Introduction to AI

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23 févr. 2014 (il y a 4 années et 1 mois)

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CS 484

Artificial Intelligence



The Thinking Machine airs

Today (9/6) at 4PM on channel 53

Monday (9/10) at 3 and 8PM on channel 53

Homework 1 due Tuesday, 9/11

write up
on The Thinking Machine

Lab 0 due Thursday, September 13

Introduction to

Artificial Intelligence

Lecture 2

CS 484

Artificial Intelligence


What is Artificial Intelligence?

Systems that think like humans

Systems that act like humans

Systems that think rationally

Systems that act rationally

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Artificial Intelligence


What has AI accomplished?

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Artificial Intelligence


What will AI accomplish?

CS 484

Artificial Intelligence


The Beginnings


Isaac Asimov publishes the three
laws of robotics


Alan Turing publishes the
, a means of determining if a machine
can think


The term Artificial Intelligence is
coined at a meeting at Dartmouth College

CS 484

Artificial Intelligence


The Turing Test

Uses the "Imitation Game"

Usual method

Three people play (man, woman, and interrogator)

Interrogator determines which of the other two is a
woman by asking questions

Example: How long is your hair?

Questions and responses are typewritten or repeated
by an intermediary

Turing Test

Machine takes the part of the man

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Artificial Intelligence


Strength of the Test

"The new problem has the advantage of
drawing a fairly sharp line between the
physical and the intellectual capacities of a
(Turing, 1950)

CS 484

Artificial Intelligence


Debating the question

"Can machines think?"

The Theological Objection

Thinking is a function of man's immortal soul

The "Head in the Sand" Objection

The consequences of machines thinking would be too

The Mathematical Objection

Given the limitations to the powers of discrete
machines, there are some questions to which it will
either give the wrong answer or fail to answer

CS 484

Artificial Intelligence


Debating the question

"Can machines think?"

The Argument from Consciousness

"Not until a machine can write a sonnet or compose a
concerto because of thoughts and emotions felt, …
could we agree that machine equals brain"
(Jefferson, 1949)

Arguments from Various Disabilities

"I grant you that you can make machines do all the
things you mentioned but you will never be able to
make one do X"

X = be kind, resourceful, friendly, …

CS 484

Artificial Intelligence


Debating the question

"Can machines think?"

Lady Lovelace's Objection

"The Analytical Engine has no pretensions to

anything. It can do
whatever we know how to order it

to perform"

The Argument from Continuity in the Nervous

Given that the nervous system is not a discrete
machine, you cannot mimic the behavior of nervous
system with a discrete
state machine.

CS 484

Artificial Intelligence


Debating the question

"Can machines think?"

The Argument from Informality of Behavior

It is not possible to produce a set of rules purporting to
describe what a man should do in every conceivable set
of circumstances. Thus it is not possible that humans
are machines.

The Argument from Extrasensory Perception

Assuming the woman has ESP, she could perform
better on a test of clairvoyance than the machine

Use a telepathy
proof room

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Artificial Intelligence


Recent Experiment

Spring, 2005 3 undergrads from Simon’s
Rock College (Bard, MA) conducted the
first “gender
twisting” Turing Test


Round 1: Participant has 5 minutes to chat with
a woman and a man masquerading as a women

Round 2: Participant has 5 minutes to chat with
a woman and ALICE

Female chat bot developed by Richard Wallace

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Artificial Intelligence


Sample interaction

What do girls do at sleepovers?

They do their own thing.

Do you wear skirts?

Only when I dress up.

You are a female.

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Artificial Intelligence



42 participants

23 didn’t give any indication that they suspected
ALICE was not a real person

Some did suspect ALICE

Are you a computer?

Would it matter to you if I were metal instead of

Question that tripped up men and bot

What size panty hose do you wear?

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Artificial Intelligence


What does it mean if a computer
passes the Turing Test?

Can the computer think?

Does the computer have a mind in exactly
the same sense that you and I have minds?

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Artificial Intelligence


Chinese Room

Thought experiment purposed by John
Searle in 1980

Given that we have constructed a machine that
behaves as though is understands Chinese, it
convinces a Chinese speaker that it speaks

Given Chinese symbols, it consults a look
up table
and produces other Chinese symbols as output

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Artificial Intelligence


Chinese Room substitution

Machine is replaced by Searle sitting in a room
where he receives Chinese symbols, looks them up
on a look
up table, and returns the Chinese symbol
indicated by the table

English speaker can now give correct answers to
Chinese questions without understanding Chinese

Since Searle doesn't understand Chinese, how can
it be said that the computer understands Chinese?

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Artificial Intelligence


Systems Reply

Although Searle himself doesn't understand
Chinese, it is reasonable to say that Searle
plus look
up table understand Chinese

Counter example: he memorized the look
up table before entering the room

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Artificial Intelligence


Robot Reply

The reason that we don't want to attribute
understanding to the room, or a computer is that
the system doesn't interact properly with the

Solution: put the computer in a robot so that it can
interact with the world

Reply: Cognition is not symbol manipulation.
Second, Searle could be inside the robot and still
not understand Chinese

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Artificial Intelligence


Chinese Room Conclusion

The mind is not a computer

Thus the Turing Test is inadequate

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Artificial Intelligence


How would you show that a
machine can think?

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Artificial Intelligence


Additional Sources

Generation5's interview with John Searle (2001).

Eliasmith, C. Chinese room.

McCarthy, J, et al. A proposal for the Dartmouth Summer Research
Project on Artificial Intelligence. 1955.


Moravec, H. Robot: Mere Machine to Transcendent Mind. Oxford
University Press, Inc. 1999.

Tompson, C. The Other Turing Test. Wired, 13.07, 2005.


Turing, A. Computing machinery and intelligence. Mind, 59, 433