"Deliberate error was unthinkable. Even the concealment of truth filled him with a sense of imperfection, of wrongness — of what, in a human being, would have been called guilt. For like his makers, Hal had been created innocent; but, all too soon, a snake had entered his electronic Eden. For the last hundred million miles, he had been brooding over the secret he could not share with Poole and Bowman…who would not learn the mission's full purpose, until there was need to know. So ran the logic of the planners; but their twin gods of Security and National Interest meant nothing to Hal. He was only aware of the conflict that was slowly destroying his integrity."