Not to have known - as most men have not - either the mountain or the desert is not to have known one's self. Not to have known one's self is to have known no one.

An abundance of some good things is perfectly compatible with the scarcity of others; that life is everywhere precarious, man everywhere small.

Science has always promised two things not necessarily related; an increase first in our powers, second in our happiness or wisdom, and we have come to realize that it is the first and less important of the two promises which it has kept most abundantly.

Nature takes no account of even the most reasonable of human excuses.

It is not a sentimental, but a grimly literal fact that unless we share this terrestrial globe with creatures other than ourselves, we shall not be able to live on it for long.

Cats seem to go on the principle that it never does any harm to ask for what you want.

The mind leaps, and leaps perhaps with a sort of elation, through the immensities of space, but the spirit, frightened and cold, longs to have once more above its head the inverted bowl beyond which may lie whatever paradise its desires may create.