The noble simplicity in the works of nature only too often originates in the noble shortsightedness of him who observes it.

Pain warns us not to exert our limbs to the point of breaking them. How much knowledge would we not need to recognize this by the exercise of mere reason.

We say that someone occupies an official position, whereas it is the official position that occupies him.

How might letters be most efficiently copied so that the blind might read them with their fingers?

There are very many people who read simply to prevent themselves from thinking.

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?

A clever child brought up with a foolish one can itself become foolish. Man is so perfectible and corruptible he can become a fool through good sense.