1 Ambiguous Cause-in-Fact and Structured Causation: A Multi-Jurisdictional Approach ERIK S. KNUTSEN SUMMARY I. INTRODUCTION II. THE LANDSCAPE OF CAUSE-IN-FACT DOCTRINE A. The Evolution of Cause-in-Fact Doctrine The But For Test The Substantial Factor or Material Contribution to Injury Test B. Ambiguous Cause-in-Fact Cases C. Modifications to Traditional Cause-in-Fact Tests The Reversal Approach: Reversing the Burden of Proof of Causation to the Defendant The Increased Risk Approach: Proving the Defendant Materially Increased the Risk of Injury The Inference Approach: Inferring Causation from the Facts of the Case D. The Importance of Ambiguous Cause-in-Fact Cases: Hints of Policy and Theory Policy Drives Modifications to Traditional Cause-in-Fact Principles The Inherent Indeterminacy of Cause-in-Fact Cases Theory Behind the Policy of Cause-in-Fact III. MODIFICATIONS TO TRADITIONAL CAUSE-IN-FACT DOCTRINE A. The Reversal Approach The Genesis of the Reversal Approach Criticisms of the Reversal Approach B. The Increased Risk Approach The Genesis of the Increased Risk Approach a. The Increased Risk Increased Injury Dichotomy in Britain and Canada b. The Increased Risk Approach in the United States Criticisms of the Increased Risk Approach Alternatives to the Increased Risk Approach a. Probabilistic Evidence, Efficiency, and Increased Risk b. Increased Risk of Injury as a Compensable Injury C. The Inference Approach Erik S. Knutsen, LL.M., Harvard Law School; LL.B., Osgoode Hall Law School; H.B.A., Lakehead University. Former Visiting Assistant Professor, Florida State University College of Law. The author wishes to thank Professor Jon Hanson of Harvard Law School for helpful comments and guidance in the early stages of this article and for continued mentorship, especially in the area of tort law. The author also wishes to thank Professor Paul C. Weiler, Henry J. Friendly Professor of Harvard Law School, for instilling both a critical approach to the torts system as well as the recognition of the value of cross-jurisdictional, comparative approaches. 249
2 250 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38: Res Ipsa Loquitur and the Inference Approach The Genesis of the Inference Approach Criticisms of the Inference Approach IV. A NEW APPROACH TO AMBIGUOUS CAUSE-IN-FACT CASES A. Structured Causation B. Reversing the Burden of Proof of Causation to Force Information C. Materially Increasing the Risk of Injury as Proof of Cause-in-Fact V. EVALUATING STRUCTURED CAUSATION A. Structured Causation Compatible with Corrective Justice View B. Structured Causation Compatible with Efficiency Theory View VI. CONCLUSION I. INTRODUCTION It has been repeatedly asserted by tort scholars that, unlike proximate cause inquiries, an inquiry into cause-in-fact is a straightforward, factual matter devoid of policy. 1 That is a myth. 2 Over the past one hundred years, courts in the United States, Canada, and Britain have wrestled with doctrinal solutions for solving difficult torts cases turning on cause-infact. Courts have traditionally applied the but for, or sine qua non, test of cause-in-fact when faced with determining cause in a torts action. Where the but for test fails, courts have reached for the substantial factor, or material contribution to injury, approach to divine what role a defendant had in causing injury to a plaintiff. The majority of cause-infact questions that come before a court can be solved using either one of these two approaches. However, there exists a pattern of torts cases where courts have found both the but for test and substantial factor test unsatisfactory. These cases are unique in that they tend to exhibit a peculiar set of facts, which makes determining a breach of the standard of care possible but determining cause-in-fact nearly impossible. For example, a doctor s negligence in prescribing the incorrect treatment for an already ill patient may be a possible cause of the subsequent death of the patient. However, the death may also have been caused by the already existing illness a non-culpable, possible cause. Often there is no way to pinpoint the actual cause of injury. All that is known is that the defendant s negligence increased the risk that the plaintiff s injury might occur. A fact finder is faced with the difficult decision of whether or not to award compensation to a plaintiff who has been exposed to a risk of injury created by a defendant s negligence but who may possibly have been injured by a cause not related to the defendant s negligence. Cause-in-fact is ambiguous. 1. See, e.g., Richard W. Wright, Causation in Tort Law, 73 CAL. L. REV. 1735, 1737 (1985) [hereinafter Wright, Causation in Tort Law] (capsulizing this trend, beginning with Prosser s comment that causation is the simplest and most obvious problem when determining tortious liability). For similar explanations about the apparent simplicity of causation, see also W. PAGE KEETON ET AL., PROSSER AND KEETON ON THE LAW OF TORTS (5th ed. 1984); H.L.A. HART & TONY HONORÉ, CAUSATION IN THE LAW (2d ed. 1985); JOHN G. FLEMING, THE LAW OF TORTS (9th ed. 1998) [hereinafter FLEMING, THE LAW OF TORTS]. 2. Indeed, torts scholars have echoed this belief for some time, beginning with Wex S. Malone, Ruminations on Cause-in-Fact, 9 STAN. L. REV. 60 (1957), and Leon Green, The Causal Relation Issue in Negligence Law, 60 MICH. L. REV. 543 (1962). See also Wright, Causation in Tort Law, supra note 1, for another capsulization of this theoretical movement.
3 2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 251 These types of cases nag at one s sense of justice and are problematic for courts expected to apply predictable, rational legal principles. If, out of a set of two or more competing, independent possible causes, the plaintiff cannot definitively prove on a balance of probabilities that one competing independent cause of her injury is the defendant s negligence, the plaintiff cannot succeed on traditional cause-in-fact principles. Yet, when a plaintiff can establish that the defendant s conduct fell below the applicable standard of care, some courts in the United States, Canada, and Britain have refused to rob the plaintiff of an opportunity to prove causation and have modified cause-in-fact doctrine to accommodate the plaintiff. Three methods that courts use to aid a plaintiff have emerged through various courts continued exposure to these types of cases: (1) a court could reverse the burden of proof of causation to the defendant to disprove causation; (2) a court could infer causation based on a reasonable conclusion on the facts of the case; or (3) a court could hold the defendant liable for materially increasing the risk of injury to the plaintiff. Because these methods depart from traditional, established torts doctrine, each of these solutions owes its existence to subtle, competing policy considerations. Understanding the application of judicially created cause-in-fact doctrine to a case where proof of cause is at best ambiguous, necessitates understanding what has driven the court to tinker with existing tort doctrine in the first place. It is the aim of this article to explore how these three modifications to traditional cause-in-fact principles operate, examine why they arose, and then use a normative lens to evaluate why they need to be consolidated into a predictable and portable outgrowth of causation doctrine. This article is divided into four substantive sections. Part II defines the landscape of cause-in-fact doctrine and explains how American, Canadian, and British courts have modified this landscape to oblige ambiguous causation cases. Part III evaluates the judicial modifications of cause-in-fact doctrine and explores the often unarticulated motivations that drive a court s use of these innovations. First, reversal of the burden of proof of causation from the plaintiff to the defendant is considered. Next, the approach that proves cause based on the defendant s material increase of risk of injury to the plaintiff is evaluated. And finally, the practice of proving causation based on reasonable inferences on the facts of the case is examined. Part IV is the pivotal division of the article, where the three alternative approaches to cause-in-fact are synthesized to produce a new, normative 3 method for deciding ambiguous cause-in-fact cases. This method, called structured causation, reifies existing torts principles in a fashion that is also compatible with a positivist interpretation of what courts have been doing. Part V explains how structured causation accomplishes the normative goals, which are compatible with the competing tort theories of efficiency and corrective justice. II. THE LANDSCAPE OF CAUSE-IN-FACT DOCTRINE Courts in the United States, Canada, and Britain have long struggled with the slippery concept of causation. Legal doctrine has been shaped over the years to assist fact finders in determining the answer to the crucial question in a negligence action: What made this incident happen? An automobile accident could be caused by icy road conditions, faulty 3. In an effort to simplify the goals of this article, and with apologies to legal philosophers for glancing over the intricacies of each term, the term normative is used throughout this article in its generally applicable sense as describing what ought to be a prescriptive fix for the law. The term positivist is used in its generally applicable sense as what is, or as an explanation for, how the law operates now and has operated in the past. For an excellent parlay into the significance of these terms in relation to the circular nature of causation in tort law, see Richard Fumerton & Ken Kress, Causation and the Law: Preemption, Lawful Sufficiency, and Causal Sufficiency, 64 LAW AND CONTEMP. PROB. 83, (2001).
4 252 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 brakes on the automobile, or the driver speeding through a stoplight without stopping. If the defendant s negligence is found to be a cause of the plaintiff s injury, then the defendant is held liable and must compensate the plaintiff. Causation is comprised of two components which are applied in succession in a negligence action to determine whether or not the defendant s negligence was the responsible cause of the plaintiff s injury. The first component, cause-in-fact, involves determining whether or not a defendant s negligence was a de facto cause of the plaintiff s injuries. In other words, cause-in-fact determines whether, but for the defendant s negligence, the plaintiff would have suffered the injury. The second causal component, proximate cause, involves determining whether or not the defendant s negligence is too remotely connected to the plaintiff s injury to be a foreseeable cause of that injury. 4 Proximate cause is an admittedly complex and policy-laden concept, which has plagued legal scholars for some time. 5 This article is concerned with the modifications and application of cause-in-fact doctrine only. Cause-in-fact is traditionally considered to be less contentious and more predictable than proximate cause. Indeed, many torts scholars and fact finders argue that cause-in-fact is a straightforward question of common sense. 6 This paper aims to revise that tradition of thinking by proffering evidence that, in a certain subset of negligence actions, cause-in-fact doctrine has the potential to be just as contentious, unpredictable, and policy laden as its counterpart, proximate cause. The recognition of this phenomenon necessarily calls for a new, structured approach to determining causation in certain cases where cause-in-fact is at issue. A cross-jurisdictional comparative approach is adopted throughout the cause-in-fact analysis for three reasons. First, modifications to traditional judicial treatment of cause-infact have become more prevalent in the United States, Canada, and Great Britain in the past thirty years. This movement toward a more flexible causal doctrine may in fact stem from the utilization of a dated cause-in-fact doctrine in a world becoming increasingly more complex. Second, the three jurisdictions exhibit a surprisingly parallel evolution of causal doctrine and are not developing cause-in-fact modifications independently but in conjunction with each other. A study of one single jurisdiction is therefore unsatisfactory as courts often utilize precedents from all three jurisdictions when charting the course of cause-in-fact principles. And third, a comparison of each jurisdiction to the other can inform a workable approach toward cause-in-fact that may be utilized in all three jurisdictions. A. The Evolution of Cause-in-Fact Doctrine 1. The But For Test The majority of common law cause-in-fact inquiries involve a court s application of one of two well-established torts principles: the but for test or the substantial factor test of causation. The but for test is the simpler of the two and is used for the majority of 4. Indeed, in Canadian and British courts, the term foreseeability appears to be preferred over that of proximate cause. 5. The famous proximate cause case, Palsgraf v. Long Island R.R., 162 N.E. 99 (N.Y. 1928), has, on its own, sparked countless analyses from Dean Prosser, Palsgraf Revisited, 52 MICH. L. REV. 1 (1952) to Edward S. Adams, et al., At the End of Palsgraf, There is Chaos: An Assessment of Proximate Cause in Light of Chaos Theory, 59 U. PITT. L. REV. 507 (1998). 6. See, e.g., Wright, Causation in Tort Law, supra note 1, at ; KEETON ET AL., supra note 1; HART & HONORÉ, supra note 1, at 24; FLEMING, THE LAW OF TORTS, supra note 1, at
5 2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 253 factual circumstances. A plaintiff in a negligence action must prove on a balance of probabilities that, but for the defendant s negligent conduct, the plaintiff would not have suffered injury. 7 Fact patterns which fit the but for test of causation are those where it can be established on a balance of probabilities that the defendant s negligence was a necessary component of the cause that gave rise to the plaintiff s injury. In most negligence actions where one plaintiff sues one negligent defendant, that defendant s negligence is usually one of two or more equally competing and mutually exclusive possible causes. A court weighs the evidence of causation to determine whether or not, on a balance of probabilities, it can be proven that the defendant caused the plaintiff s injury. 2. The Substantial Factor or Material Contribution to Injury Test Some causation matters do not properly fit a straightforward application of the but for test. The substantial factor test, or the material contribution to injury approach as it is called in Canada, is used primarily in cases where multiple possible causes for a plaintiff s injuries exist, each cause being sufficient on its own to have caused the alleged injury. 8 The causes can either be concurrent or successive, but they must be independently sufficient to have potentially caused the entire injury to the plaintiff. In these cases, the but for test does not work. It is circular for a court to ask whether or not but for one cause the plaintiff would not be injured because the other existing cause is still sufficient to have resulted in the injury. For example, the but for test is unworkable in sorting out the cause-in-fact of damage to a plaintiff s property resulting from two separately burning fires that converge together to cause indivisible damage. 9 If one fire is caused by the defendant s negligence and one is caused by natural circumstances, a court is not aided by asking whether, but for the one fire, the plaintiff would not have suffered damage. The second fire exists and makes dividing the source of causation impossible. Therefore, a court uses the substantial factor test of causation to determine if a defendant s negligent conduct was a material element, or substantial factor, in bringing about the injury of the plaintiff. The role of the defendant s negligence in bringing about this injury must be beyond the de minimus range in order to be considered the cause of the injury. Courts have relied predominantly on the but for test of causation and, in most cases, a fact finder has little difficulty in determining whether or not a defendant s negligence is, on a balance of probabilities, a cause-in-fact of a plaintiff s injury. The repeated use of this test, and its nearly automatic application with little explanation in court judgments, may 7. The but for test was enunciated in the United States in New York Cent. R.R. v. Grimstad, 264 F. 334 (2d Cir. 1920), in which a man drowned after falling off a boat that carried no life preservers. The court held that the boat owner was not liable. Id. at 335. Although the boat owner was negligent not to have life preservers on board, that negligence was not a but for cause of the death of the man. Id. The but for test is often invoked in Canadian cases, such as Kozak v. Funk (1995), 135 Sask. R. 81 (Sask. Q.B.), varied, (1997), 158 Sask. R. 283 (Sask. C.A.). The Kozak decision acknowledges the importation to Canada of Lord Denning s articulation of the but for test in the British decision, Cork v. Kirby MacLean, Ltd.,  2 All E.R. 402 (C.A.). 8. For the American substantial factor test, see RESTATEMENT (SECOND) OF TORTS 431 (1965). The Supreme Court of Canada recently reaffirmed the material contribution to injury approach in a case involving multiple successive accidents. See Athey v. Leonati,  3 S.C.R. 458, in which the injured plaintiff, who suffered from a pre-existing degenerative back condition, was involved in two separate automobile accidents within two months time. The multiple accidents and pre-existing back condition were all potential causes for Athey s subsequent herniated spinal disc. Id. at 459. The Supreme Court of Canada awarded compensation to Athey and held that the defendant automobile drivers materially contributed to Athey s injury. Id. 9. These were the exact facts in Kingston v. Chicago & N.W. Ry., 211 N.W. 913 (Wis. 1927), in which the Wisconsin Supreme Court held that the negligent creation of one fire on the part of the defendant was a substantial factor in bringing about the damage to the plaintiff s property from the conjoining fires. Id. at 915.
6 254 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 have led some torts scholars to believe that the but for test was nothing more than a dry application of a legal principle to easily discernible facts at hand. Even with the more complicated substantial factor test, court rhetoric usually points to a relatively easy judgment call about whether or not a defendant s negligence was a material element in causing the plaintiff s injury. B. Ambiguous Cause-in-Fact Cases Courts have sometimes been faced with causal patterns where neither the but for test nor the substantial factor test of causation produce satisfactory results. There exists a specific subset of cause-in-fact cases where a court allows a plaintiff to recover even though she cannot prove on a balance of probabilities that the defendant s negligence was either a but for cause of her injury or a substantial factor in bringing about that injury. The factual structure of these cases centers first around a plaintiff being able to prove on a balance of probabilities that the defendant breached the applicable standard of care. Next, there must exist two or more competing but independent possible causal explanations for the resultant injury of the plaintiff. One possible cause must be a result of the defendant s negligence. The other possible cause, or causes, must result from some other factor unrelated to the defendant s conduct. Cause-in-fact may be said to be ambiguous. There must also be an admitted lack of sufficient evidence to tip the scales beyond a balance of probabilities; otherwise, the but for causation test comes into play. Finally, the plaintiff must show some evidence connecting the defendant s negligent behavior to the cause of her injury, although the evidence will not be substantial enough to prove that the defendant s negligent behavior was more likely than not the cause-in-fact of the injury. In other words, the plaintiff must prove that the defendant s negligence contributed to the global risk factors to which the plaintiff was exposed. The defendant s contribution to those global risk factors must exhibit a nature that would likely have aided in bringing about the particular kind of injury the plaintiff suffered. In these specific types of cases which turn on cause-in-fact, a plaintiff using the but for or substantial factor test would fail to prove the defendant was the cause-in-fact of her injury. Specific evidence of the source of cause as stemming from either the defendant s negligence or the other competing causal explanation is virtually nonexistent. However, the mere fact that the plaintiff can prove the defendant s breach of the standard of care, coupled with at least some evidence that suggests a connection between that breach and the cause of the particular injury suffered, often prompts a court to bend the rules of cause-in-fact in favor of the injured plaintiff. Courts of all jurisdictions sometimes seem loathe to deny compensation for a plaintiff in this circumstance. The severity of harm to the plaintiff, the amount of compensation sought, and the perceived undesirability of the negligence of the defendant are all factors that weigh into a court s causal determinations. The theoretical and resultant policy reasons behind this tendency will be explored throughout this article. What is important to note at this stage of the analysis is that courts have begun to shape alternative cause-in-fact doctrines to assist plaintiffs faced with these ambiguous cause-in-fact conundrums. Some examples are in order to demonstrate the precise fact pattern of what will be called ambiguous cause-in-fact cases. The key in recognizing an ambiguous cause-in-fact case is identifying the fact that prima facie evidence of the defendant s negligence as a cause-in-fact of the plaintiff s injury is as inconclusive and unavailable as evidence of an alternative possible cause-in-fact. In non-causal terms, no one knows, or will ever know, precisely what happened.
7 2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 255 In Haft v. Lone Palm Hotel, 10 a father and son were found mysteriously drowned in a pool operated by the defendant. The local statute mandated either lifeguard service or proper signage if no lifeguard was on duty. The defendant did not comply with either of these requirements, and there was no evidence as to how the deaths occurred. The California court broke with traditional torts principles and reversed the burden of proof of causation to the defendant, who then had to disprove his role in causing the accident. 11 This case fits the pattern of an ambiguous cause-in-fact scenario because the plaintiff can prove that the defendant was negligent but cannot precisely link that negligence to a morelikely-than-not cause of the injuries suffered. A court is therefore faced with two options. It can choose to compensate the plaintiff and accept that there exists a chance that perhaps the defendant really is not liable for the injury. Or, in the alternative, the court could deny compensation for the plaintiff, even though evidence of the defendant s negligence points to the negligent behavior being a possible cause of the injuries. The traditional torts principles of but for and substantial factor causation do not offer courts much assistance in cases like Haft. Courts must judge whether or not to modify cause-in-fact rules in the interest of compensating plaintiffs. Canadian courts are also challenged by ambiguous cause-in-fact cases. The Supreme Court of Canada in Snell v. Farrell 12 adopted a modified causation test in indemnifying the plaintiff in a medical malpractice action. The defendant, Dr. Farrell, negligently performed eye surgery on Mrs. Snell, a diabetic with a number of pre-existing health complications. During the surgery, Mrs. Snell suffered blindness in her one eye. She simultaneously experienced a stroke in that same eye, which could also have caused her blindness. Evidence at trial could not conclusively point to whether or not her blindness was caused by Dr. Farrell s negligence or by Mrs. Snell s deteriorating health condition. The Supreme Court of Canada bypassed the traditional but for test of causation and inferred causation on the part of Dr. Farrell. This case also fits the pattern of an ambiguous cause-in-fact scenario: Although the plaintiff could prove that the defendant s negligence contributed to the global risk factors for the particular type of injury suffered, she could not link that negligence to the actual cause of the injury. Both Dr. Farrell s negligence and Mrs. Snell s poor health were independent and equally plausible causes of Mrs. Snell s blindness. Similarly, British courts are tempted to bend the rules of causation in favor of plaintiffs in ambiguous cause-in-fact cases. The famous case of McGhee v. National Coal Board, 13 cited in precedents and scholarship in both Canada and the United States, involved the House of Lords innovative approach to solving the seeming unworkability of a causal scenario. 14 In McGhee, the plaintiff was a brick kiln worker who rode home from work every day caked in brick dust. He developed dermatitis and sued his employer. At issue was whether or not the cause-in-fact of the dermatitis was the employer s negligence in not providing shower facilities for its employees. There existed a possibility that the dermatitis was a result of some other non-negligent cause. Again, an application of the but for test left the plaintiff uncompensated and the negligent defendant unpunished because cause was ambiguous. The court therefore decided to indemnify the plaintiff and modify cause-in-fact doctrine to allow for recovery. The House of Lords decreed that the defendant had P.2d 465 (Cal. 1970). 11. This approach has since been rejected by the California Supreme Court for asbestos-related cancer injuries. The burden of proof remains with the plaintiff. See Rutherford v. Owens-Illinois, Inc., 941 P.2d 1203, 1206 (Cal. 1997). 12.  2 S.C.R  1 W.L.R. 1 (H.L. 1972). 14. McGhee was recently upheld in principle by the House of Lords in Fairchild v. Glenhaven Funeral Servs. Ltd.,  3 W.L.R. 89 (H.L.).
8 256 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 materially increased the risk of injury to the plaintiff and that this material increase of risk of injury was enough to deem that the defendant had caused the injury. 15 These three examples of ambiguous cause-in-fact cases demonstrate a recurring evidentiary pattern. They also demonstrate a strong desire on the part of fact finders to adjust legal doctrine to favor plaintiff recovery over allowing a negligent defendant to escape liability in the face of negligent conduct. Ambiguous cause-in-fact cases do not commonly arise in courts but are a unique subset of cases. However, they are more likely to work their way to trial as the characteristic lack of causal evidence makes settlement difficult. Furthermore, ambiguous cause-in-fact cases are doctrinally significant as courts shape causal policy while wrestling with whether or not to modify traditional tort principles. In other words, despite the small number of ambiguous cause-in-fact cases that do exist, much of the evolution of cause-infact principles results from the appearance of these cases in the court system. The increasing complexity of the causation disputes brought to court, coupled with the advancement of science and computer technology, may result in more ambiguous cause-infact cases being tried. Medical malpractice, computer negligence, and even automobile accident tort actions are all being affected by the increased availability of scientific evidence that may assist in proving cause-in-fact. However, the adversary system s usage of competing science and competing expert witnesses may be increasing not the ability to pinpoint cause-in-fact, but the tendency to prove that cause is only a matter of perspective, made up of shades of gray. This trend may actually prompt more and more cases to be characterized as ambiguous cause-in-fact cases because science has the ability to ferret out alternative competing possible causes for a plaintiff s injuries. This could also foster a parallel increase in courts utilization of modifications to traditional cause-in-fact doctrine. C. Modifications to Traditional Cause-in-Fact Tests Ambiguous cause-in-fact cases have spawned three judicial modifications to traditional cause-in-fact doctrine. 16 A brief introduction to the three modifications follows in order to flesh out the debate behind a fact finder s use of one competing cause-in-fact approach over another. Each approach will then be discussed and evaluated in detail. 1. The Reversal Approach: Reversing the Burden of Proof of Causation to the Defendant The first approach, as mentioned in Haft v. Lone Palm Hotel, 17 involves reversing the burden of proof of causation to the defendant. This requires the defendant to marshal evidence to disprove causation. If the defendant cannot prove that his negligence was not the cause of the plaintiff s injury, he is deemed to have caused the plaintiff s injury. This causal approach appears to be used most often when a fact finder determines that a defendant will likely have more information about causation than would the plaintiff. The approach owes its origin to those cases of multiple defendants acting together to cause a 15. McGhee,  1 W.L.R. at 6. Lord Wilberforce went further than the rest of the House of Lords and seemed to advocate a reversal of the burden of proof of causation to the defendant. Id. at Lewis Klar notes that the law has three options when the but for and substantial factor tests fail: (1) the law can redefine the nature of cause and modify the but for test or ignore it; (2) the law can shift the onus for the burden of proof of causation or require something less than a balance of probabilities to prove causation; or (3) the law can redefine the nature of the plaintiff s injury. LEWIS KLAR, TORT LAW 324 (2d ed. 1996) [hereinafter KLAR, TORT LAW] P.2d 465 (Cal. 1970).
9 2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 257 single, indivisible harm, such as two hunters negligently and simultaneously firing upon one plaintiff. 18 The reasoning behind the court s departure from traditional tort principles rests on the belief that the plaintiff was robbed of the ability to prove causation because the defendant s negligence destroyed that proof. For example, in a medical malpractice ambiguous cause-in-fact case, the burden of proof of causation may be reversed to the defendant hospital when the hospital s nursing team fails to properly maintain the patient s medical chart, thereby resulting in that patient receiving substandard medical treatment The Increased Risk Approach: Proving the Defendant Materially Increased the Risk of Injury The second modification to traditional cause-in-fact principles first appeared in the McGhee v. National Coal Board 20 case. There, the majority of the House of Lords determined that a defendant employer s negligence was the cause-in-fact of the plaintiff s injuries if the plaintiff could prove that the defendant materially contributed to the injury of the plaintiff. 21 A material contribution to an injury was held to be synonymous with saying that the defendant materially contributed to the risk of injury. Lord Wilberforce went further to state that if a plaintiff proved the defendant materially contributed to the risk of injury occurring, the burden of proof on the causation issue shifted to the defendant. 22 Lord Wilberforce s modification of cause-in-fact doctrine combines the reversal approach with a novel material contribution to the risk of injury approach. A surprising number of courts in Canada, the United States, and Britain adopted causal doctrines similar to that espoused by Lord Wilberforce, which allow a plaintiff to prove cause-in-fact based on evidence of the defendant materially increasing the risk of injury to the plaintiff. Unlike the majority of the House of Lords, some courts made a distinction between materially increasing the risk of injury and materially contributing to the injury itself. 23 The increased risk approach was seen as a flexible, discretionary method for dealing with ambiguous cause-in-fact cases. A smaller number of courts also utilized the reversal approach in conjunction with the increased risk approach, keeping more closely with Lord Wilberforce s original concept. 18. Compare Summers v. Tice, 199 P.2d 1 (Cal. 1948), with Cook v. Lewis,  S.C.R. 830 (nearly identical U.S. and Canadian decisions). 19. This was the fact situation in Joseph Brant Mem l Hosp. v. Koziol,  S.C.R However, the Supreme Court of Canada overruled the Ontario Court of Appeal s use of Cook v. Lewis,  S.C.R. 830, to reverse the burden of proof to the nursing staff. Joseph Brant Mem l Hosp.,  S.C.R. at 501. See also Look v. Himel,  O.J. No (Ont. Gen. Div.), available at 1991 WL , and Pike v. Peace Arch Dist. Hosp. Soc y,  33 A.C.W.S.2d 490 (B.C.), available at 1985 A.C.W.S.J. Lexis 21146, where Canadian courts have entertained but rejected the reversal idea in cases involving negligent upkeep of hospital notes. A similar type of reversal did in fact occur in the American case of Ybarra v. Spangard, 154 P.2d 687 (Cal. 1944), where the court used the doctrine of res ipsa loquitur to, in effect, reverse the burden of proof of causation to the defendant physicians. See infra Part III.C for a discussion of the conceptual differences between the inference approach to cause-in-fact and using res ipsa loquitur to make determinations based on circumstantial evidence. 20.  1 W.L.R. 1 (H.L. 1972). 21. Id. The speeches of Lord Reid, Lord Simon of Glaisdale, Lord Salmon, and Lord Kilbrandon discuss the increased risk approach as functionally equivalent to the substantial factor, or material contribution to injury test. See infra Part II.A for a discussion of the fundamental difference between basing cause on increase of risk, as opposed to mere presence of an alternative but independently sufficient cause. Courts in Canada and Britain have erroneously blurred the distinction between the two concepts. 22. McGhee,  1 W.L.R. at For a complete discussion of the cases exhibiting this trend, see infra Part III.B.1.
10 258 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38: The Inference Approach: Inferring Causation from the Facts of the Case The third approach to ambiguous cause-in-fact cases, as demonstrated in cases like Snell v. Farrell, 24 has become the dominant method for dealing with ambiguous cause-infact cases. If a plaintiff can prove that a defendant was negligent but cannot also prove that the negligence was, on a balance of probabilities, a but for cause of the injury, courts have allowed a plaintiff to recover, provided that the plaintiff s evidence nearly establishes but for causation. If the evidence comes close to proving causation on a balance of probabilities, a court may infer causation on the part of the defendant. U.S., Canadian, and British courts use these causal inferences in situations when the defendant is allowed to escape liability despite the existence of some positive evidence that indicates the defendant s negligence may be a possible cause of the plaintiff s injury. A difficulty with this incarnation of cause-in-fact doctrine is that it is relatively unstructured and unpredictable, leaving a great deal of discretion to the fact finder and his or her evaluation of both the sufficiency of the evidence and the relative wrongdoing of the defendant. D. The Importance of Ambiguous Cause-in-Fact Cases: Hints of Policy and Theory Before discussing in detail the three approaches to ambiguous cause-in-fact cases, it is important to at least briefly introduce the subtle theoretical and policy subtexts at work that steer each approach. 1. Policy Drives Modifications to Traditional Cause-in-Fact Principles A preliminary question that must be answered is: Why modify traditional cause-infact principles in the first place (i.e., what is the normative goal to be gained)? It has been shown that the particular fact circumstances of ambiguous cause-in-fact cases render the but for or substantial factor tests of causation unworkable and deny compensation to the plaintiff. Because there are two independent, competing alternative causes of a plaintiff s injury, one cannot say but for one cause, the plaintiff would not have been injured. The existence of the second alternative cause negates the answer: But for the negligent cause, the other non-negligent cause still exists as a potential source for the injury. Similarly, the defendant s negligence cannot be a substantial factor in the cause of injury because the two competing possible causes are independently exclusive of one another. Either one possible cause was the source of the injury or the other one was. Therefore, an application of either test leaves a plaintiff uncompensated, even though it is clear that the defendant created a risk of a specific injury and the plaintiff was exposed to that risk and suffered the specific injury. Something troubles most courts faced with ambiguous cause-in-fact cases, which prompts them to attempt to assist the plaintiff through a modified causation standard. It likely stems from the fact that the plaintiff can prove that the defendant behaved negligently. A court must choose between the lesser of two evils: compensate the plaintiff or allow the negligent defendant to escape liability. There is a powerful unsettling rhetoric at work in permitting the negligent defendant to escape liability, through no fault of the plaintiff, merely because proof of causation does not quite meet a balance of probabilities standard. It is no wonder that a court most often chooses to side with the plaintiff. Yet, in doing so, a court must make a decision based not on the facts presented but on pure policy. 24.  2 S.C.R. 311.
11 2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 259 As Nancy Lee Firak notes, the policy furthered is this: [T]hat plaintiff, having suffered a recognized injury should be entitled to compensation; and that defendant, having created a risk of the kind that injured plaintiff, should bear the cost of compensation. 25 Cause-in-fact decisions based on normative policy are anathema to some torts scholars. Indeed, many insist that policy-based cause-in-fact determinations cannot exist. But ambiguous cause-in-fact cases stand as a definitive example that, sometimes, cause-infact decisions can be based purely on policy. Dean Prosser, 26 John Fleming, 27 and Leon Green 28 have advocated that cause-in-fact determinations are factual decisions where evidence is simply applied to traditional causation doctrine. H.L.A. Hart and Tony Honoré argue that layperson common sense guides cause-in-fact decisions, and no policy is ever invoked. Richard Wright attempts to create a non-normative tool for analyzing cause-infact. 29 Yet all these notions appear to ignore the practical reality that courts are bending traditional rules to accommodate ambiguous causation cases. The fecundity of discretion embodied in these ambiguous causation cases demonstrates that courts do resort to policy decisions where a straightforward factual application of traditional principles falls short of a court s perceived goal. It should be noted that, despite recent modifications to causal doctrine, not all ambiguous cause-in-fact cases are resolved in favor of the plaintiff. In Knotterus v. North Park Street Railway Co., 30 a roller coaster derailed, causing injuries to the plaintiff. There was evidence that the derailment could have been caused by a large wood chip which the wind had blown from an area where the defendant s employees were performing construction work. Alternatively, there was evidence that the derailment may have been caused by defective work performed by the owner of the amusement ride who was not a party to the action. The evidence adduced proved neither cause beyond a balance of probabilities, but both the trial and appellate courts found for the defendant. Thus, the apparent lack of predictability in this subset of causation cases further underlines that courts are basing their decisions on some unarticulated justice goals. An increasing reliance on normative policy to solve difficult causation issues has been demonstrated in most ambiguous cause-in-fact cases. This tendency will become lucid in the ensuing analysis of the specific methods of dealing with ambiguous cause-in-fact cases. Wex Malone argues that cause-in-fact is not some dry, calculable thing but full of policy. 31 His belief in the inextricable tie between normative policy and cause-in-fact has been echoed by Guido Calabresi, 32 D.M.A. Strachan, 33 John Borgo, 34 and Harper, James and 25. Nancy Lee Firak, Alternative Forms of Liability: Developing Policy Aspects of the Cause-in-Fact Requirement of Tort Law, 20 ARIZ. ST. L.J. 1041, 1068 (1988). 26. See PROSSER, supra note 1, at See FLEMING, THE LAW OF TORTS, supra note 1, at See Green, supra note 2, at This test, called the NESS (Necessary Element of a Sufficient Set) test, requires that, in order to hold a particular event in a causal chain as the cause, it must be a necessary element in that chain which brought about the plaintiff s particular injury. Richard Wright, Causation, Responsibility, Risk, Probability, Naked Statistics, and Proof: Pruning the Bramble Bush by Clarifying the Concepts, 73 IOWA L. REV. 1001, 1019 (1988) [hereinafter Wright, Clarifying the Concepts]. Wright s formulaic approach to cause-in-fact is criticized by Richard Fumerton and Ken Kress as giving the appearance of being a non-normative prescription to causation, but, in fact, Wright s approach is just as normative as that which it hopes to replace. Fumerton and Kress argue that the very idea of lawful sufficiency is itself subjective. One presupposes the other. See generally Fumerton & Kress, supra note N.W. 529 (Mich. 1892). 31. Malone, supra note 2, at Guido Calabresi, Concerning Cause and the Law of Torts: An Essay for Harry Kalven, Jr., 43 U. CHI. L. REV. 69, (1975).
12 260 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 Grey. 35 Each commentator stresses that courts base causal decisions on policy considerations such as perceived efficiency, deterrence considerations, compensation goals, or the desire to redress a perceived wrongdoing. The rise of alternative modes of proving causation beyond the traditional but for test may be a renewed recognition of the importance of maintaining the above stated policy goals in an increasingly complex world. But for causation is becoming increasingly more difficult to prove in court as science and technology create not more certainty in causal evidence, but more shades of grey. 36 There is a corresponding need to increase regulation of new activities which impose risk of harm as a byproduct of scientific advancement. The tort system serves as a malleable method of regulating these new industries. As a result, unlike scientific causality, legal causality is becoming easier to prove in order to have the tort system serve this regulatory function by imposing liability on negligent defendants. Furthermore, the reverberative effect of the law and economics movement may also be affecting the decline of strict proof of cause. Law and economics characterizes causation as less of a determinative element in an efficient tort system than, for example, an applicable liability standard of either negligence or strict liability. 37 All these factors combine to create a normative, judicially created causal doctrine. 2. The Inherent Indeterminacy of Cause-in-Fact Cases The three judicial modifications to the traditional but for test of causation are rife with policy underpinnings. Each approach allows a great deal of judicial discretion. What is most curious is that a court does not usually articulate the reasoning behind the application of modified rules of causation in ambiguous cause-in-fact cases. The judge merely announces that a certain approach will be taken, states the appropriate precedential authority, and then finds for the plaintiff or defendant. 38 The written decision is usually 33. D.M.A. Strachan, The Scope and Application of the But For Causal Test, 33 MOD. L. REV. 386, 389 (1970) (noting that the but for test of cause-in-fact attempts to be objectively scientific but, in fact, is subject to policy considerations). 34. John Borgo, Causal Paradigms in Tort Law, 8 J. LEGAL STUD. 419, (1979) (arguing that causal determinations are not goal neutral but subject to the underlying policy considerations of the courts). 35. Fowler Harper and Fleming James, Jr. survey Calabresi s notion that cause-in-fact is actually designed to serve human goals and the inherently demonstrable flexibility of causal determinations reflects the operation of these goals. 4 FOWLER V. HARPER & FLEMING JAMES, JR., THE LAW OF TORTS 20.2 n.1, at (2d ed. 1986). 36. Judith Jarvis Thomson, The Decline of Cause, 76 GEO. L.J. 137 (1987) (outlining that, because of the increasing demands of regulating new technological industries, causation is becoming increasingly blurry, and this phenomenon has aided plaintiffs during the past two decades). 37. For arguments regarding the importance of liability standards over causal policy, see in particular Richard Epstein, A Theory of Strict Liability, 2 J. LEGAL STUD. 151 (1973), in which he argues that the but for test is inaccurate, too philosophical, too reliant on hypotheticals, and too administratively costly. In its place, Epstein proposes a regime of strict liability where a party who harms another party is strictly liable for that harm. For alternative economic proposals of liability regimes which reduce the importance of cause-in-fact in traditional torts scenarios, see Steven Shavell, An Analysis of Causation and the Scope of Liability in the Law of Torts, 9 J. LEGAL STUD. 463 (1980) [hereinafter Shavell, An Analysis of Causation]; Steven Shavell, Uncertainty Over Causation and the Determination of Civil Liability, 28 J.L. & ECON. 587 (1985) [hereinafter Shavell, Uncertainty Over Causation], and WILLIAM M. LANDES & RICHARD A. POSNER, THE ECONOMIC STRUCTURE OF TORT LAW (1987) [hereinafter LANDES & POSNER, ECONOMIC STRUCTURE]. Shavell, Landes, and Posner posit that the use of more probabilistic, statistical evidence coupled with a furthered understanding of the ex post causal risks involved in a torts situation would lead to a simplification of the causation analysis in a negligence regime. 38. Examples abound of this judicial reluctance to explain the departure from traditional causal principles. Generally, once an alternative causal approach is first developed in the common law, its use as a future precedent is reduced to a nearly automatic application when a court deems its use necessary. In Audet (Guardian ad Litem of) v. Bates,  78 A.C.W.S.3d 406 (B.C.), available at 1998 A.C.W.S.J. Lexis 81941, the British Columbia Supreme Court adopted the inference approach as advocated in Snell v. Farrell,  72 D.L.R.4th 289 (B.C.). The case dealt with whether or not the pinching of a fetus s umbilical cord by a physician later caused brain
13 2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 261 tacit on the subject of what pressed the judge first to adopt a modified rule of causation and second to find for the particular party. While there exist three distinct forms of adjusted causal doctrine to deal with ambiguous cause-in-fact cases, all three forms may not differ in actual effect on the outcome of the case. In fact, the only difference between reversing the burden of proof of causation and inferring causation or finding a material increase of risk of injury may be a semantic difference. Throughout the analysis of ambiguous cause-in-fact approaches, it will become apparent that no ambiguous cause-in-fact case cited in this study would have been decided any differently had any one of the three causal tools been utilized by the courts. Fact finders who reach for a modified causation test may be searching only for a method of rhetoric to find for the party that, for normative reasons, they believe should be successful in the action. 39 Judicially determined cause-in-fact exists not in absolutes but on continuums. The crucial difference, states Stephen Pincus, between the but for test[,]... on one hand, and the increased risk test, material contribution test or substantial factor test, on the other, is linguistic. 40 Courts that decide ambiguous causein-fact cases might appear unpredictable, unstable, and somewhat maverick. Their causal determinations do not seem fettered by the particular cause-in-fact approach they apply. 3. Theory Behind the Policy of Cause-in-Fact Competing traditional positivist and normative tort theories have long attempted to provide an explanation for why judges make causal determinations and, subsequently, how they should make causal determinations. These explanations may provide some insight into what policy considerations are behind a court s decision in ambiguous cause-in-fact cases. Traditionally, tort law has been seen as a legal regime designed to both compensate the injured and deter undesirable behavior. Acting as a rough and ready public insurance system, tort law provides a mechanism to redress the needs of a plaintiff who has suffered damages. At the same time, the fear of tort liability can act as a deterrent to curb potentially harmful social behavior. Cause-in-fact decisions could therefore turn on a fact finder s desire to compensate an apparently needy plaintiff or, alternatively, to deter egregious behavior on the part of the defendant. This insurance-deterrence duality has taken on significance by shaping two influential modern tort theories. damage to the child. The court inferred causation to the defendant physician in this ambiguous cause-in-fact case by merely stating that it was adopting the inference principle from Snell v. Farrell and inferring causation: In the absence of evidence from Dr. Bates consistent with the likelihood of a contrary cause, I am permitted to, and do, infer as fact that the artificial rupture of the membranes was the cause of the prolapse which eventually injured Teddy. The approach which I have followed in the determination of causation is that mandated by the Supreme Court of Canada in the case of Snell v. Farrell. Audet,  78 A.C.W.S.3d at 424. This lack of judicial reasoning and straightforward application of alternative cause-in-fact approaches is typical of most judgments concerning ambiguous cause-in-fact scenarios. 39. Such is the argument of Stephen Pincus, who posits that a linguistic analysis of causation cases demonstrates that the language chosen by the fact finder is nearly immaterial once traditional causal principles are abandoned. Stephen N. Pincus, Progress on the Causal Chain Gang: Some Approaches to Causation in Tort Law and Steps Toward a Linguistic Analysis, 24 OSGOODE HALL L.J. 961, (1986). 40. Id. at 994.
14 262 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 The corrective justice movement views as integral the moral significance in the relationship struck between an injured plaintiff and the wrongdoer defendant. 41 Causal judgments, under this theory, are made based on perceptions about a plaintiff s normative loss at the hands of the defendant. Fact finders are prompted to restore the moral balance between the injured plaintiff and negligent defendant. The insurance and deterrence functions of tort law should therefore be utilized to further the goal of redressing the moral wrongdoing of the defendant. The law and economics movement argues that tort law s goal is the efficient maximization of wealth. 42 Using money as a measure of worth, efficiency theory puts faith in the market and freedom of contract to check and counter rising accident and administrative costs of the torts system in attempting to strike the most efficient balance. The theory uses a rational actor model where players in the tort system behave rationally by being risk-neutral cost avoiders. Law and economics theorists are not concerned with the distribution of wealth, but rather the maximization of the total possible wealth in each torts transaction. To this end, legal economists believe that the structure of the insurance and deterrence effects of tort law should be aimed at promoting efficient behavior. Both corrective justice and efficiency theory will be used as positivist lenses to explain the development of new causal solutions utilized by courts. Afterward, each theory will be used in its normative sense to test the validity of a novel approach to ambiguous cause-infact cases. III. MODIFICATIONS TO TRADITIONAL CAUSE-IN-FACT DOCTRINE A. The Reversal Approach One method of resolving ambiguous cause-in-fact cases involves reversing the burden of proof of causation to the defendant to disprove causation. A plaintiff must first prove 41. See the work of corrective justice theorists Ernest J. Weinrib, Lewis N. Klar, and Richard Wright. For Weinrib s conception of corrective justice, see Ernest J. Weinrib, The Special Morality of Tort Law, 34 MCGILL L.J. 403 (1989) [hereinafter Weinrib, Special Morality]; Ernest J. Weinrib, Causation and Wrongdoing, 63 CHI.- KENT L. REV. 407 (1987); Ernest J. Weinrib, A Step Forward in Factual Causation, 38 MOD. L. REV. 518 (1975) [hereinafter Weinrib, A Step Forward]; TORT LAW: THE INTERNATIONAL LIBRARY OF ESSAYS IN LAW AND LEGAL THEORY (Ernest J. Weinrib ed., 1991). Weinrib references moral philosophy of the Greeks and Kant in forming his notion that tort law should be a system for redressing moral wrongs and making plaintiffs whole again. See generally Weinrib, Special Morality, supra. For Wright s conception of corrective justice, see Richard Wright, Actual Causation vs. Probabilistic Linkage: The Bane of Economic Analysis, 14 J. LEGAL STUD. 435 (1985) [hereinafter Wright, Actual Causation]; Richard Wright, The Efficiency Theory of Causation and Responsibility: Unscientific Formalism and False Semantics, 63 CHI.-KENT L. REV. 553 (1987) [hereinafter Wright, The Efficiency Theory]; Wright, Causation in Tort Law, supra note 1. Wright perceives corrective justice to be the maintenance of responsibility between a victim and a wrongdoer. He argues that no other system is as effective in performing this important role. Wright, Clarifying the Concepts, supra note 29, at 1004, Klar echoes Wright s notions of tort law enforcing responsibility and underscores Weinrib s insistence that moral philosophy is the unique underpinning driving the torts system. See Lewis N. Klar, The Role of Fault and Policy in Negligence Law, 35 ALTA. L. REV. 24, (1996) [hereinafter Klar, Fault and Policy]. 42. For differing views of the law and economics conceptions of efficiency in causation, see the works of the legal economists Richard Epstein, Steven Shavell, William Landes, and Richard Posner, supra note 37. Shavell uses economic theory to argue that causation may be logically deduced to a relative economic certainty. Shavell, Uncertainty Over Causation, supra note 37, at 589. While this may be true on an ex post analysis, it is questionable how Shavell s economic variables could be discerned on an ex ante basis. Wright, Actual Causation, supra note 41, at 446. Therefore, the value of his efficiency model on a normative basis may be limited. Id. at 447. Similarly, Landes and Posner engage in an ex post causal risk analysis and, in turn, reduce the operation of causation as a determinative element of the negligence action. Id. at 454. For sharp criticism of Shavell, Landes, and Posner, as well as the entire efficiency movement, see Wright, The Efficiency Theory, supra note 41.
15 2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 263 that the defendant s conduct fell below the applicable standard of care. This breach of the standard of care must have increased the risk of the particular injury suffered by the plaintiff. If the defendant cannot prove that his negligence was not the cause of the plaintiff s injury, he is deemed to have caused the plaintiff s injury. This causal tactic appears to be used most often when a fact finder determines that a defendant will likely have more information about causation than would the plaintiff. Judge Learned Hand best captured the spirit of reversing the burden of proof to the defendant by stating: The single tortfeasor cannot be allowed to escape through the meshes of a logical net. He is a wrongdoer; let him unravel the casuitries resulting from his wrong The Genesis of the Reversal Approach The judicial history of this modification to the traditional but for test reveals some of the difficulties of resolving ambiguous causation cases solely in this fashion. Reversing the burden of proof to the defendant to disprove causation was first used in the United States and Canada in cases involving multiple defendants whose negligent actions came together to produce a single, indivisible harm. 44 The impossibility of sorting out which of the multiple defendants was solely responsible for the harm led courts to craft legal doctrine that aimed to accommodate for the perceived injustice of robbing a plaintiff of any chance of recovery through factors beyond the plaintiff s control. It was the collusion of negligent action that destroyed a plaintiff s ability to prove cause-in-fact. Furthermore, it was thought that the two negligent defendants were informationally better equipped to sort out who had the greater role in bringing about the injury. Imposing joint and several liability on the multiple defendants who were unable to disprove causation seemed to have an information-forcing effect, which prompted the defendants to sort out amongst themselves who would compensate the plaintiff. 45 The philosophical underpinnings of these multiple defendant cases were transformed into a possible solution to determining causality in ambiguous cause-in-fact cases. In McGhee v. National Coal Board, 46 Lord Wilberforce of the House of Lords appeared to reverse the burden of proof of causation to the defendant employer. The plaintiff employee could prove that the employer materially increased the risk of workplace injury by not providing shower facilities to allow workers to clean themselves; however, he could not prove that it was this negligence that caused his dermatitis. In the spirit of Cook v. Lewis 47 and Summers v. Tice, 48 Lord Wilberforce held that this material increase in risk of injury was enough to prompt a switch in the traditional burden of proving causation: And if one asks which of the parties, the workman or the employers, should suffer from this inherent evidential difficulty, the answer as a matter in policy and justice should be that it is the creator of the risk who, ex hypothesi must be 43. Navigazione Libera T.S.A. v. Newton Creek Towing Co., 98 F.2d 694, 697 (2d Cir. 1938). 44. Most prominent are the shooting cases. See, e.g., Summers v. Tice, 199 P.2d 1 (Cal. 1948); Cook v. Lewis,  1 S.C.R In fact, the earliest known reversal of the burden of proof of causation was a Mississippi Supreme Court case. See Oliver v. Miles, 110 So. 666 (Miss. 1927). This case had identical facts to Summers v. Tice and Cook v. Lewis, where two hunters negligently fired at one plaintiff. 45. Saul Levmore, Gomorrah to Ybarra and More: Overextraction and the Puzzle of Immoderate Group Liability, 81 VA. L. REV. 1561, 1562 (1995) (canvassing information-forcing effects that various liability regimes can have on negligent defendants who withhold information from plaintiffs). 46.  1 W.L.R. 1 (H.L. 1972). 47.  1 S.C.R P.2d 1 (Cal. 1948).
16 264 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 taken to have foreseen the possibility of damage, who [sic] should bear its consequences. 49 The McGhee case was subsequently used in Canada in five ambiguous cause-in-fact cases to switch the burden of proof of causation to a defendant. 50 Furthermore, the Supreme Court of Canada reversed the burden of proof of causation to the defendant manufacturer of substandard breast implants in Hollis v. Dow Corning. 51 Justice LaForest relied on Cook v. Lewis 52 to find in favor of the plaintiff. The manufacturer s negligence in failing to provide proper product risk information to physicians had seriously undermined 53 the plaintiff s power to prove that her defective breast implants were the cause of her serious health problems. In the United States, causal reversal was also used to sort out difficult ambiguous cause-in-fact cases. In Haft v. Lone Palm Hotel, 54 the defendant hotel owners had to disprove that their negligence in not providing lifeguards or proper signage at their pool did not cause the death of a father and young son. Here, the identifying characteristic of ambiguous cause-in-fact cases, absence of proof as to how the deaths were caused, prompted Justice Tobriner to determine that: [T]he shift of the burden of proof in the instant case may be said to rest on a policy judgment that when there is a substantial probability that a defendant s negligence was a cause of an accident, and when the defendant s negligence makes it impossible, as a practical matter, for plaintiff to prove proximate causation conclusively, it is more appropriate to hold the defendant liable than 49. McGhee,  1 W.L.R. at See Nowsco Well Servs. Ltd. v. Canadian Propane Gas and Oil Ltd.,  7 Sask. R. 291 (Sask. C.A.) (A truck containing highly flammable contents spontaneously exploded while parked near an open flame. The burden of proof of causation was reversed to the truck driver, who failed to disprove causation.); Rivtow Equip. Ltd. v. W.J. Watt Constr. Ltd.,  73 Sask. R. 161 (Sask. Q.B.) (A logging machine was mysteriously damaged by fire while left in the forest unattended. The burden of proof of causation was reversed to the machine operator, who failed to disprove causation.); Lomax v. Arsenault,  41 Sask. R. 227 (Sask. Q.B.) (A government agency diverted water from a private fish pond. An unusually cold winter froze the pond nearly to the bottom, and the fish stock perished. The question before the court was whether the reduction of the water in the pond caused the fish to die or whether the fish would have died in any event, with the water at the previous level. The burden of proof was reversed to the agency, who was able to prove that its negligence was not the cause of the death of the fish.); E. Kootenay Cmty. Coll. v. Nixon and Browning,  35 A.C.W.S.2d 29 (B.C.), available at 1985 A.C.W.S.J. Lexis (A variety of factors greatly slowed construction of a college building, causing an enormous and unprojected cost-overrun. The burden of proof of causation was reversed to the architects, who were unable to prove that their tardiness was not the cause-in-fact of the extra costs incurred for construction.); Letnik v. Toronto (City),  2 F.C. 399 (Fed. Ct.) (The captain of a ship negligently struck another moored ship in harbor. Two weeks later, the struck ship mysteriously sank while still moored in harbor. The court reversed the burden of proof to the negligent captain who was unable to disprove that striking the ship did not cause it to sink.). It is interesting to note that Canadian academic commentary suggests that Canadian courts post- McGhee regularly reversed the burden of proof of causation to the defendant in torts cases. In fact, that seems to be a misconception, perhaps created by the notoriety of the above five cases, which did reverse the burden of proof. It is hard to imagine that a causal tactic used in only five cases within a decade could be characterized as routine. For example, Mitchell McInnes states that, after McGhee, Canadian courts routinely reversed the burden of proof once a plaintiff established that a defendant had increased the risk of the injury that actually occurred. Mitchell McInnes, Causation in Tort Law: A Decade in the Supreme Court of Canada, 63 SASK. L. REV. 445, 447 (2000). Similarly, Allan M. Linden notes that the McGhee innovation was embraced in Canada. ALLAN M. LINDEN, CANADIAN TORT LAW 107 (6th ed. 1997). 51.  4 S.C.R. 634,  1 S.C.R  4 S.C.R. at P.2d 465 (Cal. 1970). Justice Tobriner relied on the reasoning in Summers v. Tice, 199 P.2d 1 (Cal. 1948), in reversing the burden of proof to the defendant.
17 2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 265 to deny an innocent plaintiff recovery, unless the defendant can prove that his negligence was not a cause of the injury. 55 Justice Tobriner relied on Ybarra v. Spanguard, 56 where the court used the doctrine of res ipsa loquitur to, in effect, reverse the burden of proof of causation (as well as all outstanding elements in the negligence action) to the defendant hospital, requiring it to disprove causation. 57 Like McGhee and Haft, evidence as to the precise cause was missing. Unlike McGhee and Haft, but similar to Hollis, the disappearance of the evidence of causation was a direct result of the defendant s negligent behavior. This important difference may have prompted a retraction in courts frequency of reversing the burden of proof of causation. The British House of Lords overruled the reversal concept of McGhee in Wilsher v. Essex Area Health Authority. 58 This case of medical negligence involved determining what caused a newborn baby to suffer blindness. The hospital was negligent in administering too much oxygen to the baby; however, the complicated birth or possible congenital defects could also have been a cause of the blindness. The evidence did not clearly point to one definitive cause. The House of Lords therefore sent the case back for a new trial in order to further examine the cause-in-fact issue. In demanding retrial of the case, the Lords indicated that McGhee laid down no new principle of law whatever 59 and that Lord Wilberforce s reversal idea was a minority opinion and not to be followed. This statement sent a signal to British courts to cease reversing the burden of proof in ambiguous cause-in-fact cases. The reverberation of the Wilsher decision was felt in Canada where the reversal idea was rejected by the Supreme Court of Canada in Snell v. Farrell. 60 Justice Sopinka called for an end to the use of McGhee as a precedent advocating reversal of the burden of proof of causation. Instead, Sopinka adopted the inference approach from Wilsher, hoping to retain the spirit of the flexible McGhee reversal approach without departing from traditional torts principles. Courts in both Canada and Britain now adopt either one of two modifications of cause-in-fact doctrine: the inference approach or the increased risk approach. In California, the reversal approach was rejected by the California Supreme Court in Rutherford v. Owens-Illinois, Inc. 61 The burden of proof for causation remains with the plaintiff in cases of cancer allegedly caused by asbestos. The differences between the Summers v. Tice situation involving multiple tortfeasors and a case involving exposure to 55. Haft v. Lone Palm Hotel, 478 P.2d 465, 476 n.19 (Cal. 1970). But see Smith v. Americania Motor Lodge, 113 Cal. Rptr. 771 (Cal. Ct. App. 1974), which qualified Haft v. Lone Palm Hotel, stating that reversing the burden of proof was only an option if the plaintiffs themselves were non-negligent. In Smith, also a drowning case like Haft, there was evidence tending to show that the children who drowned were themselves negligent in entering the pool, which had proper warning signs and may have been barricaded by a rope. The children were aged ten and eleven and were capable of reading. The court held that the children were negligent in ignoring printed warnings, crossing a barricade, and swimming in an unsupervised pool. Id. at P.2d 687 (Cal. 1944). 57. In Part III.C, infra, this paper will outline the conceptual differences between cause-in-fact doctrine and using res ipsa loquitur to make determinations based on circumstantial evidence. 58.  1 A.C (H.L.). The inference approach as advocated in Wilsher will be discussed below. See infra Part III.C. It is important to also note that the material increase to risk approach espoused by McGhee was recently reaffirmed by the House of Lords in Fairchild v. Glenhaven Funeral Servs. Ltd.,  3 W.L.R. 89 (H.L.). Lord Rodger of Earlsferry wrote that Wilsher glossed over McGhee in a way that does not do justice to the reasoning about causation. Id. at  1 A.C. at  2 S.C.R P.2d 1203 (Cal. 1997).
18 266 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38:249 carcinogenic materials were highlighted by the court in determining that reversals of the burden of proof were not warranted in this type of a case. 62 The Restatement (Second) of Torts still maintains that the burden of proof of causation remains with the plaintiff Criticisms of the Reversal Approach However, no jurisdiction is without criticism of the reversal approach. There exists a fundamental problem in transferring causation doctrine from a multiple defendant-single possible cause of injury situation to a single defendant-multiple possible cause of injury situation. The shooting cases from which the reversal concept is derived involved fact patterns where the defendant s actual conduct deprived the plaintiff of any ability to prove cause. The reasoning behind the reversal lies in the belief that the negligent defendants had greater information about causality than the plaintiffs, who, by virtue of the defendants actions, had no information. In the majority of ambiguous cause-in-fact cases, though not all, proof of causation is not destroyed by the defendant s negligence but is merely absent. 64 Such was the case in McGhee where the defendant s negligent behavior did not negate the employee s ability to isolate the cause of his dermatitis. Such was also the case in Haft v. Lone Palm Hotel, where the lack of warning signs did not destroy the plaintiff s ability to determine why the drownings occurred. These cases go beyond the information forcing purpose of burden reversal and force the defendant to prove that his breach of duty was not the cause of the plaintiff s injury. 65 There is no informational disadvantage overcome by applying the reversal approach in these types of cases because neither side has any more causal information than the other. Therefore, it is questionable whether reversing the burden of proof to the defendant is any different than merely stating that the defendant is liable for causing the injury on a breach of the standard of care alone. Indeed, Fraser and Howarth believe that cases like McGhee use causal language to address liability concerns based on the defendant s breach of the duty of care. 66 If the plaintiff cannot prove causation because causal information does not exist anywhere, the defendant may be no more able to disprove causation. The reversal notion may therefore be acting as a disguise for a court wishing to find liability based solely on evidence of a breach of duty. The causation step is removed by asking the defendant to disprove something neither he nor anyone else could disprove. Richard Epstein is critical of the reversal modification of cause-in-fact doctrine. He states that: P [a plaintiff] must normally prove a case by a preponderance of evidence. If there is any question of negligence, then P gets to double dip when weak evidence of causation is piled on top of weak evidence of negligence. Even a rule that requires P to present the preponderance of evidence on negligence and causation separately could allow recovery when the chances that P s full case is 62. However, Joseph H. King, Jr. has advocated the use of the reversal approach for determining cause-infact in pre-existing injury cases. See Joseph H. King, Jr., Causation, Valuation, and Chance in Personal Injury Torts Involving Pre-existing Conditions and Future Consequences, 90 YALE L.J. 1353, 1394 (1981). 63. RESTATEMENT (SECOND) OF TORTS 433B(1) (1965) ( [T]he burden of proof that the tortious conduct of the defendant has caused the harm to the plaintiff is upon the plaintiff. ). 64. Weinrib notes that in McGhee, the opportunity to prove cause-in-fact was not impaired by the defendant s negligent behavior; rather, proof was absent. Weinrib, A Step Forward, supra note 41, at G.L. Fridman states that the McGhee case in particular goes beyond Cook v. Lewis,  1 S.C.R. 830, and forces the defendant to prove he did not cause the plaintiff s injury by his breach of duty. G.L. FRIDMAN, TORTS (1990). 66. J.D. Fraser & D.R. Howarth, More Concern for Cause, 4 LEGAL STUD. 131, (1984).
19 2003] AMBIGUOUS CAUSE-IN-FACT AND STRUCTURED CAUSATION 267 made out is only just over 25 percent, as when P wins barely by a 50-plus percent of each issue separately. It is risky to allow P to use a close victory on the issue of negligence or breach of statutory duty as presumptive evidence of causation. It is doubtful that any court would adopt this inference on questions of causation when raised in the context of contributory negligence, so why adhere to that rule here? 67 Even though Epstein challenges the logic of adherence to the reversal approach, the fact remains that courts in all three jurisdictions have occasionally reversed the burden of proof in ambiguous cause-in-fact cases. 68 Something is prompting them to cloak liability for substandard care in causal language, even when there can be no gain by forcing information from a defendant who has no more information than the plaintiff. When the negligent defendant in an ambiguous cause-in-fact case has an informational advantage over the plaintiff, reversing the burden of proof of causation may have the desired effect of forcing that information to come to the surface. Yet when causal evidence is not being withheld by the defendant but is merely absent for both parties, reversing the burden of proof has the effect of automatically holding the defendant liable for causing the injury. Courts appear to be giving the defendant a chance to exonerate herself while really holding the defendant liable for a breach of standard of care. In other words, it is a rhetorical tool available for courts to do what they want. 69 B. The Increased Risk Approach A second method for resolving ambiguous cause-in-fact cases centers around holding a negligent defendant liable for materially increasing the risk of injury to the plaintiff. This approach is like the reversal approach in that it is used primarily to compensate an injured plaintiff despite a lack of causal evidence. Unlike the reversal approach, it has an information-forcing effect on the defendant. Therefore, it is perhaps more suited to situations where neither plaintiff nor defendant can muster enough causal evidence to determine what exactly was the cause of the plaintiff s injury. The increased risk approach operates as follows: A plaintiff must first establish that the defendant breached the applicable standard of care. The plaintiff must tender some cause-in-fact evidence, but this evidence will not be enough to prove on a balance of probabilities that the defendant was the cause of the injury. Next, the plaintiff must establish that the defendant s breach of the duty of care materially increased the risk of the particular injury. The plaintiff must have been exposed to that risk and then suffered that particular injury. Despite the fact that the plaintiff cannot definitively link the negligent increase in risk with the exact cause of injury that she suffered, courts have held the defendant liable based on materially increasing the risk for that particular type of injury. 67. RICHARD A. EPSTEIN, TORTS 250 (1999). 68. Curiously, Gillian Demeyere posits that the McGhee reversal approach merely dresses the civil standard of proof rule as part of a substantive standard. This is akin to the concept that the choice of substantive law for solving causation problems may be linguistic in nature and not tied to any novel function of the law. See Gillian Demeyere, The Material Contribution Test: An Immaterial Contribution to Tort Law: A Comment on Briglio v. Faulkner, 34 U.B.C. L. REV. 317, 330 (2000). 69. With the absence of the causation step, the reversal approach s effect is almost akin to Epstein s regime of strict liability.
20 268 TEXAS INTERNATIONAL LAW JOURNAL [VOL. 38: The Genesis of the Increased Risk Approach The present-day increased risk approach in Canada and Britain, like the reversal approach, seems to have grown out of a previously existing tort doctrine in Britain: the material contribution to injury doctrine. 70 In the United States, by contrast, ruminations of the increased risk approach appeared as early as It is important to distinguish the contribution to injury doctrine from the contribution to risk of injury approach as both are separate and distinct legal tools that are used for different purposes. Courts have continually blurred the distinctions between the two, and this blurring has resulted in a confusing web of causal rhetoric in court judgments. a. The Increased Risk Increased Injury Dichotomy in Britain and Canada In Bonnington Castings v. Wardlaw, 72 the British House of Lords determined that a defendant employer was liable for the injury of its worker. The worker developed lung disease from the accumulation of noxious dust inhaled from two concurrent sources, one of which was the employer s work site. Although the dust created from the employer s workplace was not itself sufficient to have caused the lung condition suffered by the plaintiff, the total combination of dust from both sources, one negligent and one nonnegligent, was the cause of the lung disease. The House of Lords held that the employer, while not responsible for the sole cause of the injury, made a material contribution to the injury through its negligence and should be liable for its entirety. 73 In cases thereafter, a plaintiff bringing a torts suit could succeed if she could prove that the negligent defendant made a material contribution to her injury, even though the defendant was not the sole contributor to the cause of the injury. The McGhee v. National Coal Board 74 case transformed the material contribution to injury doctrine into a more murky form, confusing material contribution to the plaintiff s injury with material contribution to the risk of injury. In McGhee, the majority of the House of Lords broke with the lower appeals court and held that materially contributing to a plaintiff s injury was a mirror concept with materially contributing to the mere risk of a plaintiff suffering injury. 75 If a plaintiff could prove that a defendant s negligence materially contributed to the plaintiff s injury, the plaintiff could succeed. Yet Lord Wilberforce, whose judgment sparked the reversal approach, spoke solely of the 70. This test is synonymous with the substantial factor test in the United States. 71. See Reynolds v. Texas and Pac. Ry., 37 La. Ann. 694 (La. 1885), discussed in detail infra Part III.B.1.b. 72.  2 W.L.R. 615 (H.L.). 73. Id. at  1 W.L.R. 1 (H.L. 1972). 75. See id. at 8 for the speech of Lord Simon of Glaisdale, in particular, which attempted to synthesize the increased risk approach with the material contribution to injury test. But see Lord Reid: Nor can I accept the distinction drawn by the Lord Ordinary between materially increasing the risk that the disease will occur and making a material contribution to its occurrence. Id. at 5. Lord Salmon stated that [i]n the circumstances of the present case it seems to me unrealistic and contrary to ordinary common sense to hold that the negligence which materially increased the risk of injury did not materially contribute to causing the injury. Id. at Furthermore, he stated: In the circumstances of the present case, the possibility of a distinction existing between (a) having materially increased the risk of contracting the disease, and (b) having materially contributed to causing the disease may no doubt be a fruitful source of interesting academic discussions between students of philosophy. Such a distinction is, however, far too unreal to be recognized by the common law. Id. at