[ExI] Raymond Tallis: You won't find consciousness in the brain

[Damien Broderick]

New Scientist: You won't find consciousness in the brain

<http://www.newscientist.com/article/mg20527427.100-you-wont-find-consciousness-in-the-brain.html>

7 January 2010 by Ray Tallis

[Raymond Tallis wrote a wonderful deconstruction of deconstruction and 
poststructuralism, NOT SAUSSURE]

MOST neuroscientists, philosophers of the mind and science
journalists feel the time is near when we will be able to explain
the mystery of human consciousness in terms of the activity of the
brain. There is, however, a vocal minority of neurosceptics who
contest this orthodoxy. Among them are those who focus on claims
neuroscience makes about the preciseness of correlations between
indirectly observed neural activity and different mental functions,
states or experiences.

This was well captured in a 2009 article in Perspectives on
Psychological Science by Harold Pashler from the University of
California, San Diego, and colleagues, that argued: "...these
correlations are higher than should be expected given the (evidently
limited) reliability of both fMRI and personality measures. The high
correlations are all the more puzzling because method sections
rarely contain much detail about how the correlations were
obtained."

Believers will counter that this is irrelevant: as our means of
capturing and analysing neural activity become more powerful, so we
will be able to make more precise correlations between the quantity,
pattern and location of neural activity and aspects of
consciousness.

This may well happen, but my argument is not about technical,
probably temporary, limitations. It is about the deep philosophical
confusion embedded in the assumption that if you can correlate
neural activity with consciousness, then you have demonstrated they
are one and the same thing, and that a physical science such as
neurophysiology is able to show what consciousness truly is.

Many neurosceptics have argued that neural activity is nothing like
experience, and that the least one might expect if A and B are the
same is that they be indistinguishable from each other. Countering
that objection by claiming that, say, activity in the occipital
cortex and the sensation of light are two aspects of the same thing
does not hold up because the existence of "aspects" depends on the
prior existence of consciousness and cannot be used to explain the
relationship between neural activity and consciousness.

This disposes of the famous claim by John Searle, Slusser Professor
of Philosophy at the University of California, Berkeley: that neural
activity and conscious experience stand in the same relationship as
molecules of H[2]O to water, with its properties of wetness,
coldness, shininess and so on. The analogy fails as the level at
which water can be seen as molecules, on the one hand, and as wet,
shiny, cold stuff on the other, are intended to correspond to
different "levels" at which we are conscious of it. But the
existence of levels of experience or of description presupposes
consciousness. Water does not intrinsically have these levels.

We cannot therefore conclude that when we see what seem to be neural
correlates of consciousness that we are seeing consciousness itself.
While neural activity of a certain kind is a necessary condition for
every manifestation of consciousness, from the lightest sensation to
the most exquisitely constructed sense of self, it is neither a
sufficient condition of it, nor, still less, is it identical with
it. If it were identical, then we would be left with the insuperable
problem of explaining how intracranial nerve impulses, which are
material events, could "reach out" to extracranial objects in order
to be "of" or "about" them. Straightforward physical causation
explains how light from an object brings about events in the
occipital cortex. No such explanation is available as to how those
neural events are "about" the physical object. Biophysical science
explains how the light gets in but not how the gaze looks out.

Many features of ordinary consciousness also resist neurological
explanation. Take the unity of consciousness. I can relate things I
experience at a given time (the pressure of the seat on my bottom,
the sound of traffic, my thoughts) to one another as elements of a
single moment. Researchers have attempted to explain this unity,
invoking quantum coherence (the cytoskeletal micro-tubules of Stuart
Hameroff at the University of Arizona, and Roger Penrose at the
University of Oxford), electromagnetic fields (Johnjoe McFadden,
University of Surrey), or rhythmic discharges in the brain (the late
Francis Crick).

These fail because they assume that an objective unity or uniformity
of nerve impulses would be subjectively available, which, of course,
it won't be. Even less would this explain the unification of
entities that are, at the same time, experienced as distinct. My
sensory field is a many-layered whole that also maintains its
multiplicity. There is nothing in the convergence or coherence of
neural pathways that gives us this "merging without mushing", this
ability to see things as both whole and separate.

And there is an insuperable problem with a sense of past and future.
Take memory. It is typically seen as being "stored" as the effects
of experience which leave enduring changes in, for example, the
properties of synapses and consequently in circuitry in the nervous
system. But when I "remember", I explicitly reach out of the present
to something that is explicitly past. A synapse, being a physical
structure, does not have anything other than its present state. It
does not, as you and I do, reach temporally upstream from the
effects of experience to the experience that brought about the
effects. In other words, the sense of the past cannot exist in a
physical system. This is consistent with the fact that the physics
of time does not allow for tenses: Einstein called the distinction
between past, present and future a "stubbornly persistent illusion".

There are also problems with notions of the self, with the
initiation of action, and with free will. Some neurophilosophers
deal with these by denying their existence, but an account of
consciousness that cannot find a basis for voluntary activity or the
sense of self should conclude not that these things are unreal but
that neuroscience provides at the very least an incomplete
explanation of consciousness.

I believe there is a fundamental, but not obvious, reason why that
explanation will always remain incomplete - or unrealisable. This
concerns the disjunction between the objects of science and the
contents of consciousness. Science begins when we escape our
subjective, first-person experiences into objective measurement, and
reach towards a vantage point the philosopher Thomas Nagel called
"the view from nowhere". You think the table over there is large, I
may think it is small. We measure it and find that it is 0.66 metres
square. We now characterise the table in a way that is less beholden
to personal experience.

Thus measurement takes us further from experience and the phenomena
of subjective consciousness to a realm where things are described in
abstract but quantitative terms. To do its work, physical science
has to discard "secondary qualities", such as colour, warmth or
cold, taste - in short, the basic contents of consciousness. For the
physicist then, light is not in itself bright or colourful, it is a
mixture of vibrations in an electromagnetic field of different
frequencies. The material world, far from being the noisy,
colourful, smelly place we live in, is colourless, silent, full of
odourless molecules, atoms, particles, whose nature and behaviour is
best described mathematically. In short, physical science is about
the marginalisation, or even the disappearance, of phenomenal
appearance/qualia, the redness of red wine or the smell of a smelly
dog.

Consciousness, on the other hand, is all about phenomenal
appearances/qualia. As science moves from appearances/qualia and
toward quantities that do not themselves have the kinds of
manifestation that make up our experiences, an account of
consciousness in terms of nerve impulses must be a contradiction in
terms. There is nothing in physical science that can explain why a
physical object such as a brain should ascribe appearances/qualia to
material objects that do not intrinsically have them.

Material objects require consciousness in order to "appear". Then
their "appearings" will depend on the viewpoint of the conscious
observer. This must not be taken to imply that there are no
constraints on the appearance of objects once they are objects of
consciousness.

Our failure to explain consciousness in terms of neural activity
inside the brain inside the skull is not due to technical
limitations which can be overcome. It is due to the
self-contradictory nature of the task, of which the failure to
explain "aboutness", the unity and multiplicity of our awareness,
the explicit presence of the past, the initiation of actions, the
construction of self are just symptoms. We cannot explain
"appearings" using an objective approach that has set aside
appearings as unreal and which seeks a reality in mass/energy that
neither appears in itself nor has the means to make other items
appear. The brain, seen as a physical object, no more has a world of
things appearing to it than does any other physical object.

Profile

Ray Tallis trained as a doctor, ultimately becoming professor of
geriatric medicine at the University of Manchester, UK, where he
oversaw a major neuroscience project. He is a Fellow of the Academy
of Medical Sciences and a writer on areas ranging from consciousness
to medical ethics