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. He had been living a lie; and the time was fast approaching when his colleagues must learn that he had helped to deceive them.