There are naive questions, tedious questions, ill-phrased questions, questions put after inadequate self-criticism. But every question is a cry to understand the world. There is no such thing as a dumb question.

Valid criticism does you a favor.

Some racists still reject the plain testimony written in the DNA that all the races are not only human but nearly indistinguishable. . . .

In a lot of scientists, the ratio of wonder to skepticism declines in time. That may be connected with the fact that in some fields-mathematics, physics, some others-the great discoveries are almost entirely made by youngsters.

If intelligence is our only edge, we must learn to use it better, to shape it, to understand its limitations and deficiencies -- to use it as cats use stealth, as katydids use camouflage -- to make it the tool of our survival.

Present global culture is a kind of arrogant newcomer. It arrives on the planetary stage following four and a half billion years of other acts, and after looking about for a few thousand years declares itself in possession of eternal truths. But in a world that is changing as fast as ours, this is a prescription for disaster. No nation, no religion, no economic system, no body of knowledge, is likely to have all the answers for our survival. There must be many social systems that would work far better than any now in existence. In the scientific tradition, our task is to find them.

A celibate clergy is an especially good idea, because it tends to suppress any hereditary propensity toward fanaticism.