Causation and liability to defensive harm

First published online: 13 June 2019An influential view in the ethics of self‐defence is that causal responsibility for an unjust threat is a necessary requirement for liability to defensive harm. In this article, I argue against this view by providing intuitive counterexamples and by revealing weaknesses in the arguments offered in its favour. In response, adherents of the causal view have advanced the idea that although causally inefficacious agents are not liable to defensive harm, the fact that they may deserve harm can justify harming them in the course of defending oneself. I argue that this strategy is ad hoc and leads to more problems than it solves. Once we allow normative facts outside our account of liability to affect a person's moral protection against harm, the lieability verdicts cannot tell us whether there is a relevant moral asymmetry between the victim and the target of defence. In conclusion, the causal view is wrong and causal responsibility for an unjust threat is not a necessary requirement for liability to defensive harm.The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement No 340956 - IOW - The Individualisation of War: Reconfiguring the Ethics, Law, and Politics of Armed Conflict