"I am convinced that the unwritten knowledge scattered among men of different callings surpasses in quantity and in importance anything we find in books, and that the greater part of our wealth has yet…"

"The world is not a heap of atoms, but a system of monads."

"I have said more than once that I would give all my books to have the fame of having discovered a single useful truth for the good of mankind."

"There is nothing without a reason."

"The doctrine that the world is governed by perfection was introduced to exclude the arbitrary will of God."