“The single simplest reason why human space flight is necessary is this, stated as plainly as possible: keeping all your breeding pairs in one place is a retarded way to run a species.”

“Motivation is the fuel, necessary to keep the human engine running.”

“Maybe the theatre isn't any place for a reasonable human being after all. It keeps your emotions in such a constant state of upheaval. It's really terribly wearing. I wonder if I could stand it, one emotional upset after the other just going on and on for the rest of my life.”

“Overall, it seems now possible to draw a reasonably good explanation of why the human condition is a singularity, why the likes of it has occurred only once and took so long in coming. The reason is simply the extreme improbability of the preadaptations necessary for it to occur at all. Each of the evolutionary steps has been a full-blown adaptation in its own right. Each has required a particular sequence of one or more preadaptations that occurred previously. Homo sapiens is the only species of large mammal – thus large enough to evolve a human-sized brain – to have made every one of the required lucky turns in the evolutionary maze. (45)”

“In the best, the friendliest and simplest relations flattery or praise is necessary, just as grease is necessary to keep wheels turning. ”

“It was the kind of promise a father makes easily and sincerely, knowing at the same time that it will be impossible to keep. The truth of some promises is not as important as whether or not you can believe in them, with all your heart. A game of baseball can't really make a summer day last forever. A home run can't really heal all the broken places in our world, or in a single human heart. And there was no way that Mr. Feld could keep his promise never to leave Ethan again. All parents leave their children one day.”