3.4.2 Descartes Indivisibility arguement for substance dualism

Question 1

What is Liebniz’s law of identicals?

Answer 1

for A and B to be the same thing, A and B must have all the same properties. If 2 things have different properties, they cannot be the same things.

Question 2

What are some properties of the mind/mental substances?

Answer 2

non-physical
non-extended
invisible
intangible
indivisible

Question 3

What are some properties of the body/physical substances?

Answer 3

physical
extended
visible
tangible
divisible

Question 4

[Descartes Indivisibility arguement]

Answer 4

P1: My mind is indivisible
P2: My body is divisible
C: My mind is not identical to my body

Question 5

Criticisms of the indivisibility argument

Answer 5

1) the mental is divisbile in some sense
2) not everything physical is divisible

Question 6

Explain the criticism that the mind is divisible in some sense

Answer 6

some mental disorders such as multiple personality disorder suggest that ‘parts’ of the mind disagree/are different from each other
surgery for epilepsy involves severing the connection between the right and left hemisphere (corpus callosum) which can cause some side affects which also suggest that there is an internal conflict and ‘parts to the mind’

Question 7

Explain the criticism that not everything physical is divisble

Answer 7

Basically the idea that if we keep dividing stuff we will inevitably reach a point where no further is physical possible. Eg waves or force fields. So some physical stuff is indivisible.

Question 8

How would Descartes respond the the criticsm that the mind is in some sense divisible

Answer 8

The mind may be ‘functionally’ divisble but it is still not divisible in the same sense that the body is- spatially so it still counts as different qualities hence mind and body are still distinct.

Question 9

Why does the indivisbility arguement ultiately fail?

Answer 9

Some may argue that even though there may come a point where physical things are no longer divisible in reality, they are still divisible in concept. But this largely depends on our understanding of physics, and if concieving such a thing requires us to ignore or change our real concept of space then perahps there is a real limit of how far you can divide something. In which case, divisibility is not an essential property of a phsyical thing, so perhaps the mind is simply a non-divisible physical thing. The arguement cannot show it is non physical .