When I use a word, said a famous literary character, it means exactly what I say it means, nothing more and nothing less.
The same principle applies to statements of the Supreme Court of Canada. The Court made that abundantly clear in the intervener's failed attempt to get a rehearing of the Court's decision in R. v. Marshall,  3 S.C.R. 456, 1999 CanLII 665 in R. v. Marshall,  3 SCR 533, 1999 CanLII 666.
But, as Marshall shows, if there's a dispute about what the Court meant, we don't get to find out the Supreme Court's last word (until that changes
the next time) on exactly what the Court meant until the next time around.
The late John Fleming wrote, in an article published in 1991 -“Probabilistic Causation In Tort Law: A Postscript” (1991), 70 Can. B. Rev. 136 at 147 – in part a case comment on Snell v. Farrell,  2 S.C.R. 311, 1990 CanLII 70 – "We are awaiting the next move in the causality game.”
I don't always make these things up.
But, in law, causality isn't a zero-sum game. There are winners and losers.
But no balance even if one believes that corrective justice is the underpinning of tort law. (Added Sept 30, 2012)
This is the Court's unofficial summary of the issues in Ediger v. Johnston SCC case no. 34408, an appeal scheduled for December 4, 2012. Ediger is an appeal (by the plaintiff) from 2011 BCCA 253 rev'g 2009 BCSC 386.
Torts — Negligence — Medical malpractice — Causation — Trial judge finding respondent obstetrician liable for applicant infant’s injuries — Whether, under principles described in Snell v. Farrell,  2 S.C.R. 311, it is open for a trier of fact to find causation by drawing an inference based on all the evidence led at trial, notwithstanding the fact that the defence has led some evidence to the contrary — Whether, in an informed consent case, the causation issue is decided in accordance with the majority or the minority opinions of the House of Lords in Chester v Afshar,  1 A.C. 134.
The applicant sued the respondent, Dr. Johnston, an obstetrician and gynaecologist, for damages arising from serious injury during her birth. The applicant sued through her mother, Carolyn Ediger. Late in Mrs. Ediger's labour, Dr. Johnston attempted a rotational "mid-level" forceps procedure to assist the delivery, but was unable to place the forceps satisfactorily. Shortly after he abandoned the procedure, the applicant's heart action slowed in a bradycardia which deprived her of necessary oxygen, and persisted until she was delivered by Caesarean section and resuscitated approximately eighteen minutes later, causing severe brain damage which is permanent.
The trial judge concluded that Dr. Johnston breached the standard of care in attempting a rotational mid-forceps delivery without first checking on the availability of back-up for Caesarean section delivery if necessary. Despite what she found to have been an interlude of between one and two minutes after the forceps attempt and before the onset of the bradycardia, the trial judge concluded that the evidence was sufficient to establish that the one caused the other. She concluded as well that the applicant had also proven her claim based on the absence of Mrs. Ediger's informed consent to the forceps procedure before the applicant’s birth. Dr. Johnston appealed the finding of liability on the issue of causation only. The Court of Appeal allowed the appeal and dismissed the action.
In Chester, if one takes the majority and dissent speeches (reasons for judgment) at face value – the split was 3-2 - the plaintiff succeeded on the normative basis that the duty of care in issue was so important that that justified dispensing completely with any requirement for a causal connection between the defendant's negligence and the plaintiff's injury. Thus, the plaintiff succeeded even though it was found that there was no causal relationship whatsoever between the negligence and the plaintiff's injury. There was, of course, a causal connection between the physician's non-negligent conduct and the injury. The injury was consequence of the non-negligent performance of an operation on the plaintiff's spine. It was one of those adverse consequences that occurred in a very small percentage of cases, for no known reason, even where the operation was performed properly. So, it is literally true that if the patient had not had the operation when she had it, she would not have suffered the injury she sustained as a result of having the operation when she had it.
On the other hand, before we attempt to guess what the SCC might say about the meaning of a U.K. decision, what with the effect of airplane travel on the environment, and the demise of the House of Lords, and the fact that the House of Lords hasn't been Canada's court of last resort (officially) for new cases since 1948 (or thereabouts), one might think that the appellant could have looked closer to home than the House of Lords for a case that the Supreme Court could plug into the statement "Whether, in an informed consent case, the causation issue is decided in accordance with the majority or the minority opinions of … ", even if Chester was used as a "see also".
For example, the majority or minority opinions of the Supreme Court of Canada in Hollis v. Dow Corning Corp.,  4 SCR 634, 1995 CanLII 55. The justification for the majority decision appears in paras. 60-61 of the reasons of La Forest J (on behalf of himself, L'Heureux‑Dubé, Gonthier, Cory, and Iacobucci JJ.)
 Simply put, I do not think a manufacturer should be able to escape liability for failing to give a warning it was under a duty to give, by simply presenting evidence tending to establish that even if the doctor had been given the warning, he or she would not have passed it on to the patient, let alone putting an onus on the plaintiff to do so. Adopting such a rule would, in some cases, run the risk of leaving the plaintiff with no compensation for her injuries. She would not be able to recover against a doctor who had not been negligent with respect to the information that he or she did have; yet she also would not be able to recover against a manufacturer who, despite having failed in its duty to warn, could escape liability on the basis that, had the doctor been appropriately warned, he or she still would not have passed the information on to the plaintiff. Our tort law should not be held to contemplate such an anomalous result.
 As I see it, the plaintiff's claim against the manufacturer should be dealt with in accordance with the following rationale. The ultimate duty of the manufacturer is to warn the plaintiff adequately. For practical reasons, the law permits it to acquit itself of that duty by warning an informed intermediary. Having failed to warn the intermediary, the manufacturer has failed in its duty to warn the plaintiff who ultimately suffered injury by using the product. The fact that the manufacturer would have been absolved had it followed the route of informing the plaintiff through the learned intermediary should not absolve it of its duty to the plaintiff because of the possibility, even the probability, that the learned intermediary would not have advised her had the manufacturer issued it. The learned intermediary rule provides a means by which the manufacturer can discharge its duty to give adequate information of the risks to the plaintiff by informing the intermediary, but if it fails to do so it cannot raise as a defence that the intermediary could have ignored this information. …
There were two dissenting judges. The crux of the dissent on this aspect of the causation issue is captured in paras. 72-73 of the dissent. The dissenting reasons are attributed to Sopinka J.
 In determining the second causation issue of whether Dr. Birch would have warned Ms. Hollis of the risk of rupture if Dow had properly warned Dr. Birch about that risk, La Forest J. proposes to eliminate the fundamental requirement of tort law that the plaintiff establish causation in order to prove the defendant's liability. Once Ms. Hollis demonstrated that Dow had breached its duty to warn of the risk of rupture, La Forest J. would hold that the plaintiff's burden of proving her case had been discharged, and that any possibility that Dr. Birch would have failed to pass on any warning is nothing more than a question of apportionment. This approach runs counter to well established tort principles. Simply put, in order to establish liability, the plaintiff must show not only a breach of duty by the defendant, but also that the breach in question was the cause of the plaintiff's injury.
 In the instant case, this burden applies to require the plaintiff to show that her injuries would not have occurred had Dow discharged its duty to warn Dr. Birch of any dangers inherent in the implants. In other words, Ms. Hollis must show that her doctor would have warned her of any dangers that had been brought to his attention and that if warned she would have refused the operation. Absent this form of proof, it cannot be said with any degree of certainty that the failure of Dow to warn physicians was the cause of the unfortunate injuries suffered by Ms. Hollis.
Maybe the rationale in Hollis is distinguishable because Hollis wasn't an action against a physician. Maybe it isn't distinguishable on some basis that makes the rationale irrelevant, then maybe the Supreme Court will have to find some other way of not softening the principle in Hollis.
It's worthwhile noting, for those who care, who the other dissenting judge was – (as she then was – that should be hint enough) – and wondering how this might affect what happens in Ediger
Chester. After all, there have been cases since Hollis (in 1995) that could be seen to indicate a change of position. They're well enough known. They lead, of course, to Clements v. Clements, 2012 SCC 32,
Did the Supreme Court mean to say, in Clements v. Clements, 2012 SCC 32, that, in an appropriate case, it might be prepared to eliminate completely the requirement for any causal relationship between the wrongdoer's negligence and the plaintiff's injury? The Court wrote at para. 16
 Elimination of proof of causation as an element of negligence is a “radical step that goes against the fundamental principle stated by Diplock L.J. in Browning v. War Office,  3 All E.R. 1089 (C.A.), at pp. 1094-95: ‘…[a] defendant in an action in negligence is not a wrongdoer at large; he is a wrongdoer only in respect of the damage which he actually causes to the plaintiff’”: Mooney v. British Columbia, 2004 BCCA 402, 202 B.C.A.C. 74, at para. 157, per Smith J.A., concurring in the result. For that reason, recourse to a material contribution to risk approach is necessarily rare, and justified only where it is required by fairness and conforms to the principles that ground recovery in tort.
However, context is important. The Court was not writing in, nor was it deciding, a case in which it was asked to decide about the complete "elimination of proof of causation". It was deciding whether it would eliminate the requirement of proof of factual causation on the balance of probability.
 To recap, the basic rule of recovery for negligence is that the plaintiff must establish on a balance of probabilities that the defendant caused the plaintiff’s injury on the “but for” test. This is a factual determination. Exceptionally, however, courts have accepted that a plaintiff may be able to recover on the basis of “material contribution to risk of injury”, without showing factual “but for” causation. …
The material contribution to risk doctrine is not the complete elimination of any requirement of a causal relationship. It is premised on the existence of the possibility that the negligent person's negligence was a cause of the injury. That premise implies that the negligent conduct is capable of causing the injury the plaintiff alleges. If there were an issue on the latter point, the plaintiff would have to establish, on the balance of probability, that the negligent conduct is capable of causing the injury. If it isn't capable, then there's no possibility the negligence could have caused the injury.
So, the Court did not have to say what Clements means, if anything, to the argument that any requirement for any causal relationship at all should be eliminated where that is necessary to ensure that the wrongdoer's duty has content.
But, as I've pointed out, a majority of the Supreme Court once said exactly that, in Hollis v. Dow Corning Corp.
Perhaps the easiest place to find a summary of the meaning of Chester is in the last paragraph of the one of the three majority speeches, which just happens to be the last paragraph in last set of reasons delivered by one of the 3 judges in the majority. We find, then, in 2004 UKHL 41 at para. 101
Nevertheless there are real difficulties (especially, perhaps, for a conscientious claimant aware of the fallibility of hindsight) in a claimant asserting that (if warned of the risks) she would never in any circumstances have submitted to surgery. There would be a danger, as Lord Hope points out, of an honest claimant finding herself without a remedy in circumstances where the surgeon has failed in his professional duty, and the claimant has suffered injury directly within the scope and focus of that duty. I agree with Lord Steyn and Lord Hope that such a claimant ought not to be without a remedy, even if it involves some extension of existing principle, as in Fairchild v Glenhaven Funeral Services Ltd  1 AC 32 (see especially the speech of my noble and learned friend Lord Bingham of Cornhill at paras 8-13). Otherwise the surgeon's important duty would in many cases be drained of its content.
[Emphasis added by me.] BAILII doesn't list an subsequent U.K. House of Lords or Supreme Court decisions explaining Chester.
 … in Chester v Afshar  UKHL 41; 1 AC 134. A doctor failed to warn a patient about the potential risks of a particular operation. There was a 1-2% chance of significant adverse injury whenever the operation was performed quite irrespective of the particular circumstances of the patient. It was not possible to identify when the risk would materialise. That risk in fact materialised following the operation. If the warning had been given, the patient would have still had the operation after considering the implications, but it would have been carried out on a different day, and the very high probability is that the injury would not have been sustained at all on that occasion. Their Lordships held by a majority of 3 to 2 (Lord Steyn, Lord Hope of Craighead and Lord Walker of Gestingthorpe; Lords Bingham of Cornhill and Lord Hoffman dissenting) that the doctor should be liable. However, the basis of liability was that the obligation to warn was an important protection of patient autonomy which should not be undermined even if it is clear that the patient would have taken the risk of having the operation in any event. The important point for the purposes of this case is that their Lordships rejected the contention that the doctor should be liable on the simple basis that in fact the patient would not have suffered the injury but for the failure to warn. In failing to warn, the doctor had not increased the risk of the operation. It was quite arbitrary when that risk would materialise; the risk was the same whenever the operation occurred. The majority only imposed liability in order to give an effective remedy for breach of the right to warn.
This, however, is in dissenting reasons. The plaintiff's action succeeded. The majority affirmed the trial judgment and dismissed the appeal. The two concurring majority reasons don't mention Chester. Nonetheless, my sense of the majority reasons is that the judges in the majority would have agreed with that statement of Chester if they thought it necessary to mention Chester.
Clements-Resurfice material contribution to risk was the Supreme Court's last move in the causality game – which is no game at all. Will Ediger contain the next?
Postscript - Added Sept 30, 2012
Some of you may have noticed I skipped the first issue stated in the Ediger summary:
Whether, under principles described in Snell v. Farrell,  2 S.C.R. 311, it is open for a trier of fact to find causation by drawing an inference based on all the evidence led at trial, notwithstanding the fact that the defence has led some evidence to the contrary.
That's because I assumed it's been answered "YES" by the reasons and result of Clements. Reread paras. 48-49 and 52-53 of the majority reasons. I suppose it would be interesting (for no useful purpose) to see when the summary was put up because, as as it says in bold, at the top of the summary: "Case summaries are prepared by the Office of the Registrar of the Supreme Court of Canada (Law Branch) for information purposes only."
If it hasn't been answered "YES" then, paraphasing what Ricky apparently never quite said said to Lucy, the Clements majority would have "lots of 'splaining to do", if they were required to 'splain. But, taking us back to where this piece began, they're not.