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Abstract
Table of Contents
Chapter 1
Chapter 2
Chapter 3
Chapter 4
Chapter 5
Chapter 6
Epilogue
Response
Further Reading
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The Mysterious Matter of Mind
Chapter Two
Cartesian Dualism: Mind and Brain
Interaction
Dualism
is an ancient concept and deeply rooted in Greek thought. The
Greeks held that a man's soul was of an entirely different essence
than his body. Furthermore, they held that these dual entities
had no interaction with one another. Indeed, the Greeks saw them
as alien to one another, the body being the prison house of the
soul. Thus dualism means much more than a mere numerical designation.
It implies the dichotomy of soul and body, an absolute split.
Rene Descartes (1596—1650)
marks the beginning of modern psychology. He was a remarkable
individual: primarily a philosopher, he was also a scientist,
physiologist, and a mathematician.
He believed in an independent non-material
soul inhabiting and finding expression in a mechanically operated
body. The reality of the body needed no proof, the reality of
the soul did. Descartes used his famous aphorism as proof: cogito
ergo sum, "I reflect, therefore I am." It is a
neat form of proof and seems unanswerable. We cannot doubt the
existence of our
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own self, because we
cannot doubt it unless there is a self to do the doubting.
It is interesting that the idea
did not originate with Descartes, though it is usually credited
to him. Some twelve hundred years before Descartes, Augustine
in his City of God (11.26) wrote:
Without any delusive representation
of images and phantasms, I am most certain that I am, and
that I know and delight in this. In respect of these truths,
I am not afraid of the arguments of the Academicians, who say,
"What if you are deceived?" For if I am deceived,
I am. For he who is not, cannot be deceived; and if I
am deceived, by this same token I am.
Descartes was
concerned about how the non-material could interact with the
material and how the "extended" substance of body could
house the "unextended" spirit called soul. He resolved
the problem of the incompatibility of the two entities by his
dualism; that is to say, by giving the problem a name.
He held that the two components
which constitute man had an independent origin and are of a fundamentally
different nature. The body could be divided up by the removal
of a leg or an arm, but the soul was indivisible. The soul occupied
the whole body in all its parts, but the reduction of the body
in any way did not reduce the soul. The body was procreated,
the soul was created. Though the two realities were of an entirely
different nature, they could react upon each other, the soul
on the body and the body on the soul. How this reaction takes
place is a mystery nevertheless; only Descartes spelled it differently
— dualism.
But he became the father of the
mind/body theory of interactionism.
Descartes' Interactionism
Descartes held
that the brain (along with the rest of the body) was purely mechanistic
in its principle of operation. This is true when body is considered
without soul — as he proposed was always the case in the
animal world where soul is lacking. Thus animals are pure automatons.
This mechanistic view of the body, including the brain, was not
questionable if soul is not
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made any essential part
of its operation. So Descartes was free to proceed with his physics
of physiology.
But what then is the nature of
the soul? His answer is simple: the sense perceptions and physical
passions of men are dependent upon the body, but awareness of
them lies in the soul. The important thing then is to inquire
how the soul becomes aware (i.e., conscious and self-conscious)
and how it succeeds in acting upon the body. Its awareness is
due to the action of the body upon it, but how does it in turn
act upon the body when it exercises will?
The point of interaction, according
to Descartes, was at the site of the pineal gland, the only place
he thought that is not duplicate as all other brain structures
were thought to be. The soul was not, however, to be viewed as
somehow shut up in the pineal gland. The gland is merely the
point of interaction, not the seat of the soul in any fuller
sense.
The body is extended matter: the
soul is unextended spirit. When, however, the extended is acted
upon by the unextended, some definite point of interaction is
required and it is to be found in the pineal gland. Yet the "soul
is united to all parts of the body conjointly." The whole
body is the soul's proper housing so long as the body remains
intact. When a member of the body — an arm or a leg, for
example — is cut off, there is no loss of part of the soul
as a consequence because the soul is unitary and indivisible.
It then occupies what is left of the body.
So without attempting to resolve
all the problems, he simply stated that there is a dualism of
mind and body, and their interaction is clearly real. The brain
is the major locus for the mind or consciousness of the soul,
yet mind or consciousness is distributed throughout the whole
body. The point of interaction between the two is the pineal
gland.
Descartes lent his authority to
the long-held view that the mind is associated in a particular
way with the brain, but he made mind and brain separate entities,
dependent upon each other only as a fountain pen and ink are
interdependent. The pen will not write without the ink and the
ink carries no message without the pen.
Descartes "substantialized"
consciousness as
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unextended reality, something
that can exist in the body but does not occupy space. Mind was
real, yet entirely separate from matter and therefore from brain.
Interactionism is his form of dualism. One extended and
the other unextended, they nevertheless interact, and this interaction
occurs at a specific site, the pineal gland. The theory cannot
be disproved so long as there are mental phenomena whose neural
correlates remain unknown. That there are mental phenomena
cannot be doubted for reasons which are logically compulsive
and were adopted (though not invented) by Descartes; they cannot
be doubted because the very act of doubting them establishes
their reality. The reality of conscious existence is confirmed
each time it is denied.
Matter and mind he construed as
created substance, each constituting a radically different and
independent form of reality. Their interaction does not stem,
he held, from a common origin. His inability to satisfy even
his most ardent admirers on the nature of their interaction resulted
in some of them adopting a view which came to be known as occasionalism,
according to which each apparent interaction of mind and
body was the result of direct divine intervention.
In the end,
the Cartesian mechanistic view exempted only two phenomena from
its all-embracing sweep, God and the soul of man. All else, all
animal life below man and man himself save only for his soul,
was encompassed in the universal chain of mechanistic causality.
The concept was a grand one and ultimately proved too appealing
to permit the one exception to be any hindrance to its application
everywhere else. The soul was first ignored, then virtually denied,
or made a mere outgrowth of the machine that was the body and
the brain. In a lecture on Thomistic psychology given at the
University of Ottawa in 1957, Professor R. H. Shevenell summed
up Descartes' influence by saying:
With Descartes, psychology lost
its soul and found its mind:
with British Empiricists, soul lost its mind and found its consciousness:
with Watson and the Behaviorists, soul lost its consciousness
and found its reflexes.
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Descartes
marked a turning point for the study of man, especially for the
study of the mind/body relationship.
Most of the
important thinkers who followed Descartes rejected interactionism.
It was not a testable hypothesis. Above all, it introduced the
supernatural into the picture and thus removed the concept from
the scientific laboratory into the theological seminary.
Critics of his ideas objected that
if soul and body were substances of entirely different natures,
interaction between them was in fact impossible. This Descartes
protested against, but he never satisfied his critics. Nor did
occasionalism fare any better because interaction between
mind and brain was now simply reduced to miracle, and miracles
are not the domain of experimental science with its prime emphasis
upon repeatability and quantification. It seemed the problem
was insoluble and needed a new approach.
What emerged was a determination
to reduce everything to physics and chemistry, or perhaps more
precisely to physics and mathematics (though there are chemists
who do not look kindly upon viewing their science as a branch
of physics). But it must have encouraged Claude Bernard's approach
to the body as a machine, and the success which attended this
approach advanced our understanding of the body so remarkably
that it became heresy to speak of dualism in the Cartesian sense.
But slowly, as the evidence has
accumulated, it appears that the monistic* view is showing signs
of insufficiency and a new dualism is in the making.
* Monistic: the opposite of dualistic, dichotomous,
hyphenate.
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Copyright © 1988 Evelyn White. All rights reserved
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