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Consciousness: Don't Give Up on the Brain
Published online by Cambridge University Press: 07 July 2010
Abstract
In the extended mind literature, one sometimes finds the claim that there is no neural correlate of consciousness. Instead, there is a biological or ecological correlate of consciousness. Consciousness, it is claimed, supervenes on an entire organism in action. Alva Noë is one of the leading proponents of such a view. This paper resists Noë's view. First, it challenges the evidence he offers from neuroplasticity. Second, it presses a problem with paralysis. Third, it draws attention to a challenge from the existence of metamers and visual illusions.
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References
1 Noë, A., Out of Our Heads: Why You are not Your Brain, and Other Lessons from the Biology of Consciousness (New York, NY: Hill and Wang, 2009), 185Google Scholar.
2 Ibid., 10.
3 Ibid., 146.
4 Ibid., 186.
5 Ibid., 10.
6 This conclusion differs from those he and Susan Hurley drew in Hurley, S. and Noë, A., ‘Neural Plasticity and Consciousness’, Biology and Philosophy 18 (2003), 131–68CrossRefGoogle Scholar. For the purpose of this discussion, however, we may concede these other conclusions.
7 A. Noë, Out of Our Heads: Why You are not Your Brain, and Other Lessons from the Biology of Consciousness, op. cit., 53.
8 It is not, however, all that weighty an argument. It appears to be quite common in the course of the history of science to know that some object or structure gives rise to some phenomenon long before having much idea how the object actually gives rise to the phenomenon. For example, it was known for millennia that the sun produces light, but only in the last hundred years or so was it discovered that the sun produces light through nuclear fusion. It was known for thousands of years that muscles were responsible for many bodily movements, but only in recent decades have scientists begun to unravel the biochemical level mechanisms that give muscles their contractile properties. Given that this is standard fare in the history of science, we should not be all that surprised to find solid evidence that the brain gives rise to conscious experiences, even though we do not have much of a clue as to how the brain actually does it.
9 A. Noë, Out of Our Heads: Why You are not Your Brain, and Other Lessons from the Biology of Consciousness, op. cit., 54.
10 Ibid.
11 Ibid.
12 Ibid., 56.
13 Roe, A., Pallas, S., Hahm, J. and Sur, M., ‘A Map of Visual Space Induced in Primary Auditory Cortex’, Science 250 (1990), 818CrossRefGoogle ScholarPubMed.
14 Ibid.
15 See the abstract to Sharma, J., Angelucci, A. and Sur, M., ‘Induction of Visual Orientation Modules in Auditory Cortex’, Nature 404 (2000), 841–7CrossRefGoogle ScholarPubMed.
16 A. Roe, S. Pallas, J. Hahm and M. Sur, ‘A Map of Visual Space Induced in Primary Auditory Cortex’, op. cit.
17 Ibid.
18 J. Sharma, A. Angelucci and M. Sur, ‘Induction of Visual Orientation Modules in Auditory Cortex’, op. cit.
19 Ibid.
20 A. Noë, Out of Our Heads: Why You are not Your Brain, and Other Lessons from the Biology of Consciousness, op. cit., 10.
21 Ibid., 146. Anthony Morse has noted that action can take the form of mental simulation or imagination, hence that it does not necessarily require physical movement, muscle contraction, or behavior. Moreover, in an unpublished paper, Nivedita Gangopadhyay draws attention to the following:
Being engaged in a skill does not require that we are at this moment actually executing any action. Just as an explorer is still an explorer when he rests overnight in his tent, just as we are engaged in tying our shoelaces when we briefly pause at one moment in the action, we can be engaged in a sensorimotor skill without at this moment actually performing any action. Nevertheless, we have to be in a state of having cognitive access to the fact that certain movements, if we were to perform them would result in certain consequences in the sensory input. O'Regan, J. K. ‘The Sensorimotor Approach to Phenomenal Consciousness’ (2006), Retrieved June 18, 2009, from http://www.whatfeelingislike.net/tiki-index.php?page=The+Sensorimotor+Approach+to+Phenomenal+Consciousness.
Neither O'Regan nor I hold that action or behavior is necessary for qualia to occur. What we have argued is that the quality of experience depends on implicit knowledge of the sensory effects of movements (whether or not one actually moves). Noë, A., ‘Magic Realism and the Limits of Intelligibility: What Makes us Conscious’, Philosophical Perspectives 21 (2007), 457–474CrossRefGoogle Scholar.
So, there are grounds for thinking that Noë's view is that neither perception nor consciousness require bodily movements. Nevertheless, there are also grounds for thinking that Noë's view is that perception and consciousness do require bodily movements, namely, the passages cited. Cf. also, Noë, A., Action in Perception (Cambridge, MA: MIT Press, 2004), 1–3Google Scholar.
22 Locked-in syndrome provides another type of problematic case for Noë. In Out of Our Heads, Noë notes that there are individuals who suffer from locked-in syndrome (A. Noë, Out of Our Heads: Why You are not Your Brain, and Other Lessons from the Biology of Consciousness, op. cit., 14–16). These individuals appear to be totally unconscious, displaying no actions or behaviors commonly taken to be indicative of consciousness, but they are nonetheless conscious. How is this possible on Noë's view? If consciousness requires the joint operation of the brain, body and world – if seeing is an activity of exploring the world – then how can there be completely inactive individuals who are nonetheless conscious?
23 This discussion borrows from Adams, F. and Aizawa, K., The Bounds of Cognition (Malden, MA: Blackwell Publishers, 2008)Google Scholar, Chapter 9.
24 Other studies not reviewed here include Smith, S. M., Brown, H. O., Toman, J. E., and Goodman, L. S., ‘The Lack of Cerebral Effects of d-Tubocurarine’, Anesthesiology 8 (1947), 1–14Google Scholar; Campbell, E., Godfrey, S., Clark, T., Freedman, S. and Norman, J., ‘The Effect of Muscular Paralysis Induced by Tubocurarine on the Duration and Sensation of Breath-holding during Hypercapnia’, Clinical Science 36 (1969), 323Google Scholar; Campbell, E., Godfrey, S., Clark, T., Robson, J. G. and Norman, J., ‘The Effect of Muscular Paralysis Induced by Tubocurarine on the Duration and Sensation of Breath-holding’, Clinical Science 32 (1967), 425–32Google Scholar; Froese, A. and Bryan, A., ‘Effects of Anesthesia and Paralysis on Diaphragmatic Mechanics in Man’, Anesthesiology 41 (1974), 242–55Google Scholar; Stevens, J., Emerson, R., Gerstein, G., Kallos, T., Neufeld, G. and Nichols, C., ‘Paralysis of the Awake Human: Visual Perceptions’, Vision Research 16 (1976), 93–8Google Scholar.
25 Topulos, G., Lansing, R. and Banzett, R., ‘The Experience of Complete Neuromuscular Blockade in Awake Humans’, Survey of Anesthesiology 38 (1993), 133CrossRefGoogle Scholar.
26 Ibid.
27 Anonymous, , ‘On Being Aware’, British Journal of Anaesthesia 51 (1979), 711–2Google Scholar.
28 Miura, S., Kashimoto, S., Yamaguchi, T. and Matsukawa, T., ‘A Case of Awareness with Sevoflurane and Epidural Anesthesia in Ovarian Tumorectomy’, Journal of Clinical Anesthesia 13 (2001), 227–9CrossRefGoogle ScholarPubMed.
29 Schwender, D., Kunze-Kronawitter, H., Dietrich, P., Klasing, S., Forst, H. and Madler, C., ‘Conscious Awareness during General Anaesthesia: Patients' Perceptions, Emotions, Cognition and Reactions’, British Journal of Anaesthesia 80 (1998), 133–9CrossRefGoogle ScholarPubMed.
30 Sandin, R., Enlund, G., Samuelsson, P. and Lennmarken, C., ‘Awareness during Anaesthesia: A Prospective Case Study’, The Lancet 355 (2000), 707–11CrossRefGoogle ScholarPubMed.
31 A. Noë, Action in Perception, op. cit., 12. Note Noë's minor mis-step of equating paralysis with quadriplegia. The case of muscular blockade indicates the difference.
32 In fact, it is Anthony Morse's contention that Noë only ever intends what is here described as the weaker view. That seems to me incorrect, but it is perhaps fair to say that the most extensively argued version of Noë's theory is the weaker possession version.
33 See, for example, Sekuler, A. and Palmer, S., ‘Perception of Partly Occluded Objects: A Microgenetic Analysis’, Journal of Experimental Psychology: General 121 (1992), 95–111CrossRefGoogle Scholar.
34 Noë uses different terms for this distinction at different times. At one point, the distinction is described as being between what one strictly speaking sees and what one perceptually experiences and, at another, as being between what one strictly speaking perceives and what is perceptually present:
A cat sits motionless on the far side of a picket fence. You have a sense of the presence of the cat even though, strictly speaking, you only see those parts of the cat that show through the fence. How is it that we can in this way enjoy a perceptual experience as of a whole cat?
These are instances of the problem of perceptual presence. We have a sense of the presence of that which, strictly speaking, we do not perceive. (A. Noë, Action in Perception, op. cit., 60).
For simplicity and clarity, the current discussion will use only the former terminology.
35 A. Noë, Action in Perception, op. cit., 163–4.
36 Ibid., 163.
37 Ibid., 164.
38 Ibid., 64–5.
39 In truth, Noë seems a bit equivocal on this score. On the one hand, there is the third paragraph of the cited text below in which Noë claims that we have a perceptual experience, or sense the perceptual presence, of the detail of the world (in the periphery?), but, on the other, he also denies that we experience detail in the periphery: ‘we don't experience the periphery of our visual field in anything like the clarity, detail, or focus with which we can take in what we are directly looking at’ (Ibid., 49).
40 Ibid., 63.
41 One can construct a similar counterexample by using a bit of text in which a central fixation point is in sharp focus, but in which the periphery is defocused. The entire text appears to be sharp, but this cannot be because one has access now to detail in the periphery (cf. the third paragraph from Noë cited above), since there is no such detail in the periphery.
Notice as well that the problem with amodal completion has been developed in terms of three dimensional objects, such as thin circular and square blocks, rather than in terms of two dimensional drawings that are typically used to illustrate the phenomenon. The problem, however, seems even more serious when we note that there is amodal completion with drawn figures. The problem is apparently harder, since movement-dependent and object-dependent motion SMK does not provide the kind of information that would inform amodal completion. This point is made in B. Nenay, ‘Four theories of amodal perception’, Proceedings of the 29th Annual Conference of the Cognitive Science Society (2007), 1333.
42 See A. Noë, Action in Perception, op. cit., 7–10. Noë also discusses Paul Bach-y-Rita's experiments with Tactile-Visual Sensory Substitution (TVSS) equipment in this connection (26–7).
43 In personal correspondence, Anthony Morse has proposed that it is because one knows that U and G look alike from 20 feet away that makes U and G generate the same perceptual experience from 20 feet away, rather than different perceptual experiences from 20 feet away. Making this move to block the counterexample would, however, undermine Noë's entire approach. Presumably in viewing the black rectangle adjacent to a white Pac-Man from position p, one knows that they look like a black rectangle adjacent to white Pac-Man from position p, so that, by parity of reasoning, from position p one should perceptually experience them as a black rectangle and a white Pac-Man, rather than as a black rectangle occluding a white circle.
44 A. Noë, Action in Perception, op. cit., 164.
45 Thanks to Gennady Erlikhman, Nivedita Gangopadhyay, Anthony Morse, and Larry Shapiro for helpful comments on an earlier draft of this paper.
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