Nagel

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Nagels Bat and the Explanatory Gap
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Nagels bat preliminaries

• Phenomenal consciousness is what makes the
  mind-body problem hard
• Materialist analyses leave out what it is like

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Nagels bat preliminaries

• How do materialist analyses leave out what it is
  like?

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Nagels bat preliminaries
Consider the type-identity theory pain c-fiber
stimulation This leaves out what its like to
feel pain. For I can imagine feeling pain
without my c-fibers firing and vice versa. Or
consider functionalism
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Nagels bat preliminaries

• Pain whatever plays causal-role X (is produced
  by damage to the body and produces avoidance
  behavior, and
• This too leaves out what its like to feel pain,
  for something could play causal-role X without it
  feeling the way pain feels.

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Nagels bat the thread of the argument

• What is it like to be a bat? Can there be a
  physical account of what it is like?

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Nagels bat the thread of the argument

• Bats are alien We cant have bat experiences
  (e.g. echolocatory experiences), we cant even
  imagine what such experiences are like.

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Nagels bat the thread of the argument

• You think you can imagine it because you can
  imagine what its like to hang upside down, emit
  high-pitched shrieks in order to navigate, etc.
• But this gets you only what it would be like for
  you to behave as a bat behaves.
• The question is What it is like for a bat to be
  a bat?

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Nagels bat the thread of the argument

• Experiences are private. You cant have my token
  experiences. Is this all that is being claimed?
• No. These what-it-is-likenesses are mental types
  that different subjects can instantiate.
• But they are subjective they embody a point of
  view.

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Nagels bat the thread of the argument

• Physical facts, by contrast, are
  objectiveaccessible from many points of view.
• Thus the difficulty in seeing how the facts about
  what its like to be a bat could be physical.
• The clash between the subjective and the
  objective.

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Nagels batthe thread of the argument

• if the facts of experience-facts about what it
  is like for the experiencing organism-are
  accessible only from one point of view, then it
  is a mystery how the true character of
  experiences could be revealed in the physical
  operation of that organism. The latter is a
  domain of objective facts par excellence (p.
  522)

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Nagels batthe thread of the argument

• The problem from another angle
• Typical cases of theoretical reduction (the
  model for materialist analyses) proceed by
  excluding the phenomenological.
• Heat molecular motion

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Nagels batthe thread of the argument

• Sensations play no role, except to fix the
  reference of the term for thing reduced.
• Heat is whatever produces heat-sensations in us
  and that property is, objectively, the motion of
  molecules.

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Nagels batthe thread of the argument

• But when it comes to reducing the sensations
  themselves, there is no excluding the
  phenomenological there is no appearance/reality
  distinction with respect to the sensations pains
  feelings of pain.

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Nagels bat the conclusion

• Does Nagel think that we can conclude that
  materialism is false?
• No. Its just that we have no conception of how
  it could be true.

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The explanatory gap

• Inspired by Nagel, some philosophers say that
  even if materialism is true, we will never
  understand or explain the mind in physical terms.

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The explanatory gap

• The focus for those who push versions of the
  thesis that there is an explanatory gap between
  the mental and the physical is phenomenal
  consciousness.
• The intuition is this No matter how much we
  learn about the structure of the brain, nothing
  that we learn will explain to us why we have
  these sorts of experiences.

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The explanatory gap

• Nothing will explain why we have these as opposed
  to completely different ones
• Or these as opposed to none at all.
• Spectrum inversion
• Zombies
• The connection between the physical and the
  phenomenal appears arbitrary.

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The explanatory gap

• Van Gulicks reply If the explanatory gap
  intuition is supposed to be generated by the
  simplicity of experiences--by their having no
  structure--then the intuition can be met.
• Experiences do have structure.
• Binary vs. unary hues
• The affective dimension of phenomenal color.

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The explanatory gap

• At best, Van Gulicks reply succeeds against the
  spectrum inversion justification for the
  explanatory gap.
• But what about the zombie justification?