Claude Shannon
Early Years
 Born in Petosky, Michigan
 Grew up in Gaylord, Michigan
 Mother was a high school principal
 Father was a Probate Judge
Early Years
 Early aptitude for mathematics and science
 Built various devices as a youth
 Model planes
 Radiocontrolled boat
 Telegraph system to a friend's house with the wire fencing
 Distant cousin to Thomas Edison
University of Michigan
 Begins studying at the University of Michigan in 1932
 Introduced to the work of George Boole
 Graduates in 1936, majoring in:
 Electrical Engineering
 Mathematics
Boolean algebra applied in circuits

After graduation, begins studying electrical engineering at MIT in 1936
 Worked under Vannevar Bush with analog differential analyzers
 Took a course from Norbert Weiner
 Spent the summer of 1937 at Bell Labs, influenced later work
Boolean algebra applied in circuits
 Works on early analog computers and designs switching circuits based on Boolean logic
 At first applied to simplify telephone switching relays
 Then proven that all Boolean algebra problems can be solved via circuits
 Foundation for all electronic digital computers
Boolean algebra applied in circuits
 Published Master’s thesis in 1937 based on this work
 A Symbolic Analysis of Relay and Switching Circuits
 Has been called “one of the most important master’s theses ever written”
 22 years old
Doctorate and Institute for Advanced Study
 Completed his doctoral degree from MIT in 1940
 Dissertation: An Algebra for Theoretical Genetics
 Application of mathematics to genetics
 Completed in less than a year
 Also spent time in a flight training program
Doctorate and Institute for Advanced Study

National Research Fellow at the Institute for Advanced Study for the year following
 This place should sound familiar by now.

Worked under mathematician Herman Weyl, interacted with:
 John von Neumann: “He was the smartest person I ever met”
 Kurt Gödel
 Albert Einstein
Doctorate and Institute for Advanced Study
Side story:
"Einstein once showed up for one of Shannon’s lectures, but was apparently looking for the tea room and left.”
Bell Labs
 Understands that he wants to solve problems related to the transmission of information
 Returns to Bell Labs in summer of 1941
 One small event prevents from focusing on his interests: World War II
Bell Labs
 To help the war effort, Shannon works under the National Defense Research Committee
 NDRC established by FDR and headed by Vannevar Bush

Works under Hendrik Bode to develop “software” for fire control systems
 Heavily influenced by previous work of Norbert Weiner
 Saw analogy between removing interference in communication signals and errors in tracking signals
Bell Labs
 Also works in cryptography at Bell Labs

Asked to inspect the encryption of a secure digital communication system, X System or SIGSALY
 Used for secure communications between the United States and the UK during WWII

Interactions were restricted, but he met a mathematician by the name Alan Turing
 Turing came to Bell Labs in January 1943 and stayed for 2 months
 Spoke about common interests outside of work
 Shannon said he received “a fair amount of negative feedback”
 Classified report by Shannon which was published in 1945
 Applied probability theory to cryptography
 Rigorously used mathematics to prove aspects of cryptography, like how a random onetime pad encryption scheme is unbreakable
 The declassified version of this report was released in 1949 under the title Communication Theory of Secrecy Systems
 Much of the concepts introduced would be later used in his later work on information theory
 One footnote of this paper literally announces the future work:
“It is intended to develop these results in a coherent fashion in a forthcoming memorandum on the transmission of information.
 Shannon’s seminal work (at least in his opinion) which was published in 1948
 Work with information theory was unofficial, unlike with fire control systems and cryptography
 Most ideas were developed from 1943 to 1945, but delayed due to the war
 War also helped though, through his time spent with cryptography
 A start for Shannon’s idea came from “Hartley’s paper”
 Ralph Hartley was a Bell Labs researcher, published Transmission of Information in 1925
 Attempted to quantitatively measure the transmission of information
 Nyquist’s work on sampling and bandwidth of transmission mediums also greatly impacted Shannon

At the time, communications remained split:
 Military kept radar under a cloak of secrecy
 AT&T was the sole operator of the telephone system
 Universities primarily focused on radio transmissions
 Shannon’s worked unified many various fields by laying a mathematical foundation irrespective of any particular system or technology
 Fundamental unit of information: a “bit”
 At one lunch, researchers were searching for a term for “binary digit”
 John Tukey said the “best and obvious choice” was the term bit
 Shannon viewed information as a measure of uncertainty
 We want to view things that are unknown to us, so we learn about them
 Communication then becomes the resolution of uncertainty
 Using his sampling theory derived from Nyquist’s work, any continuous signal can be discretized and turned into a digital one

Once digital, any message can then be encoded in variety of ways
 Same number of bits for each symbol
 Varying amount of bits per symbol
 Varying amount of bits per combinations of symbols
 We can analyze the frequency of certain combinations of symbols to compress the transmission
 Then leads to the question: How much compression is possible?
 Shannon’s measure of information tells us how many bits are required to efficiently encode information
 Analysis of the structure of a source allows for more efficient encoding by removing redundancy
 This all equals more cat videos
 Back to redundancy, Shannon showed that adding redundancy allowed for the suppression and correction of errors in the transmission of messages

However, redundancy can introduced more intelligently than just repeating the message
 This paper proves an upper limit for transmitting data for every method of communication
 Maximum amount of bits per second
 Shannon combined the ideas of Hartley and Nyquist, relating bandwidth and error rates, to give a mathematical definition for the capacity of a given channel

Furthermore, he proved that any method of transmission could be done at capacity and be errorfree
 The catch is that he only proved they exist, not how to actually get them
Aftermath

At 32 years old, Shannon garnered interest from around the world with his work

Not all was positive though
 Mathematician Joseph Doob argued that the proofs were not rigorous enough
 Paper was successful due to the pragmatic focus that Shannon had with a background in both mathematics and electrical engineering
Aftermath
 Ultimately, the entirety of A Mathematical Theory of Communication was proven to be correct

After meeting in 1948, Shannon marries Mary Elizabeth “Betty” Moore in March of 1949
 Betty was a mathematician in her own right at Bell Labs, and would often help Shannon with his idea
 Also, Shannon hated to write and Betty would help dictate in addition to helping Shannon formulate his thoughts
Back to MIT
 After 15 years with Bell Labs, Shannon leaves in 1956
 Returns to MIT in order to maintain the intellectual freedom to pursue his interests
 He began teaching advanced courses in information theory, and MIT became a leading institution in the field
 His personality lead him to avoid much teaching or advising, but he continued pursuing problems
Back to MIT
 Contributed to work in Artificial Intelligence
 Supervised Marvin Minsky and John McCarthy during summer lab jobs, both of whom are pioneers in A.I.
 Advised Leonard Kleinrock and Ivan Sutherland who would go on to work with the Internet and computer graphics respectively
More about his personal life
 His love of devices continued past his youth
 Wrote about machines playing chess
 Created a mechanical “mouse” that could solve a maze, part of his work in A.I.
 Collaborated to created a machine for card counting then test
 Tried to build a machine to solve a Rubik’s cube
 A calculator that used Roman numerals
More about his personal life
 In 1951, Betty gave Shannon a unicycle, which he rode in the hallways at Bell Labs
 Shannon was also an avid juggler which, in tandem with a unicycle, clearly helped him to focus
 Allegedly had a trumpet that would shoot fire
Later years

Shannon officially retired from MIT in 1978
 By many accounts, he had already retired from teaching, preferring his own interests

Applied mathematics to juggling and published a juggling theorem
 Went up to the juggling club at MIT and asked if he could measure them
 Soon after, invited them over to watch juggling videos, play with his devices, and eat pizza

Did well financially by investing in tech companies founded by friends
 Teledyne
 Codex
 HewlettPackard
 Sometime within the early 1990’s, Shannon developed Alzheimer’s disease
“He vaguely remembered I juggled, and cheerfully showed me the juggling displays in his toy room, as if for the first time. And despite the loss of memory and reason, he was every bit as warm, friendly, and cheerful as the first time I met him.”
 After spending a few years in a nursing home, Shannon passed away on February 24th, 2001, at the age of 84
 His wife said “He would have been bemused” by the digital world he helped to create