job description by pptfiles


									Summer 2011
Monday, 07/11
• Last week’s PP Slides now on-line.
• Quiz: overall happy with it. Everyone who turned in a
  Quiz passed. Some comments:
      1. Use Examples!
      2. Behaviorism is a materialist theory.
      3. Behaviorism is not just about our ways of
      thinking of mental states.
• Movie: Blade-Runner this Thursday.
• Today we’ll start talking about Functionalism in some
  detail. The contrast should also help clarify the other
  two theories we’ve looked at so far.
Prelude: Zen & The Art of Motorcycle
  Prelude: Zen & The Art of Motorcycle

“That's all the motorcycle is, a system of concepts worked out
in steel. There's no part in it, no shape in it, that is not out of
someone's mind. I've noticed that people who have never
worked with steel have trouble seeing this...that the
motorcycle is primarily a mental phenomenon. They associate
metal with given shapes...pipes, rods, girders, tools, parts...all
of them fixed and inviolable, and think of it as primarily
physical…John looks at the motorcycle and he sees steel in
various shapes and has negative feelings about these steel
shapes and turns off the whole thing. I look at the shapes of
the steel now and I see ideas. He thinks I'm working on parts.
I'm working on concepts.” (Robert Pirsig)
    Prelude: Zen & The Art of Motorcycle

•   What could this possibly mean? In what sense is
    a motorcycle a “mental phenomenon”? Isn’t it a
    paradigm of a physical item?
•   It can’t be that the bike is mental because it’s
    made by human beings. And it would be loony
    to claim that it’s made out of mind-stuff.
•   So is Pirsig a loony or just confused?
     Prelude: Zen & The Art of Motorcycle

• Let’s look at one part of a bike, the engine.
• Pirsig’s friend, John, thinks of an engine as just a
  certain type of construction made of steel that’s built
  out of certain parts of a particular shape (e.g. pipes,
  rods, etc.).
• John is an Identity Theorist about engines. He thinks
  there is some specific set of physical properties that all
  engines have in common. Anything that doesn’t have
  these properties (e.g. parts, shape, etc.) would not
  count as an engine by John’s lights.
   Prelude: Zen & The Art of Motorcycle

• But Pirsig seems to have hit on an important
  insight about artifacts.
• The idea/concept of an engine does not specify
  how an engine might be designed and built—
  whether it uses gasoline, electricity or bio-fuels,
  whether it is a piston or rotary engine, how many
  cylinders it has, whether it uses a carburetor or
  fuel injection, etc.
   Prelude: Zen & The Art of Motorcycle

• The concept of an engine is defined by a job
  description, or causal role, not a description of
  mechanisms that execute the job.
• As long as a device is capable of transforming
  energy into motion, it counts as an engine.
• If a device meets the job-description but involves
  a team of angels blowing cool air into a cylinder,
  that device would count as an engine all the
  Prelude: Zen & The Art of Motorcycle
• The different parts of the bike (and consequently a
  bike itself) may be realized in all sorts of radically
  different ways.
• When John is looking at a part of a bike, he just sees
  the particular realization of that part of the bike.
• When Pirsig looks at the part, he sees something
  more abstract, something that can be realized in all
  sorts of radically different ways. That’s why he says
  that he’s not working with parts, but is working with
   Prelude: Zen & The Art of Motorcycle

• Concepts of other artifacts and many biological
  concepts are similar.
• What makes an organ a heart is the fact that it pumps
• The human heart may physically differ from hearts in
  reptiles or birds. But these all count as hearts because
  of the job they do in the organism.
• A mechanical heart would still count as a heart as long
  as it meets the abstract job description for a heart.
• Claims: Like concepts of artifacts & biological
  concepts, mental concepts carry no constraint
  on the actual physical-biological mechanisms
  that realize or implement them.
• Our concepts of mental states are defined by
  their job descriptions or causal roles.
• For example, the concept pain is defined by
  the job-description “tissue-damage detector”.
• Like Behaviorism, Functionalism can be a thesis
  about both our concepts of mental states and
  about the mental states themselves.
• F is a functional property (or kind) just in case F
  can be characterized by a definition of the
  following form:
   For something x to have F =def for x to have some
  property P such that C(P), where C(P) is a
  specification of the job description or causal work
  that P is supposed to do in x.

• For example, the property of being a mousetrap
  is a functional property because it can be given
  the following functional definition:
   x is a mousetrap =def x has some property P such
  that P enables x to trap and hold or kill mice.
• Just like with engines or pain, there are
  indefinitely many “realizers” of the property of
  being a mousetrap.

• Functional properties (e.g. being a mouse-
  trap) are “second-order” properties that can
  be realized or implemented by “first-order”
  properties (e.g. being a specific kind of
  physical device).
• Property Q realizes functional property F in
  system x just in case C(Q), that is, Q fits the
  job-description C in x.
• On its own, functionalism is compatible with
  dualism. It allows that a mental state such as pain
  could be realized in a non-physical way.
• But many functionalists wanted to place
  constraints on possible realizations of mental
  states. One example of such constraint is
  realization physicalism.
• Notice that the latter is no longer a thesis about
  our concepts of mental states but a metaphysical
  thesis about the mental states themselves.
Functionalism vs. Behaviorism and the
           Identity Theory

• One good way to understand the difference
  between these views is to see how each of
  them answers the question: What do all
  mental states of a particular psychological
  kind (e.g. all pains) have in common in virtue
  of which they fall under the same
  psychological kind?
Functionalism vs. Behaviorism and the
           Identity Theory

• The Identity Theorist answers: what all pains
  have in common that makes them instances of
  pain is a certain neurobiological property,
  namely, being an instance of C-fiber
• This is because mental kinds (e.g. pains) are
  just physical kinds (e.g. C-fibers firings).
Functionalism vs. Behaviorism and the
           Identity Theory

• The Behaviorist answers: What all pains have
  in common is a certain behavioral property.
• Two organisms are both in pain just in case
  they are disposed to exhibit the behavior
  patterns characteristic of pain (e.g. escape
  behavior, withdrawal behavior, and so on).
• This is because, for the Behaviorist, mental
  kinds (e.g. pains) are just behavioral kinds (e.g.
  tendencies to groan, wince, escape, etc.).
Functionalism vs. Behaviorism and the
           Identity Theory
• The Functionalist answers: what all pains have
  in common that makes them instances of pain
  is that they meet the job description of being
  “tissue-damage detectors”.
• Compare: what makes something a
  mousetrap, a carburetor, or a thermometer is
  its ability to perform a certain function, not
  any specific physical/chemical structure or
    Functionalism vs. Behaviorism
• Behaviorism identifies mental states with
  behavior and behavioral dispositions.
• Functionalism identifies mental states with real
  internal states that can cause behavior &
  behavioral dispositions as well as other mental
• For the behaviorist, to be in pain is to be disposed
  to wince and groan. For the functionalist, it is to
  be in an internal state that causes winces and
    Motivations for Functionalism
• One problem for the identity theorist was that
  pain might turn out to be correlated with
  different brain processes in different creatures.
• One response that some of you raised was to
  introduce different notions, like “pain-in-humans”
  and “pain-in-octopus” and so on, but to reject
  talk of “pain-in-general”.
• But there’s a strong intuition that pain is a mental
  state that we might share with other creatures.
   Motivations for Functionalism
• One problem for the behaviorist was that
  there seems to be no such thing as the
  distinctive behavior associated with a single
  mental state.
• The functionalist has systematic ways to
  describe the connection between any one
  mental state and all the other mental states in
  a creature’s psychology.
• We’ll be looking at two such ways in the next
  couple of days.
        Machine Functionalism

• Many functionalists have thought about the
  mind in analogy with the operations of a
  computing machine. They tried to understand
  the mind as a software – a sophisticated job
  description– run on the hardware of the brain.
• On this view, we should expect mental states
  to be multiply realizable. Consider the
  following computers that may run the same
  (simple) software.
              For Tomorrow

• We’ll look into Machine Functionalism in
  much more detail.
• Read Putnam’s short article “The Nature of
  Mental States”.
• I highly recommend reading the section on
  Turing Machines from Kim’s chapter before
  tomorrow’s class.

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