CS485 ARTIFICIAL INTELLIGENCE
C HAPTER I
Dorra Louati
MedTech
January 10, 2023
Book: Russell and Norvig Artificial Intelligence: A Modern Approach
Assignment : Read Chapters 1 and 2 for this week’s material
Slides : adapted from https://people.eecs.berkeley.edu/~russell/slides/
https://cs50.harvard.edu/ai/2020/
AIMA Slides @Stuart Russel and Peterf Norvig. https://cs50.harvard.edu/ai/2020/license/
C OURSE C HAPTERS
1. Introduction to AI
2. Knowledge
3. Uncertainty
4. Optimization (*)
5. Learning
6. Neural Networks (*)
7. Ethics and furthermore
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C HAPTER I : I NTRODUCTION TO AI
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2 AI categories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.1 Acting humanly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2.2 Thinking humanly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 Thinking rationally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.4 Acting rationally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3 AI history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
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Part I
W HAT IS AI?
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I NTRODUCTION
▶ The automation of activities that we associate with human thinking, activities such as
decision-making, problem solving, learning . . .” (Bellman, 1978).
▶ “The study of mental faculties through the use of computational models” (Charniak and
McDermott, 1985).
▶ ”The study of how to make computers do things at which, at the moment, people are better”
(Rich and Knight, 1991)
▶ ”The branch of computer science that is concerned with the automation of intelligent behavior”
(Luger and Stubblefield, 1993)
Views of AI fall into four categories:
Thinking humanly Thinking rationally
Acting humanly Acting rationally
Examining these, we will plump for acting rationally (sort of)
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A CTING HUMANLY: T HE T URING 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 offooling 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
Problem: Turing test is not reproducible, constructive, or
amenable to mathematical analysis
https://youtu.be/M8caQDBHQpA
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T HINKING HUMANLY: C OGNITIVE S CIENCE
1960s “cognitive revolution”: information-processing psychology replaced
prevailing orthodoxy of behaviorism Requires scientific theories of internal activities of the brain
▶ What level of abstraction? “Knowledge” or “circuits”?
▶ 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
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T HINKING RATIONALLY: L AWS OF T HOUGHT
Normative (or prescriptive) rather than descriptive
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 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?
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A CTING RATIONALLY
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
Aristotle (Nicomachean Ethics): Every art and every inquiry, and similarly every action and pursuit, is
thought to aim at some good
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R ATIONAL AGENTS
An agent is an entity that perceives and acts
Abstractly, an agent is a function from percept histories to actions:
f : P∗ → A
For any given class of environments and tasks, we seek the
agent (or class of agents) with the best performance
Caveat: computational limitations make perfect rationality unachievable
→ design best p̆rogram for given machine resources
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AI PREHISTORY
Philosophy logic, methods of reasoning
mind as physical system
foundations of learning, language, rationality
Mathematics formal representation and proof
algorithms
computation, (un)decidability, (in)tractability
probability
Psychology adaptation
phenomena of perception and motor control
experimental techniques (psychophysics, etc.)
Linguistics knowledge representation
grammar
Neuroscience physical substrate for mental activity
Control theory homeostatic systems, stability
simple optimal agent designs
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P OTTED HISTORY OF AI
1943 McCulloch & Pitts: Boolean circuit model of brain
1950 Turing’s “Computing Machinery and Intelligence”
1952–69 Look, Ma, no hands!
1950s Early AI programs, including Samuel’s checkers program,
Newell & Simon’s Logic Theorist, Gelernter’s Geometry Engine
1956 Dartmouth meeting: “Artificial Intelligence” adopted
1965 Robinson’s complete algorithm for logical reasoning
1966–74 AI discovers computational complexity
Neural network research almost disappears
1969–79 Early development of knowledge-based systems
1980–88 Expert systems industry booms
1988–93 Expert systems industry busts: “AI Winter”
1985–95 Neural networks return to popularity
1988– Resurgence of probabilistic and decision-theoretic methods
Rapid increase in technical depth of mainstream AI
“Nouvelle AI”: ALife, GAs, soft computing
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S TATE OF THE ART
Which of the following can be done at present?
▶ Play a decent game of table tennis
▶ Drive along a curving mountain road
▶ Drive in the center of Cairo
▶ Play a decent game of bridge
▶ Discover and prove a new mathematical theorem
▶ Write an intentionally funny story
▶ Give competent legal advice in a specialized area of law
▶ Translate spoken English into spoken Swedish in real time
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