Old age is rather like another country. You will enjoy it more if you have prepared yourself before you go.

Chaos breeds geniuses. It offers a man something to be a genius about.

That's all teaching is; arranging contingencies which bring changes in behavior.

No one asks how to motivate a baby. A baby naturally explores everything it can get at, unless restraining forces have already been at work. And this tendency doesn't die out, it's wiped out.

Science, not religion, has taught me my most useful values, among them intellectual honesty. It is better to go without answers than to accept those that merely resolve puzzlement.

The problem of far greater importance remains to be solved. Rather than build a world in which we shall all live well, we must stop building one in which it will be impossible to live at all.

Better contraceptives will control population only if people will use them. A nuclear holocaust can be prevented only if the conditions under which nations make war can be changed. The environment will continue to deteriorate until pollution practices are abandoned. We need to make vast changes in human behavior.