Introduction to AI

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23 févr. 2014 (il y a 3 années et 8 mois)

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CS 484


Artificial Intelligence

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Announcements


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

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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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What has AI accomplished?

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What will AI accomplish?

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The Beginnings


1942


Isaac Asimov publishes the three
laws of robotics


1950


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


1956


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

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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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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
man"
(Turing, 1950)


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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
dreadful


The Mathematical Objection


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

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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, …

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Debating the question

"Can machines think?"


Lady Lovelace's Objection


"The Analytical Engine has no pretensions to
originate

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

to perform"


The Argument from Continuity in the Nervous
System


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

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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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Recent Experiment


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


Setup


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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Sample interaction

Subject
:
What do girls do at sleepovers?

Bot
:
They do their own thing.

Subject
:
Do you wear skirts?

Bot
:
Only when I dress up.

Subject
:
You are a female.

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Outcomes


42 participants


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


Some did suspect ALICE


Subject
:
Are you a computer?


Bot
:
Would it matter to you if I were metal instead of
flesh?


Question that tripped up men and bot


Subject
:
What size panty hose do you wear?

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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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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
Chinese


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

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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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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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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
environment


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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Chinese Room Conclusion


The mind is not a computer


Thus the Turing Test is inadequate

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How would you show that a
machine can think?

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Additional Sources


Generation5's interview with John Searle (2001).


http://www.generation5.org/content/2001/searle.asp


Eliasmith, C. Chinese room.


http://www.artsci.wustl.edu/%7Ephilos/MindDict/chineseroom.html


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


http://www
-
formal.Stanford.EDU/jmc/history/dartmouth.html


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


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


http://
www.wired.com/wired/archive/13.07/posts.html?pg=5


Turing, A. Computing machinery and intelligence. Mind, 59, 433
-
460.


http://www.loebner.net/Prizef/TuringArticle.html