Habit is a second nature which prevents us from knowing the first, of which it has neither the cruelties nor the enchantments.

As long as men are free to ask what they must, free to say what they think, free to think what they will, freedom can never be lost and science can never regress.

A powerful idea communicates some of its strength to him who challenges it.

Happiness is beneficial for the body, but it is grief that develops the powers of the mind.

If a little dreaming is dangerous, the cure for it is not to dream less but to dream more, to dream all the time.