Abstract

Those of us who are not pacifists face an obvious challenge. Common-sense morality contains a stringent constraint on intentional killing, yet war involves homicide on a grand scale. If wars are to be morally justified, it needs be shown how this conflict can be reconciled. A major fault line running throughout the contemporary just war literature divides two approaches to attempting this reconciliation. On a ‘reductivist’ view, defended most prominently by Jeff McMahan, the conflict is largely illusory, since such killing can be justified by aggregating individuals’ ordinary permissions to use force in self- and other-defence. In opposition, a rival ‘nonreductivist’ approach holds that these considerations are insufficient for the task. One prominent version of non-reductivism grounds the permission to kill in combatants’ membership in certain kinds of group or association. The key claim is that participation in certain morally important relationships can provide an independent source of permission for killing in war. This paper argues that non-reductivism should be rejected. It does so by pushing a dilemma onto non-reductivists: if they are successful in showing that the relevant relationships can generate permissions to kill in war, they must also jettison the most intuitive restrictions on conduct in war—the constraint on intentionally killing morally innocent non-combatants most saliently. Since this conclusion is unacceptable, non-reductivism should be rejected