Artificial Intelligence

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Artificial Intelligence

• October 27, 2008

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Cannibals and Missionaries
CCCMMM
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Aristotle, 384-322 BC

• Developed a set of formal procedures
• -- the syllogism --
• to capture the essence of rational thought
• All cats are mammals
• Some cats have no tails
• Some mammals have no tails

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The Brazen Head
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The Characteristica Universalis of Leibniz
"It is obvious that if we could find characters
or signs suited for expressing all our thoughts
as clearly and as exactly as arithmetic expresses
numbers or geometry expresses lines, we could do
in all matters insofar as they are subject to
reasoning all that we can do in arithmetic and
geometry. For all investigations which depend on
reasoning would be carried out by transposing
these characters and by a species of calculus."
(Preface to the General Science, 1677.
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Leibnizs Stepped Reckoner
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1834 Charles Babbage invents the Analytical
Engine, programmed with punched cards
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1842 Ada Lovelace writes the first computer
program. (To calculate the Bernoulli numbers)
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Samuel Butler, Erewhon, 1871

• there is no a priori improbability in the
  descent of conscious (and more than conscious)
  machines from those which now exist,
• Erewhons The Book of the Machines

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• The present machines are to the future as the
  early Saurians to man. The largest of them will
  probably greatly diminish in size. Some of the
  lowest vertebrates attained a much greater bulk
  than has descended to their more highly organised
  living representatives, and in like manner a
  diminution in the size of machines has often
  attended their development and progress.
• Erewhons The Book of the Machines

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• I fear the extraordinary rapidity with which
  they are becoming something very different to
  what they are at present. No class of beings have
  in any time past made so rapid a movement
  forward. Should not that movement be jealously
  watched, and checked while we can still check it?
  And is it not necessary for this end to destroy
  the more advanced of the machines which are in
  use at present..?
• Erewhons The Book of the Machines

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Can a Computer Think?
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Can a Submarine Swim?
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The ELIZA Effect
Joseph Weizenbaum, MIT, 1966
Patient I went for a long boat ride
Therapist Tell me about boats.
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AI in the 40s, 50s and 60s

• Games and Puzzles

• Arthur Samuel, Checker-playing program,
• 1947-1967

2. C.E. Shannon, Programming a Computer For
Playing Chess, Philosophy Magazine, Vol. 41, pp.
256-275 (1960)
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1992 Chinook plays Tinsley
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1994 Chinook plays Lafferty
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AI in the 40s, 50s and 60s

• Games and Puzzles

3. Newell, Shaw and Simon, General
Problem Solver, 1963 (abandoned 1967).
4. John McCarthy, LISP
5. Rosenblatt, Perceptrons
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Newell and Simon with some general problems
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LISP
(defun factorial(n) (cond(( n 0) 1)
t ( n (factorial(- n 1))))))
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Concave
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AI in the Seventies and Eighties

• A belated realization in most situations,
  intelligent behaviour requires knowledge

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AI in the Seventies and Eighties

• Minsky, Frames
• Winograd, SHRDLU
• Rumelhart and McClellan, Parallel Distributed
  Programming (return of the Perceptron)
• Expert Systems

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Rumelhart and McClellandParallel Distributed
Processing

• Representing knowledge by the strengths of
  associations between different concepts, rather
  than as lists of facts, yields programs that can
  learn from example.

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Expert Systems(rule-based)

• Represent knowledge as a number of ifthen
  rules plus an inference engine.

E.g, IF temperature is high AND rash is
present, THEN patient has measles.