Its very variety, subtlety, and utterly irrational, idiomatic complexity makes it possible to say things in English which simply cannot be said in any other language.
Robert A. HeinleinCourage is the complement of fear. A man who is fearless cannot be courageous. [He is also a fool.]
Robert A. HeinleinRandom chance was not a sufficient explanation of the Universe---in fact, random chance was not sufficient to explain random chance; the pot could not hold itself.
Robert A. HeinleinBut 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.
Robert A. Heinlein