"I desire to live in such a way that I can spend the rest of my life without having committed any fault."

"I am accustomed to take my sleep for granted, and I often imagine that I dream of the most important things, when after all I am only dreaming."

"The whole of philosophy is like a tree, whose roots are metaphysics, whose trunk is physics, and whose branches are all the other sciences."

"The greatest good for each of us is to live freely and happily."

"I would not advise anyone to read my books who has not the leisure and inclination to meditate seriously with me."