Summers v. Tice, 33 Cal. 3d 80 (1948) (en banc) is the first case in which a court upheld causation burden-shifting under the novel tort law theory of alternative liability. The case is the forerunner of other burden-shifting theories, such as market share liability, and spawned the development of modern product liability litigation.
Under Summers v. Tice, if an injured person cannot prove which of two negligent defendants was the actual cause of their injuries but can show that a third person could not have caused their injuries, the burden of proof shifts to the defendants.
On November 20, 1945, Charles A. Summers went quail hunting with Harold W. Tice and Ernest Simonson. Summers told them to "keep in line" and take care when shooting. Tice and Simonson were each armed with 12-gauge shotguns with shells containing 7½ size bird shot.
While hunting, Summers walked up a hill ahead of the others, creating a triangle formation amongst the hunters. Both Tice and Simonson had a clear view of Summers and knew where he was.
Tice flushed a quail, which flew up about four feet above Summers' head. Tice and Simonson shot at the quail in the plaintiff's direction at about the same time. Summers was hit twice: once in the right eye and once in his upper lip.
Summers sued Tice and Simonson in separate cases for his injuries as a result of their negligence. In each case, the trial court ruled in Summers' favor. The defendants appealed. The Second District Court of Appeal in Los Angeles affirmed. The defendants appealed to the California Supreme Court, which consolidated the appeals.
Supreme Court of California
In his appeal, Appellant Simonson argued that there was insufficient evidence of negligence and that he was not a joint tortfeasor because he was not acting in concert with Tice. Appellant Tice didn't dispute negligence in his case but argued that the defendants were not joint tortfeasors.
In other words, each defendant argued that plaintiff Summers (called the "respondent" on appeal) had failed to prove which of his hunting companions was the cause-in-fact of the plaintiff's injuries.
In an opinion authored by Justice Carter, the unanimous court sitting en banc rejected the defendants' arguments. First, Justice Carter summarily disposed of Simonson's negligence argument. He wrote that there was ample evidence that pointing a gun toward someone and pulling the trigger does not meet the standard of ordinary prudence.
The court then turned to the question of causation. Each of the defendants shot in the plaintiff's direction. Each defendant was negligent, but only one of them could have shot the plaintiff's eye. Relying on several authorities, including the Restatement of Torts, the court decided that the burden of proving cause-in-fact shifts to the defendants in such a case.
The defendants, who are typically in a better position than the plaintiff to know whether they were the cause of an injury, are then required to exonerate themselves. The court reasoned that as a matter of law and good public policy, it was better for tortfeasors to bear the burden of a loss than an innocent plaintiff.
Rule of Law
If a plaintiff cannot show which of two negligent wrongdoers is the cause-in-fact of an injury, the burden of proof shifts to the defendants to prove that they were not.