Black-letter propositions
- 01
But-for cause asks whether harm would have occurred absent the breach.
- 02
When multiple forces are independently sufficient at the same time, each can be treated as factual cause.
- 03
Alternative liability can shift proof when all defendants were negligent and one caused harm.
- 04
Loss-of-chance doctrine in some medical cases permits recovery for reduced survival probability under specified rules.
- 05
Toxic and probabilistic injuries require reliable general and specific causation evidence.
Use this attack sequence under time
Frame the issue
Identify exact injury and counterfactual.
Resolve the next checkpoint
Test but-for cause.
Resolve the next checkpoint
If overdetermined, use multiple-sufficient-cause analysis.
Resolve the next checkpoint
Consider burden-shifting doctrines.
Finish the conclusion
Keep actual and proximate cause separate.
Common wrong turns
- Substantial factor is not a free-floating substitute whenever but-for proof is hard.
- Increasing risk does not always establish factual cause.
- Alternative liability requires all likely tortfeasors before the court under traditional doctrine.
Worked example
Two negligently set fires merge, and either alone would have destroyed the house at the same time.
Each fire is a multiple sufficient cause despite failure of literal but-for logic, so both actors can be factually responsible.
Practice this topic
Cause in fact and its companions
Cornell lists cause in fact as one of the elements typically required for negligence, separate from proximate cause. It states that the defendant's actions must be the actual cause of the harm to the plaintiff. With more than one negligent defendant, joint and several liability makes each independently liable for the full injury, which Cornell says arises often in toxic tort claims such as asbestos-related mesothelioma where the injury is indivisible.
After paying, a jointly liable defendant may bring an action for contribution against co-defendants, who pay in proportion to their blame.
Applying the tests
Cornell's example of contribution has A found 10 percent responsible and B 90 percent for a $100,000 judgment. V may collect the full amount from A, and A may then demand $90,000 from B. That shows why apportionment of responsibility among multiple tortfeasors matters even after a plaintiff wins.
Cornell's negligence summary treats cause in fact and proximate cause as two elements, so establish actual causation first and address foreseeability afterward.
The negligence summary lists cause in fact as its own element and describes proximate cause as requiring that the breach be the actual cause of the harm. When facts include several possible sources of the injury, work through them one at a time, identify which the plaintiff can tie to the defendant, and then turn to apportionment and contribution among those who share responsibility.
Frequently asked questions
What is the controlling rule for actual cause, multiple causes, and loss of chance?+
Actual causation normally uses but-for analysis but adapts for multiple sufficient causes and narrowly defined uncertainty doctrines.
How should I analyze actual cause, multiple causes, and loss of chance on the bar exam?+
Identify exact injury and counterfactual. Test but-for cause. If overdetermined, use multiple-sufficient-cause analysis. Consider burden-shifting doctrines. Keep actual and proximate cause separate.
Is cause in fact a separate element of negligence?+
Yes. Cornell lists both cause in fact and proximate cause among the five elements that may typically be required.
Why does joint and several liability matter for multiple causes?+
Each liable party is independently liable for the full extent of the injuries, and the plaintiff may collect from any one, according to Cornell.
What is contribution on the bar exam?+
An action by a defendant who paid more than its share to recover from co-defendants in proportion to their blame, per Cornell's summary.
How does Cornell illustrate contribution?+
A and B are found 10 and 90 percent responsible for a $100,000 judgment, V collects all from A, and A recovers $90,000 from B.
Where does joint and several liability often arise?+
In toxic tort claims such as asbestos-related mesothelioma, where the injury is indivisible, according to Cornell.