There are two ways of forming an opinion. One is the scientific method; the other, the scholastic. To the scientific mind, experimental proof is all-important, and theory is merely a convenience in description, to be junked when it no longer fits. To the academic mind, authority is everything, and facts are junked when they do not fit theory.

But space travel can't ease the pressure on a planet grown too crowded not even with today's ships and probably not with any future ships-because stupid people won't leave the slopes of their home volcano even when it starts to smoke and rumble. What space travel does do is drain off the best brains: those smart enough to see a catastrophe before it happens, and with the guts to pay the price-abandon home, wealth, friends, relatives, everything-and go. That's a tiny fraction of one percent. But that's enough.

Never attempt to teach a pig to sing; it wastes your time and annoys the pig.

Physicians had gone to their graves calling Pasteur a liar, a fool, or worse—without examining evidence which their “common sense” told them was impossible.

A prude is a person who thinks that his own rules of propriety are natural laws.

We each have a moral obligation to conserve and preserve beauty in this world; there is none to waste.

You do not truly own anything that you can't carry in both arms at a dead run