"I entirely abandoned the study of letters, resolving to seek no other science than that which could be found in myself, or at least in the great book of the world."

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

"The light of natural reason is sufficient to give us a clear and distinct conception of God."

"To be a good philosopher, one must be a good mathematician."

"I can easily conceive that there is nothing in the world, that there is no heaven, no earth, no minds, no bodies; is it not then likewise true that I do not exist?"