“What do any of us really know about love?”

“do you really know what it means to be in love with an unsuitable woman?" "Is there any other kind?”

“I don't know if any of us really know what we are capable of until it comes to it.”

“I don't have any regrets, really, except that one. I wanted to write about you, about us, really. Do you know what I mean? I wanted to write about everything, the life we're having and the lives we might have had. I wanted to write about all the ways we might have died.”

“I love you sons of bitches. You’re all I read any more. You're the only ones who’ll talk all about the really terrific changes going on, the only ones crazy enough to know that life is a space voyage, and not a short one, either, but one that’ll last for billions of years. You’re the only ones with guts enough to really care about the future, who really notice what machines do to us, what wars do to us, what cities do to us, what big, simple ideas do to us, what tremendous misunderstanding, mistakes, accidents, catastrophes do to us. You're the only ones zany enough to agonize over time and distance without limit, over mysteries that will never die, over the fact that we are right now determining whether the space voyage for the next billion years or so is going to be Heaven or Hell.”

“You can know all there is to know about life and mankind, but what do you really know about yourself?”