The Extended Mind (PowerPoint)

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					 The Extended Mind

Advanced Topics in Mind and
   Knowledge Lecture 6
     Varieties of Externalism I
• The debate over semantic externalism
  questions whether mental content is
  individuated purely according to internal
  factors (ones in our heads/brains/bodies).
• But what about the thoughts which
  possess this content? Both sides of the
  semantic debate have tacitly assumed that
  internalism regarding thoughts is true.
• Is this the case?
     Varieties of Externalism II
• First, let’s clarify the question a little. Hurley
  (1998) distinguishes between ‘contents’ and
  their ‘vehicles’. So far we’ve concentrated on
  contents, but what are vehicles?
• Vehicles are the mental processes which
  subserve, or make possible, particular thoughts.
• The content of a thought tells us what it is. Its
  vehicle tells us how it happens (Hurley 2006).
           The Extended Mind I
•   Clark and Chalmers (1998) argue for
    externalism regarding mental vehicles, using
    two thought experiments: tetris and Otto.
•   Tetris involves rotating shapes to fit them
    together without leaving any gaps. Intuitively,
    there are two ways we could do this:
    1. Using our imagination to visualise a rotation.
    2. Pressing a button to produce a rotation.
•   The first case looks like a mental process, and
    the second not.
    Tetris, Cyborgs and Martians
•   But what about these further cases:
    3. A cyborg has the computational machinery
       from (2) implanted in his head.
•   Would we then classify the rotation as a
    mental process? Maybe, maybe not.
    4. A Martian whose natural brain includes the
       machinery in (2) and (3).
•   Surely in this case we have a mental
        The Extended Mind II
• The extended mind hypothesis invites us
  to treat (2), (3) and (4) as equivalent – the
  only difference being whether the mental
  process occurs inside the head or not.
• But isn’t this a significant difference?
  – Perhaps it isn’t. According to functionalism,
    what matters for cognition is a particular role
    being filled, not what fills that role. Why
    should we think that what fills the role needs
    to be in our heads?
            Otto’s Memory I
• But image rotation is a relatively peripheral
  mental process – maybe externalism is true in
  such cases, but not for central cognitive
  processes involving beliefs and desires etc.
• Clark and Chalmers’ second example suggests
• Otto has mild Alzheimer’s and so a poor memory
  – he carries a notebook in which he records
            Otto’s Memory II
• On hearing of an exhibition, Otto checks the
  address (53rd St.) in his notebook and goes
• Compare Inga, who remembered where the
  exhibition was and went.
• Clark & Chalmers: both had the same belief (that
  the exhibition was on 53rd St.) even before Otto
  checked his notebook.
• So Otto’s long-term beliefs aren’t all in his head.
• And if Otto’s aren’t, then neither are ours!
      Objections and Replies
• The Extended Mind seems to polarise
  opinions – it’s often regarded as obviously
  false, or obviously true.
• There have been a number of objections
  made, many of which run parallel to
  responses to the arguments for semantic
  externalism. We’ll consider a couple here.
         The Control Objection
• Loosely parallels narrow content:
• Even if external objects and processes are
  sometimes involved in cognition, isn’t it internal
  biological processes which control the others,
  and have the ‘final say’?
   – Reminiscent of ‘Cartesian theatre’ in which a
     homunculus observes the internal workings of the
     body, and does all the ‘real work’.
   – Why identify the control mechanism with the agent?
     (Clark 2003, forthcoming).
   – There may be no processes which have the ‘final say’
     (Dennett 1995).
• Similarly to two-factor theories of content, it may
  be that mental processes are both internal and
• Stalnaker (forthcoming) observes that external
  processes (e.g. diaries) are publicly available
  and susceptible to sabotage, so we tend to be
  circumspect in using them. This is quite unlike
  access to internal resources.
   – Clark (forthcoming) replies that we do not always use
     external resources cautiously, and that is enough to
     support vehicle externalism.