Question 1

If the 'but for' test is satisfied, is the defendant automatically liable?

Accepted Answer

No. Satisfying the 'but for' test only establishes factual causation. The claimant must still prove legal causation (that the damage was not too remote and the chain of causation was not broken) and that the defendant owed a duty of care which they breached. Causation is just one of the four essential elements of a negligence claim.

Question 2

Does the 'thin skull' rule contradict the rule from *The Wagon Mound*?

Accepted Answer

Not exactly. They work together. *The Wagon Mound* requires the *type* of harm to be foreseeable. The 'thin skull' rule clarifies that if the type of harm is foreseeable (e.g., a burn), the defendant is liable for the full *extent* of that harm, even if the extent is much greater than expected due to the claimant's specific vulnerability (e.g., a pre-cancerous condition being triggered by the burn, as in *Smith v Leech Brain*). It's a qualification, not a contradiction.

Question 3

What's the difference between factual and legal causation?

Accepted Answer

Factual causation (the 'but for' test) is a preliminary, scientific or logical inquiry: did the defendant's act, as a matter of fact, cause the outcome? Legal causation (remoteness and intervening acts) is a policy-based legal filter. It asks whether, even if the defendant factually caused the harm, it is fair and just to hold them legally responsible for it. It limits liability to consequences that are not too remote or have not been superseded by a later event.

Causation and remoteness of damage

What you need to know

Causation and remoteness of damage