In Consciousness in
Action, Susan L. Hurley attacks a popular picture of thought in
contemporary philosophy of mind. According to this picture, for any given
subject, thought is what mediates between perception and action. More
specifically, perception is viewed as a mechanism that provides the subject
with inputs of information from the environment, and action is constituted by
those bodily movements that the perceptual inputs generate as outputs. The
mind, then, is the set of mechanisms that transforms those perceptual inputs
into behavioral outputs. Let us call this the "input-output picture"
of mind.

The main thesis of Consciousness
in Action is that the input-output picture of mind is the result of
conflating two different levels of description of subjects as
information-processing systems. In order to explain cognitive behavior, one may
attribute certain states that we individuate partly by reference to their
content to the relevant subject (typically, beliefs and desires), and view her
behavior as what a rational subject would do if she were in such states, given
the laws of folk psychology. This is the "personal level" of
description. Alternatively, one may see the subject as a mechanical system,
purely governed by causal laws. This is the "sub-personal level" of
description. (Strictly speaking, there is no such thing as the sub-personal
level, since one may take the subject to be the object of different
"special sciences", such as biology or chemistry.) Now, Hurley’s main
tenet regarding the input-output picture of mind is that it conflates the
distinction between perception and action, which applies at the personal level,
and the input-output distinction, which applies at the sub-personal level.

This thesis is argued
in connection to one problem through the book, namely, how to explain the unity
of consciousness. The unity of consciousness is the feature of some of our
mental states whereby they are experienced as united. Thus, for instance, when
I see a bus approaching, its shape and color, as well as its movement, are
experienced by me as properties of a single object. In Consciousness in
Action, Hurley argues that the unity of consciousness has both personal and
sub-personal elements. At the personal argument, the unity of consciousness is
partly constituted by the fact that a minimum consistency of the intentional
states that we attribute to the subject in order to make sense of her behavior
is necessary for her to experience them as united. The rejection of the
input-output picture of the mind manifests itself most clearly in the
explanation of the sub-personal elements of the unity of consciousness. For it
is argued that both action and perception are, at the sub-personal level,
complex functions that include not only functions from inputs that originate in
the environment to outputs that originate in the subject, but also feedback
functions whose outputs return back to the subject as inputs. The idea then
seems to be that, at the sub-personal level, both perception and action share
some of these dispositions, which makes them codependent. This codependence is
what we experience as "having a perspective" when we act on the basis
of our view of the situation we are in.

The position that
Hurley argues for is extremely original and most interesting. The book is well argued
and clearly written. It is divided into ten essays that are, to a large extent,
self-contained. (In fact, some of the issues above and some of the arguments
involved appear repeatedly in different essays.) Its intended audience is interdisciplinary,
with some passages that will be more accessible to philosophers and some
passages that will be more accessible to scientists. No matter what group you
are in, this is definitely a book that you will find worth reading.

© 2002 Jordi Fernández

Jordi
Fernández is a Visiting Assistant Professor at the Philosophy Department at Bowdoin College.

Categories: Philosophical