Descartes argument for dualism
Descartes has shown in meditation 2 that he can
understand himself purely as a thinking thing
In meditation 5 he has shown that he can
understand bodies purely in terms of their
spatial, extended characteristics
Whatever can be understood clearly and
distinctly as distinct really is distinct
Therefore there is a real distinction between
mind and body.
Is it true that we can understand our minds
independently of anything physical?
Is it true that whatever we can understand
as distinct is really distinct?
Lightning is identical to an electrical
discharge, but it was a scientific discovery
that these “two” things were really one.
Could the same be true of mind/body?
Another argument for dualism
Physical things are spatially extended
(have a certain size, exist in space)
Minds have no spatial extension
Whatever is identical must have all
properties in common.
Therefore minds and bodies are distinct
things.
The Mind/Body Problem
Descartes is an interactionist dualist. He
believes that there is causal interaction
between minds and bodies.
http://prosblogion.ektopos.com/
When I move
my hand my mind causes
my body to move.
When I stub my toe, my body causes my
mind to experience pain
It’s hard to understand how
interaction is possible
It seems that when two things causally interact,
they must share a common medium, they must
be able to “meet up” somehow
One billiard ball can cause another to move
only because they are both in space and can
touch each other
The Moon and Earth do not touch, but they
share the medium of space. Even “action at a
distance” presupposes a common medium
But if the mind is not in space, it cannot
meet up with the body, nor is it possible for
anything physical to come into contact to
the mind.
Therefore (the critic argues) dualism leads
to the conclusion that mind body
interaction is impossible
But this is crazy—therefore there is
something wrong with dualism
Dualist Responses
Causal interaction is in general
mysterious. There is no special problem
for mind/body interaction
Just because we do not understand how
mind/body interaction can work, does not
mean it cannot work (see above)
experience teaches they do interact.
Another mind/body problem
It is a presuposition of science that the
physical world is causally closed. This
means that the cause of every physical
event (if it has a cause) is also something
physical.
But interactionist dualism denies this. If
interactionist dualism is true, there are
some events in the brain that are caused
by a non-physical thing, the mind.
Alternatives to substance dualism
Materialism: If the mind identical brain
processes, there is no mind/body problem,
since the mind itself is something physical.
Idealism: If matter is it itself mental or mind
dependent, again no mind/body problem
Alternative versions of dualism
Property dualism: there is only one kind of
thing (matter) but this thing sometimes has
mental properties
Epiphenomenalist dualism: The body
interacts causally with the mind, but not
vice/versa. Mental states are byproducts
of brain activity (like car exhaust)