The point about zero is that we do not need to use it in the operation of daily life. No one goes out to buy zero fish.

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.

Inventive genius requires pleasurable mental activity as a condition for its vigorous exercise

You cannot be wise without some basis of knowledge, but you may easily acquire knowledge and remain bare of wisdom.

I am sure that one secret of a successful teacher is that he has formulated quite clearly in his mind what the pupil has got to know in precise fashion. He will then cease from half-hearted attempts to worry his pupils with memorizing a lot of irrelevant stuff of inferior importance.

The difference between ancients and moderns is that the ancients asked what have we experienced, and moderns asked what can we experience.

Philosophy begins in wonder. And, at the end, when philosophic thought has done its best, the wonder remains.