Introduction%20to%20Cognitive%20Science%20Philosophy

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Introduction to Cognitive SciencePhilosophy

• Nov 2005 Lecture 2 Joe Lau Philosophy
  HKU

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Last week

• The role of philosophy in cognitive science
• A brief history of cognitive science
• Philosophical theories of the mind

Today

• The computer model of the mind
• Challenges to the computer model

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The computer model of the mind

• Weak version - Computations are necessary for
  explaining mental processes.
• The mind has a computational level of
  description.
• Strong version - Computations are necessary and
  sufficient for explaining mental processes.

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Implications of the strong version

• The right kind of computation will be sufficient
  for the existence of a mind.
• For all / some mental states?

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Alan Turings 1950 paper

• Alan Turing (1950). Computing Machinery and
  Intelligence. Mind 49 433-460.
• Introduced computers to philosophy.
• Argued for the plausibility of thinking machines.
• Proposed the Turing test for intelligence.

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Alan Turing (1912-1954)http//www.turing.org.uk/t
uring/

• Famous British mathematician / logician
• Mathematical theory of computation.
• Practical design of electrical computers.
• Helped cracked the German U-boat Enigma code in
  WWII.
• A homosexual, arrested in 1952.
• Committed suicide.

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Objection Computers cannot think

• The theological objection
• Heads in the sand objection
• The mathematical objection
• The argument from consciousness
• Arguments from various disabilities
• Lady Lovelaces objection
• Argument from continuity
• Argument from informality
• The ESP argument

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The theological objection

• Thinking is a function of man's immortal soul.
  God has given an immortal soul to every man and
  woman, but not to any other animal or to
  machines. Hence no animal or machine can think.
• Turing
• Animals can also think.
• Do not underestimate Gods ability.
• Theological arguments are unreliable.

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The Heads in the sand objection

• The consequences of machines thinking would be
  too dreadful. Let us hope and believe that they
  cannot do so.

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Computers cannot make mistakes

• Turing Why is this an objection to the
  possibility of a thinking machine?
• Turing Errors of functioning vs. conclusion.
• Statistical reasoning, heuristic reasoning can
  lead to false conclusions.
• All the swans I have seen are white.So all swans
  are white.
• If an email contains sex,it is a spam email.

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Lady Lovelaces objection

• Ada Bryon 1815-52
• Daughter of poet Byron
• Promoted Babbages machines
• Predicted that machines can write music and
  assist research
• First programmer? (Probably not)

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An often-quoted comment

• The Analytical Engine has no pretensions
  whatever to originate anything. It can do
  whatever we know how to order it to perform. It
  can follow analysis but it has no power of
  anticipating any analytical relations or truths.
  Its province is to assist us in making available
  what we are already acquainted with.

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Computers cannot be creative

• Is creativity necessary for thinking?
• It can do whatever we know how to order it to
  perform.
• Is determinism the problem?
• Determinism A deterministic system is a system
  whose behavior is fixed by its initial state and
  the laws of physics.
• How do we know that determinism is not true of
  us?
• What if a computer includes some random element?

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Determinism and creativity

• Why is determinism incompatible with creativity?
• Creativity requires breaking rules. Computers
  always follow rules.
• Distinguish between programming rules and
  conventional rules.

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Computation and creativity

• It can follow analysis but it has no power of
  anticipating any analytical relations or truths.
• How can computation produce new ideas?
• Random element
• Rearrange old ideas
• Learning
• Search, and other methods

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Look-ahead tree

• But will the computer be sad if it loses?
• The problem of emotions.

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Can machines have emotions?

• No machine can be angry or depressed when it
  cannot get what it wants.
• But are emotions necessary for thinking?

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Three dimensions of emotions

• Behavior associated with emotions
• Facial expressions
• Other actions
• Cognitive states
• Anger Believing that someone has been wronged.
• Jealousy Wanting what the another person has.
• Subjective feelings
• Valence - Pleasure, displeasure
• Bodily feelings - Racing heartbeat

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Emotional behavior

• Facial expressionshttp//www.takanishi.mech.wased
  a.ac.jp/research/eyes/we-4/
• Behavior not difficult
• Aggression
• Withdrawal
• But do they correspondto real emotions?

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Cognitive states in emotions

• Beliefs and desires
• Anger Believing that someone has been wronged.
• Jealousy Wanting what the another person has.
• Computational explanations of
• Belief system
• Big database reasoning mechanism.
• Desires
• A value system degrees of desires.
• Assigning value ratings to possible situations.
• Linked to action.

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The problem of consciousness

• Phenomenal consciousness
• Subjective feelings
• Qualitative properties of experiences
• Qualia
• Can computations explain qualia?
• A bad argument
• A computer can never be conscious because we can
  never know or prove that it is.

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The problem of consciousness

• Leibnizs mill argument (1646-1716)
• And supposing there were a machine, so
  constructed as to think, feel, and have
  perception, it might be conceived as increased
  in size, while keeping the same proportions, so
  that one might go into it as into a mill. That
  being so, we should, on examining its interior,
  find only parts which work one upon another, and
  never anything by which to explain a perception.
  Thus it is in a simple substance, and not in a
  compound or in a machine, that perception must
  be sought for.
• Is this a good argument?

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Objection to the argument

• Fallacy of composition
• Every part of X lacks property P.
• So X lacks property P.
• Example
• Every part of the car is inexpensive.
• So the whole car is inexpensive.
• But consciousness might be an emergent property
  of the whole system.

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The fading qualia argument

• See section 3 of Chalmers (1995). Absent Qualia,
  Fading Qualia, Dancing Qualia. In Thomas
  Metzinger (ed.) Conscious Experience. Imprint
  Academic.
• http//consc.net/papers/qualia.html
• Thought experiment
• Imagine that you are looking at a red wall, while
  your brain cells are replaced by functionally
  equivalent nano-computers one by one.
• What would happen to your qualia?
• Fading gradually
• Disappearing suddenly
• No change

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Implications of the argument

• Qualia determined by functional organization.
• Neurophysiological properties not directly
  relevant to consciousness.
• Qualia can occur in non-biological systems.

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Strength of the argument

• Not a conclusive proof.
• Maybe functional equivalence is impossible
  through replacement.
• Maybe qualia will change.
• A plausibility argument
• Default position pending additional
  considerations.

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Other issues

• Discussed intentional states and qualia.
• How about
• The self
• Freewill
• Any other mental phenomena?