Making a Difference: Liability and Necessity

Abstract Building on Stapleton’s analysis, this chapter aims to improve understanding of the role of necessity—of making a difference to the occurrence of an outcome—to legal liability, and the relationship of this idea to causal requirements in law. It proceeds in three sections. First, it considers the role of necessity in the current law, broadening attention beyond the traditional focus on compensation, to consider the role of necessity in relation to liability to other legal responses, such as rescission. This analysis shows the importance, in determining the relevance of necessity, of distinguishing different kinds of liability. Making a difference sometimes affects the availability of a particular form of legal liability, rather than the existence of liability. Second, it considers how, conceptually, liability without necessity should be understood, arguing that it is sometimes causal, and sometimes non-causal. Third, it examines possible justifications of liability in the absence of difference-making. In light of this discussion, it identifies various respects in which the current law needs modification.