"The mind is more easily known than the body."

"The existence of God is clearly demonstrated by the very idea of God."

"I desire to live in peace and to continue the life I have begun, adopting as my motto 'to live well, one must live concealed'."

"The nature of the mind is entirely distinct from that of the body."

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