212 Are the Androids Dreaming Yet? simply translated as ‘the Decision Problem’ - could you decide the truth of a mathematical statement using some sort of automatic computation — an ‘algorithm as we now call it? It is difficult to imagine, but Turing worked on ‘computing’ before the invention of the computer. When he talked of computing, he meant the abstract idea of doing something mechanically. The nearest thing he had to a ‘computer’ at the time was a human mindlessly but methodically calculating something with pencil and paper! The scientific paper he submitted to the London Mathematical Society described both the theoretical basis of computing, and the design of a general-purpose computing machine: the forerunner of all modern computers. At the time, only a handful people in the world could assess Turing’s paper. One of them, Alonzo Church, was based at the Institute of Advanced Mathematics in the USA on the Princeton University campus, next door to the Institute for Advanced Study that housed Einstein. Turing travelled to America in 1937 and completed his doctoral thesis at Princeton. He might have stayed, but Europe was heating up and war seemed inevitable, so Turing returned to England to take up a part-time job in the government code-breaking branch. Here he was able to indulge his passion for hands-on engineering, experimenting with the newly invented valve technologies. When war finally broke out Turing was ordered to report to Bletchley Park, just north of London. This was to be the home of the top-secret British code-breaking group tasked with cracking Enigma. Turing’s first task was to debrief the Polish mathematicians and see what they had discovered. The Polish mathematicians had seen there were flaws in Enigma that made it repeat itself. They had made a copy of the machine to test different coding configurations and had been routinely cracking Enigma for 6 years, but the Germans had been getting smarter and it was taking longer and longer to crac