Criticisms of Dualism
Descartes argument for dualism
• I can clearly and distinctly conceive of the
mind without the body and the body
without the mind
• If I can clearly and distinctly understand
two things as distinct they really are
distinct.
• Therefore the mind and body are two
distinct things.
• The mind is characterized by one sort of
property, thought
• Physical things are characterized by
another sort of property, extension.
• Two different kinds of things understood in
terms of two radically different kinds of
properties
The Mind Body Problem
• If mind and body are really share no
properties in common, then it is impossible
for them to interact.
• But mind and body do interact
• Therefore Descartes’ substance dualism is
false
Another mind/body problem
• It is a law of nature that matter and energy
can be neither created or destroyed
• But if the mind causally interacts with the
body, there is some new energy that
comes into existence when the mind
causes the brain to be in a certain state
• So interactionist dualism violates a
fundamental principle of science
Substance and property dualism
• Substance dualism: two different things,
mind and body
• Property dualism: Only one kind of thing,
but human beings and animals have
certain properties that are not physical—
mental properties
Kinds of property dualism
• Epiphenomenalism: mental properties are
byproducts of the physical body. They are
caused by brain processes, but do not
cause physical states. Its like smoke
coming out of a locomotive engine.
• Interactive property dualism: mental
properties do have causal effects on the
brain
Emergence and non-reducibility
• Property dualism holds that mental
properties are emergent properties
• When organisms reach a certain degree of
complexity, they get mental properties
• Property dualism also holds that mental
properties are non-reducible. You cannot
understand the nature of mental properties
by appealing to physical properties
Examples of Emergence
• Biological properties are emergent on
chemical properties. Being solid is
emergent on the properties of lots of of
molecules and their interactions, same
with being colored.
• But each of these are reducible. You can
understand, for example, how a living cell
works in terms of the chemical processes
in that cell.
Do mental properties have to be
emergent?
• Churchland: mental properties could be
like electromagnetic properties. A different
part of nature not reducible to others.
• But electromagnetism is displayed on all
levels of reality, mental properties are only
in complex organisms.
• How do we know this?
Panpsychism
• A property dualism might insist there are
mental properties all the way down.
• This would make the emergence of
conscious beings more comprehensible
• But it would also involve the belief that
mental properties exist in so-called
inanimate things.
The introspective argument for
dualism
• Descartes held that because thinking,
reasoning, mental processes seem to be
distinct from physical states, they really
are.
• Churchland argues that this may not be
so. Colors don’t seem to be a matrix of
molecules reflecting light, warmth does not
feel like molecules vibrating.