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"
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.
Go to John's Book Page.
Go to John's
Home Page.