"I hope that posterity will judge me kindly, not only as to the things which I have explained, but also as to those which I have intentionally omitted so as to leave to others the pleasure of discovery…"

"The will is by its nature so free that it can never be constrained."

"The existence of God is as evident as that of a triangle."

"I think, therefore I am — this is the first and most certain conclusion that anyone who philosophizes in order should arrive at."

"I know that I am a thinking thing, and that I have an idea of God."