The Supreme Court of Canada has been offered another chance to provide a useful explanation of the “robust, pragmatic, common sense” approach to the application of the but-for test in negligence. An application for leave to appeal where that could be one of the issues canvassed in the reasons for judgment, if leave is granted, has been under consideration for about 5 months.
Leave to appeal was sought in St-Germain c. Benhaim, 2014 QCCA 2207, reversing 2011 QCCS 4755. The SCC case number is 36291. The SCC case information page indicates that the leave application material went to the leave panel as of May 19, 2015.
Addendum Nov 3, 2015: leave has been granted: 2015 CanLII 69434 (SCC)
An usual aspect of this case is that, although it is a civil law appeal of a Quebec CA judgment, the SCC may consider common law causation principles, too. The majority in the Que CA expressly relied on an inference said to be justified by Snell v. Farrell  2 SCR 311, 1990 CanLII 70 (SCC), as the basis for holding that the plaintiff had established factual causation on the balance of probabilities. The concurring appellate judge held that factual causation had been established on the basis of presumptions mandated by the Que civil law.
The majority wrote:
 We have had the advantage of reading the reasons of our colleague Fournier, J.A. and agree with him in the result that the appeal should be allowed. We agree, in particular, with his analysis that the judge made no reviewable error in her evaluation of the damages suffered by the appellants and that the respondents be condemned, solidarily, to pay the appellants the amounts identified in our colleague’s reasons.
 We have, however, arrived at our conclusion that the respondents’ fault caused the losses suffered by a different route from that proposed by Justice Fournier.
 With due respect for the trial judge, we are of the view that she erred in law in finding that the fault of the respondent physicians was not the probable cause of the losses associated with the death of Mr. Émond. While the judge provided an often exemplary account of the law applicable to causation in the section of her reasons entitled “Principes de droit applicables”, she did not apply the law correctly in her analysis of the evidence.
 Specifically, the judge did not apply what the Supreme Court of Canada has called an “unfavourable inference” of proof of causation against the respondents.  …
[fn 30] The unfavourable inference was described in Snell v. Farrell, 1990 CanLII 70 (CSC),  2 S.C.R. 311 at 330, confirmed in a Quebec medical malpractice setting in St. Jean v. Mercier, 2002 CSC 15 (CanLII),  1 S.C.R. at 491 at 530 (paras. 111-112).
 First, by reason of the physicians’ negligence, it was impossible for the appellants to show scientifically, by direct evidence of staging of cancer, that the fault resulted in a delay in the treatment of the disease that ultimately caused … [É]’s death. The judge should have taken into account the fact that it was the negligence of the respondents that undermined the appellants’ ability to prove the fact that … [É]’s cancer was at an early stage in November 2005.
 Second, the appellants filed in evidence authoritative medical statistics that there was a 78% probability that the cancer was at stage I when it was discovered fortuitously. That “little affirmative evidence”, to use the expression of Sopinka J. in Snell,  served to discharge, prima facie, their burden of proving that Mr. Émond’s cancer was, on the balance of probabilities, at stage I at that time.
[fn 31] Snell, ibid., at 329-330.
 In the absence of proof to the contrary, the combination of these two facts – the impossibility of proving causation by reason of the physicians’ fault and the statistical proof that … [É] was likely at stage I – gave rise to the adverse inference that the negligence had caused the losses connected to his death. The respondents failed to provide a concrete answer to the prima facie statistical proof by showing that … [É] was among the 22% of persons for whom a fortuitous discovery of cancer is at a later, inoperable stage.
 Applying the ultimate burden of proof – which, of course, always rests with the plaintiffs – we are of the respectful view that the judge should have found the unanswered statistical proof advanced by the appellants allowed causation to be inferred, to the disadvantage of the respondents, given the absence of concrete evidence to the contrary.
 With due regard for the trial judge’s opinion, causation was therefore established on the balance of probabilities and the judge should have found the negligent doctors civilly liable for the losses resulting from … [É]’s death.
 We hasten to say, in fairness of the trial judge, that the application of the negative inference in instances of medical liability is rare in Quebec law: indeed, on the facts in St. Jean, it was not applied by the Supreme Court in that case. It bears mentioning that courts have sometimes wrongly confused it with a reversal of the burden of proof, a mistake the judge did not make in her carefully-written reasons.
I mentioned the common law aspect of St-Germain c. Benhaim a few months ago. This link will take you to that post.
While St-Germain has two persons whose separate conduct was held to be faulty and causative, I’m going to go out on a limb and suggest that, on the facts of the case, it should not result in either the consideration or application of any version of a material contribution to risk case as an alternative basis, in a civil law context, for a finding that the causation requirement was or was not satisfied. Anything more than that on this issue is a discussion for another day.