It is generally agreed that using lethal or otherwise serious force in self-defense is justified only when three conditions are satisfied: first, there are some grounds for the defender to give priority to his own interests over those of the attacker (whether because the attacker has lost the protection of his right to life, for example, or because of the defender’s prerogative to prefer himself to others); second, the harm used is proportionate to the threat thereby averted; third, the harm is necessary to avert that threat. The first and second conditions have been exhaustively discussed, but the third has been oddly neglected. Meanwhile a prominent school of thought has arisen, in the ethics of war, which seeks to ground the justification of killing in war in principles of individual self-defense. They too have failed to offer any substantive analysis of necessity, while at the same time appealing to it when it suits them to do so. In this paper, I attempt a detailed analysis of the necessity constraint on defensive force, and explore the implications of that analysis for the attempt to transpose principles of individual self-defense into the context of warfare.

Killing civilians is worse than killing soldiers. Although this principle is widely affirmed, recent military practice and contemporary just war theory have undermined it. This article argues that killing an innocent person is worse the likelier it was, when you acted, that he would be innocent: riskier killings are worse than less risky killings. In war, killing innocent civilians is almost always riskier than killing innocent soldiers. So killing innocent civilians is worse than killing innocent soldiers. Since almost all civilians are innocent in war, and since killing innocent civilians is worse than killing liable soldiers, killing civilians is worse than killing soldiers.

Killing civilians is worse than killing soldiers. If any moral principle commands near universal assent, this one does. Few moral principles have been more widely and more viscerally affirmed. And yet, in recent years it has faced a rising tide of dissent. Political and military leaders seeking to slip the constraints of the laws of war have cavilled and qualified. Their complaints have been unwittingly aided by philosophers who, rebuilding just war theory from its foundations, have concluded that this principle is at best a useful fiction. Sparing Civilians aims to turn this tide, and to vindicate international law, and the ruptured consensus. In doing so, Seth Lazar develops new insights into the morality of harm, relevant to everyone interested in normative and applied ethics.

How should deontologists concerned with the ethics of killing apply their moral theory when we don’t know all the facts relevant to the permissibility of our action? Though the stakes couldn’t be higher, and uncertainty is endemic where killing is concerned, few deontologists have an answer to this question. In this paper I canvass two possibilities: that we should apply a threshold standard, equivalent to the ‘beyond a reasonable doubt’ standard applied for criminal punishment; and that we should fit our deontological ethical theory into the apparatus of decision theory. I show that the first approach faces insurmountable obstacles, while the second holds much more promise for deontologists than they might first have assumed.

Deontologists have long been upbraided for lacking an account of justified decision- making under risk and uncertainty. One response is to develop a deontological decision theory—a set of necessary and sufficient conditions for an act’s being permissible given an agent’s imperfect information. In this article, I show that deontologists can make more use of regular decision theory than some might have thought, but that we must adapt decision theory to accommodate agent- centered options—permissions to favor or sacrifice our own interests, when doing so is overall morally worse. Accommodating options requires more than just amend- ing the decision-theoretic ‘value function’. We must change the decision rule as well.

Many of us believe (1) Saving a life is more important than averting any number of headaches. But what about risky cases? Surely: (2) In a single choice, if the risk of death is low enough, and the number of headaches at stake high enough, one should avert the headaches rather than avert the risk of death. And yet, if we will face enough iterations of cases like that in (2), in the long run some of those small risks of serious harms will surely eventuate. And yet: (3) Isn't it still permissible for us to run these repeated risks, despite that knowledge? After all, if it were not, then many of the risky activities that we standardly think permissible would in fact be impermissible. Nobody has yet offered a principle that can accommodate all of 1-3. In this paper, I show that we can accommodate all of these judgements, by taking into account both ex ante and ex post perspectives. In doing so, I clear aside an important obstacle to a viable deontological decision theory.