CHAPTER 3

Meeting a genius

peter hilton

I

had the good fortune to work closely with Alan Turing and to know him well for the last

12 years of his short life. It is a rare experience to meet an authentic genius. Those of us

privileged to inhabit the world of scholarship are familiar with the intellectual stimula-

tion furnished by talented colleagues. We can admire the ideas they share with us and are

usually able to understand their source; we may even often believe that we ourselves could

have created such concepts and originated such thoughts. However, the experience of shar-

ing the intellectual life of a genius is entirely different; one realizes that one is in the pres-

ence of an intelligence, a sensitivity of such profundity and originality that one is filled with

wonder and excitement.^1

leading light

Alan Turing was such a genius, and those, like myself, who had the astonishing and unex-

pected opportunity created by the strange exigencies of the Second World War to be able to

count Turing as colleague and friend will never forget that experience, nor can we ever lose its

immense benefit to us.

Before the war, in 1935–36, Turing had done fundamental work in mathematical logic

and had invented a concept that has come to be known as the ‘universal Turing machine’ (see

Chapter 6). His purpose was to make precise the notion of a computable mathematical func-

tion, but he had in fact provided a blueprint for the most basic principles of computer design

and for the foundations of computer science.

I joined the distinguished team of mathematicians and first-class chess players working on

the Enigma code in January 1942. Alan Turing was the acknowledged leading light of that team.

However, I must emphasize that we were a team—this was no one-man show! Indeed, Turing’s

contribution was somewhat different from that of the rest of the team, being more concerned

with improving our methods, especially the machines we used to help us, and less concerned

with our daily output of deciphered messages. It was due to the efforts of Turing and the entire