Doing Philosophy

1
Doing Philosophy

• Philosophical theories are not primarily
• about facts. Therefore, there is no right or
  wrong.
• Philosophical arguments are well-argued opinions.
• A philosophy course such as this concerns both
  facts and opinions, e.g.
• What is functionalism (fact)? What is the
  problem of multiple realization (fact)? Is
  functionalism a good theory of the mind
  (opinion)? Is materialism a better theory than
  dualism (opinion)?

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Doing Philosophy in this Course

• Ask questions
• in class
• on the course blog
• Think for yourself.
• Justify your opinions with good logical
  arguments, also can appeal to scientific evidence
  and personal experience

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Tutorials

• There are four tutorial groups
• All groups meet in the Philosophy Department,
  Room MB 305
• Group 1 Thurs. 200
• Sept. 20, Oct. 4, Nov. 1, Nov. 15
• Group 2 Tues. 200
• Sept. 25, Oct. 23, Nov. 6, Nov. 20
• Group 3 Tues. 300
• Sept. 25, Oct. 23, Nov. 6, Nov. 20
• Group 4 Tues. 100
• Oct. 2, Oct. 30, Nov. 13, Nov. 27
• Please sign up today in the break. Otherwise,
  send me an email.

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Functionalism

• Things are defined by their functions
• Two ways to define function
• Function inputs and outputs (machine
  functionalism)
• e.g. mathematical function, e.g. , -, x, /
• 2 x 3 6, when input is 2 and 3, output is 6
• Multiple realizability can be realized in
  different materials or through different
  processes

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• Functionalism defined as inputs and outputs
  continued
• e.g. beliefs, desires
• I am thirsty (i.e. I desire water) is defined
  in terms of inputs and outputs. When there are
  inputs x and y, there is output z
• Input Output
• (x) Water is available (z) I drink water
• (y) There is no reason not to drink the water

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• 2) Function use (teleological functionalism)
• Function is defined by what something does.
• e.g. a heart pumps blood.
• e.g. a belief plays a role in reasoning a
  premise in a practical syllogism
• Premise 1 I believe x is water
• Premise 2 I desire water
• Premise 3 There is no reason not to drink x
• Conclusion I drink x

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• No matter if you interpret functional as an
  input-output relation (machine functionalism) or
  use (teleological functionalism), mental states,
  such as thirst are multiply realizable.
• A computer can conduct multiplication.
• An alien can have thirst, pain, etc.
• A computer can have thirst, pain, etc.

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Functional definition of mind

• If x acts like a mind, it is a mind.
• If, when compared to a mind given similar inputs,
  x gives similar outputs, x is a mind.
• If a computer can converse (take part in
  linguistic input and output exchanges/play the
  role of an intelligent conversational partner)
  just like a person, the computer is as
  intelligent as a person. It has a mind.

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The Chinese Room Argument
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Background

• Thought Experiments
• Instead of scientific experiments, philosophers
  have thought experiments
• Thought experiments are conducted in the
  imagination
• They test concepts looking for consistency and
  contradictions, often using intuitions to make
  judgments

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• The Turing Test
• In 1950, a computer scientist, Alan Turing,
• wanted to provide a practical test to answer
• Can a machine think?
• His solution -- the Turing Test
• If a machine can conduct a conversation so well
  that people cannot tell whether they are talking
  with a person or with a computer, then the
  computer can think. It passes the Turing Test.
• In other words, he proposed a functional
  solution to the question, can a computer think?

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• There are many modern attempts to produce
  computer programs that pass the Turing Test.
• In fact, in 1991 Dr. Hugh Loebner started the
  annual Loebner Prize competition, with prize
  money offered to the author of the computer
  program that performs the best on a Turing Test.
• The winner of the Loebner prize in 2004 was a
  program called ALICE.
• You can try her (and other talkbots) out on this
  website
• http//cogsci.ucsd.edu/asaygin/tt/ttest.htmltalk
  tothem

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Searles Chinese Room Argument

• John Searle
• Famous philosopher at the
• University of California, Berkeley
• Most well-known in philosophy of language,
  philosophy of mind and consciousness studies
• Wrote Minds, Brains and Programs in 1980, which
  described the Chinese Room Argument

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Searles Chinese Room Argument

• The Chinese Room argument is one kind of
  objection to functionalism, specifically to the
  Turing Test
• Also an attack on strong AI
• Searle makes distinction between strong AI and
  weak AI
• Strong AI the appropriately programmed computer
  really is a mind, in the sense that computers,
  given the right programs can be literally said to
  understand
• Weak AI Computers can simulate thinking and help
  us to learn about how humans think
• Searle objects only to strong AI.

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The Chinese Room

• Searle cannot understand any Chinese.
• He is in a room with input and output windows,
  and a list of rules about manipulating Chinese
  characters.
• The characters are all squiggles and squoggles
  to him.
• Chinese scripts and questions come in from the
  input window.
• Following the rules, he manipulates the
  characters and produces a reply, which he pushes
  through the output window.

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• The Chinese answers that Searle produces are very
  good.
• In fact, so good, no one can tell that he is not
  a native Chinese speaker!
• Searles Chinese Room passes the Turing Test. In
  other words, it functions like an intelligent
  person.
• Searle has only conducted symbol manipulation,
  with no understanding, yet he passes the Turing
  Test.
• Therefore, passing the Turing Test does not
  ensure understanding.
• In other words, although Searles Chinese Room
  functions like a mind, it is not a mind, and
  therefore functionalism is wrong.

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• Syntax vs. semantics
• Searle argued that computers can never understand
  because computer programs are purely syntactical
  with no semantics.
• Syntax the rules for symbol manipulation, e.g.
  grammer
• Semantics understanding what the symbols (e.g.
  words) mean
• Syntax without semantics The bliggedly blogs
  browl aborigously.
• Semantics without syntax Milk want now me.

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• Searle concludes that symbol manipulation alone
  can never produce understanding.
• Computer programming is only symbol manipulation.
• Computer programming can never produce
  understanding.
• Strong AI is false and functionalism is wrong.

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• What could produce real understanding?
• Searle it is a biological phenomenon and only
  something with the same causal powers as brains
  can have understanding.

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Objections

• The Systems Reply
• Searle is part of a larger system. Searle doesnt
  understand Chinese, but the whole system (Searle
  room rules) does understand Chinese.
• The knowledge of Chinese is in the rules
  contained in the room.
• The ability to implement that knowledge is in
  Searle.
• The whole system understands Chinese.

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• Searles Response to the Systems Reply
• Its absurd to say that the room and the rules
  can provide understanding
• 2) What if I memorized all the rules and
  internalized the whole system. Then there would
  just be me and I still wouldnt understand
  Chinese.
• Counter-response to Searles response
• If Searle could internalize the rules, part of
  his brain would
• understand Chinese. Searles brain would house
  two
• personalities English-speaking Searle and
  Chinese-
• speaking system.

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The Robot Reply What if the whole system was put
inside a robot? Then the system would interact
with the world. That would create understanding.
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Searle inside the robot
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• Searles response to the Robot Reply
• The robot reply admits that there is more to
  understanding than mere symbol manipulation.
• 2) The robot reply still doesnt work. Imagine
  that I am in the head of the robot. I have no
  contact with the perceptions or actions of the
  robot. I still only manipulate symbols. I still
  have no understanding.
• Counter-response to Searles response
• Combine the robot reply with the systems reply.
  The robot as a whole understands Chinese, even
  though Searle doesnt.

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• The Complexity Reply
• Really a type of systems reply.
• Searles thought experiment is deceptive. A room,
  a man with no understanding of Chinese and a few
  slips of paper can pass for a native Chinese
  speaker.
• It would be incredibly difficult to simulate a
  Chinese speakers conversation. You need to
  program in knowledge of the world, an individual
  personality with simulated life history to draw
  on, and the ability to be creative and flexible
  in conversation. Basically you need to be able to
  simulate the complexity of an adult human brain,
  which is composed of billions of neurons and
  trillions of connections between neurons.

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• Complexity changes everything.
• Our intuitions about what a complex
• system can do are highly unreliable.
• Tiny ants with tiny brains can
• produce complex ant colonies.
• Computers that at the most basic level are just
  binary switches that flip from 1 to 0 can play
  chess and beat the worlds best human player.
• If you didnt know it could be done, you would
  not believe it.
• Maybe symbol manipulation of sufficient
  complexity can create semantics, i.e. can produce
  understanding.

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Conclusion

• The Turing Test
• Searle is probably right about the Turing Test.
  
• Simulating a human-like conversation probably
  does not guarantee real human-like understanding.
  
• Certainly, it appears that simulating
  conversation to some degree does not require a
  similar degree of understanding. Programs like
  ALICE presumably have no understanding at all.
• .

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• 2) Functionalism
• Functionalists can respond that the functionalist
  identification of the of the room/computer and a
  mind is carried out at the wrong level.
• The computer as a whole is a thinking machine,
  like a brain is a thinking machine. But the
  computers mental states may not be equivalent to
  the brains mental states.
• If the computer is organized as a really long
  list of questions with canned answers, the
  computer does not have mental states such as
  belief or desire.
• But if the computer is organized like a human
  mind, with concepts, complex organization and
  homuncular modules, the computer can have
  beliefs, desires, etc.

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3) Strong AI Could an appropriately programmed
computer have real understanding? Too early to
say. I am not convinced by Searles argument that
it is impossible. The right kind of programming
with the right sort of complexity may yield true
understanding. e.g. homuncular
modularity mixing of levels self-updating
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• 4) Syntax vs. Semantics
• How can semantics (meaning) come out of symbol
  manipulation? How can 1s and 0s result in real
  meaning? Its mysterious. But then how can the
  firing of neurons result in real meaning? Also
  mysterious.
• One possible reply meaning is use
  (Wittgenstein). Semantics is syntax at use in the
  world.

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• 5) Qualia
• Qualia raw feels phenomenal experience
  what it is to be like something
• Can a computer have qualia? Again, it is hard to
  understand how silicon and metal can have
  feelings. But it is no easier to understand how
  meat can have feelings.
• If a computer could talk intelligently and
  convincingly about its feelings, we would
  probably ascribe feelings to it. But would we be
  right?

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• 5) Searles claim understanding can only occur
  in biological systems with the same causal
  properties as the brain
• There is no basis for this hypothesis. It is
  unclear what special causal properties the brain
  meant to have. I doubt that Searle is right about
  this.

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Readings for next week

• Sterelny, Kim, The Representational Theory of
  Mind, Section 1.3, pgs. 11-17
• (on reserve in Philosophy Dept.)
• Sterelny, Kim, The Representational Theory of
  Mind, Section 3.1-3.4, pgs. 42-49 (on reserve in
  Philosophy Dept.)
• Further optional readings will be posted in the
  coming week