Consciousness

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Consciousness
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Consciousness vs. Thought

• Thought
• Humans have it
• Weve discussed whether others have it.
• Consciousness
• Humans have it.
• At least some other animals have it.

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Thought

• Thoughts
• Have propositional content
• Are representational
• Can have them when one is not conscious.
• Examples
• Beliefs Ignat believes that snow is white
• Desires Ignat desires that all the votes are
  counted.

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Consciousness

• Sensory and affective awareness
• Does not have propositional content
• Conscious states do not represent
• Examples
• Feeling pain
• Seeing a dog (but not necessarily as a dog)
• Hearing middle C

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Qualia

• Qualia are the qualitative aspects of conscious
  experience
• Examples
• The sensation you have when you hear nails
  scratch a blackboard
• The sensation of tasting chocolate

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A science of consciousness?

• Visual sensation is an aspect of consciousness
  Can it be studied by cognitive science?
• Sure
• The neuroscience of vision
• Artificial visual systems

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Can there be a science of qualia?

• Thats our question for today
• Can cognitive science tell us what its like to
  taste chocolate, to see red, the hear the
  scratching on the blackboard?
• A positive answer may requires more than mapping
  the biological and/or functional states.

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Example 1 Bats

• What is it like to be a bat?
• Can a description of a bats objective features
  answer this question?
• Nagel We can imagine having webbed feet, wings,
  etc.
• But such imaginings fall short.

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Objective vs. Subjective

• Having webbed feet, wings, the visual system of a
  bat, etc. are objective features of bats.
• Having bat consciousness is a subjective feature.
• To know what its like to be a bat requires
  occupying the point of view of a bat.
• Only bats can occupy a bat point of view.

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Absent Qualia Argument

• An argument against functionalism
• Functionalism says that mental states are medium
  independent in us they are carried out in the
  brain, but could be carried out by other
  hardware.
• Absent Qualia argument attempts to show that
  functionalism cant account for consciousness

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The Absent Qualia Argument

• Imagine a person, Ignat1, who has the
  normal range of experiences. Now imagine that
  cognitive science has figured out what is going
  on in Ignat1's mind, and removes Ignat1's brain
  and replaces it with a set of homunculi - little
  people in the head - which carry out the
  functions previously carried out by Ignat1's
  brain. Lets call this homunculi-headed person
  Ignat2. Ignat2 behaves just like Ignat1. But
  Ignat1 had experiences - qualia. Ignat2 does not.
  Or does he?

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The Knowledge Argument

• Another argument designed to raise skeptical
  doubts about our ability to scientifically study
  consciousness
• A thought experiment which asks us to imagine
  what we know about the mind at the endpoint of
  science.

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The Knowledge Argument

• Mary experiences only black and white, in a black
  and white room, but she knows everything there is
  to know about science, including neuroscience. So
  she knows everything there is to know about color
  as well, though, ex hypothesis, she hasnt
  experienced color.

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The Knowledge Argument

• What happens when Mary steps out? Of course she
  has the experience of color. But is there
  anything she now knows about the world which she
  didnt know before?
• Jackson The answer is yes She knows what its
  like to experience color.

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Zombies

• Imagine a person who is physically just like
  other human beings, and behaves just like other
  human beings, yet lacks consciousness. Theres
  nothing that its like to be such a person, a
  zombie.
• Are zombies possible?

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Inverted Spectrum Problem

• The visible spectrum goes from Red, orange,
  yellow, green, blue, to violet. Imagine that a
  person uses color words just the way you do, but
  has the color spectrum reversed. When you see
  red, she sees violet. When you see orange, she
  sees blue. Of course she uses the word Ared_at_ when
  she sees what you would call red. The inversion
  would be undetectable.

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Responding to these arguments

• To Nagel subjective experience can be
  objectively understood.
• Requiring a point of view to understand a
  phenomenon is precisely what science attempts to
  get away from.

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Mary knows it all

• To the knowledge argument
• Mary has new experiences when leaving the room.
• But she doesnt acquire any new knowledge.

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All Qualia are Present

• Imagine a completed Cog
• We may never get there because the project is
  too hard.
• But it doesnt follow that Cog would lack
  consciousness.

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The Function of Consciousness

• What is the function of Consciousness?
• Crick and Koch Consciousness coordinates sensory
  and affective states.
• Look for neurobiological evidence of such
  coordination.