Abstract

This article concerns the problem of factual uncertainty in negligence law. We argue that negligence law’s insistence that fair terms of interaction be maintained between individuals—a requirement that typically manifests itself in the need for the plaintiff to prove factual or “but-for” causation—sometimes allows for the imposition of liability in the absence of such proof. In particular, we argue that the but-for requirement can be abandoned in certain situations where multiple defendants have imposed the same unreasonable risk on a plaintiff, where the plaintiff suffers the very sort of harm that rendered the risk unreasonable, and where the plaintiff cannot prove which of the defendants was the but-for cause of her loss. This approach provides one way to understand the Supreme Court of Canada’s recent decision in Resurfice Corp. v. Hanke. We find support for our approach in various concepts that underlie negligence liability quite generally. These underlying concepts are normative in nature, and manifest core notions of justice and fairness. We argue that approaches to the problem of factual uncertainty that appeal to such normative principles to make sense of atypical cases of causation are in no way inconsistent with the nature and structure of negligence law. Rather, the opposite is true: in taking negligence law seriously as law, such approaches are instead reflective and supportive of it.