"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."

"To be is to be a value."

"The more perfect a substance is, the more it mirrors the universe."

"Nothing is accomplished all at once, and it is one of my great maxims, and one of the most completely verified, that Nature makes no leaps: a maxim which I have called the law of continuity."

"I also take it for granted that every created thing, and consequently the created monad also, is subject to change, and indeed that this change is continual in each one."