Never insult anyone by accident.

Don't explain computers to laymen. Simpler to explain sex to a virgin.

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.

Everything is theoretically impossible, until it is done.

Democracy is a poor system of government at best; the only thing that can honestly be said in its favor is that it is eight times as good as any other method the human race has ever tried.

I don't see how an article of clothing can be indecent. A person, yes.

Love is that condition in which the happiness of another person is essential to your own... Jealousy is a disease, love is a healthy condition. The immature mind often mistakes one for the other, or assumes that the greater the love, the greater the jealousy.