 I need the notion of perfection for dealing with morals. For, when I see that some actions tend toward our perfection and that of others, while others tend toward our imperfection and that of others, the sensation of perfection excites a certain pleasure [voluptas] and the sensation of imperfection a certain displeasure [nausea]. And the emotions [affectus], by virtue of which the mind is, in the end, inclined or disinclined, are modifications of this pleasure and displeasure; I explain the origin of natural obligation in this way… From this also comes the general rule or law of nature that our actions ought to be directed toward the highest perfection of ourselves and others. (Leibniz 1989a: 231–232)