If a dog jumps into your lap, it is because he is fond of you; but if a cat does the same thing, it is because your lap is warmer.

Everything of importance has been said before by somebody who did not discover it.

Aristotle discovered all the half-truths which were necessary to the creation of science.

When you're average, you're just as close to the bottom as you are the top.

The point about zero is that we do not need to use it in the operations of daily life. No one goes out to buy zero fish. It is in a way the most civilised of all the cardinals, and its use is only forced on us by the needs of cultivated modes of thought.

[In many circumstances,] the most important thing about a proposition is not that it be true, but that it be interesting.

No period of history has ever been great or ever can be that does not act on some sort of high, idealistic motives, and idealism in our time has been shoved aside, and we are paying the penalty for it.