"The body is a machine."

"Divide each difficulty into as many parts as is feasible and necessary to resolve it."

"To conquer myself rather than fortune, and to change my desires rather than the order of the world."

"I think, therefore I am, is the first and most certain truth that occurs to anyone who philosophizes in an orderly way."

"It is precisely because I am in the habit of using my senses to think of things that I find it difficult to think of anything else."