You’ll have to follow the bouncing ball or, in this case, the quotations from the cases. The commentary follows the quotations.
1. Aristorenas v. Comcare Health Services, , 83 OR (3d) 282, 274 DLR (4th) 304, 2006 CanLII 33850
 The “robust and pragmatic” approach is not a distinct test for causation but rather an approach to the analysis of the evidence said to demonstrate the necessary causal connection between the conduct and the injury. Importantly, a robust and pragmatic approach must be applied to evidence; it is not a substitute for evidence to show that the defendant’s negligent conduct caused the injury.
 The “robust and pragmatic” approach was described by Sopinka J. inSnell [Snell v. Farrell,  2 SCR 311, 1990 CanLII 70,] at pp. 300-302:
I am of the opinion that the dissatisfaction with the traditional approach to causation stems to a large extent from its too rigid application by the courts in many cases. Causation need not be determined by scientific precision.…
In many malpractice cases, the facts lie particularly within the knowledge of the defendant. In these circumstances, very little affirmative evidence on the part of the plaintiff will justify the drawing of an inference of causation in the absence of evidence to the contrary.
The legal or ultimate burden remains with the plaintiff, but in the absence of evidence to the contrary adduced by the defendant, an inference of causation may be drawn although positive or scientific proof of causation has not been adduced. If some evidence to the contrary is adduced by the defendant, the trial judge is entitled to take account of Lord Mansfield’s famous precept. This is, I believe, what Lord Bridge had in mind in Wilsher when he referred to a “robust and pragmatic approach to the … facts.”
It is not, therefore, essential that the medical experts provide a firm opinion supporting the plaintiff’s theory of causation. Medical experts ordinarily determine causation in terms of certainties whereas a lesser standard is demanded by the law. As pointed out in D.W. Louisell, Medical Malpractice, the phrase “in your opinion with a reasonable degree of medical certainty”, which is the standard form of question to a medical expert, is often misunderstood [citations omitted].
 It is important to note that Sopinka J. does not reduce the ultimate burden of proof from a balance of probabilities. Rather, the “robust and pragmatic” approach is adopted in evaluating the facts of the case and deciding whether they meet the civil standard. Put another way, the burden of proof is the same, but a series of facts and circumstances established by the evidence led at trial may enable the trial judge to draw an inference even though medical and scientific expertise cannot arrive at a definitive conclusion.
. . .
 In Snell, Sopinka J. indicated that causation did not have to be established with scientific precision but that there still needed to be evidence and other considerations that, when viewed pragmatically and robustly, would satisfy a trier of fact on a balance of probabilities that there was causation.
 The “robust and pragmatic” approach is succinctly set out at para. 16 of Athey:
In Snell v. Farrell, this Court recently confirmed that the plaintiff must prove that the defendant’s tortious conduct caused or contributed to the plaintiff’s injury. The causation test is not to be applied too rigidly. Causation need not be determined by scientific precision; as Lord Salmon stated in Alphacell Ltd. v. Woodward, and as was quoted by Sopinka J., it is “essentially a practical question of fact which can best be answered by ordinary common sense”. Although the burden of proof remains with the plaintiff, in some circumstances an inference of causation may be drawn from the evidence without positive scientific proof [citations omitted].
 In Athey [Athey v. Leonati,  3 SCR 458, 1996 CanLII 183] Major J. speaks of avoiding a rigid application of the test or requiring scientific precision. He also says that common sense can aid in the determination of causation. Further, an inference may be drawn without scientific proof. While this language does evoke a more “relaxed” standard to proving causation, it does not alter the requirement that the plaintiff must establish causation on a balance of probabilities. In my view the “robust and pragmatic” approach modifies the type of evidence as well as the factors that the court may consider. It does not modify the amount of proof required to establish causation.
 The above distinction can be illustrated by applying the “robust and pragmatic” approach to the facts in Snell. InSnell, neither expert was able to express with certainty an opinion as to what caused the harm or when it occurred. As a result, the court used a combination of evidence and other considerations to support a finding of causation on a balance of probabilities:
- First, while experts were not able to testify as to causation on a standard of scientific precision, there was some evidence that the negligent operation had led to the injury.
- Second, the trial judge was satisfied that there was a greatly increased risk of injury because of the negligence.
- Third, there was a finding by the trial judge that “virtually rule[d] out natural causes”.
- Fourth, the defendant was in a better position to observe what occurred. He also was in a better position to interpret what he saw.
- Fifth, the negligent operation resulted in a situation where it was impossible for anyone else to detect the precise cause of the injury.
 Taking these factors into consideration, Sopinka J. found that it was open to infer causation. The approach is “robust and pragmatic” because this type of evidence might not otherwise satisfy the “but for” test.
 Snell and other cases have recognized that it is important to require that the plaintiff provide some sort of evidence (or other considerations) that indicates that the defendant was the cause of the harm suffered. InSnell, Sopinka J. at p. 299, disapproved of permitting the plaintiff to “simply prove that the defendant created a risk that the injury which occurred would occur.” In Fairchild v. Glenhaven Funeral Services,  3 W.L.R. 89 (H.L.), Lord Rodger of Earlsferry provided this caution about applying the “robust and pragmatic” approach:
[E]ven though it is always for the judge rather than for the expert witness to determine matters of fact, the judge must do so on the basis of the evidence, including the expert evidence. The mere application of “common sense” cannot conjure up a proper basis for inferring that an injury must have been caused in one way rather than another … (para. 150).
 It is, therefore, a misapplication of the “robust and pragmatic” approach to make a finding or draw an inference of causation where no factors of the kind set out in Snell are present and the proper evidentiary foundation is absent.
 Snell, supra, at 292.
 See for example Snell, supra, at pp. 304-305.
 Snell, supra, at 305.
2. Madill v. Sithivong, 2012 BCCA 62
 I accept the appellants’ position that a court must be cautious when inferring causation from a temporal sequence: that is, from a consideration of pre-accident versus post-accident condition (White v. Stonestreet, 2006 BCSC 801, 151 A.C.W.S. (3d) 233 at paras. 74 – 75).
3. Erickson v. Sibble, 2012 BCSC 1880
 The Court is called upon to exercise caution in inferring legal causation by exclusive or substantial reference to a temporal sequence of events: Madill v. Sithivong, 2012 BCCA 62 at para. 20; White v. Stonestreet, 2006 BCSC 801 at paras. 74-75. But the judicial insistence of caution does not signify judicial thinking that temporal reasoning is an illegitimate analysis or a branch of logic to be seldom invoked, as the defendants appear to urge.
4. Midgley v. Nguyen, 2013 BCSC 693
 The court must be cautious when inferring causation from a temporal sequence; that is, from a consideration of pre-accident versus post-accident condition. In cases where causation is asserted primarily on a temporal relationship between the negligent conduct and injury in question, the authorities mandate that a “close scrutiny of the evidence is required because the inference from a temporal sequence to a causal connection is not always reliable”: Hardychuk [Hardychuk v. Johnstone, 2012 BCSC 1359] at para. 130. See also: Madill v. Sithivong, 2012 BCCA 62 at para. 20; White v. Stonestreet, 2006 BCSC 801 at paras. 74-75. However, the authorities recognise that temporal reasoning is not an illegitimate analysis if invoked in the appropriate circumstances: Erickson v. Sibble, 2012 BCSC 1880 at para. 223.
4. Fontaine v. Van Kampen, 2013 BCSC 1702
 The court will exercise caution in inferring legal causation by exclusive or substantial reference to a temporal sequence of events, which often takes the form of comparing the plaintiff’s condition in the pre and post-Accident scenarios: Madill v. Sithivong, 2012 BCCA 62 at para. 20; White v. Stonestreet, 2006 BCSC 801 at paras. 74-75. As I have noted in past decisions, it does not follow that the judicial insistence of caution signifies judicial thinking that temporal reasoning is an illegitimate analysis or a branch of logic to be seldom invoked: see also, Midgley.
5. Chasczewski v. 528089 Ontario Inc., 2012 ONCA 97
 The question whether the standard of care was met should be decided before the question of factual causation: see Bafaro v. Dowd, 2010 ONCA 188, 260 O.A.C. 70; and Randall v. Lakeridge Health, 2010 ONCA 537, 270 O.A.C. 371. It must be resolved first for two reasons. First, without a finding that the defendant has breached the standard of care, the question of causation becomes moot. Second, and more important for this case, it is the defendant’s particular substandard act or omission that must be shown to have caused the harm; therefore, it is necessary to identify that act or omission to determine what, if any, connection it has to the harm at issue. In other words, causation can only be assessed in the context of a breach of the standard of care.
McArdle, Estate v. Cox, 2003 ABCA 106
 It is a critical fault to reorder negligence analysis by placing the causation before that of the standard of care. How can a judge decide whether, but for the defendant’s substandard action, the plaintiff would not have been injured, if the characterization and application of the standard of care decision depends on the causation decision? The suggestion that causation be analysed before standard of care truly is putting the cart before the horse.
6. Maher v. Sutton, 2013 BCSC 1808
 The plaintiff John Maher seeks damages for loss and injury that he alleges he suffered as a result of having corrective laser eye surgery on March 27, 2008. Mr. Maher alleges that the defendants were negligent in in their treatment of him and that the defendants proceeded with the surgery without his informed consent. …
. . .
 The consensus of the medical evidence before me is that Mr. Maher suffers from dry eye syndrome and that his fluctuating visual acuity is attributable to variable tear flow. I am satisfied on the evidence before me that these conditions are a result of the laser treatment undergone on March 27, 2008. Both Dr. Fromer and Dr. Goldberg agree that dry eye syndrome is a recognized complication of laser surgery. Dr. Holland, although not qualified as an expert in this case, did testify that he observed dry spots on the left eye during his examinations of Mr. Maher.
 Dr. Goldberg’s evidence was that it is thought that the disruption of tear flow is attributable to the severing of nerves when cutting the flap to expose the lens of the eye. The enhancement procedure Dr. Sutton performed did not involve the cutting of any such nerves because Dr. Sutton lifted the existing flap previously cut by Dr. Lin. However, there is no evidence that Mr. Maher suffered from persistent dry eye prior to the surgery performed by Dr. Sutton. Dr. Fromer does not limit the cause of dry eye to the severing of nerves.
 I base my finding that the difficulties experienced by Mr. Maher are attributable to the surgery on a common sense view of the evidence. Mr. Maher did not experience the symptoms prior to the surgery. His symptoms are recognized complications of laser eye surgery. In Clements v. Clements, 2012 SCC 32, the Court stated as follows:
 The “but for” causation test must be applied in a robust common sense fashion. There is no need for scientific evidence of the precise contribution the defendant’s negligence made to the injury. See Wilsher v. Essex Area Health Authority,  A.C. 1074, at p. 1090, per Lord Bridge; Snell v. Farrell,  2 S.C.R. 311.
 A common sense inference of “but for” causation from proof of negligence usually flows without difficulty. Evidence connecting the breach of duty to the injury suffered may permit the judge, depending on the circumstances, to infer that the defendant’s negligence probably caused the loss. See Snell and Athey v. Leonati,  3 S.C.R. 458. See also the discussion on this issue by the Australian courts: Betts v. Whittingslowe,  HCA 31, 71 C.L.R. 637, at p. 649; Bennett v. Minister of Community Welfare,  HCA 27, 176 C.L.R. 408, at pp. 415-16; Flounders v. Millar,  NSWCA 238, 49 M.V.R. 53; Roads and Traffic Authority v. Royal,  HCA 19, 245 A.L.R. 653, at paras. 137-44.
 The above quotation addressed the issue of causation once negligence has been established. In this case no negligence in the performance of the surgery itself is alleged. However, I conclude that the same principles apply in determining causation in cases involving alleged lack of informed consent. In such cases the Court should apply the “but for” test for causation in a robust and common sense fashion to determine whether the surgery caused the injuries complained of. In this case I conclude that the plaintiff has established that the symptoms he complains of were caused by the enhancement procedure performed by Dr. Sutton.
As (and if) you read the Maher reasons, you’ll see that it was after para. 45 that the trial judge set out his analysis of and decision on the issues of negligence in the performance of the procedure and whether there was informed consent. I’ve quoted all of the law the judge set out on the issues of causation in either cause of action.
I’ve also quoted everything the trial judge said about the evidence as to possible causes of the dry eye condition.
Although the reasons state, in para. 43 “Dr. Fromer does not limit the cause of dry eye to the severing of nerves” the reasons do not indicate whether there was any evidence as to what other causes there might be for this condition. Instead there is only: “there is no evidence that Mr. Maher suffered from persistent dry eye prior to the surgery performed by Dr. Sutton”.
In the end, however, the DEFENDANTS have no reason to complain about the result of the trial as the trial judge dismissed the action finding that there was: (1) no negligence in the performance of the operation and (2) there WAS informed consent.
So, if there was no other evidence, and if the trial judge erred at all, it didn’t harm the defendants.
But, if there was some other evidence that the trial judge might have referred to, that failure is a problem for both plaintiff and defendants.
7. Does anyone care to speculate why it is that, more than twenty years after Snell, some judges (and lawyers) seem to be confused about both the purpose of the Snell “robust and pragmatic” approach to the use of the but-for test and when it is to be applied?
Recall how Sopinka J. introduced the discussion that led to the robust and pragmatic approach mantra.
The question that this Court must decide is whether the traditional approach to causation is no longer satisfactory in that plaintiffs in malpractice cases are being deprived of compensation because they cannot prove causation where it in fact exists.
Causation is an expression of the relationship that must be found to exist between the tortious act of the wrongdoer and the injury to the victim in order to justify compensation of the latter out of the pocket of the former. Is the requirement that the plaintiff prove that the defendant’s tortious conduct caused or contributed to the plaintiff’s injury too onerous? Is some lesser relationship sufficient to justify compensation? …
Snell,  2 SCR 311 at p. 326.
8. Consider what the trial judge did in Maher.
If we take the reasons at face value, we have to conclude that, in Snell terms, the plaintiff was not able to lead “positive” – i.e., medical – evidence of any causal connection between any aspect of Dr. Sutton’s conduct, let alone only the defendant’s alleged negligent conduct.
Yet, the trial judge was prepared, in considering the factual causation issue in the lack of informed consent cause of action – since that action would necessarily fail if the procedure was not a cause of the alleged injury – to use a standard of proof in the causation inquiry which was less than what medicine, itself required. The trial judge did not explain, anywhere in the reasons, why it was appropriate, in the absence of a finding of wrongdoing by S, to use law’s lower standard of proof. Para. 45 says no more than that the robust and pragmatic approach should also be used in deciding causation in cases alleging informed consent.
I’m not suggesting that there might not be a good reason, in informed consent cases, to deal with causation first, at least where the issue is whether it could be said the alleged injury is any form of consequence of the procedure performed as it was, the premise being the procedure was performed properly.
There should be no doubt that the trial realized that there would be no point in undertaking any portion of the informed consent analysis, beginning with duty and standard, if the alleged injury was not, in fact, causally related in any sense, to the procedure. But that question is different from the question of whether the injury was, in some sense, said to be causally related to the fact the operation was performed.
An extreme example of a circumstance that could be claimed to be a connection would occur where the operating room exploded, as a result of a meteor strike, while the patient was in the OR. Could the patient claim that, had he or she received adequate disclosure of the risks, advice, he or she would have sought a second opinion, or at least taken more time to think about consenting, so wouldn’t have had the procedure on the day the meteor struck?
I’m extending the consequences of the decision of the majority of the House of Lords in Chester v. Afshar,  UKHL 41,  1 AC 134,  3 WLR 927,  4 All ER 587.
9. Do you think that, perhaps, the SCC needs to do a better job in explaining, for Canadian tort law, what the but-for test now means, when it is to be applied, and how it is to be applied?
10. Perhaps we can agree that the SCC’s current explanation, as found in Snell, Athey and Clements v. Clements,  2 SCR 181, 2012 SCC 32 is at least as incomplete as the Court said, in Clements, its explanation of the “material contribution test” had been in Resurfice.
11. Perhaps we can agree that the Court needs to provide more and better explanation. I’m aware of one pending leave to appeal application which could produce some of that consideration.
12. Of course, if the SCC were to do that – clear up the confusion, I’d have no valid reason, or fewer valid reasons: clarity does not necessarily mean adequacy – for writing about this subject. I’d have to consider writing about, say, apportionment of fault. So, I suppose I need to be careful about I wish for.
posted Oct 5, 2013; revised: additions to para. 8 Oct 5, 2013