The nuclear arms race is like two sworn enemies standing wai... - Carl Sagan

"I consider it an extremely dangerous doctrine, because the more likely we are to assume that the solution comes from the outside, the less likely we are to solve our problems ourselves."

"You can get into a habit of thought in which you enjoy making fun of all those other people who don't see things as clearly as you do. We have to guard carefully against it."

"One glance at a book and you hear the voice of another person, perhaps someone dead for 1,000 years. To read is to voyage through time."

"The truth may be puzzling. It may take some work to grapple with. It may be counterintuitive. It may contradict deeply held prejudices. It may not be consonant with what we desperately want to be true. But our preferences do not determine what's true."

"We can judge our progress by the courage of our questions and the depth of our answers, our willingness to embrace what is true rather than what feels good."