"He had defined intuition for Sondra: it was what remained after all the facts had been forgotten. But intuition could also be something else. Sometimes it was the subconscious mind, establishing deep connections long before the thinking part of the brain could explain them."

"When in doubt, follow the money trail. People could lie, motives could be disguised, even acts could be misunderstood. Money was as constant as human nature."

"Hans Rebka sat on a rounded pyramid never designed for contact with the human posterior, and thought about luck. There was good luck, which mostly happened to other people. And there was bad luck, which usually happened to you. Sometimes, through observation, guile, and hard work, you could avoid bad luck—even make it look like good luck, to others. But you would know the difference, even if no one else did. Well, suppose that for a change good luck came your way. How should you greet that stranger to your house? You could argue that its arrival was inevitable, that the laws of probability insisted that good and bad must average out over long enough times and large enough samples. Then you could welcome luck in, and feel pleased that your turn had come round at last. Or you could hear what Hans Rebka was hearing: the small, still voice breathing in his ear, telling him that this good luck was an impostor, not to be trusted."

"It is not clear to me whether the insouciance of youth will be the doom of humanity or its salvation. I prefer to think the latter, but I have my doubts."

"Many plans featured that old standby, prayer. Its historical record of effectiveness apparently discouraged few people, although I, regrettably, am among the skeptics. All the churches were full. It is not clear to me exactly what prayers were being offered by their occupants. The temporary suspension, perhaps, of the laws of physics? The art galleries and theaters also reported record crowds. If religion is an opiate, art is an anodyne."

"I’d make a case for saying anything that propagates itself in an intentional way qualifies to be thought of as alive."

"The limits we assign to Nature sometimes define our own lack of imagination."

"That’s the trouble with the younger generation. They don’t understand why a thing can’t be done, so they go ahead and do it."

"If you win too easy, better ask what’s going on that you don’t know about."

"“D’you know what homeostasis is?” “I used to, before I rotted my brain with politics.”"

"And there you had it. Most people hate to learn that they are wrong. Not McAndrew. When he’s proved wrong, he’s ecstatic. It means he’s learned something new, and that’s his main reason for existence."

"I think my inner voices are pretty good when it comes to warning of trouble. The problem is, I don’t always listen to them."

"Maddy was not consumed by the immediate pressures of the here and now. She had been provided with a fatal indulgence: time to think."

"The laws of probability not only permit coincidences; they absolutely insist on them."

"It’s no surprise that there are people like Anna Griss in the world. There always have been. Go back fifty thousand years, to a time when most of us were just grubbing along, looking for a decent bush of ripe berries or a fresher lump of meat. A few, like McAndrew, were busy inventing language or numbers, or painting the walls of the cave. And some, just a handful but too many in every generation, were seeking an edge over the rest of us: Water access, or mating rules, or restricted entry to heaven. No matter how few they were, Anna Griss would have been one of them."

"“I wonder why somebody would go to all that trouble to make a complete fool of himself.” “Come on, Gina, we both know why.” “Oh, I guess you’re right. Money will always do it.” Of course."

"“It doesn’t make sense,” he said huskily. “Nothing ever does before you understand it, and then it seems obvious.”"

"If I’ve learned one thing wandering around inside and outside the Solar System, it’s this: Nature has more ways of killing you than you can imagine. When you think you’ve learned them all, another one pops up to teach you humility—if you’re lucky. If not, someone else will have to decide what did you in."

"One thing you have to teach the young is that it’s wrong to run away from problems."

"It is remarkable that observation of the faint agglomerations of stars known as galaxies leads us, very directly and cleanly, to the conclusion that we live in a Universe of finite and determinable age. A century ago, no one could have offered even an approximate age for the Universe. For an upper bound, most nonreligious scientists would probably have said “forever.” For a lower bound, all they had was the age of the Earth."

"The Asteroid Belt contains everything from substantial bodies like Ceres, seven hundred and fifty kilometers across, all the way down to house-sized boulders, pebbles, and grains of sand. One good rule of thumb is that for every object of a given size, there will be ten times as many one-third that size."

"Like many things in life, the problem I had been so sure I could solve proved more difficult than it sounded."

"Maddy listened closely to John’s voice. It was calm, but with an odd undercurrent of excitement. She thought, That weirdo, he’s enjoying this. If I were a failing component, I’d get more of his attention than I do now. Engineers!"

"Some of the Argos Group records are awful strange. If I had to guess, I’d say there’s fiddlin’ going on that don’t sound like violins."

"But no one, no matter how intelligent, could make good inferences from bad data."

"The first ten-thousandth of a second after the Big Bang is far more interesting that the entire rest of the history of the universe."

"Engineers are dangerous because they’re obsessed by facts and you can’t divert them or buy them off."

"The mills of bureaucracy may or may not grind fine, but they certainly grind exceeding slow."

"You just can’t tell. Brains won’t correlate with appearance."

"It’s the usual sensation mongering; the news services will say anything for an effect."

"Other people’s jobs always seemed easier than yours until you actually had to do them."

"You went through life in public office, laying claim to high morality when you knew quite well that at heart you were totally immoral. You were well acquainted with the majority of the seven deadly sins. Certainly pride, anger, and greed had their place in your life. You could claim a lifelong familiarity with and affection for lust. And then, at an age when a man ought know himself, you discovered that your immorality had its limits."

"The more foolproof you think something is, the worse the failure when it happens."

"They saw every event through the distorting lens of their own paranoia."

"“Captain Roker, I don’t like your insinuation,” he said. “McAndrew is a physicist—so am I. You may not be smart enough to realize it, but physics is a field of study, not a surgical operation. Castration isn’t part of the Ph.D. Exams, you know.”"

"An old axiom: when you are totally confused, don’t make things worse by talking."

"As usual he looked tired, but that was normal. Geniuses worked harder than anyone else, not less hard."

"Nothing was more fascinating than information. It was infinite in quantity, or effectively so, limited only by the total entropy of the universe; it was vastly diverse and various; it was eternal; It was available for collection, anywhere and anytime. And, perhaps best of all, E. C. Tally thought with the largest amount of self-satisfaction that his circuits permitted, you never knew when it might come in useful."

"The possible future is not just longer than the past. It is unimaginably longer."

"Once you were committed to a course of action, you didn’t waste your time looking back and second-guessing the decision, because every action in life was taken on the basis of incomplete information. You looked at what you had, and you did all you could to improve the odds; but at some point you had to roll the dice—and live or die with whatever you had thrown."

"Humans were inexplicable only if you assumed that they were logical."

"“Any great thoughts?”… “The younger generation are clearly unfitted to run the world, but one day they are going to do it anyway.”"

"I sometimes think that the only thing in life that I find truly irresistible is the challenge to finagle something that everyone else says can’t be done."

"Unfair to other students? Probably. I was not going to worry about that. Show me a totally impartial teacher, and I’ll show you a robot."

"But maybe we wrongly define the higher human functions. How we think and feel about everything except questions of pure logic is decided maybe five percent in our brains, ninety-five percent in our glands. And how many events in human history have been the result of logical thought? Just try to name one."

"The first space colonies had been conceived as utopias, planned by Earth idealists who wouldn’t learn from history. New frontiers may attract visionaries, but more than that they attract oddities. Anyone who is more than three sigma away from the norm, in any direction, seems to finish out there on the frontier. No surprise in that. If a person can’t fit, for whatever reason, he’ll move away from the main group of humanity. They’ll push him, and he’ll want to go."

"Old habits did not just die hard. They refused to die at all."

"The answers come pat and fast. You see, what the downsiders want isn’t an explanation; it’s a catchphrase they can use instead of an explanation."

"The bad thing about being a world-class worrier was that being right was worse than being wrong."

"Humans harnessed a negligible fraction of tidal energy, although the available energy is huge. Other species do rather better, and the intertidal zones are the most biologically productive regions of the world, more so than even the tropical rainforests."