"The body is a machine."

"It is a mark of a truly great mind to be able to make a great discovery with few means."

"I found it possible to reject all my former beliefs, and to admit nothing as true that I had not clearly conceived."

"I am accustomed to sleep, and in my dreams to imagine the same things that lunatics do when awake."

"I always wanted to learn to distinguish the true from the false, in order to see clearly in my actions and to walk with confidence in this life."