“Have you noticed how often it happens that a really good idea -- the kind of idea that looks, as it approaches, like the explanation for everything about everything -- tends to hover near at hand when you are thinking hard about something quite different? There you are, halfway into a taxi, thinking about the condition of the cartilage in the right knee joint, and suddenly, with a whirring sound, in flies a new notion looking for a place to light. You'd better be sure you have a few bare spots, denuded of anything like thought, ready for its perching, or it will fly away into the dark.”

“Everything about this is embarrassing" she said. "D'you know how embarrassing it is to mention good and evil in a scientific laboratory? Have you any idea? One of the reasons I became a scientist was not to have to think about that kind of thing.”

“The idea hovered and shimmered delicately, like a soap bubble, and she dared not even look at it directly in case it burst. But she was familiar with the way of ideas, and she let it shimmer, looking away, thinking about something else.”

“You know what girls are like. They turn twenty or twenty-one and all of a sudden they start having these concrete ideas. They get super realistic. And when that happens, everything that seemed so sweet and lovable about them begins to look ordinary and depressing.”

“You sit at the board and suddenly your heart leaps. Your hand trembles to pick up the piece and move it. But what chess teaches you is that you must sit there calmly and think about whether it's really a good idea and whether there are other, better ideas.”

“He thought about his son’s stone flying across the yard, the youthful idea that you could toss away the future ifyou didn’t like it—and he realized, suddenly, what he needed to do.”