Causation, and differences in types of causal contribution, underpin various issues in the ethics of war and defensive harming. For example, one of the key ideas about defensive harming is that of moral liability to defensive harm. A standard view of liability is that a person forfeits her right not to suffer harm if she is morally responsible for a threat of unjust harm to others. Her specific connection to the threat might matter in several ways – the degree, type, and proximity to causation might all make a difference to her liability. Some writers argue that although civilians causally contribute to threats of unjust harm in war, they do not contribute enough to render themselves liable to (lethal) attack. Others argue that making distinctively military causal contributions, such as providing weapons, makes one a candidate for liability, but contributing food or medical supplies does not. Still others argue that one’s position in the causal chain bears on one’s liability: only those who directly pose threats of unjust harm, or who are sufficiently causally proximate to them, are liable to defensive harm.
However, despite their centrality to some of the most important issues in the ethics of war and self-defence, there has been very little exploration of whether these claims withstand scrutiny from the perspective of our best accounts of causation. To cast some light on this, the Conversations on War project, which is run by the Stockholm Centre for the Ethics of War and Peace and the YTL Centre at King’s College, London, set out to explore how philosophers working on the ethics of war can draw on research in other areas of philosophy to improve our accounts of harming in war, and how research on the ethics of war might challenge or illuminate work in those other areas. In this post, we summarise our introduction to a symposium that arose from these conversations that offers a substantial critical analysis of the role of causation in contemporary work on the ethics of war and self-defence, and is an important move towards making work on just war theory and defensive harm less insular.