It is a good morning exercise for a research scientist to discard a pet hypothesis every day before breakfast. It keeps him young.

The man who views the world at 50 the same as he did at 20 has wasted 30 years of his life.

Float like a butterfly, sting like a bee.

Houston, Tranquility Base here. The eagle has landed.

Civilization is the distance man has placed between himself and his excreta.

The creator of the universe works in mysterious ways. But he uses a base ten counting system and likes round numbers.

There is a theory which states that if ever anyone discovers exactly what the Universe is for and why it is here, it will instantly disappear and be replaced by something even more bizarre and inexplicable. There is another theory which states that this has already happened.

In the beginning, the universe was created. This made a lot of people very angry, and has been widely regarded as a bad idea.

The difference between the right word and the almost right word is the difference between lightning and a lightning bug.

Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so.