The stars incline, but do not impel.

To get anywhere, or even to live a long time, a man has to guess, and guess right, over and over again, without enough data for a logical answer.

The second best thing about space travel is that the distances involved make war very difficult, usually impractical, and almost always unnecessary. This is probably a loss for most people, since war is our race's most popular diversion, one which gives purpose and color to dull and stupid lives. But it is a great boon to the intelligent man who fights only when he must-never for sport.

When one teaches, two learn.

Sense is never common.

Peace is an extension of war by political means. Plenty of elbow-room is pleasanter -- and much safer.

Whenever women have insisted on absolute equality with men, they have invariably wound up with the dirty end of the stick. What they are and what they can do makes them superior to men, and their proper tactic is to demand special privileges, all the traffic will bear. They should never settle merely for equality. For women, "equality" is a disaster.