Philosophy 4610

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Philosophy 4610

• Philosophy of Mind
• Week 6 Functionalism Application and Objections

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The computer model Turing Machines

• In the late 1940s before there even were
  computers at all Alan Turing gave a general
  functional model that actually works as a
  description of all actual computers, and more
  generally all information-processing systems.

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Turing machines
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Turing machines

• The Turing machine is a kind of general
  functional architecture for any computer or any
  information-processing system whatsoever.
• Turing machines are also multiply realizable we
  can build them out of whatever materials we like.
  In fact, the description of the Turing machine
  program has nothing to do with the physics or
  chemistry of the actual underlying states.

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The computer model and cognitive science

• The idea of functional description and the
  computer model gave scientists access to a very
  general and abstract way of talking about mind in
  terms of what they do.
• This allowed researchers in artificial
  intelligence, computer science, psychology,
  engineering, and many other fields to address a
  unified subject-matter the science of
  information-processing (whatever the material
  basis or substrate).
• This is what came to be called cognitive
  science. It brings together research in all
  these different fields into a unified field of
  study of information-processing systems, defined
  in functional terms.

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Functionalism and the computer model Summary

• Functionalists are (usually) physicalists, but
  instead of identifying mental states with
  behavior or with physical brain states, they
  identify them with functionally described states
  of the whole organism.
• This allows them to identify and describe mental
  states that can be shared even by organisms or
  systems with very different material substrates.
• Functional analysis treats the mind as an
  information-processing system on the level of
  functional description, essentially the same as a
  computer.
• By allowing researchers in different areas of
  psychology and engineering to communicate, this
  model of mind has proved deeply influential in
  the development and growth of cognitive science
  from the 1960s to today.

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Hofstadter Prelude Ant Fugue

• If functionalism is right, then a mind is simply
  a complex pattern of functional organization. We
  can specify this organization completely
  independently of describing the actual underlying
  nature (physical, chemical, or biological) of the
  parts that make it up.
• If functionalism is right, it ought to be
  possible to realize a mind in any number of
  different kinds of system.

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Hofstadter Aunt Hilary

• Aunt Hilary (not to be confused with Hilary
  Putnam) is an ant colony.
• The individual ants in this colony interact just
  as (in the same functional relations as) brain
  cells in an actual human brain.
• By tracing out paths, Aunt Hilary is able to
  communicate with anyone just as a normal human
  being can.

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Aunt Hilary Minds and Brains

• Achilles There must be some amazingly smart ants
  in that colony, Ill say that.
• Anteater I think you are still having some
  difficulty realizing the difference in levels
  here. Just as you would never confuse an
  individual tree with a forest, so here you must
  not take an ant for the colony. You see, all the
  ants in Aunt Hillary are as dumb as can be. They
  couldnt converse to save their little thoraxes!
• Achilles Well then, where does the ability to
  converse come from? It must reside somewhere
  inside the colony! I dont understand how the
  ants can be unintelligent, if Aunt Hillary can
  entertain you for hours with witty banter.
• Tortoise It seems to me that the situation is
  not unlike the composition of a human brain out
  of neurons. Certainly no one would insist that
  individual brain cells have to be intelligent
  beings on their own, in order to explain the fact
  that a person can have intelligent conversation.
  (p. 166)

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Aunt Hilary and Functionalism

• In the Aunt Hilary case, the system has
  capabilities of understanding and
  information-processing that emerge only on the
  level of the functional organization of the whole
  system.
• Aunt Hilary has the same abstract functional
  organization as a human brain. Therefore, if
  functionalism is right, Aunt Hilary is capable of
  doing all the things we can do thinking,
  communicating, understanding, and having
  consciousness or awareness.
• Does this seem plausible?

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Block The Chinese Nation (homunculi-head)

• To try to find out whether functionalism is
  right, Block gives another example of a strange
  case where a system that seems quite different
  from a mind could also have the same functional
  organization.
• His point is to argue that functionalism must be
  wrong, since there is no way such a system could
  have the mental states that we do.

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Block The Chinese Nation

• First, we take an ordinary human being, scoop out
  the brain, and hook up the input neurons to
  tiny radio transmitters.
• Then we give radio transmitters to every man,
  woman and child, together with simple
  instructions about which signals to send to other
  transmitters and when.

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Block The Chinese Nation

• By setting things up this way, we could get the
  whole population of China to (collectively)
  realize the same functional organization as a
  human brain.
• Nevertheless, according to Block it is highly
  implausible that the whole country has any mental
  states (of course the individual people still do,
  but this is irrelevant). In particular, he finds
  it implausible that the whole nation has any
  consciousness or experience

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Block The Chinese Nation

• What makes the homunculi-headed system just
  described a prima facie counter example to
  (machine) functionalism is that there is prima
  facie doubt whether it has any mental states at
  all -- especially whether it has what
  philosophers have variously called qualitative
  states, raw feels, or immediate
  phenomenological qualities. In Nagels terms
  (1974), there is a prima facie doubt about
  whether there is anything which it is like to be
  the homunculi-headed system. (p. 97)

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Block The Chinese Nation

• One of the most important features of minds seems
  to be consciousness or conscious awareness. We
  can say whether something has consciousness in
  terms of whether there is something it is like to
  be that thing.
• There is something that its like to be me, or
  you, or my cat. But according to Block, theres
  nothing it is like to be the whole nation of
  China.

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Objections to Functionalism Summary

• Functionalism holds that a mind is just a complex
  functional pattern of organization it doesnt
  matter what kind of simple parts realize this
  organization, as long as they interact in the
  same functionally defined way.
• If this is right, systems of many different kinds
  can all realize the same abstract organization or
  pattern in particular, human brains and
  computers might share the same kind of
  organization as information-processing systems.
• But then it is also possible to imagine systems
  having the same kind of functional organization
  (e.g. ant colonies or whole nations) that do not
  seem like minds at all. If these systems would
  not have some mental states that we do, then
  functionalism is false.