Old people think young people haven't learned about love. Young people think old people have forgotten about love.

All normal life, Peter, consciously or otherwise, resent domination. If the domination is by an inferior, or by a supposed inferior, the resentment becomes stronger.

Why continue? Because we must. Because we have the call. Because it is nobler to fight for rationality without winning than to give up in the face of continued defeats. Because whatever true progress humanity makes is through the rationality of the occasional individual and because any one individual we may win for the cause may do more for humanity than a hundred thousand who hug their superstitions to their breast.

What lasts in the reader's mind is not the phrase but the effect the phrase created: laughter, tears, pain, joy. If the phrase is not affecting the reader, what's it doing there? Make it do its job or cut it without mercy or remorse.

If knowledge can create problems, it is not through ignorance that we can solve them.

On Earth, we are unmanned by our longing for a pastoral past that never really existed; and that, if it had existed, could never exist again...on the Moon, there is no past to long for or dream about. There is no direction but forward.

To make discoveries, you have to be curious about why the universe is the way it is.