Substance Dualism (Mind)

Question 1

Key ideas of substance dualism

Answer 1

• Humans are composed of two distinct substances - Mind and Body
• These can exist without eachother, e.g. decomposition of the body does not mean the mind also dies - Mind can survive bodily death
• Mind and body causally interact via the pineal gland. e.g. stimulation of body organs cause the mind to experience sensations, acts of will (in the mind) cause the body to move
• Although distinct, mind and body are in intimate union - so you don’t usually feel distinct from your body, rather you are extended throughout it

Question 2

Indivisibility argument

Answer 2

• Descartes explains that you can cut up the human body indefinitely, however you cannot divide the mind as your ‘self’ seems to be one thing.
• This is discovered through introspection.
• And, it’s not possible for the same substance to be divisible and indivisible as they are incompatible properties.

Therefore:

P1. The body is divisible
P2. The mind is indivisible
C. Therefore the mind is not the body

Question 3

Response to the Indivisibility Argument: Mind is divisible

Answer 3

Modern neuroscience shows how when the brain is divided, so is consciousness. This is used to show how introspection isn’t reliable and the brain can be divided.

There is evidence of patients who have the connection between the two hemispheres cut having two distinct centres of consciousness without being aware of it.

Shows that introspection is not reliable to determine that the mind is indivisible as the patients aren’t aware of having 2 centres of consciousness.

Question 4

Conceivability Argument

Answer 4

Descartes says if he has a ‘clear and distinct idea’ of two separate things, they cannot be the same.

• In other words, if I can recognise the essential nature of two things to be clearly distinct, they must actually be distinct things.

So:

P1. If i can clearly and distinctly recognise the natures of two things to be different they must be different things.

P2. I clearly and distinctly recognise the nature of the mind to be consciousness and nothing more.

P3. I clearly and distinctly recognise the nature of the body to be extension and nothing more.

C. Therefore the mind is a distinct substance to the body

Question 5

Response to the Conceivability Argument: Masked Man fallacy

Answer 5

Arnauld questions Descartes first premise with this fallacy.

P1. I recognise Batman is a masked crusader.
P2. I recognise Bruce Wayne is a playboy millionaire.
C. Therefore Batman is not Bruce Wayne.

This is an example of supposedly having a clear and distinct idea of two things, but actually having an incomplete idea of something, making it appear to be two when it is actually one.