CASUALTY TERMS & CONCEPTS · 5 MIN READ

Causation and Scope of Liability

Causation has two layers. Cause-in-fact asks whether the harm would have happened but for the defendant's conduct; when two or more forces were each sufficient to cause the harm, the substantial-factor test (and the modern multiple-sufficient-causes analysis) fills the gap so no defendant escapes because another cause was also sufficient. Scope of liability — the modern name for proximate cause — then asks whether this harm is one the law should charge to this defendant. The Restatement (Third) frames it as the risk standard: an actor is liable only for harms that result from the risks that made the conduct tortious in the first place. This descends from Palsgraf, where Cardozo limited duty to foreseeable plaintiffs in the zone of danger while Andrews would have treated proximate cause as a policy judgment about directness. Intervening events test that scope. An intervening cause that is within the original risk — including a foreseeable criminal act — does not cut off liability; only a superseding cause outside the risks created by the defendant breaks the chain. A negligently parked tanker with a defective brake that a thief later sends rolling downhill still produces liability, because a rolling tanker striking someone is exactly the risk that made the parking negligent. The eggshell-skull rule adds that once liability attaches, the defendant pays for the full extent of the harm even when a hidden preexisting condition makes the injury freakishly severe — unforeseeable extent never defeats recovery. Special doctrines solve proof problems with multiple actors. Alternative liability from Summers v. Tice shifts the burden to each of two negligent shooters to exonerate himself when only one unidentifiable shot hit the plaintiff, on pain of joint liability. Market-share liability from Sindell v. Abbott Laboratories apportions damages among manufacturers of a fungible product by their market shares when the specific maker cannot be identified. Concert of action imposes joint liability on those who act pursuant to a common design or knowingly give substantial assistance to another's tort — the drag-race doctrine. Loss-of-chance permits recovery in medical cases for the destroyed probability of a better outcome.