by John G. Taylor
MIT Press, 1999
Review by Paul Bohan Broderick, Ph.D. on May 26th 2002
John Taylors The Race for Consciousness is successful as a guided tour of many
important topics in neuroscience and related disciplines. It is not successful
in every regard. The Race for
Consciousness is not the final word on either this model or in consciousness
in general. It does not really provide any evidence that the race for the final
explanation of consciousness has begun in earnest.
The text is not limited to the
exciting results of the moment. Taylors broad experience in neuroscience,
coupled with an obvious respect for the history of the study of conscience,
makes for a respectable reading experience (so long as one does not expect a
book of pop science). Along the way various proposals are put forward to lend
support the Relational Theory of Consciousness (henceforth, RTC). Taylor
originally proposed this model in 1973 and this book provides a useful
introduction for the non-specialist.
There are significant books that
chronicle particular races in the history of science. As I was reading this
book, it occurred to me that I didnt know of any books on the history of
science that focused on the concept of a scientific race. There have been many
instances where the race metaphor has been appropriate, where there were
competitors who were aware of each other shared a goal and a general approach
to that goal (though perhaps disagreeing on the details of how the course
should be run). Taylor uses the race metaphor throughout his book. In this
case, the metaphor was poorly chosen. Perhaps a metaphor based on touring would
have been more appropriate. There no indication that someone might soon break
free from the pack and cross the finish line hinted at in the title. There are
however a great number of things to be seen along the way that are great opportunities
for learning, for those unfamiliar with the material, or wonder, for those who
are revisiting this material.
Although the many research teams
working on various approaches to consciousness are clearly aware of each other,
they dont arent all racing to the same finish line. This reflects that there
isnt really a single problem of consciousness ripe for solving. Instead
there are a number of problems of varying degrees of difficulty and
independence. Although Taylor identifies the finish line of the race for
consciousness with what David Chalmers calls The Hard Problem, he tends to
redefine it in a way that makes it not nearly as difficult as the problem that
Chalmers presents. Taylors project is to discover the features that neural
events possess when they cross the threshold from brain state to brain state
with consciousness, in his words what are the sufficient conditions for
consciousness? The hard problem is much closer to why are these the
sufficient conditions for consciousness? Given that this is not the same thing
as explaining consciousness, Taylors presentation is bold, detailed and, as
far as this non-scientist can judge, stands a fair chance of being correct.
For example, by discussing zombie
arguments as empirical questions, Taylor avoids the force of these thought
experiments. The strongest defenders of the zombie argument, Chalmers in
particular (as presented in The Conscious Mind, 1996, Oxford University
Press), admit that there are probably no zombies, and that any entity
functionally identical to a conscious entity will probably be conscious. The
problem is that the inference from structures and functions to consciousness
can at most show that some structures correlated with consciousness experience.
These states may have some Darwinian explanation, in the sense that having the
functions enabled by those structures provides some survival advantage. Whats
lacking is an explanation of why another set of qualitative, first person
predicates can also be associated with those particular structures and
functions. This is not to say that a scientific explanation is impossible, just
that the tools necessary for the explanation are not currently available.
Taylors theory does not seem to provide the missing pieces either.
One of Taylors most prominent
goals is to propound the Relational Theory of Consciousness. The theory
concerns a suitably constrained set of relations between memories and occurrent
inputs (including, but not limited to direct inputs from sensory modalities).
Although presented in occasionally dry prose, the relation theory has a poetic
idea at its core: consciousness is a intricate fusion of memory and perception.
Neither all perceptions nor all memories become conscious, but when the two
work together in just the right way then qualitative experience becomes
possible. The impact of sunlight on the retina does not cause a consciousness
of sunlight. Consciousness arises only because that shade of light evokes
specific memories. Of course, the beauty of the ideas involved does make
suspect that explanatory sufficiency is not the only criteria at work in the
development of Taylors theory. I make the RTC sound much softer than it is.
The relation between memories and occurrent thoughts and perceptions is both
specific and complex. Taylor presents the details of these relations as
explicitly as possible within the scope of a 400-page book.
The RTC is a theory of relations
that are not themselves brain states. Taylor asserts that the theory does limit
consciousness to being purely reducible to brain states. In one sense, it meant
to be internalist since the position of the brain in the larger environment is
not taken as being at all constitutive of consciousness. Specifically the
relations are between neural events that encode memories and those that are
occurrent thoughts and perceptions. Memories are taken to be the traces of
prior contact with external objects, so there may well be a stealth externalism
hidden within Taylors explicitly and strongly asserted internalism.
One nice feature of Taylors tour
of contemporary neuroscience is the attention given also the history of the
field. Not only does Taylor use references to the history of philosophy to add
color, he uses somewhat detailed discussion of the history of neuroscience to
add depth. The discussion of the development of imaging technology was usefully
place. Taylors discussion of clinical investigations into the neural
correlates of consciousness performed during the 1960s and 70s presents
interesting material that is often not as well known as it should be.
The detailed presentation is the
great strength of this book. In a relatively small number of pages, this book
covers a great variety of topics in neuroscience without loosing too much
detail. The discussion never falls into a breathless exultation of recent ground
breaking results. History is not ignored, nor is the philosophical importance
of these results. While the relational theory of mind might not be the final
theory of consciousness, it does make for a nice unifying theme to the
discussion. Many well-chosen illustrations enhance the text. Some readers might
consider the text hard going, others might complain that the treatment of
important issues is superficial. There is only so much that can be achieved in
380 pages and Taylor has does a nice job of balancing these competing demands.
While The Race for Consciousness does
not deliver what its title promises, it does deliver a great deal.
2002 Paul Bohan Broderick
Paul Bohan Broderick, Department of
Philosophy, Kent State University, OH.