It must be admitted that there is a degree of instability which is inconsistent with civilization. But, on the whole, the great ages have been unstable ages.

We think of the number "five" as applying to appropriate groups of any entities whatsoever - to five fishes, five children, five apples, five days... We are merely thinking of those relationships between those two groups which are entirely independent of the individual essences of any of the members of either group. This is a very remarkable feat of abstraction; and it must have taken ages for the human race to rise to it

I have always noticed that deeply and truly religious persons are fond of a joke, and I am suspicious of those who aren't.

It is impossible to meditate on time and the mystery of nature without an overwhelming emotion at the limitations of human intelligence.

It is impossible not to feel stirred at the thought of the emotions of man at certain historic moments of adventure and discovery - Columbus when he first saw the Western shore, Pizarro when he stared at the Pacific Ocean, Franklin when the electric spark came from the string of his kite, Galileo when he first turned his telescope to the heavens. Such moments are also granted to students in the abstract regions of thought, and high among them must be placed the morning when Descartes lay in bed and invented the method of co-ordinate geometry.

Art flourishes where there is a sense of adventure, a sense of nothing having been done before, of complete freedom to experiment.

Nature, even in the act of satisfying anticipation, often provides a surprise.