"Men act like brutes in so far as the sequences of their perceptions are determined only by the principle of memory."

"The universe is a machine divinely constructed."

"Everything that is possible demands to exist."

"For I hold that it is only when we can prove everything we assert that we understand perfectly the thing under consideration."

"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."