Substance Dualism

• Qualia

  Subjective conscious experience, there is ‘something it is like’ to experience qualia
• The easy problem of consciousness


  How to identify what the brains components actually do.

  Eg the Hippocampus is where memories are formed
• The hard problem of consciousness


  How is it that neurological processes bring about conscious subjective experiences.

  Why is the performance of certain functions accompanies by certain experiences.
• Dualism

  • 2 things make up humans
  • mental (the mind)
  • Physical (the body)
  • Mind cannot be reduced to the physical
• Monism


  The view that there is just one kind of substance
• Physicalism

  • monists believe in physicalism
  • only one kind of substance exists - physical
  • so mind must be physical also
• Descartes and Substance Dualism

  • Believed that the mind + body are two different substances
  • physical vs mental substances
  • ie a chair vs a soul
• Advantages of believe that mind = soul

  • Explains how personal identity is manifested after death (mind is fundamental to identity)
  • gives clarity on what is meant by the soul
• the physical - is extended

  the mental - is not extended
• Descartes indivisibility argument

  1. the body is a divisible substance
  2. the mind is an indivisible substance
  3. therefore the mind and the body are two separate substances

  Makes use of LEIBNIZ LAW

  • If two things share the same properties then they are the same thing
  • Descartes applies this understanding to the mind
• Objection to indivisibility argument


  The mind is divisible

  • 1950-60 : Robert Sperry would cut the callosum to treat epilepsy and split brain disorder, patients were somewhat fine
  • Separate left and right hemispheres
  • Mind CAN be physically split
• Objection to indivisibility argument


  Not everything that is physical can be divided

  • Not possible to splice something until it is reduced to atoms
  • smallest unit of measurement may not be divisible
  • concievible that something physical may be indivisible
• Descartes Concievibility argument


  I can imagine my mind existing without my body - proves they are distinct

  1. I can imagine my mind existing without my body existing
  2. if I can imagine one thing (x) existing without another thing (y) existing then they can’t be the same thing (Leibniz law)
  3. Therefore mind and body are not the same, they are separate substances
• Descartes Passage

  1. I have a clear and distinct idea of mind and body
  2. if they can be separated they are distinct (not separable)
  3. the mind is essential to being oneself (could lose body but not mind)
  4. clear and distinct perception of mind is unextended
  5. clear and distinct idea of body is extended
  6. since they are distinct and they aren’t the same, my mind could exist without my body
• The masked-man fallacy - objection to the conceivability argument


  Just because mind and body are two distinct things does not mean they are seperate

  1. My idea of Clark Kent is a mild mannered reporter
  2. My idea of superman is a super powerful hero
  3. Therefore Clark Kent and superman are not the same person

  Doesn’t reveal anything about the world other than ones own belief

  • Just because it is conceivable that the mind and body are separate doesn’t prove that they are
  • Not a factual claim
• Mind w/o a body is inconceivable- objection to concievability argument

  • familiar friends and family are flesh and blood, not dismembered brains
  • one could argue that it is not conceivable to imagine these people would be recognisable had they lost their bodies
• Objection to Descartes Dualism - There is evidence that the mind is physical

  • Phineas Gage
  • brain scans show that different parts of the brain light up in corrolation with different mental states
  • can ‘turn off’ general consciousness with general anaesthetic or even lobotomies
• Objection to Descartes dualism - the interactionist problem

  • Princess Elizabeth of Bohemia thought there was a question as to how mind + body interacted

  1. It is inconceivable for two things to causally interact unless their surfaces come into contact
  2. the mind has no surface
  3. inconceivable for mind and body to interact
  4. if it is inconceivable it is impossible
  5. mind body interaction is impossible
• Descartes response to interactionist problem

  • Descartes argues that mind and body union can only be understood through itself
  • not seeing how something is possible is not the same as seeing that it is impossible
  • objects falling to earth, gravity pulls the object downward but this is never expressed through contact with the objects surface - just the weight impelling it downwards