Alan Turing: The Enigma Read Online Free PDF Page A

were out searching for a supposed boyfriend of mine. It was all a mare’s nest.
Perfect virtue and chastity had governed all our proceedings. But the poor sweeties never knew this. A very light kiss beneath a foreign flag under the influence of drink, was all that had ever occurred. Everything is now cosy again except that the poor boy has had rather a raw deal I think. I’ll tell you all when we meet in March at Teddington. Being on probation my shining virtue was terrific, and had to be. If I had so much as parked my bicycle on the wrong side of the road there might have been 12 years for me. Of course the police are going to be a bit more nosy, so virtue must continue to shine.
I might try to get a job in France. But I’ve also been having psychoanalysis for a few months now, and it seems to be working a bit. It’s quite fun, and I think I’ve got a good man. 80% of the time we are working out the significance of my dreams. No time to write about logic now!
    Ever, Alan
    The style is a reminder thatwhilst Turing’s plain-speaking English might be compared with that of Orwell or Shaw, it also had a strong element of P. G. Wodehouse. Both letters perhaps indicate a state of denial about the seriousness with which those in charge of the nosy ‘sweeties’ would contemplate his Euro-adventures.
    Alan Turing used logarithms of betting odds as the key to the work he had done for the ‘racket’ of cryptography, and his sustained fascination with probability is illustrated by that reference to a one-in-ten chance of being caught. In his 1953 stoic humour there is a link with innocent Anti-War undergraduate days of twenty years earlier, when he analysed Alfred Beuttell’s Monte Carlo gambling system. While the tectonic forces of geopolitics ground away, Alan Turing dodged his way through as a nimble, insouciant, individual. The lucky streak did not last for ever.
    As well as these addenda, this Preface should also confess to corrigenda. Inevitably, a number of errors are perpetuated by reprinting this text. Here are some examples. Note (2.11) on normal numbers understates the significance of normal numbers and of his friend David Champernowne’s 1933 contribution. It seems possible that Turing’s study of such infinite decimals suggested his model of ‘computable numbers’. The note (3.40) on Turing’s work on the Skewes number is inaccurate: his incomplete manuscript actually dates from about 1950 when he briefly resumed this work, and corresponded briefly with Skewes. Audrey née Bates (p. 401) did more interesting and substantial work than is suggested; her Master’s thesis involved representing Church’s lambda calculus on the Manchester computer, an advanced idea which was never published. This sharpens the point made on the footnote on that page, concerning how Turing failed to turn his vision for programming and logic into the creation of a lively school of research and innovation. One clue to the problems he faced comes from her recollection that ‘Max Newman made the immortal statement that “there is nothing to do with computers that merits a Ph.D.”’ The NDRC (p. 300) was the US National Defense Research Committee; a machine called EDVAC (p. 355, footnote) was built. In 1945-47 Alan Turing lodged in Hampton village, a milesouth of the Hampton Hill incorrectly mentioned on page 317, and the house is now marked by a blue plaque, as indeed are the places of his birth and death. Further additional and corrective material may be found on www.turing.org.uk .
    The curious cocktail of topics in this Centenary Preface is also offered as an aperitif for the story itself, inviting the reader to travel back over that now full century, and to enter the world of 1911. In making that journey as author, I had the peculiar experience of living a previous life. The strangeness is now doubled since I am as far now removed from that Reagan era as it was from Eisenhower’s. The landscape has changed: the science-fiction