Transcript Knowledge and Reality Lecture 3 Functionalism

Functionalism
Mind and Body
Knowledge and Reality;
Lecture 3
Recall the dualism vs materialism debate. The
materialist says that science discovers what
the world is like. Water… fire… thunder
…now we know. We now even understand
life itself. There has been amazing progress in
understanding the world. The materialist’s
idea is that, soon, even the mind will be
understood and explained. And the idea or
ideal here is to reduce mind to brain, for
example pain to certain brain states.
Functionalism says, by contrast,
that what we are made of is not
important.
Computer model of the mind.
A.I.
Hardware/software distinction.
What it is to be a certain mental
states is its role in a system, not
what it is made of.
Mental states are (=) functional
roles…. In particular.
A) inputs of effects on the body.
B) effects on other mental states.
C) bodily behaviour.
Artificial intelligence (AI)
We don’t need to worry about messy brain science,
instead we can understand the mind by building a
robot.
The philosophy/psychology/computer science
interface.
The question is not: what are we made of?
As Hilary Putnam says, we might be made of Swiss
cheese or soul substance and it wouldn’t matter.
Ned Block’s coke machine analogy. One state leads
to another. One can give an abstract description of
the coke machine. The same with us.
Two systems can be made of different stuff
but be functionally similar (isomorphic).
The kind of explanation appropriate for such
systems is different… just as we can explain
why we can’t put a square peg in a round hole
without mentioning molecules… Different
levels of explanation are involved.
For example …. Pain tends to be caused by
damage to the body, it tends to cause distress,
and tends to cause us to wince. The state
playing that role is (=) pain.
And the same for other mental states.
It follows that mental states could be
differently constituted.
We could be made of chocolate, water.
There can be space aliens with minds
who are made of completely different
stuff/substance?
And … this means that psychology is
autonomous of physical science. (That’s
a matter of knowledge of mind.)
Functionalism: mental states are defined as
dispositional-causal relations between other
mental states and inputs and outputs. (Contrast
with behaviourism.)
John Searle
Objects to
functionalism
Younger version
• For functionalism, and AI: The brain is a
computer, the mind is a program.
• Someone could write a program to enable a
computer to simulate understanding Chinese. It
passes the ‘Turing test’.
• Does it understand Chinese?
• His famous ‘Chinese room example’. (Choose
another language if you are Chinese.)
• Imagine lots of Clerks in little offices shifting
around tiles with Chinese characters on them.
• Searle says, the room has syntax, not
semantics.
• This is supposed to show that Functionalism
is no good, and it can’t account for
intentionality, the fact that we mean things,
intend to refer to things in the world.
• But, as you know… philosophers
always have replies….
The Holism reply
The whole room understands Chinese
although no individual clerk does.
Searle says that this is question-begging?
The Robot reply
• Put the whole room in a robot, and have
it move around, get content from
inputs…
• In that case maybe ‘syntax’ does imply
‘semantics’.
Maybe one can combine the holism
and robot replies?
• But is that enough to create meaning, that
is, thoughts with worldly content?
• The input tiles might originate in a part of
the world. But how does that make the sign
on that tile a sign for that part of the world?
Even if it somehow is, due to a regular
causal account (Jerry Fodor), and these tiles
are then processed in a complex system,
that would not give the room a notion of
truth, of correspondence with the world. But
without that there is no intentionality.
• So….. the functionalism and the AI
program are controversial.
Perhaps there are other problems with any
broadly materialist approach…. In
particular… from
raw feelings….. As we’ll see
…………………………………..next time…