Introduction to AI (Artificial Intelligence)

What is artificial intelligence?

Artificial Intelligence is the branch of computer science concerned with making computers behave like humans.

Major AI textbooks define artificial intelligence as “the study and design of intelligent agents,” where an intelligent agent is a system that perceives its environment and takes actions which maximize its chances of success. John McCarthy, who coined the term in 1956, defines it as “the science and engineering of making intelligent machines,especially intelligent computer programs.”

The definitions of AI according to some text books are categorized into four approaches and are summarized in the table below :

Systems that think like humans

“The exciting new effort to make computers think … machines with minds,in the full and literal sense.”(Haugeland,1985)

Systems that think rationally

“The study of mental faculties through the use of computer models.”

(Charniak and McDermont,1985)

Systems that act like humans

The art of creating machines that perform functions that require intelligence when performed by people.”(Kurzweil,1990)

Systems that act rationally

Computational intelligence is the study of the design of intelligent agents.”(Poole et al.,1998)

The four approaches in more detail are as follows :

(a) Acting humanly : The Turing Test approach

  • Test proposed by Alan Turing in 1950
  • The computer is asked questions by a human interrogator.

The computer passes the test if a human interrogator,after posing some written questions,cannot tell whether the written responses come from a person or not. Programming a computer to pass ,the computer need to possess the following capabilities :

  1. Natural language processing to enable it to communicate successfully in English.
  2. Knowledge representation to store what it knows or hears
  3. Automated reasoning to use the stored information to answer questions and to draw new conclusions.
  4. Machine learning to adapt to new circumstances and to detect and extrapolate patterns

To pass the complete Turing Test,the computer will need

  1. Computer vision to perceive the objects,and
  2. Robotics to manipulate objects and move about.

(b)Thinking humanly : The cognitive modeling

We need to get inside actual working of the human mind :

(a) through introspection – trying to capture our own thoughts as they go by;

(b) through psychological experiments

Allen Newell and Herbert Simon,who developed GPS,the “General Problem Solver” tried to trace the reasoning steps to traces of human subjects solving the same problems.

The interdisciplinary field of cognitive science brings together computer models from AI and experimental techniques from psychology to try to construct precise and testable theories of the workings of the human mind

(c) Thinking rationally : The “laws of thought approach”

The Greek philosopher Aristotle was one of the first to attempt to codify “right thinking”,that is irrefuatable reasoning processes. His syllogism provided patterns for argument structures that always yielded correct conclusions when given correct premises—for example,”Socrates is a man;all men are mortal;therefore Socrates is mortal.”.

These laws of thought were supposed to govern the operation of the mind;their study initiated a field called logic.

(d) Acting rationally : The rational agent approach

An agent is something that acts. Computer agents are not mere programs ,but they are expected to have the following attributes also : (a) operating under autonomous control, (b) perceiving their environment, (c) persisting over a prolonged time period, (e) adapting to change.

A rational agent is one that acts so as to achieve the best outcome.


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