(Springer Verlag, Berlin, 1977), p. 357.13 13Eccles, Human Mystery, p. 3. Subsequent references in the text to this book will be flagged ‘HM’.
14 14Gottlob Frege, ‘The thought’, in his Collected Papers on Mathematics, Logic and Philosophy (Blackwell, Oxford, 1984), pp. 351–72.
15 15This error is still common among neuroscientists, and informs the research of Benjamin Libet and his colleagues that we discuss below (see §§9.1–9.2).
16 16Quoted by Eccles, without a reference, in Popper and Eccles, Self and its Brain, p. 374.
17 17Ibid., p. 358.
18 18See, e.g., F. Crick, The Astonishing Hypothesis ( Touchstone, London, 1995), pp. 22, 232, and E. Kandel and R. Wurtz, ‘Constructing the visual image’, in E. R. Kandel, J. H. Schwartz and T. M. Jessell (eds), Principles of Neural Science ( Elsevier, New York, 2001), pp. 492, 502. ( The binding problem is discussed in §4.2.3 below.)
19 19A. K. Engel, P. R. Roelfsema, P. Fries, M. Brecht and W. Singer, ‘Role of the temporal domain for response selection and perceptual binding’, Cerebral Cortex, 6 (1997), pp. 571–82.
20 20So, for example, Crick called his theory of attention ‘the searchlight hypothesis’, since, he claimed, the reticular complex and the pulvinar promote only a small proportion of the activity of the thalamus on its way to the cortex, and this activity can be likened to a searchlight that lights up a part of the cortex. Crick suggested that the thalamic reticular complex and the pulvinar interact with the brain stem and with cortical mechanisms to reach a salient decision as to which neuronal groups that are active will be ‘brought into consciousness’ by the spotlight of attention (F. Crick, ‘Function of the thalamic reticular complex: the searchlight hypothesis’, Proceedings of the Natlional Academy of Science USA, 81 (1984), pp. 4586–5490). Similarly, the notion of a scanning device or ‘monitor’ in the brain was invoked by Weiskrantz in connection with his investigations of blind-sight. In his view, the awareness that a normally sighted person has of whether he sees something in his visual field and of what he sees results from the operation of a neural monitoring system. Conscious experience, according to Weiskrantz, is the product of the monitoring function of the brain ( L. Weiskrantz, ‘Neuropsychology and the nature of consciousness’, in C. Blakemore and S. Greenfield (eds), Mindwaves ( Blackwell, Oxford, 1987), pp. 307–20). It is interesting that whereas Crick and Weiskrantz apply these metaphors to the brain, Eccles applied them to the mind.
21 21Neuroscientists’ misdescriptions of split-brain patients’ abilities and their exercise is examined and rectified in §17.3 below.
22 22W. Penfield, The Mystery of the Mind: A Critical Study of Consciousness and the Human Brain (Princeton University Press, Princeton, 1975), p. 1. Subsequent references in the text to this volume will be flagged ‘MM’.
23 23J. H. Jackson, ‘On the anatomical, physiological and pathological investigations of epilepsies’, West Riding Lunatic Asylum Medical Reports, 3 (1873), pp. 315–19.
24 24Penfield obviously meant that it was the closest approximation to the concept of a butterfly.
25 25Indeed, to explain what the mind or spirit is, Penfield quoted Webster’s Dictionary: ‘the element … in an individual that feels, perceives, thinks, wills and especially reasons’ (MM 11).
26 26It is striking to compare Penfield’s conception of this matter with Descartes’s remarkable simile in his Treatise on Man: ‘when a rational soul is present in this machine [namely, the body] it will have its principal seat in the brain, and reside there like the fountain keeper who must be stationed at the tanks to which the fountain’s pipes return if he wants to produce, or prevent, or change their movements in some way’ (AT XI, 131). Here the tank is the ventricle in which the pineal gland is allegedly suspended, the pipes are the nerves and the water the animal spirits.
3 The Mereological Fallacy in Neuroscience
3.1 Mereological Confusions in Cognitive Neuroscience
Ascribing psychological attributes to the brain
Leading figures of the first two generations of modern brain-neuroscientists were fundamentally Cartesian. Like Descartes, they distinguished the mind from the brain, and ascribed psychological attributes to the mind. The ascription of such attributes to human beings was, accordingly, derivative – as in Cartesian metaphysics. The third generation of neuroscientists, however, repudiated the dualism of their teachers. In the course of explaining the possession of psychological attributes by human beings, they ascribed such attributes not to the mind but to the brain or parts of the brain.
Neuroscientists assume that the brain has a wide range of cognitive, cogitative, perceptual and volitional powers. Francis Crick asserts:
What you see is not what is really there; it is what your brain believes is there.… Your brain makes the best interpretation it can according to its previous experience and the limited and ambiguous information provided by your eyes.… the brain combines the information provided by the many distinct features of the visual scene (aspects of shape, colour, movement, etc.) and settles on the most plausible interpretation of all these various clues taken together.… what the brain has to build up is a many-levelled interpretation of the visual scene.… [Filling-in] allows the brain to guess a complete picture from only partial information – a very useful ability.1
So the brain has experiences, believes things, interprets clues on the basis of information made available to it, and makes guesses. Gerald Edelman holds that structures within the brain ‘categorize, discriminate, and recombine the various brain activities occurring in different kinds of global mappings’, and that the brain ‘recursively relates semantic to phonological sequences and then generates syntactic correspondences, not from preexisting rules, but by treating rules developing in memory as objects for conceptual manipulation’.2 Accordingly, the brain categorizes; indeed, it ‘categorizes its own activities (particularly its perceptual categorizations)’, and conceptually manipulates rules. Colin Blakemore argues that
We seem driven to say that such neurons [as respond in a highly specific manner to, e.g., line orientation] have knowledge. They have intelligence, for they are able to estimate the probability of outside events – events that are important to the animal in question. And the brain gains its knowledge by a process analogous to the inductive reasoning of the classical scientific method. Neurons present arguments to the brain based on the specific features that they detect, arguments on which the brain constructs its hypothesis of perception.3
So
