Dualism

• Substance dualism


  Minds exist and are not identical to bodies or to parts of bodies.
• The indivisibility argument


  P1: My mind is indivisible.

  P2: My body is divisible.

  C: Therefore my mind is not my body.
• The conceivability argument


  P1: If I can clearly and distinctly conceive of the essential natures of two things separately, it must be metaphysically possible to separate them.

  P2: I can clearly and distinctly perceive my mind as a thinking and unextended thing.

  P3: I can clearly and distinctly perceive my body as an unthinking and extended thing.

  C: It must be metaphysically possible to separate mind and body as they are distinct substances.
• Property dualism


  There are at least some mental properties that are neither reducible to nor supervenient upon physical properties.
• The philosophical zombies argument 


  P1: It is conceivable that there are philosophical zombies.

  P2: If it is conceivable that there are philosophical zombies, it is metaphysically possible that there are zombies.

  P3: If it is metaphysically possible that there are zombies, then phenomenal properties of consciousness are neither physical properties nor supervene upon physical properties.

  C: Therefore physicalism is false and property dualism is true.
• The knowledge/Mary argument


  P1: Mary knows everything there is to know about the physical processes involved in colour vision.

  P2: But she learns something new when she experiences colour vision herself.

  C1: Therefore there is more to know about colour than the complete physical facts of it.

  C2: Physicalism is false.
• The argument from analogy (response to the problem of other minds)


  P1: I observe that I have a mind.

  P2: I also observe that mental states are systematically connected with my behaviour and the states of my body.

  P3: And I observe that other people who have bodies like mine behave similarly to me.

  C1: So it is likely that their bodies and behaviours are connected to mental states too.

  C2: Therefore it is likely that others have minds.
• The existence of other minds is the best hypothesis (response to the problem of other minds)


  P1: Humans have complex behaviour.

  P2: If humans have minds then this would explain their behaviour.

  P3: There is no available alternative theory which explains behaviour as well.

  C: Therefore it is likely that humans have minds.
• The conceptual interaction problem (issue facing interactionist dualism)


  P1: It is inconceivable for two things to causally interact, unless their surfaces come into contact with each other.

  P2: According to substance dualism the mind is unextended and has no surface.

  C1: Therefore it is inconceivable for the mind to interact with the body.

  P3: What is inconceivable is impossible.

  C2: So mind-body interaction is impossible.
• The empirical interaction problem (issue facing interactionist dualism)


  P1: The causal closure principle states that all physical events have purely physical causes.

  P2: Human actions are physical events.

  C: So human actions have purely physical causes and dualist interactionism is false.
• Phenomenal properties


  The what it is like of thought.
• Qualia


  Intrinsic and non-intentional phenomenal properties that are introspectively accessible.
• Intentionality 


  The quality of certain mental states which directs them beyond themselves and to things in the world, the aboutness of thought.
• The mental is divisible (response to indivisibility argument)

  • Some epilepsy patients have had their corpus callosum severed and have reported experiencing a divided mind.
  • For example a patient experienced picking an item off the shelf and placing it in the basket with one hand, then immediately putting it back with their other hand.
  • This means the mind can be divided and P1 is false.
• Not everything physical is divisible (response to indivisibility argument)

  • The mind being indivisible does not mean it is not physical.
  • Many things we consider physical such as wetness are indivisible.
  • The mind may be a physical property of the brain/body, meaning it is not divisible but substance dualism is incorrect as the mind is not a mental substance.
• Mind without body is not conceivable (response to conceivability argument)

  • It is impossible to think of the mind without physical dimensions or properties.
  • Even if the mind does have no spatial dimensions, this means its existence is not empirically verifiable.
• What is conceivable may not be metaphysically possible (response to conceivability argument)

  • Arnauld argued that someone ignorant of maths may believe they can conceive of a right-angled triangle which doesn't follow Pythagoras' theorem.
  • However this does not make such a triangle metaphysically possible.
  • Similarly Descartes' may be ignorant of how mind and body work so what he conceives may not be metaphysically possible.
• What is metaphysically possible tells us nothing about the actual world (response to the conceivability argument)

  • If something is metaphysically possible it doesn't follow to infer that it could happen in our reality.
  • Descartes hasn't proved that physicalism is impossible, so it is equally conceivable that minds are not distinct from bodies.
  • This means we are no closer to discovering what is true in our actual world.
• A philosophical zombie world is not conceivable

  • While a philosophical zombie world may seem conceivable, it contains a hidden contradiction.
  • Verificationists would argue that any statements about zombies are not empirically verifiable and thus meaningless.
  • Dennett argues that philosophical zombies are a contradiction because it is like saying someone shows all the signs of health but is unhealthy.
• What is conceivable may not be metaphysically possible (response to philosophical zombies argument)

  • Water not being H20 is conceivable but not metaphysically possible.
  • Similarly being able to conceive of a philosophical zombie world does not make it metaphysically possible.
• What is metaphysically possible tells us nothing about the actual world (response to philosophical zombies argument)

  • The natural laws of our world make zombies impossible.
  • Therefore the argument has no affect on our reality and how we live our lives.
• Mary does not gain propositional knowledge just ability knowledge

  • Upon experiencing colour, Mary gains the ability knowledge of being able to sort objects by colour.
• Mary does not gain propositional knowledge just acquaintance knowledge

  • Upon experiencing colour Mary becomes acquainted with the phenomenal character of colour vision but she does not gain any propositional knowledge.
• New knowledge/old fact (response to Mary's room)

  • Mary gains knowledge of what it is like to experience colour upon her release.
  • However this is not a new fact, it is simply a different way of expressing a concept she already knew.
  • E.g. learning that Bruce Wayne is Batman.
• The problem of other minds

  • A sceptical worry about whether it is possible to know that other people have minds.
  • Minds are private so there is no way for me directly observe someone else's mind, I can only infer that they have a mind from their behaviour.
  • However this evidence is insufficient to deductively prove that others have minds.
• Dualism makes a category mistake (Gilbert Ryle)

  • Substance dualism makes the category mistake of believing the mind is in the same category as physical things.
  • He gives the example of someone seeing the colleges, libraries and accomodation at Oxford University and then asking where the university is.
  • In the same way substance dualists are mistaken when they treat minds in the same way as physical substances.
• Interactionist dualism 


  Both mental events and physical events can cause both mental events and physical events.
• Epiphenomenalist dualism

  • Physical events can cause both physical events and mental events.
  • However mental events can cause neither physical events nor mental events.
  • The mind is a byproduct of brain activity and has no causal power.
• The challenge posed by introspective self knowledge

  • If epiphenomenalists are right then talk of our mental states are not caused by our mental states.
  • This would make word such as toothache which describe mental states meaningless.
  • However it is absurd to suggest that we cannot meaningfully talk about our own introspectively accessible mental states, so epiphenomenalism is flawed.
• The challenge posed by the phenomenology of our mental life

  • It seems certain that an act of will or volition causes many of our actions.
  • E.g. the mental state from a toothache causes me to go to the dentist.
  • Denying this is an affront against facts which are self-evidently revealed through everyday experience.
• The challenge posed by natural selection/evolution

  • Species evolve traits that give them survival or reproductive advantages.
  • Consciousness does not seem to provide an evolutionary advantage.
  • Therefore if epiphenomenalism is true and consciousness has no causal power, we should not expect consciousness and mental states to exist now.
  • Their existence suggests they confer a survival advantage and thus have causal influence.