Proximate Cause Untangled

Mark A. Geistfeld

The many facets of tort liability are filtered through the requirement of proximate cause, which has made the element confusing and the source of considerable controversy. Is proximate cause properly determined by the directness test or the foreseeability test, each of which has been both widely adopted and roundly criticized? Is there any defensible conception of a direct cause? Is foreseeability an adequately determinate method for limiting liability? If so, is foreseeability relevant to duty, to proximate cause, or to both elements? Disagreement about all these matters stems from the failure to fully untangle the role of proximate cause across all elements of the tort claim.

In a negligence case, for example, duty determines the risks that factor into the duty to exercise reasonable care. This property implies that the duty must be limited to the risks of foreseeable harm in order for the standard of reasonable care to govern only those harms. Foreseeability for this purpose is defined by the general zones of danger or reference classes that the reasonable person would consider when estimating the likelihood of accidental harm, reducing foreseeability to a behavioral concept that is adequately determinate for resolving the issue of breach. The element of proximate cause then provides a case-specific requirement that the plaintiff’s injury must be within a general category of foreseeable harms encompassed by both the tort duty and its breach—a necessary predicate for liability. The prima facie case accordingly requires the foreseeability test to establish proximate cause for the breach of a duty that is limited to the risks of foreseeable harm.

Once liability has been established, the damages phase of the case requires a further inquiry to fix the full extent of compensable harm proximately caused by the tortious conduct. The foreseeability test produces inequities in the determination of damages that the directness test fairly resolves. This inquiry is structured by the uniformly adopted rule that permits full recovery for an unforeseeably large harm, such as a crushed skull, that was directly caused by a tortious force that would normally cause minor injury, such as a bump on the head. This rationale also explains why the intentional torts exclusively rely on the directness test, eliminating culpability as a confounding factor in the analysis of proximate cause. Instead of being competing formulations, the directness and foreseeability tests each address different components of a tort claim, explaining why each one is both widely adopted and yet roundly criticized when employed as the only method for determining proximate cause.