The appellate court recently made clear in Douglas v. Arlington Park Racecourse that the sole proximate cause of plaintiff’s injury may be something—other than the defendant—no matter what their status may be in the lawsuit and no matter how many they may number. The point is that something else was the proximate cause of plaintiff’s injury.¹

Take the law school example: plaintiff and two defendants go hunting in the woods. While aiming at their target, both defendants fire in the plaintiff’s direction, and he is unfortunately hit. The plaintiff sues both defendants, who argue at trial that he cannot prove causation because something other than their shot may have caused his injury. That is evidence of sole proximate cause.²

But what if four people are hunting? Or four hundred?

As the appellate court held, the answer is the same. “The sole proximate cause theory should be just as viable with two or more nonparty actors as it is with a single nonparty.”³ The reason is that “‘a defendant is relieved from all liability if it can show that the injury was legally caused in its entirety by other persons or entities—that is, that the sole proximate cause of the injury was elsewhere, and not in the defendant.’”⁴

In Douglas, the plaintiff, a professional jockey, fell during a horserace.⁵ His vertebrae was fractured, damaging his spinal cord and leaving him paralyzed.⁶ He sued the developer and manufacturer of the racetrack surface, the distributor that sold and installed it, and the owner and operator of the racetrack.⁷ After the manufacturer and distributor settled, the owner and operator argued at trial that they merely followed the manufacturer’s instructions, so either there was no negligence at all or the manufacturer’s instructions were at fault.⁸ They also argued that something else, another jockey, was the sole proximate cause of the plaintiff’s fall and injury.⁹

At trial, the defendants requested and obtained a jury instruction on sole proximate cause, telling the jury that “if you decide that the sole proximate cause of injury to the plaintiff was the conduct of some other person other than the defendant, then your verdict should be for the defendant.”¹⁰ The trial court also gave a special interrogatory, asking the jury whether “the conduct of some person other than the defendants the sole proximate cause of the plaintiffs’ injuries?”¹¹ Ultimately, the jury found for the defendants and answered “yes” to the special interrogatory.¹²

With his post-trial motion, the plaintiff argued the trial court had erred in giving the jury instruction and special interrogatory on sole proximate cause.¹³ The trial court agreed, vacating the jury verdict and granting plaintiff a new trial, because the defendants argued two proximate causes—the negligence of the other jockey and the manufacturer of the racetrack surface—so the defendants could not argue sole proximate cause.¹⁴

On appeal, the appellate court reinstated the defense verdict because the “sole proximate cause theory should be just as viable with two or more nonparty actors as it is with a single nonparty.”¹⁵ Indeed, as the appellate court explained, the supreme court has applied sole proximate cause where the evidence showed asbestos exposure from a dozen or more alternative sources, Nolan v. Weil-McLain, 233 Ill. 2d 416, 444 (2009), and faulty construction work by two different companies, Ready v. United/Goedecke Servs., 238 Ill. 2d 582, 591 (2010). So, it makes no difference whether something was 100 percent responsible, or whether the 100 percent was split among many other things. Nor does it “matter whether the intervening force is one act or a combination of acts, so long as it entirely breaks the causal connection between the defendant’s conduct and the plaintiff's injuries.”¹⁶

As the appellate court concluded, the sole proximate cause “argument is that none of the fault can be attributed to Defendant A, and thus the plaintiff has failed to carry its burden of proof as to Defendant A.”¹⁷ In fact, the defendant need not plead sole proximate cause as a defense because the burden of proving proximate cause remains, at all times, on the plaintiff.¹⁸ As long as a defendant points to “some evidence in the record,” the defendant may argue that evidence at trial and receive a jury instruction and special interrogatory on sole proximate cause.¹⁹

The critical point is that, like any causation question the plaintiff wants to take to the jury, the “sole proximate cause theory is simply one way a defendant argues that the plaintiff failed to carry its burden of proof on proximate cause”—specifically, by arguing that something else was the proximate cause of plaintiff’s injury.