Download John McCarthy`s Advice Taker - Computer Science & Engineering

Programs with Common Sense
Mingzhe Du and Hongying Du
April, 2011
This paper “Programs With Common Sense” was written by John McCarthy in 1959, Stanford University
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Department of Computer Science and Engineering
Outline
• Programs with common sense
• Introduction
• Basic Concept
• The Construction of Advice Taker: an example
• Common sense database
• Common sense problem
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Why common sense: Software Is BRITTLE
• Example
• Google: “Is the Eiffel tower taller than the
Dubai Burj Al Arab?”
•
VS
• Eliza: a computer therapist in 1965, MIT
http://www.manifestation.com/neurotoys/eliz
a.php3
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Eliza: a computer therapist in 1965, MIT http://www.manifestation.com/neurotoys/eliza.php3
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Eliza: a computer therapist in 1965, MIT http://www.manifestation.com/neurotoys/eliza.php3
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
John McCarthy
• born in Boston in 1927
• Invention of Lisp
• one of the founders of
artificial intelligence
and knowledge representation.
• Programs with Common
Sense –
the birth of knowledge representation
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
• Introduction and Concept
• The Construction of Advice Taker: an example
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
• Advice Taker: is a proposed program for solving
problems by manipulating sentences in formal
languages.
• The basic program will draw immediate conclusions
from a list of premises. These conclusions will be
either Declarative or Imperative sentences.
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
Imperative Sentence
When an imperative sentence is deduced the program takes a
corresponding action. These actions may include printing
sentences, moving sentences on lists, and reinitiating the basic
deduction process on these lists.
Declarative Sentence
Describing the situation in which action is required together with a
few imperatives that say what is wanted.
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
• Main Advantages: we expect the advice taker’s
behavior will be improvable merely by making
statements to it, telling it about its symbolic
environment and what is wanted from it.
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
• A program has common sense if it automatically
deduces for itself a sufficiently wide class of
immediate consequences of anything it is told and
what it already knows.
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
• “We base ourselves on the idea that: In order for a
program to be capable of learning something it
must first be capable of being told it.”
-- John McCarthy
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
Features an intelligent system should have:
• All behaviors must be representable in the system.
• Interesting changes in behavior must be
expressible in a simple way.
• All aspects of behavior except the most routine
must be improvable.
• The machine must have or evolve concepts of
partial success.
• The system must be able to create subroutines
which can be included in procedures as units.
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
• Our Ultimate Objective
Make programs that learn from their
experience as effectively as
humans do.
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Department of Computer Science and Engineering
Programs with common sense
• Introduction
• The Construction of Advice Taker: an example
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
• An example:
• Assume that I am seated at my desk at home
and I wish to go to the airport.
• My car is at my home also.
• The solution of the problem is to walk to the car
and drive the car to the airport.
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Department of Computer Science and Engineering
Programs with common sense
• 17 Premises
• a predicate ``at''. ``at(x,y)'' is a formalization of
``x is at y''.
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
Here prog(y,u) is the program of first carrying out y and then u.
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
• Deduction Process
• According to
• x: home, y: desk, z: car
• We can deduce
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Department of Computer Science and Engineering
Programs with common sense
• Similarly, we can get
• Then
According to
We can deduce
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Department of Computer Science and Engineering
Programs with common sense
• According to
• We can deduce
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Department of Computer Science and Engineering
Programs with common sense
• According to
• We can deduce
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Programs with common sense
• The need for a computer to be able to perform
commonsense reasoning
• The need for a computer to have a formal
representation of the commonsense
• The representation of such knowledge, along with
an inference method to reason with this
knowledge, was an essential part of any artificial
intelligence
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Controversy
• Philosopher and linguist Yehoshua Bar-Hillel:
• The example of formal commonsense reasoning
given in the paper was oversimplified and that
any proper formalization of an example would
necessarily be much longer and more complex.
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Common sense database: open
mind common sense
• In 1999, Common Sense Computing Initiative
began at the MIT Media Lab to collect common
sense from volunteers on the internet.
• Now, the English site has over a million sentences
from over 15,000 contributors.
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
A planning problem:
The Wolf and the Bush
• A small girl is walking through a forest to visit her
grandmother, and she passes a bush behind which
a Wolf is hiding, planning to pounce out and eat
her. Just as she gets close, however, the Wolf
hears the singing of the woodcutters as they start
work nearby. The Wolf therefore decides to stay
hidden and not pounce on the little girl after all.
• The problem is to explain why the Wolf decides to
stay behind the bush.
•
•
Contributed by Pat Hayes and Lokendra Shastri (9th July, 1997)
More examples at http://www-formal.stanford.edu/leora/commonsense/
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
Common sense problem
• If one encounters no difficulty along the way, one
should be suspicious of the adequacy of the
solution.
• It’s more difficult than they appear at first glance.
• Few of the problems listed in that website are
currently solvable without considerable
simplification.
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering
References
• John McCarthy, Programs With Common Sense, 1959,
Mechanisation of Thought Processes, Proceedings of the
Teddington Conference on the Mechanization of Thought
Processes, 77–84
• Patrick Hayes and Leora Morgenstern, On John McCarthy’s
80th Birthday, in Honor of His Contributions, 2007, AI
Magazine 28(4): 93-102
• http://www.aaai.org/AITopics/pmwiki/pmwiki.php/AITopi
cs/CommonSense
• http://openmind.media.mit.edu/
• http://www-formal.stanford.edu/leora/commonsense/
UNIVERSITY OF SOUTH CAROLINA
Department of Computer Science and Engineering