The greatest productive force is human selfishness.

Teaching causes people to go into situations from which they cannot escape, except by thinking. Do not handicap children by making their lives easy.

We have our hands, we have our brains, we have the challenge all around us, and we have within (from whatever source) the will to strive. That is enough; there is no need to assert 'belief' in that which we do not, as yet, know.

Art is the process of evoking pity and terror, which is not abstract at all but very human. What the self-styled modern artists are doing is a sort of unemotional pseudointellectual masturbation . . . whereas creative art is more like intercourse, in which the artist must seduce -- render emotional -- his audience, each time.

The Stone trembled and threw herself outward bound, toward Saturn. In her train followed hundreds and thousands and hundreds of thousands of thousands of restless, rolling Stones . . . to Saturn . . . to Uranus, to Pluto . . . rolling on out to the stars . . . outward bound to the ends of the Universe.

There is no worse tyranny than to force a man to pay for what he does not want merely because you think it would be good for him.

Many short-sighted fools think that going to the Moon was just a stunt. But the astronauts knew the meaning of what they were doing, as is shown by Neil Armstrong's first words in stepping down onto the soil of Luna: "One small step for a man, one giant leap for mankind."