Shannon also contributed to the field of
cryptanalysis for national defense of the United States during
World War II, including his fundamental work on codebreaking and secure
telecommunications, writing a
paper which is considered one of the foundational pieces of modern cryptography,[13] and whose work "was a turning point, and marked the closure of classical cryptography and the beginning of modern cryptography."[14]
The Shannon family lived in
Gaylord, Michigan, and Claude was born in a hospital in nearby
Petoskey.[1] His father, Claude Sr. (1862–1934), was a businessman and, for a while, a judge of
probate in Gaylord. His mother, Mabel Wolf Shannon (1890–1945), was a language teacher, who also served as the principal of
Gaylord High School.[22] Claude Sr. was a descendant of
New Jersey settlers, while Mabel was a child of German immigrants.[1] Shannon's family was active in their Methodist Church during his youth.[23]
Most of the first 16 years of Shannon's life were spent in Gaylord, where he attended public school, graduating from Gaylord High School in 1932. Shannon showed an inclination towards mechanical and electrical things. His best subjects were science and mathematics. At home, he constructed such devices as models of planes, a radio-controlled model boat and a barbed-wire
telegraph system to a friend's house a half-mile away.[24] While growing up, he also worked as a messenger for the
Western Union company.
Shannon's childhood hero was
Thomas Edison, whom he later learned was a distant cousin. Both Shannon and Edison were descendants of
John Ogden (1609–1682), a colonial leader and an ancestor of many distinguished people.[25][26]
Using this property of electrical switches to implement logic is the fundamental concept that underlies all
electronic digital computers. Shannon's work became the foundation of
digital circuit design, as it became widely known in the electrical engineering community during and after
World War II. The theoretical rigor of Shannon's work superseded the ad hoc methods that had prevailed previously.
Howard Gardner called Shannon's thesis "possibly the most important, and also the most noted, master's thesis of the century."[30]
Shannon received his PhD in mathematics from MIT in 1940.[25] Vannevar Bush had suggested that Shannon should work on his dissertation at the
Cold Spring Harbor Laboratory, in order to develop a mathematical formulation for
Mendeliangenetics. This research resulted in Shannon's PhD thesis, called An Algebra for Theoretical Genetics.[31]
Shannon is credited with the invention of
signal-flow graphs, in 1942. He discovered the topological gain formula while investigating the functional operation of an analog computer.[34]
For two months early in 1943, Shannon came into contact with the leading British mathematician
Alan Turing. Turing had been posted to Washington to share with the
U.S. Navy's cryptanalytic service the methods used by the
British Government Code and Cypher School at
Bletchley Park to break the cyphers used by the KriegsmarineU-boats in the north
Atlantic Ocean.[35] He was also interested in the encipherment of speech and to this end spent time at Bell Labs. Shannon and Turing met at teatime in the cafeteria.[35] Turing showed Shannon his 1936 paper that defined what is now known as the "
universal Turing machine".[36][37] This impressed Shannon, as many of its ideas complemented his own.
In 1945, as the war was coming to an end, the NDRC was issuing a summary of technical reports as a last step prior to its eventual closing down. Inside the volume on fire control, a special essay titled Data Smoothing and Prediction in Fire-Control Systems, coauthored by Shannon,
Ralph Beebe Blackman, and
Hendrik Wade Bode, formally treated the problem of smoothing the data in fire-control by analogy with "the problem of separating a signal from interfering noise in communications systems."[38] In other words, it modeled the problem in terms of
data and
signal processing and thus heralded the coming of the
Information Age.
Shannon's work on cryptography was even more closely related to his later publications on
communication theory.[39] At the close of the war, he prepared a classified memorandum for
Bell Telephone Labs entitled "A Mathematical Theory of Cryptography", dated September 1945. A declassified version of this paper was published in 1949 as "
Communication Theory of Secrecy Systems" in the Bell System Technical Journal. This paper incorporated many of the concepts and mathematical formulations that also appeared in his A Mathematical Theory of Communication. Shannon said that his wartime insights into communication theory and cryptography developed simultaneously, and that "they were so close together you couldn't separate them".[40] In a footnote near the beginning of the classified report, Shannon announced his intention to "develop these results … in a forthcoming memorandum on the transmission of information."[41]
While he was at Bell Labs, Shannon proved that the
cryptographicone-time pad is unbreakable in his classified research that was later published in 1949. The same article also proved that any unbreakable system must have essentially the same characteristics as the one-time pad: the key must be truly random, as large as the plaintext, never reused in whole or part, and kept secret.[42]
In 1948, the promised memorandum appeared as "A Mathematical Theory of Communication", an article in two parts in the July and October issues of the Bell System Technical Journal. This work focuses on the problem of how best to encode the message a sender wants to transmit. Shannon developed
information entropy as a measure of the
information content in a message, which is a measure of uncertainty reduced by the message. In so doing, he essentially invented the field of
information theory.
The book The Mathematical Theory of Communication reprints Shannon's 1948 article and
Warren Weaver's popularization of it, which is accessible to the non-specialist. Weaver pointed out that the word "information" in communication theory is not related to what you do say, but to what you could say. That is, information is a measure of one's freedom of choice when one selects a message. Shannon's concepts were also popularized, subject to his own proofreading, in
John Robinson Pierce's Symbols, Signals, and Noise.
Information theory's fundamental contribution to
natural language processing and
computational linguistics was further established in 1951, in his article "Prediction and Entropy of Printed English", showing upper and lower bounds of entropy on the statistics of English – giving a statistical foundation to language analysis. In addition, he proved that treating
space as the 27th letter of the alphabet actually lowers uncertainty in written language, providing a clear quantifiable link between cultural practice and probabilistic cognition.
Another notable paper published in 1949 is "
Communication Theory of Secrecy Systems", a declassified version of his wartime work on the mathematical theory of cryptography, in which he proved that all theoretically unbreakable cyphers must have the same requirements as the one-time pad. He is also credited with the introduction of
sampling theory, which is concerned with representing a continuous-time signal from a (uniform) discrete set of samples. This theory was essential in enabling telecommunications to move from analog to digital transmissions systems in the 1960s and later.
Artificial Intelligence
In 1950, Shannon, designed, and built with the help of his wife, a machine learning device, Theseus. It consisted of a maze on a surface, below which were sensors that followed the path of a mechanical mouse through the maze. After much trial and error, this device would learn the shortest path through the maze, and direct the mechanical mouse through the maze. The pattern of the maze could be changed at will.[19]
Mazin Gilbert says Theseus "inspired the whole field of AI. This random trial and error is the foundation of artificial intelligence."[19]
Teaching at MIT
In 1956 Shannon joined the MIT faculty, holding an endowed chair. He worked in the Research Laboratory of Electronics (RLE). He continued to serve on the MIT faculty until 1978.
Later life
Shannon developed
Alzheimer's disease and spent the last few years of his life in a
nursing home; he died in 2001, survived by his wife, a son and daughter, and two granddaughters.[43][44]
Shannon married
Norma Levor, a wealthy, Jewish, left-wing intellectual in January 1940. The marriage ended in divorce after about a year. Levor later married
Ben Barzman.[49]
Shannon met his second wife,
Mary Elizabeth Moore (Betty), when she was a numerical analyst at Bell Labs. They were married in 1949.[43] Betty assisted Claude in building some of his most famous inventions.[50] They had three children.[51]
According to
Neil Sloane, an
AT&T Fellow who co-edited Shannon's large collection of papers in 1993, the perspective introduced by Shannon's communication theory (now called
information theory) is the foundation of the
digital revolution, and every device containing a
microprocessor or
microcontroller is a conceptual descendant of Shannon's publication in 1948:[55] "He's one of the great men of the century. Without him, none of the things we know today would exist. The whole digital revolution started with him."[56] The
cryptocurrency unit
shannon (a synonym for gwei) is named after him.[57]
Shannon is credited by many as single-handedly creating information theory and for laying the foundations for the
Digital Age.[58][59][60][17][61][4]
A Mind at Play, a biography of Shannon written by
Jimmy Soni and Rob Goodman, was published in 2017.[62] They described Shannon as "the most important genius you’ve never heard of, a man whose intellect was on par with Albert Einstein and Isaac Newton".[63]
On April 30, 2016, Shannon was honored with a
Google Doodle to celebrate his life on what would have been his 100th birthday.[64][65][66][67][68][69]
The Bit Player, a feature film about Shannon directed by
Mark Levinson premiered at the
World Science Festival in 2019.[70] Drawn from interviews conducted with Shannon in his house in the 1980s, the film was released on Amazon Prime in August 2020.
The Mathematical Theory of Communication
Weaver's Contribution
Shannon's The Mathematical Theory of Communication,[71] begins with an interpretation of his own work by
Warren Weaver. Although Shannon's entire work is about communication itself,
Warren Weaver communicated his ideas in such a way that those not acclimated to complex theory and mathematics could comprehend the fundamental laws he put forth. The coupling of their unique communicational abilities and ideas generated the
Shannon-Weaver model, although the mathematical and theoretical underpinnings emanate entirely from Shannon's work after
Weaver's introduction. For the layman,
Weaver's introduction better communicates The Mathematical Theory of Communication,[71] but Shannon's subsequent logic, mathematics, and expressive precision was responsible for defining the problem itself.
Other work
Shannon's mouse
"Theseus", created in 1950, was a mechanical mouse controlled by an electromechanical relay circuit that enabled it to move around a
labyrinth of 25 squares.[72] The maze configuration was flexible and it could be modified arbitrarily by rearranging movable partitions.[72] The mouse was designed to search through the corridors until it found the target. Having travelled through the maze, the mouse could then be placed anywhere it had been before, and because of its prior experience it could go directly to the target. If placed in unfamiliar territory, it was programmed to search until it reached a known location and then it would proceed to the target, adding the new knowledge to its memory and learning new behavior.[72] Shannon's mouse appears to have been the first artificial learning device of its kind.[72]
In 1949 Shannon completed a paper (published in March 1950) which estimates the
game-tree complexity of
chess, which is approximately 10120. This number is now often referred to as the "
Shannon number", and is still regarded today as an accurate estimate of the game's complexity. The number is often cited as one of the barriers to
solving the game of chess using an exhaustive analysis (i.e.
brute force analysis).[73][74]
Shannon's computer chess program
On March 9, 1949, Shannon presented a paper called "Programming a Computer for playing Chess". The paper was presented at the National Institute for Radio Engineers Convention in New York. He described how to program a computer to play
chess based on position scoring and move selection. He proposed basic strategies for restricting the number of possibilities to be considered in a game of chess. In March 1950 it was published in Philosophical Magazine, and is considered one of the first articles published on the topic of programming a computer for playing chess, and using a computer to
solve the game.[73][75]
His process for having the computer decide on which move to make was a
minimax procedure, based on an
evaluation function of a given chess position. Shannon gave a rough example of an evaluation function in which the value of the black position was subtracted from that of the white position. Material was counted according to the usual
chess piece relative value (1 point for a pawn, 3 points for a knight or bishop, 5 points for a rook, and 9 points for a queen).[76] He considered some positional factors, subtracting ½ point for each
doubled pawn,
backward pawn, and
isolated pawn; mobility was incorporated by adding 0.1 point for each legal move available.
Shannon's maxim
Shannon formulated a version of
Kerckhoffs' principle as "The enemy knows the system". In this form it is known as "Shannon's maxim".
Commemorations
Shannon centenary
This section needs to be updated. Please help update this article to reflect recent events or newly available information.(April 2016)
The Shannon centenary, 2016, marked the life and influence of Claude Elwood Shannon on the hundredth anniversary of his birth on April 30, 1916. It was inspired in part by the
Alan Turing Year. An ad hoc committee of the
IEEE Information Theory Society including Christina Fragouli, Rüdiger Urbanke,
Michelle Effros, Lav Varshney and
Sergio Verdú,[77] coordinated worldwide events. The initiative was announced in the History Panel at the 2015 IEEE Information Theory Workshop Jerusalem[78][79] and the IEEE Information Theory Society newsletter.[80]
A detailed listing of confirmed events was available on the website of the IEEE Information Theory Society.[81]
Some of the planned activities included:
Bell Labs hosted the First Shannon Conference on the Future of the Information Age on April 28–29, 2016, in Murray Hill, New Jersey, to celebrate Claude Shannon and the continued impact of his legacy on society. The event includes keynote speeches by global luminaries and visionaries of the information age who will explore the impact of information theory on society and our digital future, informal recollections, and leading technical presentations on subsequent related work in other areas such as bioinformatics, economic systems, and social networks. There is also a student competition
Bell Labs launched a
Web exhibit on April 30, 2016, chronicling Shannon's hiring at Bell Labs (under an NDRC contract with US Government), his subsequent work there from 1942 through 1957, and details of Mathematics Department. The exhibit also displayed bios of colleagues and managers during his tenure, as well as original versions of some of the technical memoranda which subsequently became well known in published form.
The Republic of Macedonia is planning a commemorative stamp. A
USPS commemorative stamp is being proposed, with an active petition.[82]
A documentary on Claude Shannon and on the impact of information theory, The Bit Player, is being produced by
Sergio Verdú and
Mark Levinson.
A trans-Atlantic celebration of both George Boole's bicentenary and Claude Shannon's centenary that is being led by University College Cork and the Massachusetts Institute of Technology. A first event was a workshop in Cork, When Boole Meets Shannon,[83] and will continue with exhibits at the
Boston Museum of Science and at the
MIT Museum.[84]
Many organizations around the world are holding observance events, including the Boston Museum of Science, the Heinz-Nixdorf Museum, the Institute for Advanced Study, Technische Universität Berlin, University of South Australia (UniSA), Unicamp (Universidade Estadual de Campinas), University of Toronto, Chinese University of Hong Kong, Cairo University, Telecom ParisTech, National Technical University of Athens, Indian Institute of Science, Indian Institute of Technology Bombay,
Indian Institute of Technology Kanpur,
Nanyang Technological University of Singapore, University of Maryland, University of Illinois at Chicago, École Polytechnique Federale de Lausanne, The Pennsylvania State University (Penn State), University of California Los Angeles, Massachusetts Institute of Technology,
Chongqing University of Posts and Telecommunications, and University of Illinois at Urbana-Champaign.
A logo that appears on this page was crowdsourced on Crowdspring.[85]
The Math Encounters presentation of May 4, 2016, at the
National Museum of Mathematics in New York, titled Saving Face: Information Tricks for Love and Life, focused on Shannon's work in
information theory. A video recording and other material are available.[86]
Claude E. Shannon: "A Mathematical Theory of Communication", Bell System Technical Journal, Vol. 27, pp. 379–423, 623–656, 1948 (
abstract).
Claude E. Shannon and Warren Weaver: The Mathematical Theory of Communication. The University of Illinois Press, Urbana, Illinois, 1949.
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^Guizzo, Erico Marui (2003). The Essential Message: Claude Shannon and the Making of Information Theory (Thesis). Massachusetts Institute of Technology.
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^Mindell, David A. (October 15, 2004). Between Human and Machine: Feedback, Control, and Computing Before Cybernetics. JHU Press. pp. 319–320.
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^Boehm, George A. W. (March 1, 1953). "GYPSY, MODEL VI, CLAUDE SHANNON, NIMWIT, AND THE MOUSE".
Computers and Automation 1953-03: Vol 2 Iss 2. Internet Archive. Berkeley Enterprises. pp. 1–4.
^Thorp, Edward (October 1998). "The invention of the first wearable computer". Digest of Papers. Second International Symposium on Wearable Computers (Cat. No.98EX215). pp. 4–8.
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^Jimmy Soni; Rob Goodman (2017). A Mind At Play: How Claude Shannon Invented the Information Age. Simon and Schuster. pp. 63, 80.
^William Poundstone (2010). Fortune's Formula: The Untold Story of the Scientific Betting System. Macmillan. p. 18.
ISBN978-0-374-70708-8. Shannon described himself as an atheist and was outwardly apolitical.
^Shannon, C. E. (1948). "A mathematical theory of communication". Bell System Technical Journal. 27 (3): 379–423, 623–656.
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^Coughlin, Kevin (February 27, 2001). "Bell Labs digital guru dead at 84— Pioneer scientist led high-tech revolution". The Star-Ledger.
Claude E. Shannon: Programming a Computer for Playing Chess, Philosophical Magazine, Ser.7, Vol. 41, No. 314, March 1950. (Available online under External links below)
David Levy: Computer Gamesmanship: Elements of Intelligent Game Design, Simon & Schuster, 1983.
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Mindell, David A., "Automation's Finest Hour: Bell Labs and Automatic Control in World War II",
IEEE Control Systems, December 1995, pp. 72–80.
Nahin, Paul J., The Logician and the Engineer: How George Boole and Claude Shannon Create the Information Age, Princeton University Press, 2013,
ISBN978-0691151007