A Life Computed

BOOKS & ARTS COMMENT

MATHEMATICS In a nearby gallery, a twisted white metal fuselage serves as a poignant reminder of the part Turing’s ideas played in develop- ing safer air travel after the war. In 1954, the A life computed world’s first commercial jet airliner, the de Havilland Comet registered ‘Yoke Peter’, exploded in mid-air, killing everyone on James Poskett navigates a sophisticated account of board — and prompted the Royal Aircraft Alan Turing’s extraordinarily varied intellectual world. Establishment at Farnborough, UK, to find the cause. By this time, Turing’s abstract idea of a lan Turing did not invent the com- and abstracted it, Codebreaker — universal computing machine had become a puter. During the 1930s, well before imagining a universal Alan Turing’s life reality. The National Physical Laboratory in the Manchester ‘Baby’, Pilot ACE computing machine and legacy Teddington, UK, had in 1950 completed the The Science Museum, Aor EDVAC machines, thousands were in that could take on Pilot ACE, an electronic computer designed London operation all across Britain. These ‘com- all of the individual (21 June 2012– to one of Turing’s first practical specifica- puters’ were women, working in teams and tasks allocated to the 31 July 2013) tions. For a short time, this computer was each performing a discrete step of a complex women in the SCS. the fastest in the world. The huge rack of mathematical operation. This was merely a thought experiment for wires, relays and coloured transistors is dis- Employed by the Scientific Comput- him at first — an aid for approaching David played alongside the Yoke Peter wreckage. ing Service (SCS) in the United Kingdom, Hilbert’s notorious ‘decision problem’ on the It helped to process the enormous amounts these doughty women solved problems in question of whether an algorithm exists for of data needed to complete detailed analy- everything from X-ray crystallography to deciding if a given mathematical statement sis of the debris, eventually revealing the jet-engine design. That world of ‘computers has a proof or not. point of structural weakness and prompting before computers’ is featured in the open- Interestingly, although sometimes armed improvements in the design and manufac- ing gallery of Codebreaker, the celebration of with little more than a pencil and slide rule, ture of de Havilland jets. mathematician Alan Turing’s life and legacy the women working for the SCS also used The exhibition also explores links between at London’s Science Museum. basic calculating machines — one of which the Pilot ACE and Dorothy Hodgkin’s work Although the SCS may seem far removed sits in the first room of Codebreaker. These on the structure of vitamin B12. One of her from Turing’s world, knowledge of its work typewriter-like contraptions, covered in original models of the vitamin, an intricate can help us to make sense of his seminal strips of red and white buttons, helped to web of more than 100 red and blue balls, 1936 article ‘On computable numbers, with speed up ballistics calculations crucial to is on show next to the story of her use of an application to the Entscheidungsproblem’. the war effort. computers. Cryptography and X-ray crystal- This is viewed by some as the origin of the The parade of objects that follows reveals lography had much in common at this time: concepts behind the modern computer. But Turing’s impact, as well as his influences, each involved recovering information from the real story is more complex. leading the visitor through a vast intellec- a scrambled signal. Turing didn’t pluck the idea of the modern tual landscape, from aeronautical design and Hodgkin’s problem was that the images computer out of thin air. He took the idea of a biochemistry to cryptography and artificial she produced indicated only the amplitudes team of human computers working together intelligence. of the diffracted waves. To establish the cor- In one gallery, a German Enigma rect structure of a molecule, she needed to machine, tucked into its neat wooden churn through an enormous number of pos- case, sits among archival photos that sible permutations of different wave phases. evoke the atmosphere of Second World So she enlisted the help of both the SCS and War intelligence. Turing is well known to the Pilot ACE, going on to win the Nobel have worked in wartime cryptanalysis at Prize in Chemistry for her work in 1964. the Government Code & Cipher School Turing’s relationships with artificial intel- at Bletchley Park, UK. But he did not ligence and developmental biology are also operate in isolation, collaborating with on show through video interviews with

Gordon Welchman on the design of the contemporary mathematical biologists LIBRARY PICTURE SCIENCE & SOCIETY electromechanical machines used to crack that run next to programmable robotic the code. These devices, each of which tortoises. Although Turing didn’t work on could mimic the action of several Enigma these machines himself, he was fascinated machines, in turn originated in the ear- by the possibility of an artificial mind, com- lier work of Polish cryptanalysts such as ing to London especially to see robots such Marian Rejewski. as these scurry across the floor at the Festi- val of Britain in 1951. Codebreaker does an impressive job of bringing these diverse histories together. Turing is rightly celebrated, not as a lone genius, but as an impressive intellect and brilliant collaborator. ■

James Poskett is a science writer based in Cambridge, UK, specializing in the history and philosophy of science. Alan Turing worked on devices to crack the German Enigma machine’s code during the Second World War. e-mail: [email protected]