The Foundations of AI

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The Foundations of AI

• Artificial Intelligence
• Mr. Sciame
• Section 2

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First Foundation
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Philosophy (428 BC Present)

• Questions for AI
• Can formal rules be used to draw valid
  conclusions?
• How does the mental mind arise from a physical
  brain?
• Where does knowledge come from?
• How does knowledge lead to action?

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Applying Rational Thought to Machines

• Aristotle Formulated Logic
• Da Vinci Designed the first calculator
• Wilhelm Schickard 1st Calculating machine
  (1623)
• Blaise Pascal The Pascal Adder (1642) The
  more famous calculating machine much like an
  odometer on a car.

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Pascal and His Adder
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The Mind as a Physical System

• René Descartes (1596-1650) was first to clearly
  discuss the distinction between mind and matter.
• A physical mind leaves no room for free will.
• If the mind was governed by physical laws, it has
  the free will of a rock deciding to fall to
  Earth.

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Dualism

• Descartes proposed dualism
• There is a part of the human mind (soul or
  spirit) outside of nature.
• This part was exempt from physical laws.
• He felt animals did not possess this dual nature
  and could be treated as machines.

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Materialism

• Alternative to dualism
• The brains operation according to the laws of
  physics constitutes the mind.
• Free will is the perception of available choices
  in the choice process.

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Establishing the Source of Knowledge

• Empiricism
• Nothing is in the understanding, which is not
  first in the senses. John Locke
• Induction
• General rules are acquired by exposure to
  repeated associations between their elements.
• Logical Positivism
• Knowledge can be characterized by logical
  theories connected to observational sentences
  that correspond to sensory inputs

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Connection of Knowledge to Action

• A vital question for AI, since intelligence
  requires actions as well as reasoning.
• There must be an understanding of how actions are
  justifiable (or rational).

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Aristotle

• We deliberate not about ends, but about means.

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Second Foundation
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Mathematics (800 AD Present)

• Questions for AI
• What are the formal rules to draw valid
  conclusions?
• What can be compared?
• How do we reason with uncertain information?
• Three contributions
• Logic
• Computation
• Probability

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The Formal Rules

• George Boole (1847)
• Boolean Logic
• Gottlob Frege (1848-1925)
• Extended Boolean logic to include objects and
  relations, used today as a basic knowledge
  representation system.
• Alfred Tarski (1902-1983)
• His theory showed how to relate objects in a
  logic to objects in the real world.

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The Limits of Logic and Computation

• Algorithms
• Step by step methods for problem solving.
• The incompleteness theorem
• Some Functions cannot be represented by
  algorithms.
• The Turing Machine (1936 Alan Turing)
• You could create a machine capable of computing a
  computable function
• No machine can tell in general whether a given
  program will return an answer, or run forever.

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Probability

• The possible outcomes of gambling events

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THIRD Foundation
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Economics (1776 to Present)

• Questions for AI
• How should we make decisions as to maximize
  payoff?
• How should we do this when others may not go
  along?
• How should we do this when the payoff may be far
  into the future?

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Historical

• Adam Smith (1776) An Inquiry into the Causes of
  the Wealth of Nations.
• First time Economics is treated as a science.
• The study of making choices that lead to
  preferred outcomes.
• Theory updated by John von Neumann (1944) The
  Theory of Games and Economic Behavior.

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Decision Theory

• The Decision Theory
• Combines Probability with Utility
• Provides a framework for decisions
• This works for large economies (it doesnt matter
  what the other guy does) smaller ones treat
  this as a game (the actions of one affect others)

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Payoff for the Future

• Herbert Simon (1978)
• Won the Nobel Prize
• Showed that making decisions that were good
  enough, rather than looking for an optimal
  decision, gave a better description of human
  behavior.

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FOURTH Foundation
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Neuroscience (1861 to Present)

• Questions for AI
• How do brains process information?

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Definition

• Neuroscience is the study of the nervous system,
  and in particular, the brain.

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The Neuron

• Parts include
• Cell Body
• Dendrites
• Axon

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Comparason
Computer Human Brain
Computational Units 1 CPU, 108 gates 1011 neurons
Storage Units 1010 bits RAM 1011 bits disk 1011 neurons 1014 synapses
Cycle Time 10-9 seconds 10-3 seconds
Bandwidth 1010 bits/second 1014 bits/second
Memory Updates/Second 109 1014
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FIFTH Foundation
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Psychology (1879 to Present)

• Questions for AI
• How do humans and animals think and act?

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Studies

• Behavioralism
• Cognitive Psychology
• Cognitive Science

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Behaviorism

• The study of animal behavior
• Relationship of stimuli to responses

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Cognitive Psychology

• The view of the brain as an information
  processing device.
• Three steps of a knowledge based agent
• The stimulus must be turned into an internal
  representation
• The representation is changed by cognitive
  processes into new internal representations
• These are translated back into actions.

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Cognitive Science

• Addresses the psychology of memory, language, and
  logical thinking
• A cognitive theory should be like a computer
  program (Anderson, 1980)
• AI Examples
• Newell and Simons The Logical Thinking Machine
• Noah Chomsky and language

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SIXTH Foundation
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Computer Engineering (1940 to Present)

• Questions for AI
• How can we build an efficient computer?
• We discussed this in our first notes.

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SEVENTH Foundation
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Control Theory and Cybernetics (1948 to Present)

• Questions for AI
• How can artifacts operate under their own control?

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Inventions of Control Devices

• 250 BC Water Clock
• 1600s Thermostat (Drebbel)
• 1800s Steam Engine (James Watt)

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Theories

• Control Theory
• A regulatory mechanism trying to minimize error
  (the difference between the current state and the
  goal state)
• Objective Function
• Designing systems that behave optimally.

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EIGHTH Foundation
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Linguistics (1957 to Present)

• Questions for AI
• How does language relate to thought?

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Books on the Subject

• Verbal Behavior B.F. Skinner
• Syntactic Structures Noah Chomsky
• Skinner
• Behaviorialist Approach
• Chomsky
• Creativity in language
• Childrens sentences.

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Natural Language Processing

• Understanding Language
• Not just sentence structure.
• Also subject matter and context