In his epoch-making study, Bertrand Russell criticized Leibniz’s ethics as “a mass of inconsistencies.” Leibniz formally emphasizes human responsibility for his/her wrong actions, and affirms the possibility of following reason in spite of the attraction of sensible pleasure. Nevertheless, Russell insisted that Leibniz’s hidden philosophy, which he really held, necessarily concludes an extreme intellectualism. This position makes morality meaningless, because it holds, “all sin is due wholly to ignorance.”

This paper responds to the criticism. First, Russell ignored the fact that the primitive passive force (which is one of the essences of Monad) produces passion via corporeal representation by confused perceptions. But passion plays an important role, i.e. the cause of evil will. However rightly human understanding judges, passion intervenes between the judgment and volition. That is why we commit sins in spite of our clear understanding.

Second, even if our perception is largely confused, we can realize that to follow reason is truly good, for God is the Supreme Reason. Then, by virtue of our good will, we can improve our understanding little by little, and pursue moral good.

Accordingly, Leibniz’s true philosophy is not an extreme intellectualism which denies morality, but a moderate intellectualism which recognizes mutual influence between human understanding and will. As good or evil will takes part in human action, those who will are responsible for it.