Intervening and Superseding Causes in Tort Law

Intervening and Superseding Causes in Tort Law

A defendant’s conduct does not always lead directly to an injury.

Sometimes another event occurs in between.

For example:

Defendant’s negligence

↓

Another event

↓

Plaintiff’s injury

That second event may be called an intervening cause.

The central legal question is:

Does the intervening event relieve the original defendant of liability?

Sometimes the answer is no.

Sometimes the intervening event becomes a superseding cause, meaning that the law treats the later event as breaking the causal connection between the defendant’s conduct and the plaintiff’s injury.

This distinction is fundamental to negligence and proximate cause.

A defendant may be a factual cause of an injury without necessarily being its legal cause.

Intervening and superseding causes are among the doctrines that help courts determine where legal responsibility should end.

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What Is an Intervening Cause?

An intervening cause is an event that occurs after the defendant’s original conduct but before the plaintiff’s injury and contributes to producing the injury.

The intervening event becomes part of the causal chain.

For example:

A driver negligently causes a collision.

↓

The injured person is taken to a hospital.

↓

A medical professional provides treatment.

↓

The plaintiff suffers additional complications.

The medical treatment is an event occurring between the defendant’s negligence and the ultimate harm.

It may therefore be an intervening cause.

But that does not automatically mean the original defendant escapes liability.

An intervening cause is simply a later event in the causal sequence.

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What Is a Superseding Cause?

A superseding cause is an intervening event that is sufficiently independent, extraordinary, or unforeseeable that the law treats it as breaking the chain of legal causation.

The distinction can therefore be expressed simply:

Every superseding cause is an intervening cause, but not every intervening cause is a superseding cause.

An intervening cause becomes superseding when the legal system determines that the later event is sufficiently significant to terminate the original defendant’s responsibility.

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Intervening vs. Superseding Causes

Concept	Meaning
Intervening cause	A later event that contributes to the plaintiff’s injury
Superseding cause	An intervening event that legally breaks the causal chain
Foreseeable intervening cause	Usually does not automatically eliminate original liability
Extraordinary intervening cause	May become superseding
Proximate cause	The broader question of whether the defendant’s conduct is sufficiently connected to the injury for legal liability

This distinction is essential.

Simply identifying another cause does not answer the proximate-cause question.

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Why Does Tort Law Need This Doctrine?

Without some limitation on causation, liability could theoretically continue indefinitely.

Imagine:

A negligently creates a danger.

↓

B responds to the danger.

↓

C reacts to B.

↓

D reacts to C.

↓

E suffers a loss.

If every event remained legally attributable to A, the concept of negligence would become practically unlimited.

Tort Law therefore needs a boundary.

Intervening and superseding causes help establish that boundary.

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Factual Cause vs. Legal Cause

This distinction becomes easier when we separate factual causation from legal causation.

Factual causation asks:

Did the defendant’s conduct contribute to the injury?

Legal causation asks:

Is the defendant legally responsible for the injury?

A defendant may be a factual cause without being a legally responsible cause.

For example, suppose a defendant negligently leaves an object in the roadway.

Another person later encounters the object and, through an extraordinary independent event, causes an injury.

The defendant’s conduct may be part of the factual history.

But the court may determine that the later event was so independent and extraordinary that the original defendant should not be legally responsible for the final injury.

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The Causal Chain

A useful way to visualize the issue is:

Defendant’s conduct

↓

Initial harm or danger

↓

Intervening event

↓

Plaintiff’s injury

The court then asks:

Is the causal connection between the defendant’s conduct and the plaintiff’s injury sufficiently strong to impose legal responsibility?

Foreseeability often plays a major role in answering this question.

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Foreseeability Is Central

The most important question concerning an intervening event is often:

Was the intervening event foreseeable?

If the event was reasonably foreseeable, it generally will not automatically sever the causal chain.

If the event was highly extraordinary and unforeseeable, it may potentially constitute a superseding cause.

But foreseeability is not always a simple yes-or-no test.

Courts may also consider:

• the nature of the original risk;
• the relationship between the events;
• the independence of the intervening conduct;
• the type of harm;
• public policy;
• and applicable jurisdictional rules.

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Foreseeable Intervening Causes

A foreseeable intervening event generally does not automatically relieve the original defendant of liability.

Consider a defendant who negligently causes an automobile collision.

The plaintiff is injured and needs medical treatment.

The plaintiff goes to the hospital.

Medical treatment is a foreseeable consequence of serious physical injury.

The defendant generally cannot simply argue:

“The doctor treated the plaintiff, so the doctor’s involvement breaks causation.”

The medical treatment is part of the ordinary consequences of the accident.

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Medical Treatment as an Intervening Cause

Medical treatment is one of the classic examples.

Suppose:

Defendant negligently injures Plaintiff

↓

Plaintiff receives medical treatment

↓

Plaintiff suffers additional injury

The treatment is an intervening event.

But it may not be a superseding cause.

Ordinary medical negligence following an injury may remain sufficiently connected to the original accident.

However, extremely unusual or extraordinary medical misconduct can raise a different question.

The precise rule varies by jurisdiction.

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Ordinary Medical Negligence

Suppose a plaintiff suffers a broken leg because of a defendant’s negligence.

A doctor negligently treats the injury.

The plaintiff suffers additional complications.

The original defendant may argue:

“The doctor’s negligence caused the additional injury.”

The court may nevertheless conclude that medical treatment was a foreseeable consequence of the original injury.

The later negligence therefore may not necessarily supersede the original defendant’s conduct.

This reflects a broader principle:

A defendant may remain responsible for foreseeable consequences of the danger the defendant created.

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Extraordinary Medical Misconduct

Now change the facts.

Suppose the medical treatment involves an extraordinarily independent event that bears little relationship to the original injury.

The defendant may argue that the later event should be treated as superseding.

Courts can disagree about exactly where that line should be drawn.

The important point is that not every later medical event automatically breaks causation.

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Rescue Attempts

Rescue is another classic example.

Suppose a defendant creates a dangerous situation.

A bystander attempts to rescue the endangered person.

The rescuer is injured.

The rescue attempt may be considered a foreseeable response to the danger.

Therefore, the rescuer’s conduct does not necessarily supersede the defendant’s negligence.

This principle reflects a basic feature of human behavior:

People often respond to danger by attempting to help.

The law can take that predictable response into account.

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The Rescue Doctrine

The rescue principle is closely associated with the famous case Wagner v. International Railway Co.

The underlying idea is that a person who creates a dangerous situation may be responsible for foreseeable rescue attempts arising from that danger.

This doctrine is sometimes expressed through the broader principle that:

Danger invites rescue.

The law does not ordinarily treat every attempt to respond to an emergency as an independent superseding cause.

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Panic and Escape

People may also react to danger by attempting to escape.

Suppose a defendant negligently creates a fire in a building.

A person panics and attempts to leave.

The person is injured while escaping.

The defendant may not necessarily argue that the plaintiff’s decision to flee was a superseding cause.

A reasonable response to danger can be foreseeable.

The precise circumstances remain important.

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Negligent Responses by Third Parties

A defendant may create a dangerous situation that causes another person to act negligently.

For example:

A defendant negligently leaves a dangerous obstruction on a road.

↓

Another driver encounters it.

↓

The driver reacts negligently.

↓

A third person is injured.

The second driver’s negligence may be an intervening cause.

But it does not necessarily become a superseding cause.

If negligent reactions to the original danger are reasonably foreseeable, the original defendant may remain within the causal chain.

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Intentional Acts by Third Parties

Intentional conduct presents a more difficult question.

Suppose a defendant negligently creates a dangerous situation.

A third person intentionally harms the plaintiff.

The defendant may argue:

“The third person’s intentional act supersedes my negligence.”

Sometimes that argument succeeds.

Sometimes it does not.

The critical issue may include whether the intentional conduct was itself a foreseeable risk created by the defendant.

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Criminal Conduct as a Superseding Cause

Criminal conduct can be particularly important.

Suppose a defendant leaves a dangerous condition that makes criminal activity substantially more likely.

A third party commits a crime.

The plaintiff is injured.

The defendant may argue that the crime is an independent superseding cause.

But criminal conduct does not automatically terminate liability.

If criminal conduct was a foreseeable risk of the defendant’s negligence, the original defendant may remain potentially liable.

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Foreseeable Criminal Conduct

Imagine a property owner knows that serious assaults have repeatedly occurred in a particular location.

The owner fails to take reasonable precautions.

A customer is later assaulted.

The criminal act may be an intervening cause.

But it may not necessarily be a superseding cause if the criminal conduct was within the foreseeable scope of the risk.

The issue is highly fact-specific.

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Highly Extraordinary Criminal Conduct

Now imagine an entirely bizarre criminal act that bears no meaningful relationship to the danger created by the defendant.

The defendant may have a stronger argument that the criminal conduct was a superseding cause.

The law may conclude that the defendant should not be responsible for consequences outside the foreseeable scope of the original risk.

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Natural Events

Natural events can also intervene.

Examples include:

• storms;
• floods;
• earthquakes;
• lightning;
• extreme weather;
• and other natural forces.

The question is not simply:

“Was there a natural event?”

The relevant question is:

Was the natural event sufficiently foreseeable or sufficiently connected to the original risk that it should remain within the causal chain?

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Ordinary Weather

Ordinary weather conditions generally do not automatically supersede negligence.

Suppose a defendant negligently creates a dangerous condition outdoors.

Rain later contributes to the danger.

If rain was reasonably foreseeable, the defendant may still be responsible.

The fact that nature participated in the injury does not automatically eliminate human responsibility.

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Extraordinary Natural Events

An extraordinary natural event can produce a different result.

Suppose a defendant’s conduct creates a minor danger.

An extraordinarily rare natural disaster later transforms that danger into a completely unexpected catastrophe.

The defendant may argue that the natural event superseded the original negligence.

Again, the outcome depends on the jurisdiction and facts.

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Acts of God

Traditional common law sometimes uses the phrase act of God to describe extraordinary natural events.

The concept can be relevant when a natural event is:

• extraordinary;
• unforeseeable;
• independent of human conduct;
• and sufficiently powerful to interrupt the causal chain.

Modern courts do not necessarily use the terminology in the same way, and the doctrine varies.

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Plaintiff’s Own Conduct

The plaintiff can also become an intervening actor.

Suppose a defendant negligently creates a dangerous condition.

The plaintiff then behaves carelessly.

The plaintiff’s conduct contributes to the injury.

This does not necessarily mean the plaintiff’s conduct is a superseding cause.

Instead, the issue may be analyzed under comparative negligence, contributory negligence, or assumption of risk, depending on the jurisdiction and facts.

This is an important distinction.

A plaintiff’s negligence does not automatically erase the defendant’s negligence.

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Intentional Self-Harm

A plaintiff’s intentional conduct can create a more difficult causation question.

If the plaintiff deliberately engages in conduct that produces the injury, courts may analyze whether the conduct was:

• foreseeable;
• independent;
• sufficiently extraordinary;
• or related to the original danger.

The precise treatment depends heavily on the facts and jurisdiction.

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Suicide and Intervening Causes

Suicide can present particularly complex causation questions.

Suppose a defendant negligently injures a person.

The person later dies by suicide.

The court may have to determine whether the suicide was:

• a foreseeable consequence of the original conduct;
• an independent intervening event;
• or a superseding cause.

There is no universal rule that every suicide automatically breaks causation.

The analysis is jurisdiction-specific and highly fact-dependent.

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The Eggshell Plaintiff Rule

The eggshell plaintiff rule also matters when evaluating intervening events.

Suppose a defendant negligently causes an injury.

The plaintiff has an unusual vulnerability.

The plaintiff experiences unusually severe consequences.

The defendant cannot ordinarily escape liability merely because the extent of the harm was unforeseeable.

This is different from a genuinely independent superseding cause.

The distinction is:

Unexpected vulnerability

does not necessarily equal

superseding cause.

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The Difference Between Unforeseeable Harm and Superseding Cause

These concepts are related but distinct.

Suppose the defendant creates a foreseeable risk of physical injury.

The plaintiff suffers a particularly severe version of that injury.

The severity may be unforeseeable.

But the original risk remains connected to the harm.

Now suppose an entirely independent event produces a fundamentally different type of harm.

That may be more likely to qualify as superseding.

Thus:

Unforeseeable severity is not necessarily the same as an unforeseeable intervening cause.

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Foreseeable Consequences of Negligence

The law generally recognizes that negligent conduct can trigger predictable consequences.

For example:

A driver negligently causes a collision.

↓

Emergency services respond.

↓

The injured person receives medical treatment.

↓

The person incurs medical expenses.

↓

The person loses income.

These consequences can remain within the causal chain.

The fact that several events occurred does not automatically eliminate liability.

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The Domino Problem

Consider a chain:

A

causes

B

which causes

C

which causes

D

which causes

E.

The law does not necessarily stop at the first additional event.

Instead, it asks whether the chain remains sufficiently connected.

The key question is not:

“Did something happen in between?”

Something almost always happens in between.

The real question is:

Did the later event become sufficiently independent and extraordinary that legal responsibility should shift away from the original defendant?

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Superseding Cause as a Limiting Principle

The doctrine of superseding cause is therefore fundamentally a limitation on liability.

It recognizes that:

Not every consequence of negligent conduct should legally be attributed to the original defendant.

The doctrine prevents the causal chain from extending indefinitely.

It also reflects judgments about fairness, predictability, responsibility, and the proper scope of Tort Law.

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The Risk Principle

A useful way to approach these cases is to ask:

What risk made the defendant’s conduct negligent in the first place?

Then ask:

Did the intervening event and resulting injury arise from that risk?

If yes, the intervening event may not supersede.

If the later event is completely independent of the original risk, the argument for superseding cause becomes stronger.

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Example: Dangerous Roadway

Imagine a construction company negligently leaves a large obstruction in a roadway.

A driver approaches.

The driver swerves to avoid it.

A passenger is injured.

The driver’s evasive action is an intervening event.

But the reaction is a foreseeable response to the danger.

The construction company’s negligence may therefore remain legally relevant.

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Example: Extraordinary Event

Now imagine that after the construction company creates the obstruction, an extraordinary and completely unrelated event causes a second accident hundreds of miles away.

The plaintiff attempts to connect the second accident to the original roadway obstruction.

The causal relationship becomes extremely weak.

The later event may be considered too remote or superseding.

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Example: Rescue

A defendant negligently starts a fire.

A firefighter enters the building.

The firefighter is injured while attempting to control the fire.

The firefighter’s actions are an intervening event.

But responding to a dangerous fire is foreseeable.

The rescue response therefore ordinarily does not automatically supersede the original negligence.

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Example: Criminal Conduct

A landlord knows of repeated violent criminal activity in a building but fails to take reasonable precautions.

A tenant is assaulted.

The criminal act is an intervening event.

But the landlord may have difficulty arguing that the assault was completely unforeseeable if the surrounding circumstances made criminal activity a recognizable risk.

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Example: Extraordinary Criminal Conduct

A defendant negligently creates a minor property hazard.

A third party later commits an extraordinary and unrelated intentional crime.

The plaintiff attempts to attribute the crime to the original property hazard.

The defendant may have a stronger argument that the crime was an independent superseding cause.

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The Role of the Jury

Whether an intervening event is foreseeable can involve factual questions.

Depending on the jurisdiction and procedural posture, a judge may decide the issue as a matter of law when reasonable people could reach only one conclusion.

In other circumstances, the jury may determine factual questions concerning:

• foreseeability;
• reasonableness;
• causation;
• and the relationship between the events.

The allocation between judge and jury varies by jurisdiction.

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Intervening Cause vs. Superseding Cause vs. Concurrent Cause

These concepts should also be distinguished from concurrent causes.

Intervening cause

Occurs after the defendant’s conduct and contributes to the injury.

Superseding cause

An intervening cause that legally breaks the chain of responsibility.

Concurrent cause

Two or more causes operate together to produce the injury.

For example:

Defendant’s negligence + Third party’s negligence → Plaintiff’s injury

Both actors may potentially be responsible.

The existence of multiple causes does not necessarily mean that one cause supersedes another.

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Multiple Tortfeasors

Sometimes several defendants contribute to the same injury.

For example:

• Driver A is negligent.
• Driver B is also negligent.
• Plaintiff is injured in the resulting collision.

Neither defendant necessarily supersedes the other.

Instead, the law may apply rules concerning:

• comparative fault;
• contribution;
• joint and several liability;
• or allocation of responsibility.

These rules vary significantly by jurisdiction.

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Intervening Causes and Strict Liability

Intervening-cause principles are not limited exclusively to negligence.

They can arise in strict-liability cases as well.

For example, a defendant may be strictly liable for certain activities or defective products, but the defendant may still argue that an independent event caused the plaintiff’s injury.

The precise role of foreseeability differs from negligence because strict liability does not depend upon proving unreasonable conduct.

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Intervening Causes and Intentional Torts

Intentional torts also raise causation questions.

Suppose one person intentionally commits a harmful act.

A later event contributes to the plaintiff’s injury.

The court may need to determine whether the later event limits the original actor’s responsibility.

However, intentional tort doctrine has its own rules concerning:

• intent;
• causation;
• transferred intent;
• damages;
• and defenses.

The negligence framework should not simply be imported wholesale.

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Proximate Cause and Superseding Cause

The concepts are closely related.

A simplified sequence is:

Duty

↓

Breach

↓

Factual cause

↓

Intervening event?

↓

Foreseeable or sufficiently connected?

↓

Proximate cause

↓

Damages

If the intervening event is sufficiently extraordinary and independent, the chain may stop before proximate cause is established.

Thus, superseding cause operates as one of the principal limitations on proximate causation.

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A Practical Exam Framework

When faced with an intervening-cause problem, work through the following steps.

Step 1: Identify the original negligence

What did the defendant do or fail to do?

Step 2: Identify the original risk

What danger did that conduct create?

Step 3: Identify the intervening event

What happened after the defendant’s conduct?

Step 4: Ask whether the event contributed to the injury

If it did, it may qualify as an intervening cause.

Step 5: Ask whether the event was foreseeable

Could a reasonable person have anticipated this type of event or response?

Step 6: Examine the relationship to the original risk

Did the intervening event arise from the danger created by the defendant?

Step 7: Ask whether the event was extraordinary

Was it highly unusual, independent, and unexpected?

Step 8: Consider whether it was superseding

Would treating the event as a superseding cause appropriately terminate the defendant’s legal responsibility?

Step 9: Consider other doctrines

Does the case involve:

• comparative negligence?
• assumption of risk?
• medical malpractice?
• criminal conduct?
• rescue?
• strict liability?
• multiple tortfeasors?

Step 10: State the conclusion carefully

Explain why the later event does or does not break the causal chain.

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Common Mistakes

Mistake 1: Assuming every intervening event is superseding

This is the most common mistake.

An intervening event may remain part of the causal chain.

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Mistake 2: Assuming any third-party conduct breaks causation

It does not.

Third-party conduct can be foreseeable.

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Mistake 3: Treating criminal conduct as automatically superseding

Criminal acts can sometimes be foreseeable risks.

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Mistake 4: Treating medical treatment as automatically superseding

Medical treatment is a foreseeable consequence of many injuries.

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Mistake 5: Ignoring rescue

Reasonable rescue attempts may be foreseeable responses to danger.

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Mistake 6: Confusing plaintiff negligence with superseding cause

A plaintiff’s negligence may instead be analyzed under comparative or contributory negligence.

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Mistake 7: Focusing only on whether the later event was unusual

The important question is not simply whether it was unusual.

The court may ask whether it was sufficiently independent and unforeseeable to justify cutting off liability.

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Mistake 8: Forgetting the original risk

The best analysis asks what risk made the defendant’s conduct negligent and whether the later event falls within that risk.

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Mistake 9: Assuming factual causation automatically establishes liability

Factual causation is necessary but does not necessarily establish proximate cause.

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Mistake 10: Treating superseding cause as a universal formula

Different jurisdictions use somewhat different terminology and tests.

The precise rule must therefore be checked against the governing jurisdiction.

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Intervening and Superseding Causes: Key Takeaways

• An intervening cause is a later event that contributes to the plaintiff’s injury.
• A superseding cause is an intervening event that legally breaks the causal chain.
• Every superseding cause is intervening, but not every intervening cause is superseding.
• Foreseeability is often central to the analysis.
• Foreseeable intervening events generally do not automatically eliminate liability.
• Extraordinary and independent events may potentially supersede the defendant’s conduct.
• Medical treatment can be an intervening cause without being superseding.
• Rescue attempts can be foreseeable intervening events.
• Reasonable reactions to danger may remain within the causal chain.
• Criminal conduct does not automatically constitute a superseding cause.
• Natural events do not automatically break causation.
• A plaintiff’s negligence is often analyzed under comparative or contributory negligence rather than superseding cause.
• The original risk created by the defendant is an important reference point.
• Superseding cause limits potentially unlimited liability.
• Factual causation and legal causation must be distinguished.
• Multiple causes can coexist without one superseding another.
• The exact legal test varies by jurisdiction.

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Frequently Asked Questions

What is an intervening cause?

An intervening cause is an event that occurs after the defendant’s conduct and before the plaintiff’s injury and contributes to producing the injury.

What is a superseding cause?

A superseding cause is an intervening event that is sufficiently independent, extraordinary, or unforeseeable that the law treats it as breaking the chain of legal causation.

What is the difference between an intervening and superseding cause?

An intervening cause is simply a later contributing event. A superseding cause is an intervening event that legally terminates the original defendant’s responsibility.

Does every intervening cause break causation?

No. Many intervening events are foreseeable consequences of the defendant’s conduct and therefore do not necessarily break causation.

Can negligence by a third party be an intervening cause?

Yes. Third-party negligence can intervene in the causal chain. Whether it is superseding depends on the circumstances.

Can criminal conduct be a superseding cause?

Yes, but criminal conduct is not automatically superseding. If criminal conduct was a foreseeable risk created by the defendant’s negligence, the defendant may remain liable.

Is medical malpractice a superseding cause?

Not automatically. Medical treatment is often a foreseeable consequence of injury. Whether later medical negligence supersedes the original defendant’s conduct depends upon the circumstances and applicable law.

Is a rescue attempt a superseding cause?

Generally, a reasonable rescue attempt is not automatically superseding because responding to a serious danger can be foreseeable.

Can a natural disaster be a superseding cause?

Yes. An extraordinarily unusual natural event can potentially supersede the defendant’s conduct, but ordinary or foreseeable natural conditions may not.

Can the plaintiff’s conduct be a superseding cause?

Potentially, but a plaintiff’s negligent conduct is often analyzed under comparative negligence, contributory negligence, or assumption-of-risk doctrines rather than automatically treated as superseding.

How does foreseeability affect intervening causes?

Foreseeability helps determine whether the later event was sufficiently connected to the original risk that the defendant should remain legally responsible.

What is the difference between factual and legal causation?

Factual causation asks whether the defendant’s conduct actually contributed to the injury. Legal causation asks whether the connection is sufficiently close for the law to impose responsibility.

Why does Tort Law recognize superseding causes?

Because legal responsibility cannot extend indefinitely through every event that follows a defendant’s conduct. Superseding-cause doctrine provides a limitation on the scope of liability.

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Further Reading

For a general overview of causation in Tort Law:

Cornell Law School — Legal Information Institute: Causation

For proximate cause:

Cornell Law School — Legal Information Institute: Proximate Cause

For foreseeability:

Cornell Law School — Legal Information Institute: Foreseeability

For negligence:

Cornell Law School — Legal Information Institute: Negligence

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Conclusion

Intervening and superseding causes address one of the most difficult questions in Tort Law:

How far should responsibility extend when something else happens between the defendant’s conduct and the plaintiff’s injury?

The answer is not simply that the original defendant is responsible for everything that follows.

Nor is the answer that every later event eliminates the original defendant’s responsibility.

Instead, Tort Law examines the causal chain.

A later event may be an intervening cause without being a superseding cause.

This distinction is crucial.

Suppose a defendant negligently creates a dangerous situation. A person reacts to that danger, emergency services respond, medical treatment follows, and additional complications occur. There may be several intervening events.

Yet the existence of multiple events does not necessarily destroy the original causal connection.

The law asks whether those events were sufficiently foreseeable, connected, and within the scope of the original risk.

This is why foreseeability is so important.

If the later event represents a recognizable consequence of the danger the defendant created, the causal chain may remain intact.

If the later event is extraordinarily unusual, independent, and disconnected from the original risk, it may become a superseding cause.

The distinction can therefore be reduced to a simple principle:

An intervening event changes the causal chain; a superseding event breaks it for purposes of legal responsibility.

This doctrine prevents Tort Law from becoming unlimited.

A defendant who creates a foreseeable danger can ordinarily be responsible for reasonable and foreseeable consequences of that danger.

But the law does not ordinarily impose responsibility for every remote consequence that happens to occur later.

The challenge is identifying the point at which the later event becomes sufficiently independent that responsibility should shift.

That is the central function of the superseding-cause doctrine.

Ultimately, the analysis returns to the same question that runs through negligence law:

Does the plaintiff’s injury fall within the legally relevant risk created by the defendant’s conduct?

If it does, an intervening event may not defeat liability.

If it does not, and the later event is sufficiently extraordinary and independent, the law may treat that event as superseding.

Understanding this distinction is essential to understanding proximate cause, foreseeability, and the limits of negligence liability.