The Mind-Body Problem

1
The Mind-Body Problem

• Descartes Meditations II and VI

2
Descartes Argument for Dualism Meditation II

• Can I now claim to have any of the features that
  I used to think belong to a body? When I think
  about them really carefully, I find that they are
  all open to doubtThinking? At last I have
  discovered itthought! This is the one thing that
  cant be separated from me. I am, I existthat is
  certain. But for how long? For as long as I am
  thinking. But perhaps no longer than that for it
  might be that if I stopped thinking I would stop
  existing and I have to treat that possibility
  as though it were actual, because my present
  policy is to reject everything that isnt
  necessarily true. Strictly speaking, then, I am
  simply a thing that thinksa mind, or soul, or
  intellect, or reason.
• I cant conceive of myself apart from thinking
• What is inconceivable is impossible
• Therefore it is impossible for me to exist apart
  from thinking I am essentially a thinking being

3
Problems

• I cant conceive of myself apart from thinking
• But others can conceive of me apart from
  thinking! I cant conceive of being deadbut
  other people can conceive of my being dead.
• And compare I cant conceive of myself not being
  here now
• What is inconceivable is impossible
• This is the assumption that conceivability is
  criterial for logical possibility. But can we
  come up with a non-question-begging account of
  conceivability?
• Therefore it is impossible for me to exist apart
  from thinking
• When we dreamlessly sleep? Are we gappy?

4
Descartes Argument for Dualism Meditation VI

• The fact that I can vividly and clearly think
  of one thing apart from another assures me that
  the two things are distinct from one
  anotherthat is, that they are twosince they
  can be separated by God. Never mind how they
  could be separated that does not affect the
  judgment that they are distinct. So my mind is a
  distinct thing from my body. Furthermore, my mind
  is me, for the following reason. I know that I
  exist and that nothing else belongs to my nature
  or essence except that I am a thinking thing
  from this it follows that my essence consists
  solely in my being a thinking thing, even though
  there may be a body that is very closely joined
  to me. I have a vivid and clear idea of myself
  as something that thinks and isnt extended, and
  one of body as something that is extended and
  does not think. So it is certain that am really
  distinct from my body and can exist without it.
• If one can clearly-and-distinctly conceive one
  thing apart from another then they are not
  identical.
• I can clearly-and-distinctly conceive of myself
  apart from my body.
• Therefore, I am not identical with my body
• So I can exist apart from my body.

5
Some Mind-Body Problems

• The ontological question what are mental states
  and what are physical states? Is one class a
  subclass of the other, so that all mental states
  are physical, or vice versa? Or are mental states
  and physical states entirely distinct?
• The causal question do physical states influence
  mental states? Do mental states influence
  physical states? If so, how?
• The problem of the self what is the self? How is
  it related to the brain and the body?
• The problem of consciousness what is
  consciousness? How is it related to the brain and
  the body?

6
The Ontological Question What is there?

• Physicalism thesis that everything is physical
  or supervenes on the physical.
• Supervenience no two possible worlds can be
  identical in their physical properties but
  differ, somewhere, in their mental, social or
  biological properties if physicalism is true at
  our world, then no other world can be physically
  identical to it without being identical to it in
  all respects.

A dot-matrix picture has global properties it
is symmetrical, it is cluttered, and whatnot
and yet all there is to the picture is dots and
non-dots at each point of the matrix. The global
properties are nothing but patterns in the dots.
They supervene no two pictures could differ in
their global properties without differing,
somewhere, in whether there is or there isn't a
dot. David Lewis
7
Supervenience

• What these hedges are like at the leaf-and-branch
  level determines what the topiary looks like
• But hedges that were different at the
  leaf-and-branch level could have the same topiary
  look

8
Non-Dualist Theories of Mind

• Physicalism mental states are identical to or
  supervene upon physical states, in particular,
  brain states.
• (Analytical or Logical) Behaviorism talk
  about mental states should be analyzed as talk
  about behavior and behavioral dispositions
• The Identity Theory (Type-Physicalism) mental
  states are identical to (so nothing more than)
  brain states
• Functionalism mental states are to be
  characterized in terms of their causal relations
  to sensory inputs, behavioral outputs and other
  mental states, that is, in terms of their
  functional role.

9
Dualist Theories of Mind

• Predicate Dualism psychological or mentalistic
  predicates are (a) essential for a full
  description of the world and (b) are not
  reducible to physicalistic predicates.
• Compare to functional terms, e.g. hurricane.
  irreducibly different in type but token identity
  between each individual hurricane and a mass of
  atoms.
• Property Dualism There are two essentially
  different kinds of properties in the world
• Substance (Cartesian) Dualism mental substance
  is distinct from material substance
• Substance the thing which possesses properties.
• For substance dualists not only the properties
  but the substance that has them is immaterial

10
The Causal Questionfor Dualists

• Problems for Interactionism
• How can such different kinds of things interact?
• Seems incompatible with closure of physics
• Problems for Epiphenomenalism
• Counterintuitive mental events seem to cause
  physical events
• Epiphenomena are inexplicable in evolutionary
  terms
• Problems for Parallelism
• Invokes pre-established harmony or very busy
  interventionist god.

11
Epiphenomenalism

• Motivation for Epiphenomenalism
• All physical events have sufficient causes that
  are themselves physical events
• But some mental eventsqualitative states, the
  what-it-is-like experienceseem to be irreducibly
  nonphysical it seems implausible to identify
  them with brain events.
• Problem intuitively some mental states cause
  behavior
• E. g. pain causes people to wince
• Moreover, part of what we mean by pain seems to
  involve an association of with characteristic
  behavior
• Well leave association intentionally vague

12
The Self Bundle Theories and Substance Theories

• Substance Something that has properties. Not a
  property or bundle of properties or mode or
  arrangement
• Is the self a substance or a bundle of
  psychological states?
• Property Dualism vs. Substance Dualism

• Substance (Cartesian) Dualism the self is an
  immaterial substance.
• Property Dualism the self is not an immaterial
  substance but either
• a bundle of immaterial states/events
• a material thing (e.g. a living organism) that
  has mental states

13
Consciousness The Hard Problem for Physicalists

• Qualia the introspectively accessible,
  phenomenal aspects of our mental lives

Thomas Nagel in What It Is Like to Be a Bat
argues that some facts can only be captured from
a subjective perspective and uses his example of
bats to illustrate the point Even if we knew
everything there is to know from an objective
perspective about a bat's sonar system we still
would not know what it is like to perceive a
given object with a bat's sonar system.
14
(Philosophical) Behaviorism

• Motivation
• We want to hold that there are no irreducibly
  non-physical causes of physical events
• But we also need to accommodate the fact that
  what we mean by terms designating mental states
  involves an association with characteristic
  behavior.
• Problems
• Intuitively, theres more to some mental states
  the problem of qualia
• Intuitively, there can be less to mental states
  its conceivable that one may be in a given state
  without even being disposed to characteristic
  behavioror that one may be disposed to
  uncharacteristic behavior (e.g. Lewis madman)
• Dispositions arent causes so, while behaviorism
  associates mental states with behavior, mental
  states dont cause behavior.

15
The Identity Theory

• Motivation
• We want to hold that there are no irreducibly
  non-physical causes of physical events
• But we also want to understand them as inner
  states that are causally responsible for
  behavior
• Problems
• Qualia again intuitively there is more to
  consciousness than brain states
• Species chauvinism if we identify a type of
  mental state, e.g. pain, with a type of brain
  state that is responsible for pain in humans,
  e.g. the firing of C-fibers, what do we do about
  non-humans who dont have the same kind of brain
  states but who, we believe, can nevertheless have
  the same kind of mental states? We want multiple
  realizability

16
Problem for the Identity Theory Multiple
Realizability

• Are mental states just identical to brain states?
• Problem Its logically possible that two guys
  are in the same type mental state but different
  type brain states, i.e. that M1 M2.
• But if M1 B1 and M1 M2 it is not logically
  possible that B1 ? B2!

M2
M1
I see a red blob.
I see a red blob.
17
Problem for the Identity Theory Multiple
Realizability

• Are mental states just identical to brain states?
• Problem Its logically possible that two guys
  are in the same type mental state but different
  type brain states.
• But if M1 B1 and M1 M2 it is not logically
  possible that B1 ? B2!

M2
M1
Woof!
I see a red blob.
18
Problem for the Identity Theory Multiple
Realizability

• Are mental states just identical to brain states?
• Problem Its logically possible that two guys
  are in the same type mental state but different
  type brain states.
• But if M1 B1 and M1 M2 it is not logically
  possible that B1 ? B2!

M2
M1
I see a red blob
I see a red blob.
19
Functionalism

• What makes something a mental state of a
  particular type does not depend on its internal
  constitution, but rather on the way it functions,
  or the role it plays, in the system of which it
  is a part.
• Topic Neutrality mental state concepts dont
  specify their intrinsic character, whether
  physical or non-physicalthats a matter for
  empirical investigation. (compare natural kind
  concepts!)
• So Functionalism is in principle compatible with
  both physicalism and dualismthough dualism is
  unmotivated.
• Multiple Realizability A single mental kind
  (property, state, event) can be "realized" by
  many distinct physical kinds.
• The same type of mental state could, in
  principle, be realized by different physical
  (or non-physical) states
• Disagreement about how liberal we should be in
  this regard (compare, e.g. Block on the Chinese
  nation, the hive mind, etc.)

20
Functionalism to the Rescue

• Functionalism what makes something a thought,
  desire, pain (or any other mental state) depends
  not on its internal constitution, but solely on
  its functionthe role it plays, in the cognitive
  system of which it is a part.
• The identity of a mental state is determined by
  its causal relations to sensory stimulations,
  other mental states, and behavior.

I see a red blob.
same output
I see a red blob.
same input
21
Multiple Realizability
Were in the same computational state!
Were in the same computational state!

• Mental states are like computational states of
  computers
• The same computational or mental state can be
  realized by different hardware or brainware!

22
Funtionalism and Qualia

• We have multiple realizability but some worries
• Disagreement about how liberal we should be in
  this regard (compare, e.g. Block on the Chinese
  nation, the hive mind, etc.)
• Still cant capture what it is like
• The Reversed Spectrum
• The Knowledge Argument (What Mary Didnt Know)
• The Zombie Argument

23
Blocks Chinese Nation Thought Experiment

• Suppose that the whole nation of China was
  reordered to simulate the workings of a single
  brain (that is, to act as a mind according to
  functionalism). Each Chinese person acts as (say)
  a neuron, and communicates by special two-way
  radio in the corresponding way to the other
  people. The current mental state of China Brain
  is displayed on satellites that may be seen from
  anywhere in China. China Brain would then be
  connected via radio to a body, one that provides
  the sensory inputs and behavioral outputs of
  China Brain.

Thus China Brain possesses all the elements of a
functional description of mind sensory inputs,
behavioral outputs, and internal mental states
causally connected to other mental states. If the
nation of China can be made to act in this way,
then, according to functionalism, this system
would have a mind.
24
The Hive Mind

• Individual bees arent too brightbut the swarm
  behaves intelligently
• Is there a hive mind?

25
Functionalism Still Has a Problem with Qualia

• Intuitively theres more to some mental states
  than input and output.
• Theres what theyre like for the individual that
  has them!
• And what theyre like might be different for
  different people

I see a red blob.
I see a red blob.
26
Intentional vs. Qualitative Content
Both of our experiences represent USD
But they have different qualitative content

• Their experiences have the same intentional
  content since they both are representations of
  the University of San Diego.
• They have different qualitative content since
  what its like for one person isnt the same as
  what its like for the other.

27
Intentionality

• Intentionality is the power of minds to be about,
  to represent, or to stand for, things, properties
  and states of affairs.
• Reference is intentional in this sense I think
  (and talk) about things
• Perceptions, beliefs, desires and intentions and
  many other propositional attitudes are mental
  states with intentionality they have content
• Intentionality is directednessunderstood by
  Brentano as the criterion for the mental
• Only mental states have intrinsic
  intentionality other things have it only in a
  derivative sense to the extent that they are
  directed by intelligent beings.

28
Intentional vs. Qualitative Content

• Intentional content the way the experience
  represents the world, e.g. my experience
  represents the peppers as looking red.
• But my twins experience also represents the
  peppers as looking red our experiences have the
  same intentional content.
• Qualitative content what the experience is
  like if these pictures represent my experience
  and my inverted-spectrum twins, our experiences
  differ with respect to qualitative content.

29
The Inverted Spectrum Argument

• The inverted spectrum argument is this when
  you and I have experiences that have the
  intentional content looking red, your qualitative
  content is the same as the qualitative content
  that I have when my experience has the
  intentional content of looking green.
• Intentional content comes from functional role,
  i.e. aptness to be produced by certain inputs and
  to produce certain outputs.
• If an inverted spectrum is possible, then
  experiential contents that can be expressed in
  public languageare not qualitative contents but
  rather intentional contents.

30
Knowledge Argument Mary in the black white room

• Mary is a brilliant scientist who isforced
  to investigate the world from a black and white
  room via a black and white television monitor.
  She specializes in the neurophysiology of vision
  and acquiresall the physical information there
  is to obtain about what goes on when we see ripe
  tomatoesand use terms like red

31
Mary gets out!

• When Mary is released from her black and white
  roomIt seems just obvious that she will learn
  something about the world and our visual
  experience of it.
• But then is it inescapable that her previous
  knowledge was incomplete.
• But she had all the physical information.
• Ergo there is more to have than that, and
  Physicalism is false.

32
Philosophical Zombies
33
The Zombie Argument

• A (philosophical) zombie is a being which is a
  perfect duplicate of a normal human
  beingincluding brain and neural activitybut
  which is not conscious.
• The Zombie Argument for property dualism
• Zombies are conceivable
• Whatever is conceivable is logically possible
• Therefore (some) mental states/properties/events
  are not identical to any brain states/properties/e
  vents
• Note this argument doesnt purport to establish
  substance dualism or, as Descartes wished to
  show, that minds/persons could exist in a
  disembodied state!

34
Dualism Pro and Con

• Pro
• Qualia
• Irreducibility of psychology
• The Zombie Argument
• The Cartesian Essentialist Argument

• Con
• Causal closure of the physical
• Simplicity

35
Back to Descartes

• Vivid and distinct conceivability as a test for
  logical possibility
• Distinguish conceiving from imagining I can
  conceive of a chilliagon even though I cant
  imagine it.
• I can be mistaken about what I conceive ofso
  clearness and distinctness required.
• Something is possible if and only if I can
  conceive of it
• I can conceive of myself not having a body
• I cant conceive of myself not existing (so long
  as Im thinking, doubting or in any other mental
  state)
• So, it is possible for me to exit without having
  a body

36
Descartes I and my ideas exist for sure

• I will set aside anything that admits of the
  slightest doubt, treating it as though I had
  found it to be outright false and I will carry
  on like that until I find something certain,
  orat worstuntil I become certain that there is
  no certainty.
• Cogito Descartes proves his own existence!
• I undoubtedly exist let him deceive me all he
  can, he will never bring it about that I am
  nothing while I think I am something. So after
  thoroughly thinking the matter through I conclude
  that this proposition, I am, I exist, must be
  true whenever I assert it or think it.
• Privileged Access we can be certain about the
  existence and character of our own ideas
• But not of the existence or character of the
  external things they purport to represent.

37
Descartes Essentialist Argument for Dualism

• If I have a vivid and clear thought of something,
  God could have created it in a way that exactly
  corresponds to my thought i.e. its logically
  possible
• The fact that I can vividly and clearly think of
  one thing apart from another assures me that the
  two things are distinct from one another.
• By necessity of identity if body and mind are
  possibly distinct then theyre actually distinct.
• So my mind is a distinct thing from my body.
• because I can conceive of my mind apart from my
  body
• Furthermore, my mind is memy essence consists
  solely in my being a thinking thing
• because I cant conceive of myself apart from my
  thinking, thinking.
• I am really distinct from my body and can exist
  without it.

38
Problem with Cartesian Dualism

• We do not need that hypothesis complex
  behavior can be explained without recourse to
  irreducibly non-physical states.
• Purely physical mechanisms can exhibit the kind
  of complex, flexible behavior, including learning
  characteristic of humans.
• All physical events have sufficient causes that
  are themselves physical events
• Physicalism is an aggressor hypothesis we
  explain more and more without recourse to
  non-physical events/states
• Agency explanations are eliminated in favor of
  mechanistic explanationsincluding explanations
  for agency itself.
• Claims to the effect that non-physical events
  cause physical events introduces an even bigger
  mystery what is the mechanism?

39
Do we have a theory that can do all this?

• Make sense of consciousness The Hard Problem
• Avoid commitment to irreducibly non-physical
  states, events or substances
• Explain the causal role of mental states as
• Effects of physical events
• Causes of behavior
• Causes of other mental events
• Allow for multiple realizability in order to
  avoid species chauvinism
• We want to be able to ascribe the same kinds of
  mental states we have to humans who may be wired
  differently, other animals and, possibly to
  beings that dont have brains at all, e.g.
  Martians, computers

40
I Dunno