Riches ennoble a man's circumstances, but not himself.

The science of mathematics presents the most brilliant example of how pure reason may successfully enlarge its domain without the aid of experience

cruelty to animals is contrary to man's duty to himself, because it deadens in him the feeling of sympathy for their sufferings, and thus a natural tendency that is very useful to morality in relation to other human beings is weakened.

There is a limit where the intellect fails and breaks down, and this limit is where the questions concerning God and freewill and immortality arise.

What can I know? What ought I to do? What may I hope?

Feminine traits are called weaknesses. People joke about them; fools ridicule them; but reasonable persons see very well that those traits are just the tools for the management of men, and for the use of men for female designs.

One who makes himself a worm cannot complain afterwards if people step on him.