 Some more radical forms of pluralism incorporate both person-based and impersonal elements. The impersonal elements of such an approach may themselves take either an aggregative or a substitutional form. Thus: consider whether a couple ought to produce a third child, a child who would be very happy if he or she were to exist but whose coming into existence would create significant burdens for that child’s two already-existing siblings. Then, we might say that the goal of maximizing wellbeing in the aggregate provides the couple with a reason to have the third child while the person-based goal of avoiding burdens on behalf of the two siblings provides the couple with a reason not to have the third child. What the couple ought to do is then determined by how these opposing reasons balance against one another (McMahan 2006; 2009).