mary by xiaoyounan


									The Knowledge Argument

       What Mary Didn’t Know
          Frank Jackson
      What Mary doesn’t know
• Mary is confined to a black-and-white room, is educated through
  black-and-white books and through lectures relayed on black
  and white television…She knows all the hysical facts about us
  and our environment, in a wide sense of „physical‟ which
  includes everything in completed physics, chemistry, and
  neurophysiology, and all there is to know about the causal and
  relational facts consequent upon all this, including of course
  functional roles.

• If physicalism is true, she knows all there is to know. For to
  suppose otherwise, that there is more to know than every
  physical fact, and that is just what physicalism denies.
Argument against Physicalism
• The knowledge argument aims to establish that conscious
  experience involves non-physical facts.

• It rests on the idea that someone who has complete physical
  knowledge about the world might yet lack knowledge about what
  conscious experience is like “from the inside.”
     What the Argument is Not
• Not an argument for the Empiricist doctrine that “all knowledge
  comes from experience”

• Not an argument for the intensionality of knowledge

    – The argument does not rest on assuming falsely that, if S
      knows that a is F and if a = b, then S knows that b is F…on
      being let out, she will not say „I could have worked all this out
      before by making some more purely logical inferences.

• Not an argument for Substance Dualism or the possibility of
  post-mortem survival
The structure of the Argument
• The Knowledge Intuition

    – Conscious experience is “knowing what it is like…”

    – Knowing all the physical facts about experience (from the
      3rd person perspective) is not enough to know “what it is
      like” to have that experience

• The Knowledge Intuition entails the falsity of physicalism.
• The thesis that everything is physical, a.k.a materialism

• A complete physics will explain all facts about the world

• psychological or biological or social features of the world
  supervene on physical facts about the world.
      Lewis on Supervenience

• A dot-matrix picture has global properties … 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

• 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
           More Supervenience
• Supervenience entered philosophy initially in ethics.

• Moral properties were said to supervene upon non-moral

• In general, value is supervenient

• So, supervenience isn’t just a matter of spatially large-scale
  properties depending on spatially small-scale properties.
Physicalism: a fact about our world?
 • Physicalism is true at a possible world w iff any world which is a
   physical duplicate of w is a duplicate of w simpliciter.

 • Physicalism is usually taken to be a matter of contingent fact

 • There are worlds at which there are non-physical facts but
   (according to physicalists) ours isn’t one of them.
                Physicalism: Pro
• Naturalism as an aggressor hypothesis

    – E.g. explaining life in naturalistic terms

• The reducibility of psychological, biological and other
  explanations to physical explanations

• The elimination of irreducible agency explanations
Physicalism: Con

The History of an Intuition
• C. D. Broad’s Archangel

• Feigl’s Martian

• Thomas Nagel’s Bat
        Broad’s Archangel
He would know exactly what the microscopic
structure of ammonia must be; but he would be
totally unable to predict that a substance with this
structure must smell as ammonia does when it
gets into the human nose…[H]e could not
possibly know that these changes would be
accompanied by the
appearance of a smell in general
or of the peculiar smell of
ammonia in particular, unless
someone told him so or he had
smelled it for himself.
            Feigl’s Martian

Could a Martian, entirely without sentiments of
compassion and piety, know about what is going on
during a commemoration of the armistice?…[He
could] predict all responses, including the linguistic
utterances of the earthlings in the situations which
involve their visual perceptions, their laughter about
jokes, or their (solemn) behavior at the
commemoration. But ex hypothesi, the Martian would
be lacking completely in the sort of imagery and
empathy which depends on familiarity (direct
acquaintance) with the kinds of qualia to be imaged
or empathized
                 Nagel’s Bat

• 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.
• These examples just pump the “knowledge intuition” but are

• It is debatable whether these archangels or Martians are
  missing something in the first place

• We can’t imagine what it’s like to be a bat because we’re
  physically very different--lack of imagination doesn’t show

• The crucial feature of the Knowledge Argument is that Mary
  learns something.
            Jackson’s next step
• To make the case against physicalism we need to show that

    – An individual that knows all the physical facts

    – Might still be lacking knowledge of some facts

• This would show that the physical facts are not all the facts
  there are.
Mary in the black and white room
  Mary is a brilliant scientist who is…forced 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 acquires…all the physical information there is to
  obtain about what goes on when we see ripe tomatoes…and
  use terms like „red‟…
             Mary gets out!
• [W]hen Mary is released from her black and
  white room…It 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.
    The Knowledge Argument

• Mary knows all the physical facts concerning human color vision
  before her release.

• But there are some facts about human color vision that Mary
  does not know before her release.

• So, there are non-physical facts concerning human color vision.
   Objections to the Argument
• The success of the argument hinges on whether Mary acquires
  new propositional knowledge.

• So we ask:

   – Is it new knowledge and

   – Is it propositional knowledge, as distinct from, e.g. know-how
     or “knowledge by acquaintance”
      Propositional Knowledge
• Knowing that as distinct from knowing how, knowing who, etc.

• Expressed by “x knows that ______” where a proposition fills
  the blank.

• This is knowledge of facts…and that’s what we need for the
  argument to go through since the claim is that there are non-
  physical facts about the world.
  Objection: Mary acquires know-
    how rather than know that
• Knowing that is neither necessary nor sufficient for know-how

    – I know lots about music theory and about the theory of piano
      playing but I can’t play

    – I’m a fluent native English speaker but can’t explain the

• After getting out of the room, Mary acquires new skills

    – As I would if I practiced!

• But she doesn’t acquire any new factual knowledge.
Response to the Know-How Objection

 • Now it is certainly true that Mary will acquire abilities of various
   kinds after her release…But is it plausible that that is all she will

 • I grant that I have no proof that Mary acquires on her release, as
   well as abilities, factual knowledge…My claim is that the
   knowledge argument is a valid argument from highly plausible,
   though admittedly not demonstrable, premises.
The Argument Proves Too Much Objection

  • Suppose that prior to her release Mary is a Dualist who knows
    all there is to know about “ectoplasm”

  • Mary still learns something so

  • The argument cuts against dualism as much as it does against
Response to the Proves Too Much Objection

 • We aren’t defending Cartesian Dualism here or arguing for the
   existence of “ectoplasm”

 • If, in the revised thought experiment, Mary learns something
   new after getting out then she doesn‟t know all there is to know
   about dualism
The Failure of Imagination Objection

 • Before getting out, Mary couldn’t even imagine what it would be
   like to, e.g. see red

 • So she didn’t really have all the information about the physical
   facts of the matter, contrary to the assumption.
Response to the Failure of Imagination Objection

   • Failure of imagination is neither here nor there

   • This is really a return to the what it is like to be a bat argument

   • The point is that she didn’t know what it was like
Objection: If we reject Physicalism we’re
    stuck with Epiphenomenalism

 • The physical world is a closed system so

 • If there are non-physical events/states they make no difference
   they’re causally idle

 • Which is to say, we’re stuck with Epiphenomenalism
Jackson’s Response c. 1993

 Epiphenomenalism is fine by me
                      And then…

• Jackson changed his mind

• The argument, he said, contained no obvious fallacy and yet its
  conclusion--that physicalism is false--must be mistaken.

• Since the conclusion is false, there must be something wrong with
  the argument--something we know not what!
          One man’s modus ponens--
        is another man’s modus tollens
                                        If it’s not worth
                                            doing well
                                         it’s not worth
                                           doing at all

• If the Knowledge Argument is sound then Physicalism is false

• But Physicalism is not false, therefore the Knowledge Argument
  is not sound--for whatever reason.

• Giving up Physicalism is too high a price to pay to
  accommodate our intuitions about qualia.
   Should we be Physicalists?
• Benefits: modern science has within it a certain picture of the
  world…best distilled as the thesis of physicalism…[and]it is a
  methodological mistake to suppose that philosophy itself should
  revise science.

• Costs: Physicalism apparently is counter to our intuitions about
  values, free-will, experience and a variety of other issues.
    Sometimes our
     intuitions are
       just lousy

George Wilson warning us that intuitions are not decisive
       How high are the costs?
• Even if we ditch our “intuitions” about values, experience, free-
  will, etc. we can still:

    – Make moral and aesthetic judgments

    – Talk about feelings and emotions

    – Distinguish intentional from unintentional actions and hold
      people responsible

• We just cash out these claims differently

• Philosophy is analysis: it is concerned with cashing out such
  claims--not with revealing truths about the universe or the
  human condition.

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