History is nothing but a problem of mechanics applied to psychology.

Change a virtue in its circumstances find it becomes a vice; change a vice in its circumstances, and it becomes a virtue. Regard the same quality from two sides; on one it is a fault, on the other a merit. The essential of a man is found concealed far below these moral badges.

His tongue is by turns a sponge, a brush, a comb. He cleans himself, he smooths himself, he knows what is proper.

There are as many kinds of modesty as there are races. To the English woman it is a duty; to the French woman a propriety.

For thirty centuries, from her sacred seat the cat looked down, and crouching at her feet, beheld the race of conquering Pharaohs kneel.

The more I study the things of the mind the more mathematical I find them. In them as in mathematics it is a question of quantities; they must be treated with precision. I have never had more satisfaction than in proving this in the realms of art, politics and history.

Amid this vast and overwhelming space and in these boundless solar archipelagoes, how small is our own sphere, and the earth, what a grain of sand!