The Law of Intervening Causation

Douglas Hodgson

• Publisher: Routledge
• Year: 2016
• ISBN:
  9781351886963
• Edition: 1
• Topic: Law
• Subtopic: Jurisprudence
• Index: Law

Utilizing a comparative examination of case-law from England, Canada, the USA, Australia, New Zealand and Ireland, this volume provides a comprehensive and systematic study of the law of intervening causation (novus actus interveniens) to present an analysis of this particular judicial limitation of liability device. The work provides a structure from which to formulate core general legal principles and identify the various legal tests utilized by the courts.

PART I
Introduction

Chapter 1

Introduction

Proving the causal connection between the defendant’s negligence and the plaintiff’s damage is often a straightforward matter. For example, a typical motor vehicle accident may be attributable to the negligent driving of one or both of the drivers. Proof of causation through the application of the traditional so-called ‘but for’ test yields a simple result that the accident would not have occurred but for the negligent driving which becomes a necessary condition of the plaintiff’s loss. Proof of the causal connection may become more complicated, however, when subsequent events conspire with the situation generated by the defendant’s negligence to produce the plaintiff’s loss. What if the plaintiff’s injuries are made worse by subsequent negligent medical treatment administered at a nearby hospital to which the plaintiff was taken? What if the pain and disability accompanying such injuries result in a state of depression which eventually drives the plaintiff to suicide? In other contexts, how is causation resolved when a merchant vessel which has been damaged through the negligent navigation of another vessel sinks while en route to port for repairs during an extraordinary and unseasonal storm? Or what is the situation where a person is injured while attempting to rescue another person who has been imperilled by the negligence of the tortfeasor? Application of the ‘but for’ test would yield the result that the defendant would be liable for everything which followed the negligent conduct – the negligent medical treatment, the suicide, the sinking of the vessel and the injury to the rescuer – because none of the events would have transpired without that negligence. But is that fair? In such cases, the defendant could plausibly argue that he or she should not be liable where an act or event has intervened between the defendant’s negligence and the plaintiff’s injury. The defendant may argue that his or her conduct no longer operates as the effective legal cause of the plaintiff’s injury, having been replaced by the intervening act or event which is said to have broken the chain of causation. Such a chain-breaking event is referred to by English judges as a novus actus interveniens and by US commentators as a ‘superseding cause’. If the intervening event breaks the chain of causation, such event rather than the defendant’s negligence will be considered the effective cause of the plaintiff’s injury in attributing legal causal responsibility. It has been a long-standing judicial technique to focus on certain intervening events which, in conjunction with the defendant’s default, precipitate or aggravate the plaintiff’s injury.¹ The crucial question becomes whether the defendant is to be held liable for loss caused by or contributed to by the intervening event. As we shall see, the answer to this question depends on a variety of considerations and is subject to the application of varying legal tests.²

A novus actus interveniens may take three different forms. From the abovementioned examples, it may consist of the conduct of the plaintiff (the suicide), the act (or omission) of a third party (the hospital and its employees), or some natural event or coincidence independent of any human agency (the extraordinary and unseasonal storm).³ The legal effect of a successful novus actus interveniens plea is to absolve the defendant or original wrongdoer of legal liability or further legal liability.⁴ As is the case with the duty of care and remoteness of damage ingredients of any cause of action in negligence, the novus actus interveniens doctrine is a judicially-developed liability limitation device. One US commentator has observed that what a court is really concerned with in determining whether intervening events constitute a superseding cause is some rule of law which restricts liability short of requiring the defendant to pay for all the harm caused by the breach of duty, and that such a restrictive rule is inevitably based on policy considerations.⁵ In Lamb v Camden London Borough Council⁶ Lord Denning M.R. stated:

The truth is that all these three – duty, remoteness and causation – are all devices by which the courts limit the range of liability for negligence or nuisance. As I said recently ‘…it is not every consequence of a wrongful act which is the subject of compensation. The law has to draw a line somewhere’. Sometimes it is done by limiting the range of the persons to whom duty is owed. Sometimes it is done by saying that there is a break in the chain of causation. At other times it is done by saying that the consequence is too remote to be a head of damage. All these devices are useful in their way. But ultimately it is a question of policy for the judges to decide.

As a limitation of liability device, the onus rests on the defendant to persuade the court that the intervening event ‘so overwhelms the original wrongdoing that the original wrongdoer [the defendant] avoids responsibility.’⁷ Or, as Singleton L.J. put it in Philco Radio and Television Corporation Ltd v J. Spurling Ltd,⁸ ‘the onus is on the defendants to show that there was a new act intervening which relieves them from responsibility.’

In cases where the defendant has raised a novus actus, commentators and some judges have found it useful to analyse the causation issues by subdividing them into ‘factual causation’ and ‘legal causation’. As Buxton L.J. has recently reaffirmed in Roberts v Bettany,⁹ resolving novus actus issues involves a determination of mixed questions of fact and law. The first step in the causal enquiry is to determine whether or not the defendant’s negligence factually caused the plaintiff’s loss. This is the factual causation stage. This is resolved by determining whether the defendant’s negligence was a necessary condition in a set of conditions jointly sufficient to produce the plaintiff’s injury, and cases involving intervening events are no exception.¹⁰ Determining the question whether the defendant’s negligent act or omission is a factual cause of the plaintiff’s loss entails ascertaining whether the defendant’s negligence was a causa sine qua non or conditio sine qua non (necessary condition) of the occurrence of that loss.¹¹ This is established through the application of the ‘but for’ test. The defendant’s conduct satisfies the but for test in circumstances where without his or her wrongful conduct the plaintiff’s loss would not have occurred. Factual causation is sometimes alternatively referred to as ‘scientific causation’ in the sense that physical laws or the laws of physics are relied on to determine whether there is an uninterrupted sequence of cause and effect stretching from the defendant’s breach of duty to the sustaining of the plaintiff’s injury.¹² Only if the defendant’s negligence is shown to have factually caused the plaintiff’s loss will the causal enquiry proceed to consider legal causation – that is, whether the defendant’s conduct should be attributed with legal responsibility for that loss. Legal causation is sometimes alternatively referred to as ‘attributive causation’. Legal causation does not involve the finding of the physical facts and their causal inter-relation but rather the separate and value-laden question of the extent to which the community should go in requiring the defendant to pay for damages which his or her conduct has in fact been a significant factor in producing along with the intervening agency. This is a question of substantive law.¹³ As the answer to the legal causation enquiry involves intuitive and evaluative judgements¹⁴ based on the judicial application of concepts of fairness and justice¹⁵ and various public policy considerations,¹⁶ predictability and uniformity in the decided cases are unattainable. Nevertheless, courts in the common law world have evolved over the past two centuries certain legal rules and tests which have been applied in resolving legal causation issues in cases involving intervening forces and these will be examined in forthcoming chapters.

Causation issues arising in the civil law context do not admit of easy resolution in many instances. Professor John Fleming has remarked, ‘[c]ausation has plagued courts and scholars more than any other topic in the law of torts.’¹⁷ It is submitted by this writer that this comment applies a fortiori in relation to novus actus cases. Judges and commentators alike have noted the challenging nature of these cases. One scholar has referred to ‘the vexed question of novus actus interveniens’.¹⁸ A Canadian judge has recently commented, ‘[w]hether or not the intervening conduct amounts to a novus actus interveniens is a question that has plagued the courts for centuries.’¹⁹ Tucker L.J. of the English Court of Appeal once stated, ‘these questions of causation and of novus actus interveniens are always difficult.’²⁰ Perhaps it may be said that tackling intervening causation issues may be likened to ‘having to draw a line between night and day; there is a great duration of twilight.’²¹

Why, then, have intervening causation cases proven so difficult for judges and scholars? One significant factor is that such cases appear to be impervious to any universal test. It is not easy to work out from the cases what test is to be applied in deciding whether an intervening event has broken the chain of causation.²² Lord Wright confessed ‘I find it very difficult to formulate any precise and all-embracing rule.’²³ This has resulted in a situation in which not all cases can be reconciled.²⁴ That there is no such all-embracing formula to cover all intervening causation cases is due in part to the varying nature of intervening events and their surrounding circumstances.²⁵ These cases are very much fact- and circumstance-sensitive. In two novus actus cas...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Dedication
• Contents
• List of Cases
• Acknowledgements
• Part I Introduction
• Part II The Legal Tests
• Part III Operative Contexts
• Part IV Conclusion
• Index