Summers v. Tice
Citation: 33 Cal. 2d 80 (Cal. 1948)
Facts
Harold Summers was hunting quail with Charles Tice and Ernest Simonson. Both Tice and Simonson negligently fired their shotguns in Summers’s direction at the same time. One pellet struck Summers in the eye, another in the lip, but it was impossible to determine which defendant fired the shot that caused each injury. Both defendants were sued.
Issue
When two negligent defendants both acted to cause plaintiff’s injury but it is impossible to determine which one’s shot actually caused the harm, who bears the burden of proof on causation?
Holding
The California Supreme Court held that the burden of proof on causation shifted to each defendant to show their negligence was not the cause. Because neither could do so, both were held jointly and severally liable.
Rule
Alternative liability: where two or more defendants act negligently and it is impossible to identify which one caused the plaintiff’s harm, the burden of proof on causation shifts to the defendants. If neither can exculpate themselves, all are jointly and severally liable.
Significance
Summers v. Tice is the foundational case for alternative liability, a doctrine that prevents defendants from escaping liability simply because of evidentiary difficulty created by their own concurrent negligence. The case is a direct precursor to market share liability (Sindell) and is central to understanding how courts handle causation under uncertainty.