PowerPoint Slides

imminentpoppedAI and Robotics

Feb 23, 2014 (3 years and 8 months ago)

76 views

John Searle

Can Computers Think?

Computational
-
Representational
Understanding of Mind (CRUM)




The central hypotheses of cognitive science
is that thinking can best be understood in
terms of representational structures in the
mind and computational processes that
operate on those structures. (Thagard)

Analogy with a Computer

Computer

Mind

Data structures +
algorithms = running
program

Mental representations +
computational procedures
= thinking

Abstract of Argument


1)

Intentionality is a product of causal features of the brain.
Certain brain processes are sufficient for intentionality.


2) Instantiating a computer program is never sufficient for
intentionality.


3) So, the explanation of how the brain produces
intentionality cannot be that it does it by instantiating a
computer program. (1,2)


4) Any mechanism capable of producing intentionality must
have causal powers equal to those of the brain.(from 1)


5)

Any attempt to create intentionality artificially would
have to duplicate the causal powers of the brain (2, 4)


Definition


Intentionality


df. The characteristic
feature of cognitive states

that they
invariably represent or are about something
beyond themselves.


intentionality = representation = meaning,

Primary Intuition



Syntax (formal rules) is not

sufficient for semantics (meaning)


Primary Intuition



Syntax (formal rules) is not

sufficient for semantics (meaning)


Belief that it is raining is not defined as a
formal shape, but as a certain mental
content with conditions of satisfaction.




“Both consciousness and intentionality are
biological processes caused by lower
-
level
neuronal processes in the brain, and neither
is reducible to something else.”

Why Intrinsic?


The mental/non
-
mental distinction must be
intrinsic to the system; otherwise, it would
be up to any beholder to treat people as non
-
mental.


Searle’s Point


Thinking is not computational operations
(process) over purely formally specified
elements. (Thinking is not following a
program, not purely formal or abstract).


Chinese Room


Set Up


Script


Initial large batch of Chinese
writing


Story


Second batch of writing plus rules
for correlating with the first


Questions


Third batch plus rules
correlating these symbols with first two and
rules saying what symbols to give back
when given third batch.

Claims


Answers are indistinguishable from those of
native Chinese speakers. Person in the room
“can pass the Turing test”


Person in the room does not understand a
word of Chinese.


System as a whole does not understand a
word of Chinese.


Main Claim Against Strong AI


Whatever formal principles you put into the
computer they will not be sufficient for
understanding, since a human will be able
to follow the formal principles without
understanding anything.


Possible Replies



The Systems Reply



Individual person doesn’t understand the
story, but the system does.





The Systems Reply



Individual person doesn’t understand the
story, but the system does.




Let the person memorize the rules, etc. so that all
processing is in the person. He still doesn’t
understand Chinese.


If inputs, outputs and program in between is
sufficient for cognition then our stomach, heart,
liver, etc. are all thinking.

The Robot Reply


Suppose we had a robot who
perceives,
walks, moves about, hammers nails, eats
and drinks, etc.


The Robot Reply


Suppose we had a robot who
perceives,
walks, moves about, hammers nails, eats
and drinks, etc.





Robot reply tacitly concedes that cognition is not
solely a matter of formal symbol manipulation.


Suppose put person inside the robot, who doesn’t
know that she is hooked up via the robot. Robot
still doesn’t have any intentional states.




The Brain Simulator Reply


Suppose we have a program that simulates
the actual sequence of neuron firings at the
synapses of the brain of a native Chinese
speaker when he understands stories and
gives answers to them.

Reply



Strong A.I. say that we don’t need to know how
the brain works to know how the mind works. We
can understand cognition as computational
processes over formal elements


Suppose man hooked up to water pipes that
simulate neural firings and synaptic connections.
Man + pipes doesn’t understand Chinese.

The Combination Reply


Imagine a robot with a brain shaped
computer lodged in its cranial cavity;
imagine the computer programmed with all
the synapses of a human brain; imagine the
whole behavior of the robot is
indistinguishable from human behavior.


Reply


Doesn’t help AI. According to strong AI,
instantiating a formal program with the right
input and output is a sufficient condition of,
indeed is constitutive of, intentionality.


We would not attribute intentionality to it if
we knew it had a formal program.



Other Objections


1)


Other Minds Reply


Only way we know
anything is by behavior.


2)

Many Mansions Reply


Some day we
will build computers that have these causal
processes.


Searle’s View


“It is not because I am the instantiation of a
computer program that I am able to understand
English and have other forms of
intentionality…but as far as we know it is because
I am a certain sort of organism with a certain
biological (i.e., chemical and physical) structure,
and this structure, under certain conditions, is
causally capable of producing perception, action,
understanding, learning, and other intentional
phenomenon.” (p. 11)


Questions

Could a Machine Think?


Yes


We are machines


Could a Man
-
made Machine Think?


Yes


Only if you exactly duplicate the causes


Could a Digital Computer Think?


Yes


We are the instantiation of a number of programs




Questions


Could something think, understand, and so on
solely in virtue of being a computer with the right
sort of program?


No


Formal symbol manipulations by themselves
don’t have any intentionality; they don’t even
symbolize anything; they have syntax but no semantics.


Problem with Multiple
Realization


Distinction between program and
realization has the consequence that the
same program could have lots of crazy
realizations that have no intentionality.
Stones, toilet paper, wind, and water pipes
are the wrong kind of stuff to have
intentionality in the first place.