Ai INTRO

Document Sample
Ai INTRO Powered By Docstoc
					What is Artificial Intelligence
(John McCarthy , Basic Questions)

      What is artificial intelligence?
      It is the science and engineering of making intelligent machines,
      especially intelligent computer programs. It is related to the similar task
      of using computers to understand human intelligence, but AI does not
      have to confine itself to methods that are biologically observable.

      Yes, but what is intelligence?
      Intelligence is the computational part of the ability to achieve goals in
      the world. Varying kinds and degrees of intelligence occur in people,
      many animals and some machines.

      Isn't there a solid definition of intelligence that doesn't depend
      on relating it to human intelligence?
      Not yet. The problem is that we cannot yet characterize in general what
      kinds of computational procedures we want to call intelligent. We
      understand some of the mechanisms of intelligence and not others.

      More in: http://www-formal.stanford.edu/jmc/whatisai/node1.html
Two prevailing schools of thought
on artificial intelligence
Proponents of "strong AI" consider that all human
thought can be broken down into a set of
mathematical operations. They expect that they
will one day be able to replicate the human mind
and create a robot capable of both thinking and
feeling, with a sense of self -- the stuff of classic
science fiction. Think of the robot Number Five
from the 80s movie Short Circuit, who suddenly
realized, frightened, that he could be
"disassembled" by the scientists who made him.

"Weak AI" proponents expect that human
thought and emotion can only be simulated by
computers. A computer might seem intelligent,
but it is not aware of what it is doing, with no
sense of self or consciousness.
What is AI?
Views of AI fall into four categories:

  Thinking humanly Thinking rationally

  Acting humanly         Acting rationally




The textbook advocates "acting rationally“
What is Artificial Intelligence?

  Thought processes vs behavior
  Human-like vs rational-like
  How to simulate humans intellect and
  behavior by a machine.
    Mathematical problems (puzzles, games,
    theorems)
    Common-sense reasoning
    Expert knowledge: lawyers, medicine, diagnosis
    Social behavior
What is Artificial Intelligence
   Thought processes
       “The exciting new effort to make computers think
       .. Machines with minds, in the full and literal
       sense” (Haugeland, 1985)
   Behavior
       “The study of how to make computers do things
       at which, at the moment, people are better.”
       (Rich, and Knight, 1991)

  The automation of activities that we associate with human
  thinking, activities such as decision-making, problem solving,
  learning… (Bellman)
Acting humanly: Turing Test
  Turing (1950) "Computing machinery and intelligence":
  "Can machines think?"       "Can machines behave intelligently?"
  Operational test for intelligent behavior: the Imitation Game




  Predicted that by 2000, a machine might have a 30% chance
  of fooling a lay person for 5 minutes
  Anticipated all major arguments against AI in following 50
  years
  Suggested major components of AI: knowledge, reasoning,
  language understanding, learning
Thinking humanly: cognitive
modeling
 1960s "cognitive revolution": information-
 processing psychology
 Requires scientific theories of internal activities
 of the brain
  -- How to validate? Requires
    1) Predicting and testing behavior of human
   subjects (top-down)
    or 2) Direct identification from neurological data
   (bottom-up)
 Both approaches (roughly, Cognitive Science
 and Cognitive Neuroscience) are now distinct
 from AI
Thinking rationally: "laws of thought"
     Aristotle: what are correct arguments/thought
     processes?
     Several Greek schools developed various forms of
     logic: notation and rules of derivation for thoughts;
     may or may not have proceeded to the idea of
     mechanization
     E.g., “Socrates is a man, all men are mortal;
     therefore Socrates is mortal”
     Direct line through mathematics and philosophy to
     modern AI
     Problems:
  1.    Not all intelligent behavior is mediated by logical
        deliberation
  2.    What is the purpose of thinking? What thoughts
        should I have?
Acting rationally: rational
agent
  Rational behavior: doing the right thing
 The right thing: that which is expected
 to maximize goal achievement, given
 the available information
 Doesn't necessarily involve thinking –
 e.g., blinking reflex – but thinking
 should be in the service of rational
 action

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:7
posted:1/31/2013
language:
pages:9
Description: Artificail Intelliegnce