Descartes

what is DESCARTES?

• substance dualist

  • made of two different substances (mind and body)

• influenced by PLATO

DESCARTES on the brain vs mind

• brain ≠ mind 

  • brain = connection between mind and body 

  • not the mind as it is physical and changeable 

• pineal gland = “seat of the soul”

  • where physical body and non-physical mind interact

  • BUT, not scientifically proven

DESCARTES 3 arguments

• argument from doubt

  • methodological scepticism

• argument from divisibility and non-divisibility

• conceivability argument

argument from doubt / methodological scepticism

“I think therefore I am”

• can imagine no body, but not no mind

• thinking / doubting proves one’s existence

support for argument from doubt

universally conceivable thought experiment

critiques of argument from doubt

• RYLE’s category mistake

• flawed argument

  • just because I think one thing is uncertain and another is certain, doesn’t mean that is the case

argument from divisibility and non-divisibility

• body can be physically cut up; mind cannot

  • contradicts Liebniz’s law (identical things must have same properties)

• so mind (indivisible) cannot be the same as physical substance (divisible)

critiques of argument from divisibility and non-divisibility

• neuroscience = mind can be divided (perception, memory)

  • DESCARTES - these are functions of consciousness, not mind

• dementia = can lose parts of mind

• some suffer split personality disorders

conceivability argument

• clear idea of

  • soul / mind = thinking, non-extended

  • body = non-thinking, extended

• conceivably separate = possibly separate

critiques of conceivability argument

• masked man fallacy

  • ‘what is conceivable is possible’ = false

  • can conceive of the impossible

• RYLE’s category mistake

  • just because you think of soul as separate, doesn’t mean it is

scholar critique of DESCARTES

RYLE - dogma of the ghost in the machine

• DESCARTES is making a “category mistake2

e.g. visitor visits uni campus, then asks where the university itself is

• wrongly assumes university is extra

• DESCARTES / dualists wrongly assume mind is extra