Nothing can contribute more to peace of soul than the lack of any opinion whatever.

A writer who wishes to be read by posterity must not be averse to putting hints which might give rise to whole books, or ideas for learned discussions, in some corner of a chapter so that one should think he can afford to throw them away by the thousand.

God: personified incomprehensibility.

We now possess four principles of morality: 1) a philosophical: do good for its own sake, out of respect for the law; 2) a religious: do good because it is God's will, out of love of God; 3) a human: do good because it will promote your happiness, out of self-love; 4) a political: do good because it will promote the welfare of the society of which you are a part, out of love of society having regard to yourself. But is this not all one single principle, only viewed from different sides?

The thoughts written on the walls of madhouses by their inmates might be worth publicizing.

The feeling of health can only be gained by sickness.

There are people who possess not so much genius as a certain talent for perceiving the desires of the century, or even of the decade, before it has done so itself.