Materialism

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Materialism

• From Hobbes to (J.J.C.) Smart

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Hobbes (1588-1679)

• contemporary of Descartes
• born earlier and died later
• with a radically different view
• Hobbes Leviathan
• best known as the first proponent of social
  contract theory.
• The state or Leviathan is really an automaton,
  an artificial man.

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Hobbes and Galileo

• Influenced by Galileo
• The principle, that objects in motion stay in
  motion, became a central part of Hobbes views.
• Influenced by Galileos geometrical method.
• A critic of Descartes see Descartes Objections
  and Replies

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Hobbes mental geography

• Mind has appearances, or representations, (He
  also calls them phantasms) caused by objects.
• Thought of a green triangle is an appearance or
  representation.
• The green triangle in the world is the object.

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How do objects bring about representations in us?

• SENSE (sensation)
• Distinguish this question from What is the
  natural cause of sense?
• Hobbes says we can ignore this question for now.

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How sense works

• The cause of sense is the external body, or
  object, which presseth the organ proper to each
  sense, either immediately, as in the taste and
  touch or mediately, as in seeing, hearing, and
  smelling which pressure, by the mediation of
  nerves and other strings and membranes of the
  body, continued inwards to the brain and heart,
  causeth there a resistance, or counter-pressure,
  or endeavour of the heart to deliver itself
  which endeavour, because outward, seemeth to be
  some matter without.

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Sense, continued

• All which qualities called sensible are in the
  object that causeth them but so many several
  motions of the matter, by which it presseth our
  organs diversely. Neither in us that are pressed
  are they anything else but diverse motions (for
  motion produceth nothing but motion). But their
  appearance to us is fancy, the same waking that
  dreaming. And as pressing, rubbing, or striking
  the eye makes us fancy a light, and pressing the
  ear produceth a din so do the bodies also we
  see, or hear, produce the same by their strong,
  though unobserved action.

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Important points

• Objects in the world physically press on our
  sense organs.
• The ultimate destination is the brain and the
  heart.
• Sense is the outward pressure of objects on us.
• Motions in objects become motions in us when we
  perceive those objects.

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Criticism of Aristotle

• Aristotle thought that along with each sensory
  item came information about the modality, e.g.
  with sight a visual aspect etc.
• Hobbes thinks it is unnecessary
• Materialism offers the same account for all kinds
  of sensation.

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Imagination

• Just sensation decayed or obscured.
• Still just motions
• motions dont spontaneously stop.
• (That would violate Galileos principle.)
• We keep getting new sensations
• New sensations (motions) obscure older sensations
  (motions).

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Sleeping is imagining

• What happens in sleep imagination can go wild,
  because the mind isnt being stirred by
  sensation.
• Sensation isnt obscuring the other motions.)
• Hobbes, contra Descartes, thinks that you can
  distinguish dreaming from waking experiences.

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Thought and Language

• When a man, upon the hearing of any speech, hath
  those thoughts which the words of that speech,
  and their connexion, were ordained and
  constituted to signify, then he is said to
  understand it understanding being nothing else
  but conception caused by speech. And therefore if
  speech be peculiar to man, as for ought I know it
  is, then is understanding peculiar to him also.
  And therefore of absurd and false affirmations,
  in case they be universal, there can be no
  understanding though many think they understand
  then, when they do but repeat the words softly,
  or con them in their mind.

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Materialism at work?

• Is Hobbes account of language a materialist
  account?
• Does he explain language and understanding in
  terms of the motions in the brain and heart?
• How would one give such an account?

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Reasoning

• How do we go from one thought to another?
• not always just a succession of sensations.
• Ruled by sensation in this sense we can only
  think about what we have, at one time or other,
  sensed. (This view is often called Empiricism.)
• Two kinds of thought
• Unregulated when at leisure to just let our
  thoughts wander - still coherent.
• Regulated when solving a problem, following a
  plan, etc.
• Reasoning is regulated thought.

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Hobbes on reasoning

• WHEN man reasoneth, he does nothing else but
  conceive a sum total, from addition of parcels
  or conceive a remainder, from subtraction of one
  sum from another which, if it be done by words,
  is conceiving of the consequence of the names of
  all the parts, to the name of the whole or from
  the names of the whole and one part, to the name
  of the other part. And though in some things, as
  in numbers, besides adding and subtracting, men
  name other operations, as multiplying and
  dividing yet they are the same for
  multiplication is but adding together of things
  equal and division, but subtracting of one
  thing, as often as we can.

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Explanation

• Note parcels these are the phantasms - the
  motions in the brain and heart.
• Putting thoughts together is literally addition -
  the moving of parcels.
• So thinking is the moving around of physical
  parcels in the brain (or heart).
• Reasoning is calculation ultimately addition and
  subtraction.

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The 20th Century Version

• J.J.C. Smart, Sensations and Brain Processes
• The Mind-Brain Identity Theory
• Mental states are identical to brain states.
• They are one and the same thing the way water is
  the same thing as H2O.
• Materialists are monists.

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Problems with Hobbes Materialism

• Question
• Does all matter think?
• Answer
• No. My toaster oven does not think.
• Question
• What distinguishes thinking from non-thinking
  matter?

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Hobbes answer

• Thinking matter has language and reasoning.
• When we reason, we manipulate the parcels and
  move them around.
• A toaster cant do that.
• But who is doing the manipulating?

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The Homunculus Problem

• Question
• Are the parcels being manipulated intelligently?
• If not
• Then theres no reasoning going on.
• If yes
• Then theres a manipulator an homunculus.
• But what makes the homunculus think

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Interview with Johns Brain

• Johns brain claims that John doesnt understand
  it.
• I dont have Johns thoughts. John has them.
• This is another version of the homunculus problem.

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Other problems for materialism

• Consider HAL
• Does HAL think?
• Does HAL have a brain a real brain?
• If not, then HAL cant think.
• But this is too restrictive.