"The light of natural reason is not less certain than that of revelation."

"I desire to live, and to continue the studies I have begun, but I have not found anyone who could tell me where to go."

"I confess that I have never found in my experience that anything which I once clearly understood could afterwards be called into doubt by me."

"I know that I exist, but I do not know what I am."

"The greatest good is to live without pain."