"The whole of philosophy is like a tree, whose roots are metaphysics, whose trunk is physics, and whose branches are all the other sciences."

"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."

"The power of judging well and of distinguishing the true from the false, which is properly what is called good sense or reason, is by nature equal in all men."

"It is not enough to know, one must also apply; it is not enough to wish, one must also do."

"I have been nourished by books, and I have found in them a great deal of good as well as a great deal of evil."