Science is uncertain. Theories are subject to revision; observations are open to a variety of interpretations, and scientists quarrel amongst themselves. This is disillusioning for those untrained in the scientific method, who thus turn to the rigid certainty of the Bible instead. There is something comfortable about a view that allows for no deviation and that spares you the painful necessity of having to think.

If I am right, then (religious fundamentalists) will not go to Heaven, because there is no Heaven. If they are right, then they will not go to Heaven, because they are hypocrites.

A scientist is as weak and human as any man, but the pursuit of science may ennoble him even against his will.

All of a sudden, space isn't friendly. All of a sudden, it's a place where people can die. . . . Many more people are going to die. But we can't explore space if the requirement is that there be no casualties; we can't do anything if the requirement is that there be no casualties.

To succeed, planning alone is insufficient. One must improvise as well.

In life, people will take you at your own reckoning.

Having reached 451 books as of now doesn't help the situation. If I were to be dying now, I would be murmuring, "Too bad! Only four hundred fifty-one." (Those would be my next-to-last words. The last ones will be: "I love you, Janet.") [They were. -Janet.]