Introduction to AI

CS 484
–

Artificial Intelligence

1

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

CS 484
–

Artificial Intelligence

3

What is Artificial Intelligence?

•
Systems that think like humans

•
Systems that act like humans

•
Systems that think rationally

•
Systems that act rationally

CS 484
–

Artificial Intelligence

4

What has AI accomplished?

CS 484
–

Artificial Intelligence

5

What will AI accomplish?

CS 484
–

Artificial Intelligence

6

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

CS 484
–

Artificial Intelligence

7

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

CS 484
–

Artificial Intelligence

8

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)


CS 484
–

Artificial Intelligence

9

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

CS 484
–

Artificial Intelligence

10

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

11

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.

CS 484
–

Artificial Intelligence

12

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

CS 484
–

Artificial Intelligence

13

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

CS 484
–

Artificial Intelligence

14

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.

CS 484
–

Artificial Intelligence

15

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?

CS 484
–

Artificial Intelligence

16

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?

CS 484
–

Artificial Intelligence

17

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

CS 484
–

Artificial Intelligence

18

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?

CS 484
–

Artificial Intelligence

19

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

CS 484
–

Artificial Intelligence

20

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

CS 484
–

Artificial Intelligence

21

Chinese Room Conclusion

•
The mind is not a computer

•
Thus the Turing Test is inadequate

CS 484
–

Artificial Intelligence

22

How would you show that a
machine can think?

CS 484
–

Artificial Intelligence

23

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