Substance dualism Flashcards
explain substance dualism
- Minds exist and are not identical to bodies or to parts of bodies
- substance dualism says that there are two kinds of substances; mental and physical substances.
- Humans are composed of two distinct substances - mind and body and each has a distinct set of mental and physical properties
- neither mind or body rely on the other to exist
- but mind and body causally interact e.g. acts of will in the mind cause the body to move
- although distinct, the mind and the body are in ‘intimate union’ with each other so you don’t feel as though you are distinct from your body but that you are extended throughout your body
explain Descartes indivisibility argument for substance dualism
P1 my body is divisible
P2 my mind is indivisible
C therefore my mind is not my body
- a human body can be cut up into parts
- but you can’t divide the mind in this way.
- evidence for this comes from introspection; when you look into your own mind you cannot detect any parts, your consciousness is one thing
- being divisible and indivisible are incompatible properties so mind and body cannot be the same substance
- argument uses Leibniz law, which says that for two things to be the same thing, they must have the same properties
explain the response to the indivisibility argument that the mental is divisible
- consciousness is not unitary
- freud argues that the mind is internally conflicted so that part of the mind is actively suppressed by another so that its desires influence our conscious experience without being fully aware of it (determined by our unconscious life and death drives that we cannot access suggesting the consciousness is divided), he says our mind is split into the conscious and unconscious
- neuroscience also proves a division in consciousness through the experience of patients who had the connection between the two hemispheres of their brain severed (corpus callosum) due to epilepsy, shown in Sperry’s split brain research that the two hemispheres were unable to communicate with each other
- This shows two distinct sets of consciousness operating without the patient being aware. e.g. a persons right hand might repeatedly go to pick something up even after they put it back on the shelf but they cannot control this.
- introspection is not reliable ^
- consciousness is literally divided when the brain is divided
explain a response to the indivisibility argument that not everything thought of as physical is divisible
- in everyday life, there are many things we would think of as physical but can’t make sense of dividing. e.g. physical states/properties of the body such as being wet or hot cannot be divided into parts.
- perhaps the mind is like this? Maybe consciousness is better understood as a property of the brain/physical substance
- as well as this, if you keep dividing the physical body you might be left with a load of atoms that are indivisible. Perhaps the mind is the same substance as the body - just an indivisible form of that substance.
explain the conceivability argument for substance dualism (Descartes)
P1 If I can clearly and distinctly recognise the natures of two things to be different then 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 from the body.
- descartes argues that if he has a ‘clear and distinct’ idea of two things then it must be possible to separate them
- consciousness forms no part of the body’s nature
- it is conceivable for mind and body to exist separately
explain the response to the conceivability argument that mind without body is not conceivable
- it seems that we can conceive of the mind as distinct, but it may be that what is a clear and distinct understanding of something is actually incomplete or confused
- one argument to show this is inspired by the verifications considerations
- a claim can be meaningful if it is grounded in some way in experience
–> terms get their meaning because they tell us something about the empirically observable world - if there is nothing in our experience which a term refers to then it is meaningless as it has no factual content
- substance dualism claims that the mind is a non-physical substance
- since the mind does not exist in the physical realm, it is not detectable by empirical means
- the claim of substance dualism is nonsense
- the claim may appear conceivable but it actually betrays a confusion and doesnt express a coherent thought
explain a response to substance dualism that what is conceivable may not be metaphysically possible
- if you are not familiar with Pythagoras theorem, it would be possible for you to conceive of a right-angled triangle that lacks this property
-of course this is not possible in reality, but what we conceive may not be a good guide to what is actually possible - descartes reasoning commits the ‘masked man’ fallacy
P1 I recognise that batman is a masked man
P2 bruce Wayne is a millionaire
C batman and bruce wayne are not the same person - the reasoning in this argument is fallacious because the conclusion is false
- Descartes reasoning commits the masked man fallacy
- it is possible to have an incomplete idea of something so it can appear as two when in reality it is one
- descartes idea of his mind may be incomplete
- the fact that I am unaware of my body being responsible for consciousness doesnt show that it isn’t in reality
explain the response to the conceivability argument that what is metaphysically possible tells us nothing about the actual world
- descartes has shown that it is conceivable that mind and body are distinct substances
- so it is a metaphysical possibility: there are possible worlds in which substance dualism is true
- but descartes hasn’t shown that physicalism is metaphysically impossible
- he hasn’t shown it to be contradictory
- but if substance dualism and physicalism are both metaphysically possible, we are no closer to knowing which situation is real for our world
