Proximate Cause

Legal Terms Explained: Proximate Cause

Proximate cause is the legal rule that limits a negligent defendant's liability to the harms a reasonable person could have foreseen. It is not about physical closeness or timing — it is the court's way of asking, "Is this injury connected enough to the defendant's conduct that it is fair to make them pay for it?"

To see why the rule exists, you have to understand the problem it solves.

But-for cause is not enough

Causation in a negligence case has two layers. The first is cause in fact, usually tested with the "but-for" question: but for the defendant's conduct, would the injury have happened? The trouble is that but-for causation reaches absurdly far. But for your parents meeting, you would never have run that red light. But for the contractor finishing the road on schedule, the crash would not have occurred at that intersection. Almost everything is a but-for cause of almost everything that follows it.

So the law adds a second layer: proximate cause, sometimes called legal cause. Even when a defendant's carelessness is a but-for cause of an injury, they are only liable if the injury was within the foreseeable scope of the risk their conduct created. But-for causation asks what happened. Proximate cause asks what the defendant should have to answer for.

The classic illustration: Palsgraf

The most famous proximate cause case is Palsgraf v. Long Island Railroad (1928). A railroad employee, helping a passenger board a moving train, dislodged a package from the man's arms. The package — unmarked — contained fireworks, which exploded on the tracks. The blast (in the court's telling) knocked over a set of scales at the far end of the platform, injuring Mrs. Palsgraf, who was standing nowhere near the commotion.

Was the employee's carelessness a but-for cause of her injury? Plainly. But Judge Cardozo's majority held the railroad was not liable: nothing about jostling a nondescript package suggested any danger to a woman standing far down the platform. The harm was outside the orbit of foreseeable risk. Nearly a century later, courts and law school classrooms still use Palsgraf to mark the boundary of negligence liability.

Intervening and superseding causes

Proximate cause questions get hardest when something else happens between the defendant's act and the injury. An intervening cause is any event that comes after the defendant's negligence and contributes to the harm. Most intervening causes do not let the defendant off the hook — if you negligently injure someone and a doctor's ordinary malpractice makes it worse, you are typically liable for the full result, because medical complications are foreseeable.

A superseding cause is different: an intervening event so unforeseeable — a deliberate criminal attack, a freak natural disaster — that it breaks the chain of causation entirely. When that happens, the original defendant's negligence is no longer the proximate cause, and liability shifts or evaporates.

Why it matters in a real case

In practice, proximate cause is where defense lawyers fight when the negligence itself is hard to deny. They concede the client was careless but argue the particular injury was a fluke nobody could have anticipated. Plaintiffs respond by framing the risk broadly: the exact sequence of events need not be foreseeable, only the general type of harm.

That framing battle — narrow fluke versus foreseeable category — decides a surprising number of cases. It is also a jury question in most jurisdictions, which means the facts and how they are told matter as much as the doctrine. If causation is contested in your case, that is precisely the kind of fight an experienced trial attorney is built for.

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