Cartesian Dualism

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Cartesian Dualism
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Real Distinction Argument

• P1. Whatever can be clearly and distinctly
  conceived apart can exist apart.
• P2. Whatever can exist apart are necessarily
  distinct from one another.
• P3. I can clearly and distinctly conceive my
  mind apart from my body.
• P4. Therefore, my mind can exist apart from my
  body.
• -----------------------------------------------
  ------------------
• C. Therefore, my mind is necessarily distinct
  from my body.

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Real Distinction Argument

• P1. Whatever can be clearly and distinctly
  conceived apart can exist apart.
• P2. Whatever can exist apart are necessarily
  distinct from one another.
• P3. I can clearly and distinctly conceive my
  mind apart from my body.
• P4. Therefore, my mind can exist apart from my
  body.
• -----------------------------------------------
  ------------------
• C. Therefore, my mind is necessarily distinct
  from my body.
• A way of talking about the possibility of
  separation even where there is no such actual
  separation.

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Real Distinction Argument

• P1. Whatever can be clearly and distinctly
  conceived apart can exist apart.
• P2. Whatever can exist apart are necessarily
  distinct from one another.
• P3. I can clearly and distinctly conceive my
  mind apart from my body.
• P4. Therefore, my mind can exist apart from my
  body.
• -----------------------------------------------
  ------------------
• C. Therefore, my mind is necessarily distinct
  from my body.
• A consequence of the necessity of the
  non-separability of identical things.

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Real Distinction Argument

• P1. Whatever can be clearly and distinctly
  conceived apart can exist apart.
• P2. Whatever can exist apart are necessarily
  distinct from one another.
• P3. I can clearly and distinctly conceive my
  mind apart from my body.
• P4. Therefore, my mind can exist apart from my
  body.
• -----------------------------------------------
  ------------------
• C. Therefore, my mind is necessarily distinct
  from my body.
• A conclusion that Descartes reached in
  Meditations 1, 2.

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Real Distinction Argument(Deriving the 3rd
Premiss)

• He cant be certain that bodies exist because the
  evidence for them is merely sensory, and the
  senses can be deceived.
• The same possibility of error does not exist for
  the claim that his mind exists. (Cogito ergo
  sum.)
• So he exists as a thinking thing. But are mind
  and body distinct? Consider their essences.
• The example of wax the essence of the wax is
  extension (occupying space) and is known not
  through the senses but through a purely mental
  contemplation
• the essence of Mind is thinking.
• The fact that the idea of thinking does not
  entail the idea of extension or vice versa shows
  that the one cannot be a mode of the other.

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Real Distinction ArgumentObjections

• He has not shown that he has a clear and distinct
  idea of the mind apart from the body.
• He assumes that unless the concept of body is a
  part of the definition of mind a complete
  concept of the mind is possible apart from that
  of the body
• BUT
• there might be necessary external relations
  between things that rules out having a complete
  concept of the one without the other. Eg.
  correlative terms like parent and child

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Real Distinction ArgumentObjections

• Excluding Body from my essence is just an
  intellectual abstraction
• Compare thinking of something as being a right
  angled triangle but doubting whether the square
  of its hypotenuse was the sum of the squares of
  the other two sides.

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Real Distinction ArgumentObjections

• The argument is a fallacy.
• p1. I can conceive of my mind as unextended.
• p2. I can not conceive of my body as unextended.
• ------------------------------------------
  -------------
• c. Therefore my body and my mind are distinct.
• BUT
• p1. I can conceive of the evening star as being
  different from Venus.
• p2. I can not conceive of Venus as being
  different from Venus.
• -------------------------------------------------
  ----------------------
• c. Therefore the evening star and Venus are
  distinct.

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The Argument from Divisibility

• P1. The mind is indivisible.
• P2. The body is divisible.
• P3. If A is identical with B, then any property
  that A has B also has.
• -------------------------------------------------
  -----------------------------
• C. Therefore, the mind is distinct from the body.

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The Argument from DivisibilityObjections

1. It makes very good sense to talk about the parts
   of a mind or even of divided minds.
2. Certain cognitive functions depend upon the body,
   such as perception, memory.
3. Descartes equivocates upon the word division

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Mind/Body Dualism

• Popular Dualism
• The Mind drives the body like a man in a tank.

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Mind/Body Dualism

• Substance Dualism
• The world consists of at least two types of
  thing, two substances, one of which is material
  and is essentially extended, and the other of
  which is mental and is essentially thinking .

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Mind/Body DualismObservations

• Mind does not give life to the body
• The soul does not dwell in the body like a pilot
  in a ship
• Descartes says that the soul is substantially
  united to the body, or mixed up in it.
• a subtle fluid the animal spirit flows
  through the nerves and is the medium of
  communication between mind and body.
• Mind Pineal gland Nerve fibres Limbs
• Sense organs Nerve fibres Pineal
  gland Mind

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Mind/Body DualismObjections

• The most common objection to substance dualism is
  that it is inconceivable that the two substances
  should be able to affect each other at all.
• Responses
• a. Occasionalism.
• b. Pre-established Harmony.
• c. Double-Aspect.

Descartes to Princess Elizabeth   I beg Your
Highness to feel free to attribute this matter
and extension to the soul because that is simply
to conceive of it as united to the body.
Princess Elizabeth to Descartes I admit it
would be easier for me to concede matter and
extension to the soul than the capacity of moving
a body and of being moved, to an immaterial being.
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Mind/Body DualismObjections

• The most common objection to substance dualism is
  that it is inconceivable that the two substances
  should be able to affect each other at all.
• There are objections to Dualism on the grounds of
  various conservation laws.
• Ockams Razor. There is no increase in
  explanatory power provided by this new substance.
  
• Scientific Psychology speaks against dualism.