"I didn’t want to find her. Not now. Our bargain had been clear, and also inevitable; and there are advantages to sleeping alone. I’ll think of them in a moment."

"“Does it help you to know that you’ve ruined my day?” “It does, yes.”"

"The moral of this story is, anything you don’t understand is dangerous until you do understand it."

"“Do you believe in hunches?” “No.” “Neither do I. Except just this once.”"

"There is no turning away from knowledge."

"Do you know what it’s like to be suddenly poor and not know how to live poor?"

"Part of being a coward is wanting security."

"The Unexpected always comes at the most awkward times."

"The dinosaurs became extinct because they didn't have a space program. And if we become extinct because we don't have a space program, it'll serve us right!"

"Everything starts as somebody's daydream."

"Half of wisdom is learning what to unlearn."

"God was knocking, and he wanted in bad."

"Think of it as evolution in action."

"That's the thing about people who think they hate computers … What they really hate are lousy programmers."

"“It’s a nitwit idea.” “Yes, sir.” “Nitwit ideas are for emergencies. You use them when you’ve got nothing else to try. If they work, they go in the Book. Otherwise you follow the Book, which is largely a collection of nitwit ideas that worked.”"

"“Perhaps I was expecting too much.” “Perhaps. We’re all waiting as fast as we can.”"

"Species evolve to meet the environment. An intelligent species changes the environment to suit itself. As soon as a species becomes intelligent, it should stop evolving."

"Rod privately suspected the Scots studied their speech off duty so they’d be unintelligible to the rest of humanity."

"And the air was full of the smell of burning bridges."

"What’s the justification for ancestor worship? You know what happens to a man without modern geriatrics: as he ages his brain cells start to die. Yet people tend to respect him, to listen to him."

"“How did you come to represent the belt?” “Aptitude tests said I had a high IQ and liked ordering people around. From there I worked my way up.” “We go by the vote.” “Popularity contests.” “It works. But it does have drawbacks. What government doesn’t?”"

"“For letting us examine their silly records they want to charge us a flat million marks!” “Pay it.” “It’s robbery.” “A Belter says that? Why don’t you have records on Mars?” “We were never interested. What for?” “What about abstract knowledge?” “Another word for useless.” “Then what makes you want useless knowledge enough to pay a million marks for it?” Slowly Nick matched his grin. “It’s still robbery. How in Finagle’s name did Earth know they’d need to know about Mars?” “That’s the secret of abstract knowledge. You get in the habit of finding out everything you can about everything. Most of it gets used sooner or later.”"

"The Perversity of the Universe Tends Toward a Maximum."

"I’m being chauvinistic, he told himself. I can’t judge an alien’s sanity by Belt standards, can I? His lip curled. Sure I can. That ship is badly designed."

"Brennan was an optimist. He didn’t expect to be caught."

"The stars are far from eternal, but for man they might as well be."

"Sometimes there’s no point in giving up."

"There is never no hope left. Remember."

"Forget the infinities: Concentrate on detail."

"We learn only to ask more questions."

"Tell them the universe is too complicated a toy for a sensibly cautious being to play with."

"The majority is always sane."

"Seen through the glow of a building orgasm, a woman seems to blaze with angelic glory."

"One mark of a good officer, he remembered, was the ability to make quick decisions. If they happen to be right, so much the better."

"The perversity of the universe tends towards a maximum. The universe is hostile."

"To witness titanic events is always dangerous, usually painful, and often fatal."

"The Gods do not protect fools. Fools are protected by more capable fools."

"Fear is the brother of hate."

"Louis knew a few xenophobes, and regarded them as dolts."

"“I don’t doubt you’re serious,” he said wonderingly. “What I doubt is your sanity.”"

"I have a kind of psychic invisibility. As long as I can stay scared, I can keep people from seeing me. That's what we have to count on."

"He kept the gun in his hand. It felt good. He was sick of having to be afraid. It was a situation to drive a man right out of his skull. If he stopped being afraid, even for an instant, he could be killed! But now, at least for the moment, he could stop listening for footsteps, stop trying to look in all directions at once. A sonic stunner was a surer bet than a hypothetical, undependable psi power. It was real, cold and hard in his hand."

"Yes, the bleeding heart was something else again. A gruesome symbol on a vivarium floor. Fingers that broke without their owner noticing. An ink drawing appearing from nowhere on a dossier cover, like a signature. A signature."

"Parlette spoke slowly and evenly. "I am trying to prevent a bloodbath. Is that clear enough for you? I'm trying to prevent a civil war that could kill half the people in this world.""

"Parlette, if you have something to say, say it. If we jump to the wrong conclusions, please assume that you’re expressing yourself badly, and don’t try to shift the blame."

"I'm no historian," said Harry. "But morals are morals. What's unethical here and now is unethical anywhere, anytime. "Kane, you're wrong. It is ethical to execute a man for theft?" "Of course." "Did you know that there was once a vastly detailed science of rehabilitation for criminals? It was a branch of psychology, naturally, but it was by far the largest such branch. By the middle of century twenty-one, nearly two-thirds of all criminals could eventually be released as cured." "That's silly. Why go to all that trouble when the organ banks must have been crying for — Oh. I see. No organ banks."

"Our society depends entirely on its technology. Change the technology, and you change the society. Most especially you change the ethics."

"Jesus Pietro was worried. The Sons of Earth, if they got this far, would go straight to the vivarium to free their compatriots. But if Matthew Keller was his own agent... If the ghost of Alpha Plateau was not a rebel, but a thing with its own unpredictable purpose... Jesus Pietro worried."

"He was shaking. A mass verbal attack can do that to a man, can smash his self-respect and set up doubts which remain for hours or days or forever. There are well-developed verbal techniques for many to use against one. You never let the victim speak without interruption; never let him finish a sentence. You interrupt each other so that he can’t quite catch the drift of your arguments, and then he can’t find the flaws. He forgets his rebuttal points because he’s not allowed to put them into words. His only defense is to walk out. If, instead, you throw him out…"

"Jesus Pietro wasn't used to dealing with ghosts. It would require brand new techniques. Grimly he set out to evolve them."