National Defence, Self-Defence, and the Problem of Political Aggression

This chapter explains why one familiar and otherwise plausible approach to the justification of killing in war cannot adequately ground commonsense views of permissible national defence. Reductionists believe that justified warfare reduces to an aggregation of acts that are justified under ordinary principles of interpersonal morality. The standard form of reductionism focuses on the principles governing killing in ordinary life, specifically those that justify intentional killing in self- and other-defence, and unintended but foreseen (for short, collateral) killing as a lesser evil. Justified warfare, on this view, is no more than the coextension of multiple acts justified under these two principles. Reductionism is the default philosophical approach to thinking through the ethics of killing in war. It makes perfect sense to ask what principles govern permissible killing in general, before applying them to the particular context of war.