 But, of course, as Turing himself recognized, there is a large class of possible “machines” that are neither digital nor biotechnological.) More generally, the crucial point seems to be that, while Turing recognized that the class of machines is potentially much larger than the class of discrete state machines, he was himself very confident that properly engineered discrete state machines could succeed in the Imitation Game (and, moreover, at the time that he was writing, there were certain discrete state machines—“electronic computers”—that loomed very large in the public imagination).