Proximate Cause

Rule

Even where a defendant’s negligence is the actual (“but-for”) cause of plaintiff’s harm, liability may be limited by the doctrine of proximate cause. A defendant is generally liable only for harms that were the foreseeable type of consequence of the negligent act, not for remote or unforeseeable harms.

Elements

To establish proximate cause (legal cause / scope of liability):

1. Actual cause (but-for / substantial factor) — a necessary predicate, handled separately
2. Foreseeability of harm type: the type of harm that occurred was a foreseeable consequence of defendant’s negligence (Wagon Mound foreseeability test)
3. No superseding cause: no unforeseeable, independent intervening act by a third party broke the causal chain
4. Plaintiff within foreseeable scope (Cardozo/Palsgraf): plaintiff was within the zone of foreseeable danger created by defendant’s conduct

Policy

• Limits on infinite liability: a single negligent act can set off a chain of consequences indefinitely; proximate cause doctrine prevents defendants from being held liable for every remote downstream effect
• Foreseeability as organizing principle: most jurisdictions use foreseeability because it aligns liability with the reason defendant’s conduct was wrongful — imposing a standard of foreseeable risk
• Eggshell plaintiff rule as counterbalance: while proximate cause limits the type of harm, once a foreseeable type occurs, the extent of harm is not limited — defendant liable for full consequences
• Third-party crime: courts struggle with whether a defendant who creates an opportunity for a third party’s crime should bear liability; modern trend allows recovery when the very risk that made defendant negligent was the risk of criminal exploitation

Competing Approaches

1. Foreseeability Rule (dominant modern approach)

Defendant’s liability depends on the reasonable foreseeability of the type of harm that resulted. If harm of that general type was foreseeable, the exact manner and extent of harm need not have been foreseen. (Wagon Mound I)

2. Direct Causation Rule (Polemis — disfavored)

Defendant is liable for all direct consequences of the negligent act, no matter how unforeseeable. Rejected by Wagon Mound I.

3. Andrews’ Broad Duty View (Palsgraf dissent)

Duty runs to society at large; proximate cause is a matter of practical politics, not logic. Factors: natural and continuous sequence, substantial factor, directness, foreseeability, remoteness in time and space.

Eggshell Plaintiff Rule

Defendant must “take the plaintiff as he finds him.” If plaintiff has an unusual susceptibility, defendant is liable for the full extent of harm, even if far greater than what would befall a normal person. (Benn v. Thomas)

• Applies to pre-existing physical and mental conditions.
• Does not apply to suicide or independent emotional harm claims.

Superseding / Intervening Causes

An independent act of a third party (or natural force) occurring after defendant’s negligence may break the chain of causation if:

• The intervening act is unforeseeable AND
• It is the direct cause of the harm.

Rules:

• Foreseeable intervening negligence does not break the chain (Derdiarian).
• Intentional or criminal third-party act usually breaks the chain, unless that type of intentional/criminal act was the very risk that made defendant’s conduct negligent (Hoboes Hollow; Restatement 2d §442B).

Palsgraf Problem (Unexpected Victims)

• Cardozo (majority): duty is specific; owed only to foreseeable plaintiffs within the apparent zone of danger. Plaintiff not foreseeable = no duty.
• Andrews (dissent): duty owed to world at large; proximate cause (not duty) is the limiting principle.

Key Cases

• Palsgraf v. Long Island Railroad — unexpected victim; Cardozo limits duty/proximate cause to foreseeable plaintiffs.
• Wagon Mound I — oil spill causing fire; foreseeability rule replaces direct causation rule.
• Benn v. Thomas — eggshell plaintiff; defendant liable for full extent of unforeseeable heart attack triggered by minor accident.
• Derdiarian v. Felix Contracting — foreseeable type of harm; intervening negligence does not break causation.

Covered In

• Torts