Mind and Machine
Turing’s Test, Searle’s Objection
Alan Turing
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A brilliant
mathematician and
computer scientist.
A leader of the team
that cracked the
German enigma code.
Killed himself in 1954
after being sentenced to
chemical castration for
homosexuality.
Can Machines Think?
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‘Can a machine think’ is hard to answer
straight-up: What do we mean by ‘think’?
How do we tell when something is thinking?
From ‘can a machine think’ Turing retreats to
asking, ‘can a machine do the things we take
to demonstrate thinking in humans’?
Can a machine fool us into mistaking it for a
human in a teletyped conversation?
Question and Answer
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Turing suggests that a question-and-answer
format allows us to compare the machine and
a person in a fair sort of way.
It will be a bit anthropocentric, as an approach
to deciding whether a machine can think.
This biases the test against the machine, but a
machine that passes the test will still be a
pretty convincing thinker!
What sort of machine?
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For Descartes, the ‘machine’ would have been a bit
of clockwork.
For Turing, it’s a digital computer (a discrete state
machine).
Nothing physical is really a DSM, but many things
are good approximations.
Consider Turing’s switch/lamp and lever machine: a
digital computer can ‘mimic’ or simulate it…
The computer
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So Turing’s final question is, could a suitably
programmed computer with a fast enough
system ‘do well’ in the imitation game (with
player B being a man)?
Turing thinks that a computer, with a high
enough storage capacity and speed, could win
30% of the time by the end of the 20th
Century.
Consciousness
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If thinking requires consciousness, and a
machine can’t be conscious, then a machine
can’t think.
This argument is associated with ‘feeling’ and
emotions, and the notion that machines
simply cannot be in these states.
Turing suggests that it leads to solipsism.
Limitations?
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A long list here. Do we have any additions?
What does Turing have to say here?
What about creativity?
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This raises two questions:
If the machine does unexpected things, what
more do you want?
If a human does something that seems creative,
how do we know that it wasn’t just hard to
predict, but truly novel or creative?
Breaking the rules?
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What rules? (We break some rules- “rules of
conduct”- but do we ever break the basic
rules- “rules of behaviour”- that our minds/
brains function by? How would we know?)
And the rules of behaviour are not always
obvious even when we see the behaviour over
a long time– cf.Turing’s 1000-bit numberchanging program.
A learning machine
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Could a suitably programmed computer be set up to
learn a language, over time, in something like the
way our brains come to enable us to speak the
language?
We can make it responsive to correction and to
encouragement, and
Also provide other avenues of input for richer
information.
Anticipates chess programs– which now play better
than any but the very best humans. (Go is next.)
Searle’s Objection
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The Chinese Room.
Does such a room understand Chinese?
Searle claims it doesn’t.
No individual part of the room understands
Chinese.
But (as the first objection goes) that doesn’t
show the room doesn’t– or does it?
Leibniz’ machine
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G.W. Leibniz objected to the idea that a
machine could think with a similar example:
The ‘expanded’ thinking machine.
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Take any machine you think is actually thinking.
Magnify it to the size of a mill, so you can
wander through and watch the works.
Where’s the thinking?
Call this the ‘we’ll know it when we see it’
criterion.
The Turk
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A famous chessplaying machine.
It defeated many
famous opponents
(including Napoleon
and Benjamin
Franklin).
A human chess-player
hidden inside operated
the apparatus.
Do we know thinking when we see it?
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What are you aware of when you’re thinking?
Suppose physicalism is true:
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If you watched someone else’s brain (or your own
brain, or a computer’s electronic activity) while
they (you) were thinking, would you expect to see
that this was thinking going on?
How would you decide whether the processes you
were watching really were some kind of thinking?
Thinking is as thinking does?
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One popular view holds that our concept of
thinking is really quite abstract:
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Thinking guides or produces certain kinds of
behaviour– it has a role or function in generating
speech, in leading to various kinds of decisions or
choices and so on.
What makes a thought the thought it is, is the
difference it makes/ the effect it has on such
behaviour.
Uphshot
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From this point of view, anything that
produces the kinds of behaviour we regard as
characteristic of thinking is thinking– even if
it’s thinking in a way that we don’t (i.e. via
different physical processes).
Searle clearly rejects this kind of abstract
view of thinking– for him, it’s not
understanding unless it has concrete
properties of some special kind.
Responses to Searle
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The system reply: the whole room understands
even though no part of it does.
The robot reply: a real Chinese speaker has
lots of other capacities (to see and report what
s/he sees in Chinese, to move around in
response to requests in Chinese, etc.). A robot
with these capacities really understands
Chinese.
More Responses
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The brain simulation reply.
A combination of all three (system/robot/brain
simulation).
What is missing here? What is Searle looking
for, that these answers don’t provide?
I suspect it’s what Leibniz was looking for:
the private, immediate awareness of
something as thinking.
Searle’s view
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Other Minds: Searle’s position leads to doubts about
whether anyone else really thinks or understands.
But Searle says:
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“It is no answer to this argument to feign
anesethesia.”(338)
The program response: ‘understanding’ can’t be
(merely) formal; a storm simulation is not a storm…
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But a storm simulation doesn’t blow down buildings
either– or else it would be an artificial storm.
And a program playing the imitation game does do
something that thinking things do. So why not call it an
‘artificial intelligence’?