"I hold that the mark of a genuine idea is that its possibility can be proved, either a priori by conceiving its cause or reason, or a posteriori when experience teaches us that it is actual in nature."

"There is nothing waste, nothing sterile, nothing dead in the universe; no chaos, no confusions, save in appearance."

"Certainly the condition of our affairs [in Europe], slipping as we are into ever greater corruption, seems to be such that we need missionaries from the Chinese who might teach us the use and practice…"

"God has chosen the best of all possible worlds, not because it is the most perfect in every respect, but because it is the most perfect in the whole."

"The monads are the true atoms of nature, and, in a word, the elements of things."