Start Here: 5 Things You MUST Know
"But for" test: But for the defendant's act, would the harm have occurred? If no, causation exists
Foreseeability limits liability — defendants are only liable for reasonably foreseeable consequences
A foreseeable intervening act does NOT break the chain. Only an unforeseeable superseding cause does
Negligence REQUIRES actual injury or damage — you cannot sue just because someone COULD have hurt you
Vicarious liability holds one person liable for another's negligence due to their relationship (employer-employee)
1. Element 3: Proximate Cause
Proximate Cause
There must be a close enough causal connection between the defendant's breach and the plaintiff's injury. The injury cannot be too remote or unforeseeable.
Four Rules for Determining Proximate Cause
1. "But For" Rule
The most basic test. Ask: "BUT FOR the defendant's action, would the injury have occurred?" If the answer is NO (the injury would NOT have happened), then causation exists.
Example: But for the driver running the red light, the pedestrian would not have been hit. Causation established.
2. Substantial Factor Rule
Used when MULTIPLE causes contribute to an injury. Was the defendant's conduct a "substantial factor" in producing the harm? Even if other factors contributed, the defendant can be liable.
Example: Two factories both dump chemicals into a river. A downstream landowner's crops are destroyed. Each factory's dumping was a "substantial factor" in the damage — both are liable.
3. Proof of Defendant's Responsibility
The plaintiff must present proof connecting THIS specific defendant's actions to the harm. You cannot just say "someone was negligent" — you must show WHO.
4. Foreseeability Rule
The defendant is only liable for consequences that were reasonably foreseeable. If the harm was completely bizarre and unforeseeable, there is no proximate cause even if the defendant was negligent.
Example: A driver negligently rear-ends a car. The car turns out to be carrying dynamite (unknown to anyone) and explodes, damaging buildings a block away. The driver may NOT be liable for the explosion — carrying dynamite in a regular car was not foreseeable.
2. Intervening Acts & Concurrent Causation
Intervening Act
A new, independent act that occurs AFTER the defendant's negligence and contributes to the harm.
Foreseeable intervening act: Defendant STILL liable. Does NOT break the chain.
Unforeseeable "superseding cause": BREAKS the chain. Defendant NOT liable.
Concurrent Causation
When two or more causes combine at the SAME TIME to produce harm. Both parties can be held liable.
Example: Two drivers simultaneously run red lights from different directions and collide, injuring a pedestrian. Both are concurrently liable.
Real-World Scenario: Foreseeable Intervening Act
The Setup: A contractor negligently leaves a gas line exposed during construction work.
What Happens: A month later, an unrelated electrician accidentally sparks near the exposed gas line, causing an explosion.
The Result: The contractor is STILL liable. An accidental ignition of an exposed gas line is a foreseeable consequence. The electrician's spark is a foreseeable intervening act, not a superseding cause. Both the contractor AND the electrician may be liable.
3. Element 4: Actual Injury or Damage
Critical Rule
The plaintiff must have suffered REAL, measurable harm — physical injury, property damage, or financial loss. Without actual damages, there is no negligence claim, even if the defendant was careless.
NEGLIGENCE (actual harm)
A driver runs a red light and hits you, breaking your arm. You have actual damages: medical bills, lost wages, pain and suffering. You CAN sue for negligence.
NOT NEGLIGENCE (no harm)
A driver runs a red light and barely misses you. You are scared but unhurt. No actual damages, so you CANNOT sue for negligence even though the driver was careless.
Key Distinction
Unlike some intentional torts (like battery, where even offensive touching without injury counts), negligence REQUIRES actual damage. No harm, no claim.
4. Imputed Negligence
Holding one person legally responsible for the negligence of ANOTHER person, even though the first person did nothing wrong personally. The negligence is "imputed" (attributed) because of their relationship.
Imputed Contributory Negligence
The plaintiff's own claim is weakened because someone else's negligence is attributed TO the plaintiff.
Example: A passenger is injured in a crash. If the driver of THEIR car was also negligent, the driver's negligence may be imputed to the passenger, reducing their recovery.
Vicarious Liability
One person is held liable for another's negligent acts because of their relationship. Most common: employer liable for employee's negligence within the scope of employment.
Example: A delivery driver causes an accident while making deliveries. The employer is vicariously liable for the driver's negligence.
Three Key Vicarious Liability Doctrines
Negligent Entrustment
Entrusting a dangerous instrument (car, weapon, tool) to someone you know or should know is incompetent, inexperienced, or reckless. If that person causes harm, YOU are liable.
Example: Letting a friend who you know has seizures borrow your car. If they have a seizure while driving and hit someone, you are liable for negligent entrustment.
Dangerous Instrumentality Doctrine
In some states, the OWNER of a dangerous instrument (like a car) is automatically liable for injuries caused by anyone operating it with the owner's permission, regardless of whether the owner was negligent in lending it.
Negligent Supervision
Failing to properly supervise someone you have a duty to supervise (parent supervising a minor child, employer supervising an employee).
Classic Exam Scenario
The Setup: A mother gives car keys to her 15-year-old son who does not have a driver's license.
What Happens: The son drives negligently and hits a pedestrian.
The Result: The mother is liable under BOTH negligent entrustment (she gave a dangerous instrument to a known incompetent) AND negligent supervision (she failed in her parental duty). The son is also liable — minors driving are held to the adult standard of care.
Cheat Sheet
Print this page for quick referenceProximate Cause Rules
- "But for" = Would harm have occurred without defendant's act?
- Substantial factor = Used for multiple causes
- Proof of responsibility = Must identify THIS defendant
- Foreseeability = Only liable for foreseeable consequences
Causation Concepts
- Foreseeable intervening act = does NOT break the chain
- Unforeseeable superseding cause = BREAKS the chain
- Concurrent causation = multiple causes at same time, both liable
- Actual injury REQUIRED for negligence (not just "could have")
Imputed Negligence
- Imputed contributory = someone else's fault attributed to plaintiff
- Vicarious liability = employer liable for employee's acts
- Negligent entrustment = lending dangerous item to incompetent
- Negligent supervision = failing to supervise someone you must
Classic Exam Scenario
- Mother gives car keys to 15-year-old son = BOTH apply
- Negligent entrustment + negligent supervision simultaneously
- Minor driving = held to ADULT standard of care
Exam Trap Alerts
1. Foreseeable vs. Unforeseeable Intervening Acts
A foreseeable intervening act does NOT break the chain of causation — the defendant is STILL liable. Only a truly unforeseeable "superseding cause" breaks the chain. The exam tests whether you know the difference.
2. No Actual Injury = No Negligence Claim
Even if someone was careless and COULD have hurt you, if you were not actually harmed, you have no negligence claim. This differs from intentional torts like battery.
3. Negligent Entrustment vs. Negligent Supervision
These are different doctrines and can apply simultaneously. The mother/son car scenario tests BOTH. Entrustment = lending the dangerous item. Supervision = failing to supervise the person.
4. Dangerous Instrumentality Is State-Specific
The dangerous instrumentality doctrine (automatic owner liability) only applies in some states. It is different from negligent entrustment, which requires knowledge of incompetence.
5. "But For" vs. Substantial Factor
"But for" works for single-cause scenarios. When MULTIPLE causes contribute to harm, use the substantial factor rule instead. Know when to apply each test.
Quick Reference Summary
"But For" Rule
Basic causation test. Would harm have occurred without defendant's act?
Substantial Factor
For multiple causes. Was defendant's conduct a substantial factor?
Foreseeability
Defendant only liable for reasonably foreseeable consequences.
Intervening Act
Foreseeable = no break. Unforeseeable "superseding" = breaks chain.
Actual Injury
Negligence REQUIRES real harm. No damage = no claim.
Vicarious Liability
Liable for another's acts due to relationship. Employer-employee most common.
Negligent Entrustment
Lending dangerous item to someone known to be incompetent.
Negligent Supervision
Failing to supervise someone you have a duty to supervise.
Concurrent Causation
Multiple causes at same time. Both parties liable.