Metaphysics of Mind

What do we mean by mind?

Features of mental states:

Phenomenal properties

-Properties of first person conscious experience.

-Humans are unique from animals because we have an awareness of the contents of our own mind. Awareness of our own mind=awareness of phenomenal properties, eg. mental states.

-The question of philosophy of mind is what these properties are- can they be reduced to physical properties, or are they non-physical?

Qualia

-Intrinsic and non-intentional phenomenal properties that are introspectively accessible

-Qualia describes phenomenal properties- describes what the subjective experience is to the person. Eg. the qualia of red

-Dualists use this term to support phenomenal properties as irreducible: Chalmers defines qualia as the qualitative character of experience (non-physical).

Intentional properties

Some mental states have intentional properties- they can be directed towards other things such as: people, the world, or other mental states. E.g the mental state of hunger is directed to food.

Beliefs have intentional properties because they don't just exist by themselves, but are directed or about something. (Fear is fear of something).

Substance Dualism

-Substance dualism posits two fundamentally distinct substances: mental and physical - as existing independently of one another.

-The mind is an immaterial, meta-physical substance

-the body is material and extended in space.

-The two substances are disparate from one another and independent within themselves.

Interactionist dualism

The mind can interact with the physical world, and the physical world can interact with the mind. (both directions).

Minds exist and are not directed to bodies or parts of bodies

Substance dualism: Descartes' divisibility argument

-aims to present the ontological differences between body and mind

-relying on the logic of Leibniz' law of identity: if two objects are identical, then they must be one object, and vice-versa.

Descartes sets out his argument as the following:

P1. Physical substances (like my body) are extended in space, and therefore divisible.

P2. My mind is indivisible, as it is not extended in space.

P3. Leibniz' law states that if two entities have identical properties, they are the same entity.

P4. My mind and my body do not have identical properties (my body is extended and divisible, my mind is extended and indivisible)

C1. My mind and my body are not the same entity- they must each be individual substances, disparate from one another.

Response to divisibility argument: The mental is divisible in some sense

-There are cases of mental illness in which the mind does seem literally divided- eg, multiple personality disorder.

-The brain is divided in to two hemispheres- the right hemisphere controls the left arm, and the left hemisphere controls the right arm. When the neurons that connect these hemispheres are cut, there have been cases where the patients mind seems to have been divided in to two. E.g a patient picked up food with one hand and hit it away with the other.

-suggests that when the brain is divided, the mind is divided- not only does this show that the mind is divisible, but that it directly correlates to the physical brain.

Response to divisibility argument: Not everything physical is divisible

-The body is not infinitely divisible- a body part can be divided and divided from atom to sub-atomic particles, but eventually one might reach a form of physical substance that is indivisible.

-Therefore: If it's possible to reach a point where physical matter becomes indivisible, then not everything that is indivisible is non-physical. Even if Descartes successfully show that the mind is indivisible, thus doesn't prove that the mind is non-physical. It's possible that the mind is the same kind of substance as the body (i.e a physical substance)- it's just an indivisible form of that same substance.

Substance dualism: Descartes' conceivability argument

Descartes' Conceivability Argument attempts to evidence Substance Dualism, by using his assertion of clear and distinct ideas to argue the validity of his perception of mind and body as two separate entities. His argument can be presented as follows in standard form:

P1: I have a clear and distinct idea of my body as an 'unthinking thing', and extended in space

P2: I have a clear and distinct idea of my mind a a 'thinking thing' and not extended in space

P3: If I can clearly and distinctly conceive of the essential natures of two things separately, it must be metaphysically possible to separate them, as there is no logical contradiction.

C1: Mind and body are separate substances.

Response to conceivability argument: mind without body is inconceivable

Behaviourism says that to have mental states is to have behavioural dispositions.

To have behavioural dispositions is to be disposed to move your body in certain ways. It is inconceivable to be disposed to move your body in certain ways if you don't have a body. So, it is inconceivable to have mental states if you don't have a body. So, mind without body is inconceivable.

Response to conceivability argument: what is conceivable may not be physically possible

Even if Descartes' argument was metaphysically possible (the argument itself contains no logical contradictions) the argument would still not necessarily entail physical possibility.

-It is not possible for a square to have five sides- this involves a logical contradiction, and therefore cannot be possible metaphysically or physically possible.

-Conversely, the concept of a unicorn does not involve any logical contradiction, and therefore can be possible metaphysically.

-However, this still does not mean that unicorns are physically possible, and furthermore this does not give us the credence to claim that unicorns actually do exist.

-This is because a concept being logically possible does not entail physical possibility- just because the concept is acknowledged as being possible in theory, does not mean that this concept physically manifests in our reality.

-Thus, the absence of logical contradiction in substance dualism -and the possibility of it being able to exist- does not consequently mean that substance dualism does actually exist in our reality.

-All that Descartes can claim is that it is a contingent truth, metaphysically possible but not actually provable.

Response to conceivability argument: what is conceivable may not be metaphysically possible

Antoine Arnaud: what is conceivable may not necessarily be metaphysically possible.

-Parallel argument to Descartes.

-Pythagoras' theorem: the square of the hypotenuse of a right angle triangle is always equal to the other two sides).

-If someone was ignorant to this theorem, they could have a clear and distinct idea of a right angled triangle which does not have this property.

-A person can clearly and distinctly conceive (through ignorance) a triangle which does not have this property; this does not subsequently mean that such a triangle is metaphysically possible. That would entail a logical contradiction.

-A right-angle triangle that does not cohere to the Pythagoras' theorem is logically and therefore metaphysically impossible; someone ignorantly conceiving such a triangle does not change this fact.

-Thus conceivability does not entail metaphysical possibility

-therefore Descartes having the ability to clearly and distinctly conceive of his mind and body as separate substances does not equate to metaphysical possibility of substance dualism.

(Arnaud shows that Descartes' idea is formed in ignorance)

Response to conceivability argument: masked man argument

Attacks Descartes' inference from the claim that mind without body is conceivable to the conclusion that mind exists without body in reality.

P1. I conceive of Batman as a caped crusader

P2. I conceive of Bruce Wayne as a billionaire who is not a caped crusader

C1. Therefore, Batman is not Bruce Wayne

Fallible because premises are based in ideas and conclusion asserts reality. But our ideas can be mistaken about reality.

-Just as an idea of Batman and Bruce Wayne as separate people doesn't mean they are, an idea of mind and body as separate doesn't mean they are.

Conceivability tells us nothing about reality.

Property dualism

-maintains the existence of only one type of substance, but argues for two irreducible categories of properties: physical and mental.

-Mental properties emerge from and therefore are dependent on physical systems like brains, rather than constituting a separate substance.

-It doesn't go as far as substance dualism in claiming that the mind is completely non-physical, but it differs from physicalism because a complete physical description of the universe would miss out qualia

-There are at least some mental properties that are neither reducible nor supervenient upon physical properties: qualia

Epiphenomenalist dualism

The physical world can cause mental states, but mental states cannot cause changes in the physical interactions. (causal interaction is one way).

Physical-> mental (needing to eat-> hunger)

But qualia don't cause anything (eating caused by needing to eat, not hunger)

Avoids causal interaction issues, because does not have to explain how mental causes changes in the physical

Supervenience

-X supervernes on Y if a change in Y is necessary for a change in X

-If something supervenes on something else, then it is dependent on that things

-Physicalism says that everything (including the mind and mental states) os either physical or supervenes on the physical. So two physically identical things are the same either way- it's impossible for two physically identitical things to be mentally different. BUT property dualism says it is possible for two physically identical things to have different qualia.

There are at least some mental properties that are neither reducible nor supervenient upon physical properties

The 'physical zombies' argument for property dualism (David Chalmers)

A philosophical zombie is a person who is physically and functionally identical to be an ordinary human- except they don't have any qualia.

P1. Philosophical zombies are conceivable

P2. If philosophical zombies are conceivable then philosophical zombies are metaphysically possible

P3. If philosophical zombies are metaphysically possible then qualia are non-physical

C1. If qualia are non-physical then property dualism is true

C2. Therefore, property dualism is true

Response to physical zombies argument: not conceivable

Physicalists would respond that we would be able to understand

Response to physical zombies argument: what is conceivable may not be metaphysically possible

Response to physical zombies argument: what is metaphysically possible tells us nothing about the real world

The 'knowledge/ Mary' argument for property dualism (Frank Jackson)

Response to 'knowledge/ Mary' argument: ability knowledge

Response to 'knowledge/ Mary' argument: acquaintance knowledge

Response to 'knowledge/ Mary' argument: new knowledge/old fact

Issue with Dualism: The problem of other minds

We only ever experience our own mental states. Everyone has their own subjective experience in our mind.

Yet even though we don't experience other peoples thoughts, we all assume they have them. We infer from their behaviour that they have a mind that causes their behaviour.

If Substance Dualism is true, there is no grounds to make this assumption. Minds and bodies are separate substances, so how do we know that that there is a mind attached to a body?

Substance Dualism leads to scepticism about the existence of other people's minds.

Response to the problem of other minds: the argument from analogy

John Stuart Mill:

P1. I have a mind

P2. My mind causes my behaviour

P3. Other people behave similarly to me in similar situations

P4. By analogy, their behaviour has the same type of cause as my behaviour: a mind

P5. Therefore, other people have minds.

response: Dubious inference to go from one instance to claim it holds in all instances. 'That dog has three legs, therefore all dogs have three legs'.

Response to the problem of other minds: the existence of other minds is the best hypothesis

We can't prove the existence of other minds, but they are the best explanation (abductive argument).

two hypotheses:

a)

b)

Also, their explanatory and predictive power: people having minds explain the ways people behave.

Response to the problem of other minds: dualism makes a category mistake

Gilbert Ryle

Issue with Substance Dualism (interactionist): causal interaction problem

How can mental things causally interact with physical things if they are separate substances?

Mental states affect how we behave.

Hungry (mental state)-> eating (physical state)

If mental state is non-physical, how does it transfer over into physical world?

Issue for interactionist dualism, not epiphenomenal.

Issue with Interactionist dualism: The conceptual interaction problem

Elisabeth, Princess of Bohemia

Issue with interactionist dualism: the empirical interaction problem

Response to causal interaction problem: epiphenomenalism

Issue with epiphenomenalist dualism: introspective self-knowledge

Issue with epiphenomenalist dualism: phenomenology of our mental life (ie as involving causal connections, both psychological and pyscho-physical)

Issue with epiphenomenalist dualism: natural selection/evolution

Physicalism

Everything is physical or supervenes upon the physical (including properties, objects and any substances that exist)

Hard behaviourism

All propositions about mental states can be reduced, without loss of meaning, to propositions the exclusively use the language of physics to talk about bodily states/movements

Carl Hempell:

Soft behaviourism

Propositions about mental states are propositions about behavioural dispositions

Gilbert Ryle:

Behavioural dispositions

Issue to behaviourism: dualist arguments applied

Issue to behaviourism: the distinctness of mental states from behaviour

Hilary Putnam's 'Super-Spartans' and perfect actors

Issue to behaviourism: problem with defining mental states satisfactorily

a) circularity

b) multiple realisability of mental states in behaviour

Issue to behaviourism: asymmetry between self-knowledge and knowledge of other people's mental states

Mind-Brain type identity theory

All mental states are identical to brain states (ontological reduction), although 'mental state' and 'brain state' are not synonymous (analytic reduction).

Issue for Mind-Brain type identity theory: dualist arguments applied

Issue for Mind-Brain type identity theory: problem with providing the type identities (the multiple realisability of mental states)

Eliminative materialism

Some or all common-sense ('folk-psychological') mental states/properties do not exist and our common-sense understanding is radically mistaken

Patricia and Paul Churchland

Issue for Eliminative materialism: our certainty about the existence of our mental states takes priority over considerations

Issue for Eliminative materialism: folk-psychology is the best hypothesis

has good predictive and explanatory power

Issue for Eliminative materialism: the articulation of eliminative materialism as a theory is self-fulfilling

Functionalism

All mental states can be characterised in terms of functional roles which can be multiply realised

Issue for Functionalism: possibility of a functional duplicate with different qualia (inverted qualia)

Issue for Functionalism: possibility of a functional duplicate with no mentality/qualia

Ned Block's China thought experiment

Issue for Functionalism: the 'knowledge/Mary' argument can be applied to functional facts

No amount of facts about function suffices to explain qualia