At this point in history (April of 1945) the word that denotes a person who sits and performs arithmetical calculations is "computer." Waterhouse has just found a whole room full of dead computers. Anyone in his right mind—anyone other than Waterhouse and some of his odd Bletchley Park friends, like Turing—would have taken one look at these computers and assumed that they were the accounting department, or something, and that each slave in the room was independently toting up figures. Waterhouse really ought to remain open to this idea, because it is so obvious. But from the very beginning he has had a hypothesis of his own, much more interesting and peculiar.