## Facts

- Charles A. Summers went quail hunting with Harold W. Tice and Ernest Simonson on open range; each defendant carried a 12-gauge shotgun loaded with birdshot.
- Before hunting, Summers discussed safe procedure and instructed defendants to exercise care and keep in line.
- During the hunt, Summers walked ahead and uphill, forming a triangle with defendants; defendants’ view of Summers was unobstructed and they knew his location.
- A quail flushed and flew between Summers and the defendants; both defendants fired toward the bird and thus in Summers’s direction from about 75 yards away.
- Birdshot struck Summers in the right eye and upper lip, causing serious injury; it could not be determined whether the injuring pellets came from one gun or both.
- The trial court found both defendants negligent, found Summers not contributorily negligent, and concluded the injury directly resulted from defendants’ shooting.

## Issues

1. When two defendants are both negligent and the plaintiff proves the injury was caused by the negligence of one of them, but cannot prove which one, does the burden shift to defendants to disprove causation?
2. If neither defendant can exculpate himself, may each be held liable for the entire, indivisible injury despite lack of proof of concerted action?

## Decision

- The California Supreme Court affirmed judgment for Summers against both defendants.
- The court upheld the finding that each defendant acted negligently by shooting toward a known, visible hunting companion.
- The court held that once plaintiff proves each defendant’s negligence and that the injury resulted from the conduct of one of them, the burden shifts to each defendant to prove his conduct did not cause the injury.
- Because neither defendant could show he did not cause the harm, each could be held liable for the whole injury.

## Legal Principles

- Where multiple defendants act negligently toward a plaintiff and it is certain the plaintiff’s injury was caused by one of them, but identification of the actual cause is impossible for plaintiff, the burden of proof on causation shifts to defendants (alternative liability).
- Absent proof by a defendant that his negligence was not a cause, each negligent defendant may be held liable for the entire, indivisible injury.
- Lack of concerted action does not bar liability when defendants’ concurrent negligence creates a single harm and their conduct creates the causal uncertainty.
- Defendants bear the risk of evidentiary uncertainty on causation when their wrongful conduct makes precise attribution impracticable.

## Conclusion

The court imposed liability on both negligent hunters because their concurrent wrongful conduct created an indivisible injury and made it impossible for the innocent plaintiff to identify the shooter; fairness required shifting the causation burden to defendants, and failure to exculpate resulted in each being liable for the full damage.


Summers v. Tice, 33 Cal. 2d 80, 199 P.2d 1 (Cal. 1948)