In Natural
Minds, Thomas W. Polger advocates the view that the human mind is the same
as its physical substrate, the brain.  His version of identity theory focuses
on consciousness as the most fundamental distinguishing feature of mental
states rather than on the concept of intentionality or that of representation. 
In doing so, Polger surrenders his special form of identity theory to the
unsettled philosophical squabbles regarding the underlying substrate(s) of
consciousness.

The stated goal of Polger’s book is quite modest in
that it intends to revive identity theory, which certainly has numerous
critics.  To accomplish this goal, the author attempts to answer two key
objections to identity theory: Hilary Putnam’s multiple realizability argument
(i.e., the possibility that organisms with brains unlike ours could
nevertheless exhibit mental states like ours), and Saul Kripke’s mind-brain
contingency argument.  More broadly, the author attempts to address the
theoretical claims of the main competitor of identity theory, metaphysical
functionalism, which can be particularly damaging to identity theory.

Although
Polger’s efforts to revive identity theory and find weaknesses in functionalism
are commendable, one may ask whether they are enough to place identity theory
back in the game.  Not surprisingly, Polger does not shy away from a possible
problem with his core argument that the mind is in fact the brain.  Indeed, he
admits that even though experimental techniques in neuroscience (e.g., fMRI)
have begun to bridge the gap between these two domains, most of the evidence
linking brains to psychological states is yet to be uncovered.  How can one
maintain an identity claim in view of the fact that it is still unclear
precisely how biochemical processes become sensory, perceptual and cognitive
processes? Polger cleverly circumvents the problem that may be posed by the
absence of clear-cut and detailed evidence.  He does so by not committing his
own version of identity theory to any specific level of analysis at which
mind-brain identity may occur. 

I
cannot say that everyone will find Polger’s approach entirely convincing. 
Nevertheless, I am sure that, all in all, readers will find his writing witty,
enjoyable and, unquestionably, disciplined.  Not surprisingly, Polger’s ability
to explore theoretical claims with simplicity and clarity is sure to make Natural
Minds attractive to readers from different walks of life.  Thus, even if
readers remain unconvinced by the author’s arguments, the book is a noteworthy
read.

© 2004 Maura Pilotti

Maura
Pilotti, Ph.D., Department of Psychology, Dowling College, New York.

Categories: Philosophical