception. While this argument might seem controversial when applied to spatial perception, the same argument is widely accepted in the case of color perception. For color experience has been shown to encode three dimensions of color value, i.e. hue, intensity, and saturation. So although we cannot yet with certainty identify the neurophysiological mechanism responsible for encoding color experience, we can say with certainty that that mechanism must encode at least three dimensions of color information. Different realizations of color experience in different phyla and species may well correspond to different qualia of color experience, and the subjective aspect of those experiences in other species is perhaps forever unknowable to us (Nagel 1974, Chalmers 1995). However psychophysical experiments in humans and animals can and have determined the dimensions of color experience, and that in turn offers concrete information about color representation in the brain. There is no reason why this argument should not hold also for spatial experience.
Davidson's anomalous monist argument (Davidson 1970, 1980) suggests that the mental domain, on account of its essential anomalousness and normativity cannot be the object of serious scientific investigation, because the mental is on a wholly different plane from the physical. This argument sounds like the ontological dualism of Descartes that disconnects mind from brain entirely, except that Davidson qualifies the previous statement with the monistic proviso that each mental event is connected with specific physical events (in the brain), although there are no laws connecting mental kinds with physical kinds. In other words there are no events which have only mental properties, and this rescues the thesis from ontological dualism. Kim (1998) points out however that this is a negative thesis, for it tells us only how the mental is not related to the physical, it says nothing about how they are related. As such this is more an article of faith rather than a real theory of any sort, and in the context of the history of the epistemological debate this can be seen as a last desperate attempt to rescue na´ve realism from its own logical contradictions. This kind of physicalism has been appropriately dubbed `token physicalism', for it is indeed a token admission of the undeniable link between mind and the physical brain, without admitting to any of its very significant implications. It is Davidson's attempt to have his cake and eat it too. In order to rationalize this view of the mind-brain relation Davidson introduces the peculiar notion of supervenience, a one-way asymmetrical relation between mind and brain that makes mind dependent on the brain, but that forever closes the possibility of phenomenological observation of brain states. The notion of supervenience is so peculiar that mind and brain are supposedly the only example in the universe of entities joined by this paradoxical relation. However as Kim observes, this is not really a theory of mind- body relation for it is silent on the nature of the dependence relation that might explain how or why the mental supervenes on the physical. Mind-body supervenience states the mind-body problem, it is not a solution to it, for the central paradox of consciousness is preserved in the paradox of supervenience.
Dretske (1995) also defends Putnam's multiple realizations argument and Davidson's concept of supervenience, although Dretske explicitly declines to consider the epistemological dualist position even as a theoretical possibility to be refuted. (Dretske 1995, p. 127) "I will have nothing to say to those who reject all forms of externalism ... I'm trying to win a battle, not the war." But the war is already lost, although Dretske has not yet heard the news, so winning the battle will turn out to be a futile gesture. The position Dretske defends is reminiscent of the confused epistemology of the critical realists, which makes one wonder whether Dretske has ever heard of Bertrand Russell's causal theory of perception. For example Dretske (1995, p. 44) describes introspection as "an instance in which an experience (of blue, say) is conceptually represented as an experience of blue via a sensory representation not of the experience, but of some other object. One comes to know ... that one is experiencing blue by experiencing, not the experience of blue, but some displaced object ... i.e. the blue object one sees." So once again the blueness of the subjective experience is not a blueness in the percipient's mind, but is supposedly a property of the external object in which that blueness is perceived. Dretske takes on the issue raised by Lovejoy (1930) about whether `being known' is necessarily equivalent to `being in our heads', but he does so by way of an invalid analogy. Dretske argues (p. 38) that "the mind isn't in the head any more than stories ... are in books." But what makes this analogy invalid is that the story printed in a book is incomplete. It does not even become a story of people and events until a human mind is present to read the patterns of ink on the page and transform them into an internal representation of people and events. A better analogy is that of an artificial intelligence or robot, whose representation of the external world does not require the intervention of a human intermediary. No matter how complex and intelligent such a robot might be built, there is no way that the sensory or perceptual information encoded by the robot can be considered to be located anywhere other than in the robot's "brain", or its explicit physical mechanism of representation.
Despite the deep and fundamental problems with these non-reductive physicalist theories, they have been, and still are the most influential metaphysical position on the mind-body problem (Kim 1998). It is interesting how this fits in with the historical pattern of the epistemological debate. For neither Putnam nor Davidson nor Dretske propose to challenge the core issues of epistemology directly, but merely present a convenient escape clause by which philosophers can evade the issue altogether while supposedly preserving their scientific integrity. This is the same kind of evasion of the fearsome facts of epistemology as was offered by the dualist account that pushed the problem into the domain of God or Spirit, and the behaviorist solution that pushed the problem of consciousness off-limits to scientific scrutiny, and the critical realist solutions that invoke semi-existent spatial entities located in non-space. And as with those earlier movements in philosophy, all that was required was to open the door of doubt a tiny crack to unleash a stampede of popular support all desperately seeking a respectable justification for their own na´ve realist intuitions. There are various other strategies to be found in contemporary philosophy to evade the epistemological issue, such as the modern dualism of nonnaturalism (Popper & Eccles 1977, Swinburne 1984, Adams 1987) which holds that consciousness is not a natural phenomenon and is therefore closed to scientific scrutiny; and anticonstructive naturalism (McGinn 1989) which suggests that consciousness is terminally mysterious, and all attempts to resolve the mind-body problem are doomed to failure from the outset; and eliminative naturalism (Churchland 1981, Churchland 1983) which suggests that consciousness is a natural phenomenon, but that there is a sense in which it cannot be explained, for the concept of consciousness is simultaneously too simplistic, too vague, and too historically embedded in false and confused theory to denote a phenomenon in need of explanation. But the deeply mysterious aspect of consciousness which motivates these pessimistic analyses is mostly involved in its confusion with the external world. Once we recognize that `external' consciousness is in fact an internal representation, and that it takes the form of a spatial structure in the brain, the mystery is transformed from a deep logical paradox to a neurophysiological or neurocomputational problem, i.e. the question of what kind of neurophysiological or computational principle could possibly account for the emergence of dynamic spatial structures in the brain.
Another somewhat different challenge to the mind-brain identity theory is posed by Smythies (1994, 1999). While Smythies explicitly refutes na´ve realism (Smythies & Ramachandran 1998) and the resultant confusion of the phenomenal body or `body image' with the objective physical body, (Smythies 1953) Smythies argues that "the brain, as a machine, is simply the wrong sort of machine to be able to actually construct the visual field and other components of phenomenal consciousness." (Smythies 1994, p. 311) Smythies cites Leibnitz's principle that for two entities to be identical, they must have identical properties. "Since events in the sensory brain and events in our sensory fields in consciousness have clearly distinct properties, - the theory fails in principle." (Smythies 1999, p. 168) Here Smythies puts his finger on the principal motivation for naive realism in modern philosophy, which is the glaring disparity between phenomenology and contemporary neuroscience. For modern neuroscience tells us that the brain is composed of innumerable discrete neurons, interconnected in a network of synaptic connections. It is hard to resolve this discrete or quantized concept of brain physiology with the continuous, unitary, and field-like character observed in the phenomenal world, an issue which is sometimes called the "grain problem" (Wilfred Sellars 1963). This either means that consciousness is a complete illusion that bears no resemblance to its corresponding neurophysiological state, or that contemporary neuroscience is in a state of serious crisis, for it offers no evidence for the continuous field- like pictorial representations that we know to be present in the brain. It is not so surprising for a neuroscientist to favor the former eliminative alternative, having more inherent faith in his own method of investigation. It is surprising however that the modern philosopher most often defers to neuroscience whenever it is in conflict with the observed properties of the mind, for it is the mind, and not the brain, which is, or at least should be the primary object of philosophical inquiry. A philosopher who cannot trust his observations of the properties of the mind unless or until they are confirmed by neurophysiology, would do better to abandon philosophy altogether as a futile enterprise, and switch to the more certain science of neurophysiology. Smythies' own solution is to propose that consciousness may be concealed in one of the hidden dimensions of reality which are sometimes proposed in modern cosmology. In some sense this is reminiscent of the semi-existent entities proposed by the critical realists for sense-data, which are spatial structures but not to be found in physical space. However by identifying the hidden dimensions of physical reality as the locus of these hidden percepts, Smythies moves the theory into scientific territory where those hidden dimensions should at least in principle be accessible to scientific scrutiny. But until modern science can actually confirm the existence of those hidden dimensions, and demonstrate how information can be stored in, and retrieved from them by physical processes, this is a speculative hypothesis that remains to be confirmed. Unlike the critical realists however, Smythies would presumably allow that the properties of those hidden dimensions of the universe are accessible phenomenologically, so Smythies' theory is an identity theory, that places sense data within the physical brain, albeit in a hidden dimension not readily accessible to scientific scrutiny except by way of conscious experience.
The continued dominance of the naive realist view in contemporary philosophy is highlighted by the fact that books like Tye's (1995) "Ten Problems of Consciousness" pass largely unchallenged, even though several of the fundamental problems of consciousness identified by Tye disappear altogether when viewed from the indirect realist perspective. For example Tye's problem number eight, the Problem of Transparency, is the same issue raised by Searle (1992), that we cannot distinguish consciousness itself from the object of which we are conscious. But consciousness is only transparent to those who fall prey to the naive illusion, and believe they are viewing the world itself directly, as if by magic. Tye's problem number nine, the Problem of Felt Location, is the question of external perception, which is also resolved by the dualist epistemology which reveals that the space of our phenomenal experience is a representation inside our head, and the paradox disappears. While indirect realism does not resolve all of Tye's ten problems as easily as it does these two, it does cast the problem in an entirely new light, whose implicatons deserve at least as much scrutiny as the naive view has been afforded, to see if this unexplored alternative might finally release the problem of consciousness from its current paradoxical impasse. But what is interesting in this case is that Tye does not consider indirect realism even as an alternative to be discussed and refuted, it is simply ignored altogether as if it had no place in the debate.
Flanagan's (1992) Consciousness Reconsidered comes closer to expressing the true mind-brain relation, for Flanagan argues that mind is a natural phenomenon that can be investigated by blending insights from neuroscience, psychology, and phenomenology. Thus it would seem that Flanagan's "constructive naturalism" is a kind of mind-brain identity theory. But Flanagan provides subtle clues that he still clings to a few last vestiges of naive realism. Although Flanagan approves of the investigation of brain processes through phenomenology, he also claims (p. 12) that "Phenomenology alone has been tried and tested. It does not work. ... Phenomenology alone never reveals anything about how `seemings' are realized, nor can it reveal anything about the mental events and processes involved in conscious mental life." But phenomenology has already revealed that perception involves a three-dimensional volumetric spatial representation, and that is a very significant fact of conscious mental life, with direct implications for how spatial "seemings" are realized in the brain. The only way that this most obvious representational fact could possibly have escaped Flanagan's notice was if he mistook this phenomenal world for reality itself. Significantly Flanagan never discusses the epistemological issue itself directly, or its very significant implications for all of the other issues of perception and consciousness, as if Flanagan were totally unaware of the existence of this theoretical alternative.
If there is anything to be learned from the long history of the epistemological debate, it is that the issue is by no means simple or trivial, and that whatever is ultimately determined to be the truth of epistemology, we can be sure that it will do considerable violence to our common-sense view of things. This however is nothing new in science, for many of the greatest discoveries of science seemed initially to be so incredible that it took decades or even centuries before they were generally accepted. But accepted they were, eventually, and the reason why they were accepted was not because they had become any less incredible. In science, irrefutable evidence triumphs over incredibility, and this is exactly what gives science the power to discover unexpected or incredible truth. Ultimately, therefore, the most convincing argument for epistemological dualism is the fact that its monistic alternatives have all been refuted on sound logical grounds, which leaves epistemological dualism as the only viable alternative. Until this most basic fact of conscious experience finally triumphs over our naive realist inclinations, philosophy and psychology are doomed to an endless and futile recapitulation of the ancient epistemological debate.
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