I have yet to see any problem, however complicated, which, when you looked at it in the right way, did not become still more complicated.

My knowledge of the human psyche is as yet imperfect. Certain areas won't yield to computation.

A fanatic's willingness to kill or be killed in the service of a cause cannot prove the rightness of that cause.

In my considered opinion, the profit to be made by permanent settlement in space is nothing less than the survival of industrial civilization, and therefore the survival of nearly the entire human race, along with such amenities as peace, freedom, enough to eat, and the chance to reach a high age in good health.

Heaven is not as narrowly literal-minded as hell.

Colonization means potential immortality for the human genus. Man's safety on Earth was never great, and it dwindles hourly. Disarmament, even world government, will not guarantee survival in an age when population presses natural resources to the limit and when the knowledge of how to work mischief on a planetary scale is ever more widely diffused among peoples who may grow ever more desperate.

The single definition of government I've ever seen that makes sense is that it's the organization which claims the right to kill people who won't do what it wants.