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

"A celibate clergy is an especially good idea, because it tends to suppress any hereditary propensity toward fanaticism."

"I don't want to believe. I want to know."

"Science is based on experiment, on a willingness to challenge old dogma, on an openness to see the universe as it really is. Accordingly, science sometimes requires courage - at the very least the courage to question the conventional wisdom."

"Science is a way of thinking much more than it is a body of knowledge."

"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."