are dualists right to claim that the mind are non-physical

• intro

  • dualism is the view that the mind and body are ontologically distinct
  • substance dualism = the mind and body are ontologically distinct substances
  • interactionist dualist = though distinct, mind and body are able to causally affect one another
• first A - epistemological solipsism

  • epistemological solipsism argues that you can only know your own mind/mental states exists, you cannot know other minds exist
  • according to dualism, I have direct and privileged access to my own mental states via introspection
  • I am unable to inspect the contents of anyone else's mind directly, because minds are private
  • because I cannot directly observe other minds, I have to infer them from what I can observe: bodies and behaviour
  • however, this is insufficient to establish what the mental states of others are, or whether they exist at all
• first C

  • the existence of other minds is the best explanation
  • P1 - humans have complex behaviour
  • P2 - if humans have minds then this would explain their behaviour
  • P3 - there is no alternative theory that explains their behaviour as well (being conscious automata or controlled by God/an evil demon does not explain our complexity of behaviour as well as a complex inner life of beliefs, desires and emotions does)
  • C - therefore, it is most likely humans have minds
• second A - argument from indivisibility


  • Descartes argues that bodies are essentially divisible e.g. you can cut off a foot or arm, meaning they can be broken into even smaller parts
  • He argues that the mind is essentially indivisible meaning that I am a unified subjective conscious entity
  • my different states are not parts of me but aspects of a single whole
  • Leibniz's law states that if X and Y do not share the same properties, then X and Y are distinct
  • so, since my mind and my body do not share the property of indivisibility, they are distinct
• second C

  possible objections to Descartes' argument from indivisibility

  • the mind is divisible in some sense (e.g. conscious/unconscious)
  • some physical things are not divisible (e.g. energy/sub-atomic particles)
• third A

  • interactionist dualism argues that although ontologically distinct, the mind and body can causally affect on another (interact)
  • Princess Elisabeth objects to interactionist dualism and argues that causation requires contact and contact requires extension (surfaces)
  • this means that either the immaterial mind is causally redundant or the mind can interact and is physical (extended)
  • the argument that the immaterial mind is redundant challenges interaction
  • the argument that the mind can interact and is physical challenges dualism
• third C - Huxley's response (epiphenomenalist solution)


  • the mind can't cause anything in the body - it is a one way system
  • the mind exists because of the physical brain and body, they facilitate the mind
  • all the same substance and therefore doesn't need a surface to interact
• third R - issues with Huxley's response


  • potentially the problem is changed is it possible for one substance have two ontologically distinct properties
  • counter-intuitive to argue the mind is causally redundant
• third C - Descartes' response

  • Descartes argues that the pineal gland in the brain connects the body and the mind
  • the gland allows the mind and body to interact
• third R - issues with Descartes response


  • it doesn't appear to solve the problem, he just seems to specify the location