Minds and Computers : An Introduction to the Philosophy of Artificial Intelligence

particular ontology – an ontology which sees the universe as comprised
of both material and immaterial substances. As well as all the mater-
ial stu
ff which makes up the physical world, the dualist holds that there
is also non-physical, immaterial stu
ff to be taken account of.
We need to be careful in drawing the distinction between the mate-
rial and the immaterial. For instance, electromagnetic radiation, while
in a certain sense insubstantial, is still material. It is part of the phys-
ical world – something we would expect physics to give us an account
of. The distinction between material and immaterial is not just a
straightforward distinction between things we can bump into in the
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dark (chairs and tables) and things we cannot (heat, light and sound).
Rather, it is a distinction between the things which are within the
purview of physics (chairs, tables, heat, light, sound) and the things
which the dualist contends exist beyond the scope of physics.
This is di
fficult to grasp in the abstract so let’s examine a particular
kind of substance dualism and see why we might be tempted to claim
that there are objects in the universe composed of non-physical,
immaterial stu
ff.
2.2 CARTESIAN DUALISM
Cartesian dualism is a view about the mind, the body and the relation
between them. It is a particular kind of dualism which takes its name
from its original proponent, René Descartes. It is essentially the view
that while the body is a material object, the mind is not. According to
the Cartesian dualist, the mind is composed entirely of immaterial
stu
ff. As such, Cartesian dualism is clearly a kind of substance
dualism as the Cartesian dualist is committed to an ontology which
admits of both material and immaterial substances.
What is distinctive about Cartesian dualism among other kinds of
mind–body dualism is that the Cartesian dualist holds that the mind
and the body enter into causal relations with each other: the mind
causes things to happen in the body and the body causes things to
happen in the mind. In other words, the immaterial mind and the
material body interact. Cartesian dualism is also known as interac-
tionist dualism for this reason.
The Cartesian dualist is committed to the following four propos-
itions:
[D1]
The body is composed entirely of material substance.
[D2]
The mind is composed entirely of immaterial substance.
[D3]
The body has a causal e
ffect on the mind.
[D4]
The mind has a causal e
ffect on the body.
As we shall shortly see, it is very di
fficult to maintain all four of these
propositions. But before we start examining objections to Cartesian
dualism, let’s first consider the arguments in its favour.
2.3 POSITIVE ARGUMENTS FOR CARTESIAN
DUALISM
There are a number of reasons why one might endorse Cartesian
dualism. I will consider the three strongest arguments in its favour: the

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argument from religion, the argument from introspective appearance
and the argument from essential properties.
2 . 3 . 1 T H E A RG U M E N T F R O M R E L I G I O N
This is perhaps the most commonly held argument in favour of
Cartesian dualism.
Many religions – Christianity amongst them – posit an afterlife and
promise a reward in the afterlife for living according to a certain nor-
mative code. Conversely, they threaten punishment in the afterlife for
failing to live according to these dictates. But ask yourself: who is it
that is to be rewarded or punished?
Such religions speak of the eternal, immutable, immaterial soul
which is contended to be, in an important sense, constitutive of the
individual. It is this eternal soul which enjoys the rewards or su
ffers
the punishments meted out in the afterlife.
In order for the concepts of reward and punishment to be applic-
able – and in order for the relevant beliefs to motivate individuals to
act in the appropriate way – it must be the case that the thing that is
rewarded or punished is the same thing that is responsible for moral
agency.
In other words, the thing which is rewarded or punished simply
must be the same thing that goes about in the world making decisions
and acting in certain ways. The soul simply must be equivalent to the
mind. After all, what sense lies in rewarding or punishing one entity
for the deeds or misdeeds of a distinct entity? And why should I be at
all concerned with acting according to a particular code if it is not, in
a very important sense, me who will enjoy the promised reward or
su
ffer the threatened punishment?
Cartesian dualists understand ‘mind’ and ‘soul’ to be synonymous
terms. While in life, the mind/soul stands in relation to a particular
body. In the afterlife, the immaterial mind/soul leaves the body to take
up independent existence and to enjoy or su
ffer the rewards of the
actions it engaged in during its materially embodied life.
So, to the extent to which one is antecedently committed to such
a religious doctrine, one must also be committed to substance
dualism as such doctrines require an immaterial soul. Furthermore,
one must also be committed to Cartesian dualism as it must be the
case that the mind/soul causes, and is thereby responsible for, the
actions of the body.
As far as arguments go, unfortunately, this is not a very good one.
It gives no independent reason whatsoever for endorsing Cartesian
dualism. What it shows is that a commitment to Cartesian dualism is
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a straightforward corollary of certain religious beliefs. This simply
means that these religious beliefs stand or fall together with Cartesian
dualism. If one doesn’t antecedently have such religious beliefs, the
argument from religion is entirely lacking in persuasive force.
2 . 3 . 2 T H E A RG U M E N T F R O M I N T R O S P E C T I V E A P P E A R A N C E
Another argument in favour of dualism proceeds from our privileged
introspective awareness of our own minds.
It is a distinctive feature of our minds that they have a reflective
capacity: we can think about our own thoughts, our own mental
states. Furthermore, we have unique and privileged access to the con-
tents of our own mental states. This access in unique in that I and
I alone am privy to my mental life. It is privileged in that, unlike my
access to everything else in the universe, my access to my own mental
life is direct and not mediated by my senses.
Given this capacity of minds for, and amenability of minds to,
direct introspection, we might be tempted to draw a distinction
between minds and physical objects, as follows.
When I introspect – when I reflect on my mental life and consider
the contents of my mental states – it doesn’t seem to me that events in
my mental life are physical events. My thinking of ice cream seems to
me to be just that – thinking of ice cream. It doesn’t seem at all to be
an electrochemical discharge in my brain. It doesn’t seem at all to be