3.4.2 Substance Dualism (copy)

Define substances and properties

Define substances and properties

Substances = exist independently, bearers of properties

Properties = depend on substances (e.g. weight, height, colour)

Explain the two substances in substance dualism

Matter, or body (physical);

• The essential property of matter is that it exists in space and time.

• Res extensa (Extended in space ) - extended thing, thing existing in space

Mind (me);

• (non-physical) the essential property of mind is that it thinks. 

• Res cogitans - thinking thing

• Occupies no physical space

What is the basis of cartesian dualism?

Humans are composed of two distinct substances - a mind and a body each with a set of distinct properties, mental and physical.

How do the mind and body causally interact?

I (a thinking thing) am not merely in my body as a sailor is in a ship. Rather, I am closely joined to it – intermingled with it, so to speak – so that it and I form a unit.

Sensations in our mind show us that we are closely joined to our bodies

Similarly acts of will in the mind cause the body to move - so the two are closely joined ‘intermingled’

Although they are substantially distinct, the mind and body are in ‘intimate union’ with each other

Hence why we don’t feel distinct from our body and are ‘not merely in my body as a sailor is in a ship’ but are extended throughout the body.

Explain the divisibility/indivisibility argument

It is possible to divide up the body but not possible to divide up the mind. So they are different.

The body is made of matter, and inherently the body is then divisible as divisibility is one of the fundamental properties of something composed of matter.

The conclusion that the mind is indivisible was reached by Descartes through introspection.

• When you look into your own mind you can’t detect any separate parts

• Your self, that which you call ‘I’ seems to intuitively be one thing

• Any conscious experience (e.g. a sensation, an emotion or a train of thought) is always an experience of the one mind which is yours

• Although there are different ways of being conscious, it is still the same mind which experiences these ways

• So I am a unitary centre of consciousness which is indivisible.

This argument relies on Leibniz’s law of identicals.

What is Leibniz’s law of identicals?

Leibniz’s law of identicals (the principle of indiscernibles) states that 2 things can only be identical if they indiscernible or impossible to tell them apart. This means they must share all the same properties (including the occupy the same space).

What is the syllogism for Descartes’ divisibility/indivisibility argument?

P1. The body is divisible

P2. The mind is indivisible

P3. Body and mind are not identical according to Leibniz’s law of identicals

C1. Therefore the body and the mind must be distinct substances

C2. Substance dualism is true

Explain the criticism of the divisibility argument that the mind/mental is divisible

Descartes conceived the mind to be the realm of the appearance of conscious experiences - so its appearance is its reality.

• BUT people are capable of self-deception

  • e.g. I might refuse to admit to myself that I have a shameful desire - one part of my mind has it, the other part denies I have it.

Freud argued 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 us becoming fully aware of it.

We can also conceptualise different aspects of the mind (e.g. conscious vs subconscious) so surely we’ve conceptually divided up the mind?

Explain Hume’s criticism of Descartes indivisibility argument

• Hume attacks Descartes’ claim that introspection reveals a unitary consciousness 

• Hume - ‘ (When I introspect) I always stumble on some particular perception or other, of heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never can observe any thing but the perception’ 

  • We are never aware of our mind as a single entity or an owner of our experiences

  • We are only aware of multiple perceptions/experiences suggesting that the mind is simply made of a bundle of conscious perceptions/experiences which are separate from each other and thus divisible

How does neuroscience question the indivisbility of the mind?

• Physicalists might argue that consciousness has its base in the physical nature of the brain, so that cutting up the brain would result in split consciousness.

• The experience of patients who have had the connection between the two hemispheres of their brain cut appears to show two distinct centres of consciousness operating without the patient being aware of this

• In such cases, the subjective reports of the way consciousness appears (through introspection) are shown to be inconsistent with reality 

• So introspection is not reliable

• The consciousness may actually be divided when the brain is divided so the mind is divisible

Explain the masked man fallacy

• P1. I recognise that Batman is a masked crusader

• P2. I recognise that Bruce Wayne is a playboy millionaire

• C1. Therefore Batman is not Bruce Wayne

The conclusion is wrong, yet the premises are true in this case, meaning the argument is fallacious.

• The issue with this reasoning is that I only recognise an aspect of Batman - my idea doesn’t reveal his full nature so I wrongly conclude that he is distinct from Bruce Wayne. 

• Similarly, Descartes’ idea of the mind may be incomplete

• Introspection reveals the mind to different to the body 

• Yet, the fact that I am unaware of my body being the same as the mind doesn’t show that it isn’t in reality.

• Leibniz’ law can only be used successfully if one is not mistaken about the perceived properties that seem to differ

• So if Descartes’ ideas are incomplete, the argument fails

What is the syllogism for the masked man fallacy?

• P1. I recognise that Batman is a masked crusader

• P2. I recognise that Bruce Wayne is a playboy millionaire

• C1. Therefore Batman is not Bruce Wayne

The conclusion is wrong, yet the premises are true in this case, meaning the argument is fallacious.

Explain Descartes’ response to the masked man fallacy

Descartes’ argument includes the claim that he clearly and distinctly recognises that nothing more is involved in his ideas of the mind and body.

If he is right that he can be certain that the essences of both mind and body are distinct then they would have to be distinct substances.

This would then make the argument valid.

Explain whether indivisibility really suggests that the mind is a non-physical thing

• Assuming that the mind is divisible, it doesn't necessarily follow that the mind is a non-physical thing.

• There are many things in everyday life which are considered physical yet are indivisible. 

  • e.g. physical states or properties of the body (like being wet or hot) cannot be divided into parts but they are not non-physical substances.

• So its indivisibility might not suggest that it is a peculiar non-physical substance, but that it is not a substance at all and simply a property of a physical substance.

Explain what is meant by logical possibility

Something logically possible is possible by virtue of the meaning of the terms.

For something to be logically possible, it does not need to be something that could actually happen (in this world) - as long as it doesn’t go against the laws of logic, it is logically possible.

If something involves any contradiction or is false by definition, it is logically impossible.

Anything that can be conceived of is logically possible.

Those things which one can logically conceive to be different can be referred to as a contingent matter.

This is verifiable analytically, by looking at the meaning of the terms.

Explain what is meant by physical possibility

Something is physically possible if its occurrence is consistent with the laws of nature that happen to exist in the actual world.

Physical possibility is a subset of logical possibility.

Physical possibility/impossibility is a contingent matter (contingent on the laws of physics).

What is physically possible is empirically true (verifiable by observation/through the senses).

Explain what is meant by metaphysical possibility

Something which could be the case in a possible world.

Something metaphysically possible is possible by virtue of the referral of the terms.

Physical possibility guarantees metaphysical possibility - a possible world is one which has the same laws of nature as our world.

It is not possible to change the essence of something but it is possible to change some of the properties of things.

e.g. you can change the colour of gold to a copper colour, but you cannot change the molecular makeup of gold.

Explain Descartes’ conceivability argument

• Descartes argues that if he has a ‘clear and distinct’ idea of two things then it must be possible in principle to separate them 

• If I recognise the essential natures of two things to be clearly distinct, then they must actually be distinct things

• The mind:

  • The essential nature of the mind is consciousness - the mind is by nature a thing which thinks

  • Extension forms no part of the mind’s essential nature

• The body 

  • The essential nature of the body is extension

• So I clearly recognize the distinct natures of mind and body

• So Descartes concludes that they are distinct

What is the syllogism for Descartes conceivability argument?

P1: If I can clearly and distinctly recognise the natures of two things to be different, therefore they must be distinct 

P2: I can conceive of the essential nature of the mind as conscious thing with no extension

P3: I can conceive of the essential nature of the body as a purely extended thing

C1: Therefore, I can clearly and distinctly recognise the natures of mind and body to be different

C2: Therefore they must be distinct

C3. Substance dualism is true

Explain the criticism of the conceivability argument that logical possibility doesn’t guarantee physical possibility

This is flawed:

• You cannot always use an argument’s opposite to form a separate argument

• e.g.

  • Although not applying to Oxbridge guarantees that you will not get an offer

  • Applying to Oxbridge does not guarantee that you will get an offer

• Why it’s flawed

  • Logical impossibility guarantees physical impossibility

  • But logical possibility does not guarantee physical possibility

    • e.g. its logically possible for horses to have 8 legs but irl they don't

  • So if one can imagine the mind and body as distinct

You can only conclude that they could be distinct.

Explain the criticism of the conceivability argument that what is conceivable may not be metaphysically possible

So Descartes’ ability to conceive of his mind without his body doesn’t show that its possible for the mind to exist without the body in reality.

Explain difference between metaphysical and logical possibility.

Say that Descartes is making a jump between the two in his argument in that he is arguing that what is logically possible guarantees metaphysical possibility.

Explain the criticism of the conceivability argument that what is metaphysically possible tells us nothing about the real world

Just because it is metaphysically possible that the mind is distinctly separate from the body does not mean that dualism is the case in the physical world as metaphysical possiblity tells us nothing of the real world.

e.g. just because its metaphysically possible that gold could be green, does not mean in the physical world that gold is green, it is simply possible in a possible world.

Explain the criticism of the conceivability argument that mind without body is inconceivable from a verificationist perspective

The argument begins by considering the conditions under which a claim can be meaningful. 

A plausible answer is that it must be grounded in some way in experience. Terms, in this view, get their meaning because they tell us something about the empirically observable world. 

Verificationists argue that terms such as 'God' are meaningless precisely because they are supposed to refer to a transcendent being.

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. 

• For verificationists this means the claim of substance dualism is nonsense. 

• So while the proposition that the mind is a non- physical substance distinct from the body may appear conceivable, actually it betrays confusion and doesn't express a coherent thought.

Explain the criticism of the conceivability argument that mind without body is inconceivable from a behaviourists perspective

Without a body, something can’t exhibit behaviour; and without behaviour, there is no mind. 

SO once we’ve understood what we mean when we talk about the mind, we will realise that mind without body is inconceivable. 

This is a very strong claim. 

• For example, if it is right, then disembodied minds, such as God, are inconceivable.

Explain the criticism of substance dualism that says the mind depends on the brain

Neuroscience strongly supports the idea that the mind is dependent on the brain as;

• The brain influences memories and their storage.

• The structure of the brain can determine personality traits.

• Overall brain volume links to intelligence.

These observations are best explained if we assume the mind isn't just causally influence by the brain but actually depends on it.

Explain the responses to the argument that the mind depends on the brain

• These are simply correlations, not necessarily causations

• Empirical evidence (observations) can only show us correlation 

• Correlations suggests but do not prove causation 

• e.g. in summer both ice cream sales and homicide rates increase (there is a correlation between the two but murders are caused by ice cream sales)

• So the correlation proves nothing

• It merely suggests dependency

Explain the criticism of substance dualism that is evolutionary history

The process whereby human beings evolved from other lifeforms over billions of years is a physical one and therefore all the capacities and properties of creatures should be able to be explained in physical terms 

Human being’s must have evolved minds as they serve in survival of the species 

These capacities are related to the evolution of our brains and have given us evolutionary advantages (in the same way that other animals have unique mental capacities)

• Consciousness has evolved as a useful tool - makes us better adapted to our environment and more able to respond/react to predators etc

Our brains differ mainly in mentality rather than in structure compared to other animals 

• But other animals are also conscious (e.g. dolphins) with consciousness developing throughout evolutionary history

This suggests our mind and brain are linked more closely than Descartes suggested and that mind exists as an evolved element of the brain not as an individual substance.

The claim that the mind is a distinct substance raises further questions concerning how and why it was created and how it became associated with a specific animal.

• These questions require an elaborate metaphysical explanation, probably involving the intervention of a benevolent God so Ockham’s razor strongly suggests an explanation in terms of one physical substance must be superior.

Explain the argument that dualism makes a category mistake

Ryle argues that Descartes makes a category mistake in assuming that the mind is a non-physical thing:

• Just because the mind is not a physical thing, that doesn’t mean it must be a non-physical thing. 

• Instead the mind might not be a ‘thing’ at all

Ryle argues that the language we use to describe the mind confuses us about the logical category it belongs to:

• The terms ‘state’ and ‘process’ appear to relate only to physical things

• Yet we refer to mental states and processes

• This leads us to think that the mind must also be a ‘thing’

• Descartes is unable to find this physical ‘thing’ so concludes that the mind must be non-physical, based on the incorrect assumption that the mind is some type of ‘thing’

Ryle instead concludes that the term ‘mind’ simply refers to a set of behavioural dispositions.

Explain Descartes’ idea of interaction

Body parts give you sense information.

This is conveyed through the nervous system to the brain by ‘animal spirits’ (described as fine fluid/vapour).

It is received by the Pineal gland which is the seat of common sense.

Unified consciousness experience (all the information comes together to form common sense which is felt) in the mind.

Explain the criticism of Descartes’ divisibility argument that says the physical is not all necessarily divisible

Can use example of quarks (may be fundamentally divisible)

Can use examples of physical stats such as running/being hot or cold

Criticises the premise of Descartes’ argument that says the body is divisible

Makes the argument valid but not sound