Case
Summers v. Tice
Answer: Summers v. Tice (Cal. 1948). The court adopted alternative liability: when multiple negligent defendants create the same risk and it is impossible to tell whose act caused the injury, the burden of causation shifts to defendants; if none disproves causation, joint and several liability can follow. ([law.cornell.edu](https://www.law.cornell.edu/wex/doctrine_of_alternative_liability))
Rule to remember
Alternative liability (from Summers v. Tice, 33 Cal.2d 80 (1948)) is a burden-shifting causation doctrine: where multiple negligent defendants create the same risk and the actual shooter cannot be identified, the burden moves to defendants to disprove causation; failure to do so can yield joint and several liability. ([law.cornell.edu](https://www.law.cornell.edu/wex/doctrine_of_alternative_liability))
Key elements and checks
- Multiple defendants acted negligently toward the plaintiff.
- Plaintiff suffered a single, indivisible harm caused by one of them, but the responsible actor is uncertain.
- The burden shifts to each defendant to prove he did not cause the harm or to apportion it among themselves.
- Absent exoneration, defendants may be jointly and severally liable for the entire injury.
- Not applicable if defendants acted in concert; no agreement is required.
In the source’s words
“This doctrine shifts the burden of proof to the defendants, requiring them to prove that they were not the cause of the plaintiff’s injuries.”
doctrine of alternative liability | Wex | US Law | LII / Legal Information Institute
“each party is independently liable for the full extent of the injuries stemming from the tortious act.”
joint and several liability | Wex | US Law | LII / Legal Information Institute
Meaningful state variation: jurisdictions differ on joint-and-several versus several-only systems, some adopting thresholds or mixed approaches that affect collection even when burden-shifting applies. Always check local law. ([law.cornell.edu](https://www.law.cornell.edu/wex/several_liability))