It is uncommon for empirical
scientists to take up philosophical issues, applying their findings and
hypotheses to the puzzles that so interest philosophers.  But the philosophy of
mind is one area that lends itself to joint efforts, and Jeffery Gray’s Consciousness:
Creeping up on the Hard Problem is a work that exemplifies the utility of
just such an interdisciplinary endeavor.

The scope of the text is
impressive; in twenty chapters, Gray takes up many of the most pressing issues
in the philosophy and science of consciousness. The first six chapters set the
groundwork for Gray’s account of what he (correctly) takes to be the central
puzzle of consciousness: the problem of epiphenomenalism, a problem which we
will consider in some detail below.  According to Gray, the biological
underpinnings of conscious experience are (cybernetic, feedback)
servomechanisms that mediate our interactions with our environment.  Chapters
7-9 present Gray’s account of consciousness efficacy, as well as other aspects
of his overall account, including the provocative suggestion that the world we
perceive is constructed by, and within, the brain.  In Gray’s words: "The
whole of the perceived world, extending to its most substantial features
(solidity, three-dimensional extension, etc.), is a construct of the brain"
(p. 89). The tenth chapter presents a critique of various forms of
functionalism, especially from the perspective of the phenomenon of synaesthesia,
while chapters 11 and 12 consider the prospects for a "global workspace"
approach, one that can successfully navigate the pitfalls of the "Cartesian
Theater."  Ultimately, however, Gray expresses skepticism over the
adequacy of such an approach.  In the next several chapters, Gray considers, in
some detail, the neural correlates of consciousness, differentiating top-down
from bottom-up approaches, and focusing, in particular, on the comparator (see
below) functions of the hippocampus and the parietal lobes.  The sixteenth
chapter considers recent work in physics, especially quantum mechanics, which
may provide insight into the nature of the consciousness-brain relation. 
Chapters 17-19 take up the tricky questions surrounding the nature of the self
(that is conscious).  Of particular importance here are 1) accounts of the self
that require an egocentric model of the external world versus ones that focus
more on (internal) body sense, and 2) the relation of the self to moral
responsibility and agency.  The final chapter provides a comprehensive overview
of the many issues and positions taken up in the text.   

It should now be clear that Gray
considers a great many of the philosophical and theoretical puzzles and
problems surrounding conscious experience and its relation to the natural
world.  I now wish to consider one such problem in more detail.  To his great
credit, Gray recognizes that it is the problem of epiphenomenalism that is the
central challenge of the so-called hard problem.  How are we to account
for the (apparent) causal efficacy of conscious experience?  And what will such
an account imply about its ultimate nature?

It is useful to distinguish two
forms of epiphenomenalism, what I will call "folk psychological" and "metaphysical"
epiphenomenalism.  According to folk psychological epiphenomenalism, conscious
experience does not play the causal roles in perception and decision-making
that that we commonly take it to play.  Perhaps it has no survival value at
all.  Gray presents a powerful case for this problem; while the fast and fluid
activities of everyday life are mediated by (unconscious) neurophysiological
servomechanisms, mechanisms that operate in the frame of tens of milliseconds,
conscious experience, it would seem, comes only after several hundred
milliseconds as a consequence of this unconscious neurophysiological
activity.  So, for example, a tennis player returns a serve before she
is conscious of it.  Contrary to common sense, the servomechanisms that mediate
this activity discharge their function hundreds of milliseconds before she
consciously experiences the serve (p. 72).  Likewise, we often engage in pain
behavior well before we are conscious of the pain (p. 76).  Even in
paradigmatic cases of volition, "decisions are taken a long time before
the subject is consciously aware of having made the decision" (p.
21).  

So the problem of folk
psychological epiphenomenalism stems from the apparent slowness with which the
brain "generates" conscious experience; the servomechanisms that
mediate an organism’s interaction with its environment are considerably faster. 
Given this counter-intuitive result, Gray suggests several possible functions
of conscious experience.  In particular, he argues that when conscious
experience does come, it is seemingly most concerned with novelty and error:
"the unexpected has an especially privileged chance of ‘gaining access’ to
consciousness . . . .  So the proposal is that consciousness acts as a late
error detector" (p. 76).  In order for error to be detected, then, there
must be unconscious servomechanisms that act as a "comparator system,"
a system that compares expectations about what is the correct state of
affairs with how things are.  Hence, the elements that enter consciousness, a
subset of the outputs of the comparator system, are those which are either "(a)
unexpected or (b) provide salient feedback for ongoing motor programs" (p.
79), and "consist in a re-representation of variables . . . initially
controlled unconsciously by the brain’s servomechanisms" (p. 275).

This account, then, suggests that
the function and survival value of conscious experience "lies in the
provision of a mechanism to take a second look (one or two hundreds of
milliseconds after on-line behavioral responding becomes possible) at something
which, in the immediacy of action, has just gone wrong" (p. 92, my
emphasis).  Gray’s late error detection account of the efficacy of conscious
experience is an interesting and potentially useful tonic for the epiphenomic. 
However, its details, implications, and potential limitations go beyond the
scope of our present discussion.

Metaphysical epiphenomenalism, on
the other hand, is a quite different problem requiring a different sort of
solution.  This is the problem of accounting for how conscious experience has any
causal powers at all, a problem which is especially (or uniquely) acute for
dualists who take conscious experience to be, say, non-physical, or,
say, a product of the brain which goes beyond its neurophysiological
properties.  In the first case, it appears that no account of their causal
relevance in a physical world will be forthcoming.  In the second case,
consciousness is seemingly located outside the causal economy of the subject’s
central nervous system.  The neurophysiological goings-on of the subject’s body
and brain are seemingly sufficient to account for its behaviour, and
thus, conscious experience is, so to speak, left entirely out of the loop. 
Note well that any solution to the problem of folk psychological
epiphenomenalism presupposes a solution to the problem of metaphysical
epiphenomenalism; Gray’s late error detection account assumes that, whatever
conscious experiences are, they are the sorts of things that can, in principle,
be part of the causal economy of the subject.

There is a straightforward, if
under-appreciated, solution to the problem of metaphysical epiphenomenalism, a
solution that situates conscious experiences within the subject’s
central nervous system by identifying them with some subset of their neurophysiological
correlates.  On this view, the "qualia" of a subject’s consciousness
are, as a matter of fact, a small subset of a subject’s neurophysiological
properties.  According to the most plausible version of consciousness-body
identity, Herbert Feigl’s dual-access theory, conscious experiences admit two
levels of access: the third-person access had by, say, a neurosurgeon
observing a subject’s brain, and the first-person access had by the subject of
the neurophysiological activity in question; from the first-person point of
view, this activity is "lived through, enjoyed or suffered."[1]
Again, such a view has the great advantage of directly integrating conscious
experiences into the causal economy of the subject.

But while he expresses skepticism
toward both neo-dualism and functionalism, Gray refuses to make this move. 
Indeed, he criticizes what he calls "dual aspect theory" (p.
111, my emphasis) which I take to be a version of dual-access theory. 
(Dual aspect theory is, strictly speaking, a property dualism.) 
Gray recognizes that such a view "would escape both epiphenomenalism and
dualism" (p.111), but objects that the claim of identity is an as yet
un-explained and (therefore) unjustified position.  In other words, Gray is
apparently impressed by the so-called explanatory gap between conscious
experience and brain activity.  While other empirical identities admit such an
explanation, this one does not, and thus, dual-access theory "expresses no
more than an pious hope" (p. 111).  Gray’s skepticism here is, I believe,
misguided.  I have argued elsewhere that the explanatory gap does not challenge
the identity thesis; indeed, according to dual-access theory, neo-dualists are
demanding the wrong sort of explanation.[2] 
What’s more, once the objections of the neo-dualist and non-reductive
functionalists are met, there are powerful reasons for accepting the identity
thesis, in the case of consciousness.  Not only does it provide a
straightforward account of the efficacy and reality of conscious experiences by
situating them within the causal economy of the subject, it is also parsimonious
and explanatorily fruitful; and this, I contend, represents more than a "pious
hope."

Such critical reservations
notwithstanding, Gray’s Consciousness: Creeping up on the Hard Problem
is an impressive text.  In few books are so many of the philosophical and
theoretical puzzles surrounding consciousness considered, and considered from
the perspective of a wealth of contemporary empirical data.  In sum, I
recommend this book to anyone interested in the metaphysics and science of
conscious experience.

© 2005 Liam
Dempsey

Liam Dempsey,
Assistant Professor, Department of Philosophy, Dalhousie University, Halifax, Nova Scotia CA