The Extended Mind

1
The Extended Mind

• Advanced Topics in Mind and Knowledge Lecture 6

2
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?

3
Varieties of Externalism II

• First, lets clarify the question a little.
  Hurley (1998) distinguishes between contents
  and their vehicles. So far weve 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).

4
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
• Using our imagination to visualise a rotation.
• Pressing a button to produce a rotation.
• The first case looks like a mental process, and
  the second not.

5
Tetris, Cyborgs and Martians

• But what about these further cases
• 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.
• A Martian whose natural brain includes the
  machinery in (2) and (3).
• Surely in this case we have a mental process?

6
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 isnt this a significant difference?
• Perhaps it isnt. 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?

7
Ottos 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 not.
• Otto has mild Alzheimers and so a poor memory
  he carries a notebook in which he records
  information.

8
Ottos Memory II

• On hearing of an exhibition, Otto checks the
  address (53rd St.) in his notebook and goes
  there.
• 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 Ottos long-term beliefs arent all in his
  head.
• And if Ottos arent, then neither are ours!

9
Objections and Replies

• The Extended Mind seems to polarise opinions
  its 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. Well
  consider a couple here.

10
The Control Objection

• Loosely parallels narrow content
• Even if external objects and processes are
  sometimes involved in cognition, isnt 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).

11
Compatibilism

• Similarly to two-factor theories of content, it
  may be that mental processes are both internal
  and external.
• 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.