Delusions are often functional. A mother's opinions about her children's beauty, intelligence, goodness, et cetera ad nauseam, keep her from drowning them at birth.

Men are more sentimental than women. It blurs their thinking.

The mind's ability to rationalize it's own shortcomings is unlimited; I am no exception.

Theology is never any help; it is searching in a dark cellar at midnight for a black cat that isn't there. Theologians can persuade themselves of anything.

To stay young requires unceasing cultivation of the ability to unlearn old falsehoods.

Never appeal to a man's 'better nature.' He may not have one. Invoking his self-interest gives you more leverage.

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.