Jürgen Schmidhuber's page on
Kurt Goedel


Konrad Zuse Babbage
Correspondence to Nature and Science (on Turing & Gödel & Zuse):

J. Schmidhuber. Turing in Context. Science, vol 1638, p 1639, 2012. Plus comment on response by A. Hodges.

J. Schmidhuber. Turing: Keep his work in perspective. Nature vol 483, p 541, 2012.

J. Schmidhuber: Colossus was the first electronic digital computer. Nature 441 p 25, 2006.

J. Schmidhuber: Turing's impact. Nature 429 p 501, 2004.

See also: J. Schmidhuber (AI Blog, Sep 2021). Turing Oversold. It's not Turing's fault, though.

In 1936, Alan Mathison Turing published an alternative to Kurt Gödel's rather cumbersome universal coding language of 1931, by introducing what's now known as the Turing machine (TM) [1]. In 1935, Turing's advisor Alonzo Church had already extended Gödel's results on the limits of proof and computation, by solving the famous Entscheidungsproblem, using his own alternative universal language called Lambda calculus, basis of LISP. In the following year, Turing used his TMs to do the same [1]. TMs subsequently became a widely used abstract model of computation.

During World War II Turing helped (with Gordon Welchman) to decipher the Nazi code, using the Colossus machine designed by Tommy Flowers, building on earlier work by Polish mathematicians Marian Rejewski, Jerzy Rozycki and Henryk Zygalski who first broke the Enigma code. Some sources say this work was decisive for defeating the Third Reich.

Later Turing suggested his famous test for evaluating whether a computer is intelligent (more on Artificial Intelligence history). Computer science's most sought after prize carries his name: the Turing award.

1912: Born in London.
1931: King's College, Cambridge.
1936: most famous paper at age 30 [1].
1939-1942: Bletchley Park, helping to decode the Luftwaffe's Enigma code.
1950: Turing test.
1954: Suicide in Wilmslow.

[1]. A. M. Turing. On computable numbers, with an application to the Entscheidungsproblem. Proceedings of the London Mathematical Society, Series 2, 41:230-267, 1936.

Leibniz Schickard
See also comment on Nature 468, 760-761 - who invented the digital computer? On Schickard, Leibniz, Babbage, Zuse, Atanasoff, Gödel, Turing, Aiken...
The letter below appeared in Nature 429, 501 (03 June 2004); doi:10.1038/429501c; © Macmillan Publishers Ltd.

Turing's war work counts for more than computers

Sir - John L. Casti, in his fine review of Alan Turing: Life and Legacy of a Great Thinker, edited by Christof Teuscher ("Touring artificial minds" Nature 428, 258; 2004), proposes that Turing had more impact on everyday life than the man named by Time magazine as Person of the Century, Albert Einstein (Time 154, 27; 1999). Casti suggests that Turing's 1936 paper provided the "theoretical backbone" for all computers to come.

Although Turing, a hero of mine, certainly was one of the greatest, we should keep in mind that his paper essentially just elegantly rephrased Kurt Gödel's 1931 results and Alonzo Church's extension thereof. It did not have any impact on the construction of the first working program-controlled computer. That was made in Berlin by Konrad Zuse in 1935-1941 and was driven by practical considerations, not theoretical ones.

In fact, the greatest impact that Alan Turing made on daily life was probably through his contribution to cracking the Enigma code, used by the German military during the Second World War, which is sometimes cited as a decisive event of the war.

Jürgen Schmidhuber
Dalle Molle Institute for Artificial Intelligence (IDSIA), Switzerland

But who was really the most influential person of the 20th century? It was none of those mentioned in the letter to the left: neither Einstein nor Gödel nor Turing nor Zuse . And it was neither Hitler nor Gandhi, for that matter.

At least scientists know that the most influential TwenCen persons were Fritz Haber & Carl Bosch. Never heard of them? They were the ones whose invention jump-started the population explosion - billions of people would not even exist without the Haber-Bosch process.

Haber Albert Einstein Schmidhuber's law: computer history speed-up