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The Mind-Body Problem

1. What is the nature of the relationship between the mind and the body?
2. Is the mind simply the brain?
3. Is the mind a different thing than the brain?

4 Features of Mind Hard to Account for

• Consciousness
• Intentionality
• Subjectivity
• Mental Causation

Theories of Mind: A Taxonomy

Dualism vs. Monism

• Dualism: --> the nature of conscious intelligence is non-physical the mental and the physical are two distinct things/spheres of events
• Monism: --> mental and physical things are not two things to be related or explained there is only one thing/sphere of events

Substance vs. Property Dualism

Substance Dualism:

• mind and body are 2 different things
• mind can be ``detached'' from body

Property Dualism:

• mind and body are NOT 2 different things
• the brain (body) is the only substance/thing
• the brain has nonphysical properties

Kinds of Property Dualism

Epiphenomenalism

• Property dualism is true.
• Mental states emerge from the brain from a certain level of complexity.
• Mental states are caused by the brain, but mental states do NOT cause effects in the brain.
• Mental states are mere phenomena.
• Example: A crest on a wave.

Interactionism

• Property dualism is true.
• Mental states emerge from brain activity.
• Mental states CAN cause states in the brain.
• Mental states are NOT reducible to brain states; they are NOT mere phenomena.

Elementalism

• Property dualism is true.
• Mental states are basic, elemental things.
• Mental states have not emerged by evolution, nor are they merely phenomena of brain states.

Materialism vs. Idealism

Materialism --> only matter exists; whatever exists depends on matter (consciousness is purely a product of matter)

Idealism --> only mind exists; whatever exists depends on mind (material things are a product of the mind)

Functionalism vs. Identity Theory

Both are versions of materialism

• Functionalism: : mental states are explained solely in terms of their effects on the body and other mental states
• Identity Theory: : Mental states just are states of the brain; they are numerically identical with states of the brain.

Behaviorism

• Functionionalist
• Mental states are to be explained in terms of the sort of behavior associated with them.
• Pain --> only wincing, crying out, etc.
• Mind is simply a set of capacities and dispositions; it is not a thing which someone has.

Computationalism

• Functionalist
• If a computer could have the appropriate inputs/outputs, then it can have mental states.
• no difference between ``wetware'' and ``hardware"--if the right program is used.

Eliminative Materialism

• Materialist
• mental states are brain states
• mental states just are what neuroscience says they are.
• ``folk'' psychology should be eliminated.

Reductionism

• Materialist
• Mental states are states of the brain
• Mental states (e.g., consciousness) can only be explained by showing how they are (can be reduced to) brain states
• ``Folk'' psychology can be explained in terms of the language of brain states

Main Arguments for Dualism

Argument from Religious Experience/Tradition

1. Religion provides a source of truth about the nature of the universe.
2. Most religions affirm dualism--believe in the immortality of the soul.
3. Hence to reject dualism is to reject one's religious heritage.
4. We are not justified in doing this.
5. Hence dualism is true.

Argument from Parapsychological Phenomena

1. Telepathy, precognition, telekinesis, clairvoyance are facts which cannot be explained by normal scientific theories.
2. All of these phenomena are easily explained by dualism.
3. Therefore, dualism is true.

Argument from Introspection

1. When we concentrate on the content of our consciousness, we are NOT aware of physical movements/activities within the brain.
2. We are only aware of a flow of thoughts, feelings, desires, and emotions.
3. These mental states as revealed in introspection are VERY different than material states in the brain.
4. Hence there is a radical difference between the mental and the physical sides of consciousness--mind.
5. Hence dualism is true.

Argument from Irreducibility

1. There are a variety of mental phenomena (sensory qualia) which cannot be explained by purely physical things.
2. Example: Seeing a color or smelling a rose.
3. These cannot be reduced MERELY to what is physically going on--a chemist or color theorist might know everything that is going on materially with these things, but yet we could say that if he has never smelt a rose or seen color, he has an incomplete knowledge of these things.
4. Complete knowledge only comes when we attend to the purely mental features of things like this--their sensory qualia.
5. Dualism is the best explanation for this situation.

Descartes' Substance Dualism

The Self is a Union of Mind and Body Med. VI

1. The essence of me is that I am a thinking thing.
2. I also (clearly and distinctly) perceive that I have a body.
3. I am not related to my body as a pilot is to a ship.
4. Therefore, I am a union of mind and body.

The Real Distinction between Mind and Body

1. I can doubt that my body exists, but cannot doubt that my mind exists. (Med II)
2. Mind is indivisible; body is divisible. (Med VI)
3. Mind is not affected by all parts of the body. (Med VI)
4. Therefore, the mind is one kind of substance, the body is another.

Essential Properties of Mind and Body

• Mind --> thought
• Body --> extension

Idea: We cannot conceive of these things without having these properties.

Problem of Interaction

Problem:

• Mind and body clearly interact.
• If mind and body are radically distinct things, how do they interact?

Obvious solution: Mind and body interact like a pilot in a ship. (D. denies this. Med VI)

Descartes' Solution:

``The soul really is joined to the whole body, and...we cannot, properly speaking, say that it exists in any one of its parts. But...there is a certain part in which it functions more particularly than in all the others...the most inward of all of its [body] parts, a certain very small gland which is situated in the middle of its substance and which is so suspended above the duct whereby the animal spirits in its anterior cavities have communication with those in the posterior that the slightest movements which place in it alter very greatly the course of these spirits; and reciprocally that the smallest changes which occur in the course of the spirits may do much to change the movements of this gland.'' from Passions of the Soul.

Malebranche's Solution: Occasionalism

1. Given dualism, God is the link between the body and the mind.
2. When I move (e.g.) my hand, God makes my arm move.
3. There is NO direct causality among things in nature.
4. Analogy: Two clocks with the same maker--not a single causality.

Problems with Occasionalism

• Fails ``Ockham's Razor'': Requires the assumption of too many controversial entities
• Easier solution: deny the validity of ONE side of dualism (e.g., affirm that only matter exists, and deny that mind is nonmaterial in substance).

Arguments Against Dualism

Gilbert Ryle's Argument Against Dualism

Structure of Ryle's Paper:

1. What Dualism Involves.
2. Problems with Dualism.
3. Where did these problems come from.

What is Dualism?

1. Every human has a body and a mind (or is both a body and a mind).
2. There is a union between body and mind.
3. Mind and body can be severed at death.
4. Body is in space and time and hence subject to the mechanical laws which govern all other bodies in space.
5. Bodily processes are public--objectively observable; unpriviledge access.
6. Minds are not in space, but are in time.
7. Mental processes are not publicly observable--are [purely] subjective; priviledged access.
8. Minds are not subject to mechanical laws.
9. Material bodies can be causally connected; barring telepathy, minds cannot causally affect other minds.
10. Minds and bodies comprise two entirely different modes of existence.

The `Ghost in the Machine'

Dualism --> a CATEGORY MISTAKE

it represents facts about mental life as if they belonged to one logical type or category when they actually belong to another. Hence dualism is a philosophical myth.

[R does NOT deny the difference between mental life and bodily existence, only the conclusion that mind and body are different things.)

Examples of Category Mistakes:

• When all the buildings of a University are seen, someone asks ``Now where's the University?''
• Upon seeing all the battalions, batteries, etc., of a division a child asks ``Where's the division?''
• Esprit de corps is not another player on a team; it is all of the players working together.
• The British Constitution is the proper functioning of several civic institutions--not an institution over and above them. To suppose so would be to make a category mistake.

POINT: Dualism assumes that because a person's thinking, feeling, etc., cannot be described in terms of the language and method of physics, that mental states must be of another counterpart system. Since body is a complex organized unit, so too is the mind, but with a different structure.

Intellectual Orgins of the Dualist Mistake

1. Descartes' conflicting motives: He was a man of science, but he wanted to preserve his religous faith. Hence he assumed the distinct reality of the mind.
2. Descartes described the mind in terms that he applied to material things--existence, stuff, attributes, cause and effect, etc., but simply assumed that these features were of a different metaphysical order.
3. Since mind belongs to the same category as body, mind must be governed by rigid non-mechanical laws.

Ryle's Conclusions

1. What is problematic about dualism is its ``illegitimately joined propositions''.
2. ``There are physical processes'' does not mean the same thing as--is not in the same category as--"There are mental processes''.

Implications

1. Mind and body should not be regarded as of the same logical type.
2. Idealism and Materialism are answers to an improper question. We should not ``reduce'' the material world to material processes, not the mental to spiritual.
3. It is perfectly reasonable to say that there exist bodies and there exist minds. But NOT that these are two different species of existence (this is the mistake).

Property Dualism

• mind and body are NOT 2 different things
• the brain (body) is the only substance/thing
• the brain has nonphysical properties

Kinds of Property Dualism

Epiphenomenalism

• Property dualism is true.
• Mental states emerge from the brain from a certain level of complexity.
• Mental states are caused by the brain, but mental states do NOT cause effects in the brain.
• Mental states are mere phenomena.

Example: A crest on a wave.

Interactionism

• Property dualism is true.
• Mental states emerge from brain activity.
• Mental states CAN cause states in the brain.
• Mental states are NOT reducible to brain states; they are NOT mere phenomena.

Elementalism

• Property dualism is true.
• Mental states are basic, elemental things.
• Mental states have not emerged by evolution, nor are they merely phenomena of brain states.

If dualism is mistaken, is there anything like it that might still hold. Yes: Property dualism. We must examine this view now.

Example of a Property Dualist Argument: Searle Minds, Brains, Ch.1

1. Mental phenomena are caused by brain processes. (18t)
2. Mental phenomena just are features of the brain. (19b)
3. Just as the solidity of a table is caused by an arrangement of atomic particles, and is a feature of the table (not any one of the particles), so too is the mind both caused by, and a feature of, the brain. (21)
4. Hence mental states have two levels of description: a higher level in mental terms, and a lower level in physiological terms. (26t)

Materialism

The Case for materialism is often aided by the explanatory power and success that materially based neuroscience has had in:

• solving clinical problems in psychiatry
• explaining in detail how the brain works

Clinical Power of Materialism

1. Many `psychological problems' seem resolvable only by addressing the neurophysiology of the brain.

R.G. Heath is credited with having really brought out this to the forefront.

H performed operations on conscious psychotic patients where he dripped neurotransmitters into certain areas of their brains. They immediately responded with swift changes in mood--e.g., crying impulsively, laughing, etc.

2. Drugs have been developed to change the behavior of neurotransmitters.

The Basic Material Structure of the Brain

• 100 billion neurons with
• 100 trillion synaptic connections

NOTE: This is a very conservative estimate. Some have it around 200 billion neurons.

Each neuron has 3 distinct parts:

• cell body
• the dendrites
• the axon

(See Figure synapse3 for details.)

Churchland's Calculation

1. Suppose (conservatively) that each connection might have 10 possible different strengths.
2. Then the total number of distinctly possible synaptic configurations is 10 to the 100 trillionth power.
3. Cf. the standard measure of the size of the universe: 10 to the 87th power.

Advantages of Parallel Distributed Processing

• Speed
• Functional Persistence

Speed is obvious. Given the nature of parallel processing, each synapse contributes only a tiny amount to the overall process.

Result: We could lose a significant amount of these, and still have a functioning system. Cf. serial: as strong as its weakest link. (Like the Internet.)

What do Materialists Make of these Facts

Materialism is the view that the only substance involved in mental states are physical ones (or physical processes).

Mental states ARE--in some sense--physical states. (Mental states are physcial substances.)

To say that mental states ARE physical states suggests IDENTITY: Mental states are identical to physical states.

But identity can be cashed out in many different ways.

Materialism and Identity

1. Things can be the same, in that they are the same TYPE.
2. Things can be the same, in that they are the same TOKENS.

Example: ``The teacher is at the back'' (6 word tokens; 5 word types.)

So in philosophy of mind this maps out like this:

Type Identity Materialism

--> a type of mental state is identical with some physicial type of state. Mental event of type x = neurophysiological event of type y.

Token Materialism

--> mental event x = neurophysiological event y. Each instance of a mental state is identical with an instance of a bodily state of some type or other.

Problems with Type Identity

• Species problematic. Assumes that everyone who believes the same thing, must have the same type of brain state.
• Cross-Species problematic. Assumes that all human pains are identical with certain types of human brain states.

But some pains might

• be pains and
• not be anything like our brain state types.

Problems with Token Identity

1. Assumes that: Person x can have mental state M1 caused by brain state B1 and person y can have M1 caused by B2.
2. Problem: What do x and y have in common?
3. Cannot have the same mental features --> dualism!
4. Cannot have the same physical features --> type identity!
5. Answer: B1 and/or B2 = M1 because they both cause M1 --> i.e., functionalism is true!

So token identity just is functionalism.

Reductionism

• Basic Idea: : X is ``nothing but'' Y.
• Principle: : Xs can be reduced to Ys iff Xs really are nothing but Ys.

Examples of Scientific Reductions:

• light IS electromagnetic wave
• temperature IS mean molecular kinetic energy
• mental states ARE physical states in the brain, etc.

Arguments for Identity Theory

Argument from Scientific Success (Neuroscience)

1. Bandwagon Arguments
2. Sound and Fury Arguments

Argument from Physical Origins

1. Each individual is a result of purely physical origins and constitution.
2. The mind should not be anything more than this.

Argument from Physical Origins of Types

1. Each TYPE of individual animal also appears to have exhaustively physical origins.
2. Evolutionary theory is the only serious explanation we have for the behavior controlling capacities of the brain and nervous system.
3. Those systems were selected for because of the reproductive advantages held by creatures thus controlled.

Argument from neural dependence

1. All known mental phenomena seem to depend on neural activity.
2. Admitting a class of entities (e.g., mental events) over and above neural events, violates Ockham's Razor.

Smart's Argument

Thesis: Mental states are nothing but brain states.

Main Support:

• Success of neuroscience (and science generally).
• Ockham's Razor.

What Smart is NOT claiming:

1. Mental states are correlated with brain states.
2. Reports of mental states mean the same things as reports of brain states.

Problems with the Identity Theory

Argument from Promisory Failure

1. Identity theory relies on the success of neuroscience in finding a one-to-one correlation between a mental event and a specific type of neural event.
2. No such correlation has been found.

Argument from Introspection

1. When we focus our attention on the contents of our consciousness, we don't clearly apprehend a neural network of pulsing electrochemical activity.
2. We apprehend a flux of thoughts, sensations, desires, and emotions.
3. Thus from introspection alone, mental states are not physical states.

Argument from Category Error

1. Leibniz' Law of identity states that two items are numerically identical just in case any property had by either one of them is had by the other as well.
2. Brain states have some specific spatial location in the brain.
3. If brain states are identical with mental states, then mental states must have the very same location.
4. It is meaningless to say (e.g.,) that my feeling of pain is located in my ventral thalamus or that my belief that the sun is a star is located in the temporal lobe of my left cerebral hemisphere.
5. Hence, the identification of mental states with brain states leads to statements which are unintelligible; they commit a category error.

John Searle's Argument vs. Identity Materialism

See (Rediscovery of the Mind, p. 37-8)

1. Identity theory faces a dilemma.
2. Either mental states involve subjective, mental introspective features or they do not.
3. If they do, then we still hold that
1. the mind exists and
2. some sort of dualism (e.g, property) is true.
4. If they do not, then either i) the meaning of mental event statements are unexplained or ii) we have gotten rid of the mind.
5. Rejecting the mind is not plausible.
6. Hence, identity theory is false.

Smart's Response:

Topic Neutral Vocabulary. Idea: We can describe mental features in purely non-mental terms--e.g., neurological language.

Problem:

1. I can mention an airplane without mentioning ``airplanes''.
2. The fact that one can mention a phenomenon without mentioning its essential characteristics still doesn't mean that thing does not exist.

Functionalism

Functionalism --> the essential features of a mental state is the set of causal relations that it has to:

• environmental effects on the body
• other types of mental states
• bodily behavior

Example: Pain is caused by bodily trauma. It causes:

1. distress, annoyance, etc.
2. and it results in winching, nursing, etc.

To say that X is in pain is just to say that X is in a state where this causality occurs.

Functionism is Different from Behaviorism:

• behaviorism hopes to define each mental state in terms of behavioral input and output, functionalism denies this.
• describing any mental state requires a reference to other mental states with which it is causally related. Hence a reductive definition of publicly observable inputs and outputs is inadequate.

Functionalism is Different from Identity Theory

It doesn't matter what ``stuff'' goes to make up these causal relations (cf. identity) what matters is not what makes up a person's brain, but the structure (the ``programme''?) of the internal activities which that matter sustains.

NOTE: Functionalism is consistent with idealism (Functionalists do not have to be materialists. But most are materialists.)

Functionalists vs. Identity Theorists

Multiple realization problem. Seems unlikely that all mental states in vastly different organisms would be materially the same thing.

An Argument for Functionalism:

1. We identify organisms as in pain, etc., by behavior.
2. We do not count an animal as thirsty (e.g.) if its unstiated behavior did not seem to be directed toward drinking and was not followed by satiation for liquid.
3. Hence for any animal to be in this state, it will have a certain rough functional organization.
4. If we discover that token identity is true we would have discovered a functional organization that is necessary and sufficient for a given psychological state--as well as a definition of ``psychological state''.
5. What type identity theorists must do is hope for discovering neurophysical laws that are species independent.
6. 4 seems more reasonable to hope for than 5.

Computationalism: Features of the Strong AI View

1. There is nothing essentially biological about the human mind.
2. Intelligence is essentially symbol manipulation.
3. Different material structures can be mentally equivalent if they are different hardware implementations of the same progam.

What's a Turing Machine?: Turing's Argument

Not a concrete machine; it is only a conceptual model of how a human ``computer'' computes.

The ``Machine''

• a typwriting device can
• type a symbol on a paper tape
• remove such a symbol
• move to the left or right one unit along the tape
• the paper is infinitely long (essential) and is divided into square--some empty; others what contain a symbol

3 ``abilities'' of Turing's Digital Computer (356)

• store
• execute
• control

Main Features of Machine (358)

1. discrete state machine: moves suddenly from one definite state to another
2. universality: it can mimic any other discrete state machine

By specifying more precisely what the symbols are the typewriter can use, we can get it to change the notations on the tape. (i.e., by a certain input, we can get a certain output).

This, though simple, is enormously powerfull--Turing thought it could take any input and transform it into any output--PROVIDED that there is a program to do so. (if very complex, it'll take a long time! But it could in principle do it.)

The mind could be considered like this.

• neurons and their synapses set up a binary system
• the system, given its speed and parallel processing, moves suddenly from one state to another --> the mind is a discrete state machine
• the mind is also a UNIVERSAL machine --> it really can mimic any other discrete state machine (i.e., brain).

Cf. what Turing says in his response to the argument from continuity in the nervous system

Now assume:

1. That mental states are dependent upon the working of the brain.
2. At a level more general that neurophysiology, the brain is a device that receives inputs and outputs (from sensory systems).
3. These relations are describable by various mathematical relationships (ratios? Probabilities?)
4. We do not need to know what these are for the claim to work; if they exist, we know that some Turing (appropriately) sophisticated one--could do it.

Summary:

1. The brain is a computational device.
2. When we talk about the mind we are describing this device.
3. We're speaking about something much more complicated than a simple Turing machine. But no QUALITATIVELY different machine.

Turing believed this: He thought that such a machine could win an ``imitation'' game--a machine could imitate a computer. (If the mind is a computer, then we can imagine a differently constructed computer doing the same things--more in 2 classes.)

Idea: There is no reason why a digital computer could not win the ``imitation game''

Note: ``no reason why'' = negative argument for AI.

Some Counter-Arguments

• The Argument from Consciousness: Response: entails solipsism
• The Argument from Various Disabilities: Response: mere storage problem
• The Lady Lovelace Objection: : Machine is Uncreative Response: burden of proof is on those who claim that humans really display originality
• The Argument from the Informality of Behavior: Response: assumes (w/o proof) that because we are not aware of behavioral rules, they do not operate/exist.

Other Problems

• A Turing machine can only be in one state at a time. Mental states come in bunches.
• Turing's test makes intelligence linguafocused; but some animals and humans are intelligent and cannot use human language.

Searle's Argument against Strong AI

1. Brains cause minds.
2. Syntax is not sufficient for semantics.
3. Computer programs are entirely defined by their syntactical structure.
4. Minds have semantic contents.
5. Hence programs can never be sufficient for having minds.
6. Hence human minds produced by brains are not merely programs.
7. Any hardware structure that has a mind must have causal power equivalent to the human brain.
8. Mental states are biological phenomena.

Dennett's Critique of Searle

(from Consciousness Explained, p. 435ff)

1. S does not attend to the sheer complexity of the CR example.
2. Fallaciously assumes that since part (i.e., S in the CR) of the system has no understanding, the whole has none either.
3. The CR argument is only an ``intuition pump'' and hence cannot be an a priori disproof.

Searle's Response to the System Objection (34)

Misses the point that the system is purely syntactical and hence can never have semantic content.

Searle's Recent Objections to Strong AI

(from Rediscovery of the Mind)

1. AI theorists do not agree on basic questions:
1. What is a digital computer?
2. What is a computational process? etc. (205)
2. Syntax is not intrinsic to physics, hence computation is not a natural thing. It is relative to an observer. (207)
3. The brain does not do ``information processing''; it merely causes mental states. (222)