Philosophical Foundations of Cognitive Science

1
Philosophical Foundations of Cognitive Science

• Week 2
• Folk Psychology
• Eliminativisim

2
The Propositional Attitudes

• John hopes that it wont rain today
• Jane believes that the book is in the library
• Wishes, doubts, desires, fears
• Russell propositional attitude
• These statements give a relation between a person
  and a proposition
• A believes that P
• A hopes that P
• etc., etc.
• The person holds a certain attitude to the
  proposition
• The proposition P is the content of the
  attitude

3
Sense/Reference

• The morning star was beautiful today
• There were too many clouds, I couldnt see the
  evening star today
• The referent of the morning star and the
  evening star turns out to be one and the same
  thing the planet Venus
• The senses of the two phrases are different

4
De Re/De Dicto

• John believes there are woodchucks in the garden
• Woodchucks are the same thing as groundhogs
• John believes there are groundhogs in the garden?

5
This week

• So what are propositional attitudes? (What does
  it mean to ascribe a propositional attitude to
  someone?)
• Are they
• A common sense way of looking at the world?
• A window onto the true nature of thought? (LOT
  next week)
• A (pre-)scientific theory about why and how
  people behave?
• If a theory, might the theory be wrong?

6
A theory?

• Prof Jones Would you be prepared to give a
  lecture at my University?
• Prof Smith Certainly. When?
• Prof Jones Can you make the afternoon of
  Tuesday, 31st March?
• Prof Smith I can. I will get the flight from
  New York to LA that arrives at 11.00am on the
  31st. Can you meet me at the airport?
• Prof Jones Of course.

7
Two competing theories

• Our best developed formal science of middle-sized
  objects Newtonian Physics.
• Good a predicting what happens if Prof. Jones
  trips at the top of the stairs
• Bad at predicting where he will be in 3 months
  time
• Another theory, that we use all the time without
  thinking about it
• Prof Jones wishes to give a lecture at Caltech.
  He plans to get the 7.00am flight from NY
  arriving at LAX at 11.00am.
• Prof Smith wishes to meet Prof Jones when his
  flight arrives. He believes that Prof Jones
  flight will arrive at 11.00am.

8
Two competing theories

• Can we predict where these middle sized objects
  (Prof Smith and Jones) will be in 3 months time?
• With Newtonian Physics
• No!
• With our folk theory of beliefs and desires
• Perfectly? No
• Really quite well? Yes
• The best (or only) theory we could realistically
  use to predict things like this? Maybe
• Fodor Yes
• Churchland No

9
Folk Psychology

• Folk Psychology?
• Folk Physics, Folk Chemistry , Folk Biology??
• There is something theory-like, and
  correctable, about our commonsense understanding
  of these domains
• One example
• Folk physics a moving object not subjected to
  any external force will eventually come to a
  halt.
• Wrong. Physics isnt like that.

10
Folk Psychology

• There really are some things called beliefs and
  desires (intentional realism)
• I dont know what they are (not part of my
  theory)
• But I do know what they do (what functional role
  they play)
• I claim that they relate to each other, and to
  observable behaviour, by some (rough and ready)
  laws

11
Folk Psychology

• Here are some (rough ready) laws of my theory
• If someone gets what they want then, ceteris
  paribus (all other things being equal) they will
  be happy
• If someone is happy then (ceteris paribus), they
  will smile, walk with a spring in their step,
  etc.
• If someone is in pain then they will want to
  withdraw from or otherwise prevent the occurrence
  of the painful stimulus
• If someone wants to do something then (ceteris
  paribus) they will do it

12
Folk Psychology

• According to Paul Churchland, this set of laws is
  exactly what a normal theory looks like (even the
  ceteris paribus clauses)
• One example
• A river erodes it outside bank
• Implicit ceteris paribus
• As long as the outside bank is not made of
  concrete
• As long as the river does not freeze over
• etc., etc.

13
Folk Psychology

• FP is a theory like any other because we
• Have postulated a set of entities
• Have described the relationships between the
  entities
• Have described the observations we can make
• According to PC, when we say that someone
  believes something, we are saying that
• The entire inter-related framework of beliefs,
  desires, wishes, wants, intentions, etc. applies
  to them
• At the current time, certain things expressed in
  that framework are true of them
• This is the normal structure of a scientific
  theory
• So FP is (appears to be)
• Systematic, speculative corrigible

14
Eliminativism

• Even if FP is a theory, why might we think that
  it is wrong?
• Explanatory failures on an epic scale
• Cant explain (amongst others)
• the mentally ill
• creativity
• imagination
• sleep dreams
• perceptual illusions
• memory itself

15
Eliminativism

• Stagnant for at least 25 centuries
• infertility and decadence (same theory that the
  ancients had)
• in fact, not just stagnant, but in retreat
  (animism)
• (but cf Ethnopsychologies)

16
Eliminativism

• Ununifiable with the rest of science
• The categories of FP stand magnificent and alone
• There is no sign that FP can be reduced to the
  natural sciences

17
Eliminativism

• All the signs are that FP is false, so it should
  go the way of other false theories
• alchemy
• the ether
• phlogiston
• etc.
• Elimination!

18
Anti-Eliminativism

• FP is indispensable
• the abstract nature of FP states (their multiple
  realizability) means that one cannot replace them
  with talk of, e.g., neurophysiological states.
• Churchland's reply
• This functionalist move could be used to save
  alchemy! So it cannot be correct.

19
Anti-Eliminativism

• FP is normative
• It is a characterisation of how we should behave,
  if we are to behave rationally.
• It is an ideal.
• It is a definition of something (rational
  behaviour), not a theory, so it cannot be false.
• Churchlands response
• We only think FP is normative because we value
  the things described by it (rationality)
• But there still might be another, better, account
  of what it is to be rational, which does not use
  the propositional attitudes we dont have a good
  enough handle on what rationality is to be sure.

20
Anti-Eliminativism

• Horgan Woodward
• Explanatory failures on an epic scale?
• Disputable FP is successful many theories based
  on FP are now starting to explain things like
  mental illness, creativity
• Moreover should FP explain all that? (cf optics
  the higher level description of light is still
  correct)

21
Anti-Eliminativism

• Horgan Woodward
• Stagnant or in retreat?
• Compare ancient theory of mind to Freud
  (unconscious beliefs and desires)
• Stagnancy does not imply falsity
• The sharp blow caused the pot to break
• Lack of water caused the camel to die

22
A replacement for FP?

• So what does Paul Churchland suggest instead of
  FP as we know it today?
• Three scenarios. These are not meant to be
  predictions of the future. They are just meant to
  show that it might be possible to replace FP with
  something better after all
• A new characterisation of brain states, so much
  better than FP that everybody starts to use it
• A new language, framed in terms of the above it
  turns out we can learn this with our general
  purpose brains it has different grammar,
  different semantics, different ideas of true and
  false, even.
• Direct brain to brain communication what you
  know of other peoples brain is then much better
  than FP, and there is nothing sentential or
  propositional about it
• These are just thought experiments, we will
  return to a more grounded proposal (championed by
  Churchland, and most closely related to the first
  of the above) in week 6
• Vector coding in connectionist parallel
  architectures

23
Reading

• You might well want to additionally look at
• Terence Horgan and James Woodward, Folk
  Psychology is Here to Stay, Ch. 12 of LYCAN (an
  interesting, clear paper)
• If you are interested, you can go to Angeline
  Lillards CV page on the web and download her
  paper Ethnopsychologies
• It seems FP is really not stagnant at all!