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as a founder of information theory, Claude Shannon combined mathematical
theories with engineering principles to set the stage for the development
of the digital computer. The term ‘bit,’ today used to describe
individual units of information processed by a computer, was coined from
Shannon’s research in the 1940s.
A Midwesterner, Claude
Shannon was born in Gaylord, Michigan in 1916. From an early age, he showed
an affinity for both engineering and mathematics, and graduated from Michigan
University with degrees in both disciplines. For his advanced degrees,
he chose to attend the Massachusetts Institute of Technology.
At the time, MIT was
one of a number of prestigious institutions conducting research that would
eventually formulate the basis for what is now known as the information
sciences. Its faculty included mathematician Norbert Wiener, who would
later coin the term cybernetics to describe the work in information theories
that he, Shannon and other leading American mathematicians were conducting;
and Vannevar Bush, MIT’s dean of engineering, who in the early 1930s
had built an analog computer called the Differential Analyzer
The Differential Analyzer
was developed to calculate complex equations that tabulators and calculators
of the day were unable to address. It was a mechanical computer, using
a series of gears and shafts to engage cogs until the equation was solved.
Once it completed its cycle, the answer to the equation was obtained by
measuring the changes in position of its various machine parts. Its only
electrical parts were the motors used to drive the gears.
With its crude rods,
gears and axles, the analyzer looked like a child’s erector set.
Setting it up to work one equation could take two to three days; solving
the same equation could take equally as long, if not longer. In order
to work a new problem, the entire machine, which took up several hundred
feet of floor space, had to be torn apart and reset to a new mechanical
While at MIT, Shannon
studied with both Wiener and Bush. Noted as a ‘tinkerer,’ he
was ideally suited to working on the Differential Analyzer, and would
set it up to run equations for other scientists. At Bush’s suggestion,
Shannon also studied the operation of the analyzer’s relay circuits
for his master’s thesis. This analysis formed the basis for Shannon’s
influential 1938 paper "A Symbolic Analysis of Relay and Switching
Circuits," in which he put forth his developing theories on the relationship
of symbolic logic to relay circuits. This paper, and the theories it contained,
would have a seminal impact on the development of information processing
machines and systems in the years to come.
provided a glimpse into the future of information processing. While studying
the relay switches on the Differential Equalizer as they went about formulating
an equation, Shannon noted that the switches were always either open or
closed, or on and off. This led him to think about a mathematical way
to describe the open and closed states, and he recalled the logical theories
of mathematician George Boole, who in the middle 1800s advanced what he
called the logic of thought, in which all equations were reduced to a
binary system consisting of zeros and ones.
which formulated the basis for Boolean algebra, stated that a statement
of logic carried a one if true and a zero if false. Shannon theorized
that a switch in the on position would equate to a Boolean one. In the
off position, it was a zero.
By reducing information
to a series of ones and zeros, Shannon wrote, information could be processed
by using on-off switches. He also suggested that these switches could
be connected in such a way to allow them to perform more complex equations
that would go beyond simple ‘yes’ and ‘no’ statements
to ‘and’, ‘or’ or ‘not’ operations.
Shannon graduated from
MIT in 1940 with both a master’s degree and doctorate in mathematics.
After graduation, he spent a year as a National Research Fellow at the
Institute for Advanced Study at Princeton University, where he worked
with mathematician and physicist Hermann Weyl. In 1941, Shannon joined
the Bell Telephone Laboratories, where he became a member of a group of
scientists charged with the tasks of developing more efficient information
transmitting methods and improving the reliability of long-distance telephone
and telegraph lines.
Shannon believed that
information was no different than any other quantity and therefore could
be manipulated by a machine. He applied his earlier research to the problem
at hand, again using Boolean logic to develop a model that reduced information
to its most simple form–a binary system of yes/no choices, which could
be presented by a 1/0 binary code. By applying set codes to information
as it was transmitted, the noise it picked up during transmission could
be minimized, thereby improving the quality of information transmission.
In the late 1940s,
Shannon’s research was presented in The Mathematical Theory of
Communications, which he co-authored with mathematician Warren Weaver.
It was in this work that Shannon first introduced the word ‘bit,’
comprised of the first two and the last letter of ‘binary digit’
and coined by his colleague John W. Turley, to describe the yes-no decision
that lay at the core of his theories.
In the 1950s, Shannon
turned his efforts to developing what was then called "intelligent
machines,"–mechanisms that emulated the operations of the human
mind to solve problems. Of his inventions during that time, the best known
was a maze-solving mouse called Theseus, which used magnetic relays to
learn how to maneuver through a metal maze.
theories eventually saw application in a number of disciplines in which
language is a factor, including linguistics, phonetics, psychology and
cryptography, which was an early love of Shannon’s. His theories
also became a cornerstone of the developing field of artificial intelligence,
and in 1956 he was instrumental in convening a conference at Dartmouth
College that was the first major effort in organizing artificial intelligence
The New Alchemists. Dirk
Hanson. Avon, 1982.
Dictionary of Scientists, Second Edition. Roy Porter, Oxford University
Degrees Above Zero: Bell Labs in the Information Age. Jeremy Bernstein,
Charles Scribner’s Sons, 1984.
Encyclopedia of Science & Technology–7th edition. McGraw-Hill,
Pioneers. David Ritchie. Simon & Schuster, 1986.
of the Mind: A History of the Computer. Joel Shurkin. Norton, 1984.
in Silicon. Robert Slater. The Massachusetts Institute of Technology,
Dreams: Information, Man and Machine. Robert W. Lucky. St. Martin’s
for the Modern Mind. Walter R. Fuchs. Macmillian, 1971.
The Five Levels of Mathematial Reality. Rudy Rucker. Houghton Mifflin,
Dictionary of Scientists. Larousse, 1994.
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