Abstract

Most common law jurisdictions require mistakes about self-defence to be reasonable. But there is a lively debate about whether reasonably mistaken self-defence should be regarded as excused or justified. On one view, reasonably mistaken self-defence is not justified but excused because the conduct is, all things considered, wrongful; on another view, reasonably mistaken self-defence is justified because the reasonable appearance of an attack gives one a right to respond. This paper argues in favour of the second view. When viewed through the lens of cases involving the defence of third parties, the first view leads to counter-intuitive results, and that the source of these results is the effort to characterize mistaken self-defence through conceptual rather than normative argument. Moreover, the second view is more compatible with both the blame-assigning and conduct-guiding aspects of criminal law