1
Q
substance dualism
A
- the view that there are two sorts of substance: mind and matter
- minds and bodies are distinct
- mental properties are properties of a mental substance
2
Q
Descartes’ divisibility argument
A
- the body is extended in space, it has parts
- the mind does not have parts (and therefore is not extended)
- Leibniz’s law of the indiscernibility of identicals: if X and Y are the same thing, then they have the same properties
- minds and bodies have different properties (one has parts, the other does not)
- therefore, mind and body are different
3
Q
objection to the divisibility argument: the mental is divisible
A
- the mind can be divided into perception, memory, emotions, etc
- reasons to think that the divisible: Freud argued that our minds are divisible into the Ego, Superego and Id; phenomena like split personality and self deception suggest the mind has parts
- the mind and body share the same property of divisibility and thus could be identical
- this attacks the premise that the mind is indivisible, in which case the mind does have the same properties as the physical body, making the indivisibility argument false
- response: the mind is only functionally divisible, not spatially divisible; this means that it is still distinct from the body
4
Q
objection to the divisibility argument: not everything physical divisible
A
- it is clear that many physical things can be divided, but can all physical things be divided
- if you carry on dividing, you might eventually reach indivisible physical objects
- if that is true, then the mind could be indivisible and physical
- response: physical things are still ‘in principle’ divisible; you can imagine half an electron but can you can’t imagine half a thought
5
Q
imagine, conceive, possible
A
- imagine: to represent something in your mind without a commitment to it being actual
- conceive: to grasp or understand something
- possible: something that could be the case, it may not be actual (non actual possibilities are called merely possible)
6
Q
types of possibility
A
- logically possible: something that can be stated without contradiction, e.g. it is possible that water is not H2O
- physical possibility: something could be, that is consistent with the laws of nature, e.g. it is possible for a human to travel to Mars
- epistemically possible: something that could be that is consistent with everything you know, e.g. it is possible that it will rain tomorrow
- metaphysically possible: something that is consistent with everything that is necessary; something that is part of a complete description of reality, e.g. it is possible that the entire universe is made of cheese
7
Q
Descartes’ conceivability argument
A
- I have a clear and distinct idea of my mind as a thinking thing that is not extended in space
- I have a clear and distinct idea of my body as a non thinking thing that is extended in space
- anything I can conceive of clearly and distinctly is something that God could create
- so, God could create my mind as a thinking thing that is not extended in space and my body as a non thinking thing that is extended in space
- so, it is possible for mind and body to exist independently of each other
- so, mind and body are two separate substances
8
Q
the conceivability argument without God
A
- I can conceive of my mind existing without my body
- therefore, it is possible that my mind exists without my body
- therefore, my mind and body are separate substances
- this is because if my mind was a part of my body or a property of my body, it would not be possible for it to exists without my body
9
Q
objection to the conceivability argument: mind without body is not conceivable
A
- behaviourism (a physicalist theory of mind) claims that mental states are behaviours
- e.g. happiness is smiling, doing a happy dance and being disposed to say ‘I feel happy’ (happiness is happy behaviour)
- if this is correct, then the mental states cannot be conceived of without a body
10
Q
objection to the conceivability argument: what is conceivable may not be metaphysically possible
A
- what is conceivable is not always metaphysically possible
- e.g. water is not H2O
- learning more about the nature of things can reveal new metaphysical truths; the same could be true for the nature of the mind
- the masked man fallacy: you are at a masquerade ball. someone says to you ‘I think that man over there is your dad’. you respond ‘I know who my dad is, but I don’t know who that man is, so he can’t be my dad’
- is this reasoning any good; it is true, from your point of view, that it is conceivable that, that is not your dad
- but if that man is your dad, then it is impossible that he is not
11
Q
response to the what is conceivable may not be metaphysically possible objection
A
- the masked man fallacy comes about because the reasoning is based upon ignorance (of who is wearing the mask)
- is Descartes’ reasoning based upon ignorance about mind and body
- maybe not, Descartes is claiming that the mind can be known directly and indubitably; he also claims that the body could not possibly be known that way
- Descartes would say that the separateness of the mind and body are clearly and distinctly understood, he would not say that the separateness of the masked man and your dad is clearly and distinctly understood
12
Q
objection to the conceivability argument: what is metaphysically possible tells us nothing about the actual world
A
- just because something is metaphysically possible does not mean that it is actual
- e.g. it is possible that unicorns exist, but what does that tell us about the actual world
- it could be possible that the mind is separate from the body, but that doesn’t mean it is
- response: Descartes would argue that if it possible that they are separate substances, then it is necessary that they are separate substances
