Soul, Mind & Body - Descartes cartesian dualism

Question 1

descartes’ substance dualism

Answer 1

Descartes was a philosopher and mercenary who has had a profound influence on western thought. He reached his theory on the soul as a result of profound scepticism about what it was possible to know.

Question 2

descartes’ though experiment

Answer 2

An evil demon deceives you into believing that the evidence of your senses is real. But in fact, it is entirely illusory. How do you know for sure that this is not the case?

The point is that you cannot be entirely certain that this is not true.

But even if you assume that there is a deceiver, it follows from you being deceived that there is a ‘you’ – that much is certain.

Question 3

thought experiment conclusion

Answer 3

While you can be deceived about the content of thoughts (eg. that there is a world which is presented to your senses), you cannot be deceived that you are a thinking subject that seems to perceive things.

In other words, there needs to be a subject – you – who is the subject of the deception.

Question 4

corgito ergo sum

Answer 4

Descartes frames this as cogito ergo sum or ‘I think, therefore I am’.

So we can have certainty that there is a mental substance or ‘thinking’, and we can be sure that that is not the same as matter - how can we be sure of this?
- By application of Leibniz’ law (if two things are the same thing, they must share all the same properties).

Question 5

argument using Leibniz’s law

Answer 5

The argument here goes:
- I can be sure that my mind exists (see the evil demon experiment).
- I cannot be sure that my body exists (see previous slide again).
- By application of Leibniz’ law, mind and body must be two separate substances (because if they were the same thing, we would be able to be certain the body existed as well).

Question 6

evaluation of descartes’ theory

Answer 6

Substance dualism does account for some features of consciousness that materialism finds difficult to explain.

Descartes’ theory fails to give a coherent account of how mind and body interact when one is physical/spatial and the other non-physical/non-spatial.
- Descartes claimed that the two interact via the pineal gland in the brain, but this is speculative.

Question 6

body and soul are not the same

Answer 6

So Descartes has arrived at the conclusion that mind and body are not the same things.
- In fact, Descartes says that the key difference is that matter (body) is extended in space and mind is unextended.

This echoes Plato’s earlier dualism in which the soul (mind) is essentially non-material and indivisible.

Question 7

descartes’ applying leibniz’s law

Answer 7

Leibniz’ law is not necessarily applicable to the difference between mind and body as it may be that the supposed difference in properties is the result of viewing our consciousness ‘from within’.

Question 8

what part of the body did Descartes claim the mind and body interact via

Answer 8

the pineal gland

Question 9

what experiment does Descartes use as proof that the mind exists

Answer 9

thought experiment

Question 10

what does the Latin phrase ‘cogito ergo sum’ mean

Answer 10

’ I think, therefore I am’