Alan Turing in America – 1942–1943

David E. Zitarelli (Temple University)

Alan Turing returned to the U.S. during WWII as a liaison between the two communities of cryptanalysts for about four months, from November 1942 to March 1943.  He arrived in New York City on November 12, 1942, before heading to the headquarters of the U.S. Secret Service (now the CIA) in Washington, D.C.  By that time, officers in the U.S. Navy were concerned that Britain was not sharing details about decoding the Enigma machine.  Turing’s official role was to disclose details to American cryptanalysts but unofficially the British Secret Intelligence Service instructed him to reveal very little.  Commonly known as MI6, this unit’s existence was not officially acknowledged until 1994.  Back in late 1942, the MI6 was especially fearful of leaks by U.S. authorities, mainly because of intrigue between the U.S. Army and U.S. Navy.  

So once again Alan Turing was caught in a web of secrecy.  And he played his part perfectly.  (A recent newspaper article contains a fascinating account of Turing’s four-month stay in the U.S. [6].)

Figure 6. Left: The British Secret Intelligence Service (MI6) building in Vauxhall, London (Source: Wikimedia Commons);
Right: American mathematician Claude Shannon (Source: MacTutor History of Mathematics Archive)

Ironically, Turing’s time in Washington inspired some of his best-known work on computers.  During that visit he engaged in a long conversation with Claude Shannon (1916-2001) about building an electronic brain.  This seems to have inspired Turing to engage in experiments on artificial intelligence in the early 1950s.