Reproduced from Living Marxism issue 72, October 1994
note from the author, 12/18/2000:
"The magazine (Living Marxism) has since fallen off the face of the earth......and has been replaced with an online publication: Spike"


THE MARXIST REVIEW OF BOOKS

Stuart Derbyshire examines the latest debate about what shapes human consciousness

Mind over matter

The Astonishing Hypothesis: The Scientific Search for the Soul, Francis Crick, Simon & Schuster, £16.99 hbk
Bright Air, Brilliant Fire: On the Matter of the Mind, Gerald Edelman, Penguin, £7.99 pbk
The Rediscovery of the Mind, John Searle, MIT Press, £19.95 hbk, £9.95 pbk
Consciousness Explained, Daniel Dennett, Penguin, £20 hbk, £7.99 pbk
How the Self Controls its Brain, John C Eccles, Springer Verlag, £23 hbk

Imagine for a moment that you have been asked to invent or design a robot that can roam around a room, avoid obstacles, pick up specified objects on the way, all without any direct human input beyond the original design and manufacture. This is the 'visual problem', the problem of how we see, that Francis Crick sets out to examine with his Astonishing Hypothesis. Crick focuses on vision because he says that the different aspects of consciousness are likely to employ a basic common mechanism such that explaining visual consciousness will aid in the total explanation of human consciousness.

Like most of the scientists under review here, Crick is trying to develop a materialist alternative to the dualism of mind and body. The crudest form of dualism is the pro-posal of a homunculus--a little man sitting in the brain analysing the inputs, like those in the Numskulls comic-strip from the Beezer. The homunculus is easily dispensed with. If there are little Numskulls sitting in our brains watching the retinal input, listening to auditory input and so forth, what is in their heads?

John Eccles' account of human consciousness utilises a more sophisticated dualism than the Numskulls. Instead of a little man, something greater than man is postulated to coordinate the mechanical activities of the brain and interpret its messages: the soul. And there can be no easy logical explanation of such a spiritual force as the soul.

The way to cut though this supernatural nonsense is to examine the relation between the experience of the human being in society and the shaping of human consciuosness. Yet this relation is ignored by Crick and the other rationally minded authors reviewed here. As a consequence they unwittingly jettison all that is associated with being conscious, things such as beauty, culture, free will and so on. Much to the annoyance of Crick and the delight of Eccles, mysticism can then fill in the vacuum left behind. A one-sided explanation of humanity in terms of biology ignores the social relations which make up our experienced self or consciousness. This is the Achilles' heel which Eccles attacks to defend dualism. 'Since materialists' solutions fail to account for our experienced uniqueness', he writes, 'I am constrained to attribute the uniqueness of the self or soul to a supernatural spiritual creation' (p180).

Crick's fanfare as he unfolds his materialist theory of consciousness is a poor attempt at disguising this inherent weakness:

'The Astonishing Hypothesis is that "You", your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behaviour of a vast assembly of nerve cells and their associated molecules.' (p3)

Crick settles on the way vision works as the model of consciousness because vision happens to be one function which is well localised in the central nervous system (to the occipital cortex at the back of the brain) and is well described by neurologists, medics and mathematicians.

More than 15 years ago David Marr described how a brain could extract visual information based on the mathematical properties of light and dark falling on the retina. Simply put, Marr explained how, via the use of a cell with a centre which is excited by light and a surround that is inhibited by light, any system can detect edges of light and dark. The specific mechanisms, however, are not important, the key point is that Marr solved the 'visual problem' outlined above without recourse to an external intelligent agent. Marr proposed in computational terms how the brain could 'see' without the need for a homunculus.

Crick's thesis is that by unravelling, 'Marr-like', all the neuronal properties of the brain, we will come to a theory of consciousness. He is wrong. The issue here is self-consciousness, not just knowledge, but knowledge of knowledge or knowing that you know. However detailed our understanding of neurology becomes, it will still not constitute an understanding of subjectivity or human consciousness. In the case of the seeing robot, the problem remains that the robot 'sees' but does not know that it sees. How can something that is operating on a computational basis become a something that knows of itself? This is the crux of the problem that has tied philosophers, neurologists, cognitive scientists and Nobel Prize-winners alike in knots.

Having asserted that you are nothing more than a collection of nerve cells, the next assertion is that the complexity of those nerve cells gives rise to consciousness. Crick claims that 'it is probable, however, that con-sciousness correlates to some extent with the degree of complexity of any nervous system' (p21). Self-awareness and the special properties of consciousness seem less inexplicable when seen in the light of the extraordinary complexity of the brain. This view is echoed by Gerald Edelman: 'But here is an astonishing fact--there are about one million billion connections in the cortical sheet. If you were to count them, one connection (or synapse) per second, you would finish counting some 32m years after you began.' (Bright Air, Brilliant Fire, p17)

I get concerned when neurologists talk of brain areas as experiencing human attributes such as pleasure or consciousness

But complexity is specific to the observer and the times; our imaginary robot has by now become a pretty complex piece of electronic gadgetry, but it still is not conscious. In fact, very many things are complex from your household washing machine to the movement of international finance, but they are not conscious either. It would seem, as John Searle rightly argues, that consciousness does not arise from complexity as such, which is lucky because the actual neurology of the brain simply does not hold out the astonishing complexity Crick and Edelman imply. The 10 billion neurons with 10 trillion connections between them may imply a bewildering level of incomprehension, but, by dividing the second number with the first we can arrive at the number of connections made by each single neuron, which is just 1000. This surprisingly low number demonstrates that the brain is organised as a collection of small local circuits which implies areas of specialised activity.

If consciousness cannot be explained in terms of the complexity of neuronal organisation alone, perhaps it lies within the complex integration of the local circuits carrying out the computations? Crick's book is dedicated to the visual circuits, his accounts of the various visual areas (V1, V2...V5) give a fascinating insight into the organisation of the occipital cortex and a keen illustration of the active, constructive, as opposed to passive, nature of vision. But Crick reduces consciousness to a banality when he tries to explain it in terms of visual illusions. After a long discussion, which can be summarised by saying 'sometimes looks can be deceptive', it becomes of intense importance to prove that the brain can still make up a visual scene in the absence of full information:

'The visual psychologist VS Ramachandran [has shown] a subject a picture of a yellow annulus (ie, a thick ring, or doughnut). The subject had to keep his eyes still and view the world with only one eye. Ramachandran positioned the yellow ring in the subject's visual field so that its outer rim was outside the subject's blind spot, while its inner rim was inside it. The subject reported that what he saw was not a yellow ring, but a complete homogeneous yellow disk.' (p55)

Hence the blind spot that we all carry due to the optical nerve occluding part of our retina goes largely unnoticed because of the brain's capacity to 'fill in'. This may be an important discovery which illustrates the active nature of vision, but the step from this process to consciousness is more than one of degree. Perhaps recognising this, Crick begins to draw in other brain mechanisms to flesh out his hypothesis, like memory circuits and the attention. A picture is built up of several cognitive or computational boxes feeding in towards some centre where consciousness will be. Thus, for Crick, 'Free will is located in or near the anterior cingulate sulcus' (p268), for John Searle 'the basis of consciousness is in...perhaps, the reticular formation' (p67). Edelman may shy away from specifying any particular area as being responsible for consciousness, but he does link the development of the hippocampus as a long-term memory store to the general complexity of the brain and presents his theory of consciousness as an emergent property arising from the development of long-term and short-term memories (p132).

Edelman may be right in suggesting that long and short-term memory are necessary for the development of consciousness, but when he calls areas of the brain 'hedonic' (pleasure-seeking) he confuses the biological substrate with the thing itself. I get concerned when neurologists talk of brain areas as experiencing human attributes such as pleasure or consciousness. The Anterior cingulate cortex is not conscious of anything, any more than hippocampal loops are happy; only social beings are conscious and, sometimes, they can be happy. Failure to recognise this empties human consciousness of its process and presents it as an 'explosion' of complexity; a mishmash of computations. This failure encourages mystical interpretation.

Daniel Dennett highlights the dualistic implications of proposing a neurological centre for consciousness, as the French philosopher Ren Descartes did with the pineal gland more than three centuries ago. The ancient belief that there is a spiritual mind in addition to the physical mind is rightly seen as unscientific and detrimental to scientific progress, but 'while materialism of one sort or another is now a received opinion approaching unanimity, even the most sophisticated materialists today often forget that once Descartes' ghostly res cogitans is discarded, there is no longer a role for a centralised gateway, or indeed for any functional centre to the brain' (p106).

Dennett does well to rid us of the need for a centre of consciousness and gives a convincing explanation of the discontinuity (blind spots) of everyday experience which requires the whole brain to be active in producing 'multiple drafts' of a final experience. However, when we finally get to Dennett's explanation of consciousness it is sorely disappointing:

'I haven't replaced a metaphorical theory, the Cartesian Theatre, with a non-metaphorical ("literal, scientific") theory. All I have done, really, is to replace one family of metaphors and images with another, trading in the Theatre, the Witness, the Central Meaner, the Figment, for Software, Virtual Machines, Multiple Drafts, a Pandemonium of Homunculi. It's just a war of metaphors.' (p455)

Dennett should have applied his valuable insight regarding the neurological centre for consciousness to his own theory. After all, Dennett has merely taken the pineal gland, the hippocampus, anterior cingulate cortex, or whatever chunk of brain takes the researchers' fancy, and, like Edelman, replaced it with the brain, or maybe the organism. This reduces to saying 'the organism is conscious' which is true, but not particularly explanatory. The continued assertion of consciousness rather than any real explanation is used by Eccles to demonstrate the common sense necessity of a supernatural explanation of humanity.

Eccles is highly critical of materialism arguing that there is nothing in physics (or materialism in general) that singles out brain processes as being in any way special. They are special only because they can be associated in a certain way with things outside classical physics, namely possible conscious experience. This is a perfectly acceptable point, which is largely ignored by Crick and the other materialists. Eccles is arguing that once biology reaches some critical point or mass it becomes more than just biology. In other words, you are not just 'the behaviour of a vast assembly of nerve cells' you are something more. This point is probably ignored because Eccles' conclusion is unacceptable to materialism, for Eccles the 'something more' is provided by God and anything else is ridiculed as 'neuronal fantasia' (p28).

Ultimately, Eccles is making a virtue of the poor understanding of how our experienced self relates to our brain and is using this as a vehicle to 'reinstate the spiritual self as the controller of the brain' (px). Like the materialists, Eccles' complete theory of 'how the self controls its brain' ends up degrading humanity, but this time in favour of divine intervention not biology. Rather than a biological milieu, Eccles proposes an a priori world of thoughts, feelings, memories, intentions and emotions 'which we must regard as a miracle beyond Darwinian evolution' (p139).

Far from being liberating as Eccles suggests, this formula reduces humanity to nothing but zombie intermediaries for an already fully formed other world. This total annihilation of rationality means that Eccles' is easily dismissed in entirety, his earlier more rational ideas sadly ignored.

A newborn child is not a priori endowed with knowledge, never mind knowledge of knowledge and subjectivity. It has to learn. A baby is naive about everything. This is not to deny biology, because of course everything that the baby learns, including its own sense of self, is only possible because of the evolutionary development of our biology. Furthermore, it is true that, through development, this sense of self will mould neurology (possibly according to Edelman's 'Theory of neuronal group selection'). Everything that we do and think has some sort of neuronal representation. 'You', however, are much more than this.

Only the pressure of having to work with others, making ideas commonly understandable, forces the subordination of our instinctual biology to our conscious will

A child may build up an extensive memory of motor responses based on instinct, but like the imaginary robot at the beginning, could still not know anything. In fact, if left entirely alone, a human being would operate in an unconscious, computational manner. Only the pressure of having to work with others, making ideas commonly understandable, forces the subordination of our instinctual biology to our conscious will. The child's intellectual growth is contingent on his mastering the social means of thought, that is language. By naming things it is possible to reflect and thus to become self-aware. The develop-ment of verbal thought changes the nature of development itself, it ceases to be a biological process and becomes a sociohistorical one. Verbal thought is determined by a historical-cultural process with specific properties and laws that cannot be found in our nature or biology. Human nature or consciousness is moulded by what we create.

It would be wrong to suggest that the authors reviewed here have made no attempt to come to grips with the social, but it is never seen as central to the development of the individual. It is always peripheral, 'background' for Searle, 'memes' or bits 'n' pieces of culture for Dennett, a product of 'our original need for value' for Edelman. Society is seen as something that our biology utilises rather than as something constitutive. Edelman may be right 'that before language evolved, the brain already had the necessary bases for meanings in its capacities to produce and act on concepts' (p126). But the key change came as man began to interact, produce tools and work together. This social development would have provided the necessary force for the development of language and consciousness. Maybe early on in our history, natural selection would have worked to weed out those who did not have language capacity or the proper hand to mould tools or whatever, but we can now be sure that we have left natural selection behind. With our biology intact for many thousands of years, human consciousness has gradually progressed and decisively separated us off from the rest of the animal kingdom. We are free from the computations of instinct to forge our own destiny.




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