The Universal Turing Machine of 1936 gets all the attention, but Turing’s O-machines of 1939 may be closer to the way intelligence (real and artificial) works: logical sequences are followed for a certain number of steps, with intuition bridging the intervening gaps. “Mathematical reasoning may be regarded rather schematically as the exercise of a combination of two faculties, which we may call intuition and ingenuity,” Turing explained. “Intuition consists in making spontaneous judgments which are not the result of conscious trains of reasoning. These judgments are often but by no means invariably correct (leaving aside the question what is meant by ‘correct’).”

As a mathematical consultant to the project, he was allowed to travel freely outside Los Alamos, a privilege denied most participants, who were required to bring their families and remain sequestered for the duration of the war. “Progress elsewhere in computing was carried to Los Alamos by von Neumann,” says Nicholas Metropolis, “who consulted for several government projects at such a pace that he seemed to be in many places at the same time.”

According to Rosenberg, after further extensive testing, and consultation with the major tube manufacturers, whose response was that “no one else had ever complained about their product, and they had enough customers without us,” von Neumann was informed that “there were no reliable tubes, and no reliable resistors.” The response from him was that “we would have to learn how to design a reliable 40-stage machine with thousands of unreliable components,” said Rosenberg.