"He hoped and prayed that there wasn't an afterlife. Then he realized there was a contradiction involved here and merely hoped that there wasn't an afterlife. "
"The ships hung in the sky in much the same way that bricks don't."
"Time, we know, is relative. You can travel light years through the stars and back, and if you do it at the speed of light then, when you return, you may have aged mere seconds while your twin brother or sister will have aged twenty, thirty, forty or however many years it is, depending on how far you traveled. This will come to you as a profound shock, particularly if you didn't know you had a twin brother or sister."
"[His] study was a total mess, like the results of an explosion in a public library."
"There is a theory which states that if anyone discovers exactly what the Universe if for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another which states that this has already happened."
"A common mistake people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools."
"For a moment, nothing happened. Then, after a second or so, nothing continued to happen."
"Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so."
"I don't believe it. Prove it to me and I still won't believe it."
"If human beings don't keep exercising their lips, he thought, their mouths probably seize up. After a few months' consideration and observation he abandoned this theory in favor of a new one. If they don't keep on exercising their lips, he thought, their brains start working."
"Time is an illusion. Lunchtime doubly so."
"You live and learn. At any rate, you live."
"The History of every major Galactic Civilization tends to pass through three distinct and recognizable phases, those of Survival, Inquiry and Sophistication, otherwise known as the How, Why and Where phases. For instance, the first phase is characterized by the question, 'How can we eat?' The second by the question, 'Why do we eat?' And the third by the question, 'Where shall we do lunch?'"