Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying.

Science is the only religion of mankind.

The rash assertion that "God made man in His own image" is ticking like a time bomb at the foundation of many faiths.

Every revolutionary idea seems to evoke three stages of reaction. They may be summed up by the phrases: 1- It's completely impossible. 2- It's possible, but it's not worth doing. 3- I said it was a good idea all along.

It has yet to be proven that intelligence has any survival value.

There's a passage about 'rivers of molten rock that wound their way... until they cooled and lay like twisted dragon-shapes vomited from the tormented earth.' That's a perfect description: how did Tolkien know, a quarter century before anyone ever saw a picture of Io? Talk about Nature imitating Art.

There is a special sadness in achievement, in the knowledge that a long-desired goal has been attained at last, and that life must now be shaped toward new ends.