A panel of the ONCA deserves a PAULI Award for its frolic of law on proof of factual causation in Sacks v. Ross, 2017 ONCA 773 (CanLII), <http://canlii.ca/t/h6hsc>.
Why PAULI?: Because the famous physicist Wolgang Pauli once said about a theory in a physics paper: “”Das ist nicht nur nicht richtig; es ist nicht einmal falsch!” (That’s not just not right; it is not even wrong!) https://rationalwiki.org/wiki/Not_even_wrong
Why PAULI? It’s the closest analogy I could think of to the Darwin Awards: the idea being that the decision will not have descendants – i.e., will not be a precedent – so it has, in that sense, killed itself without progeny by eliminating itself from the legal equivalent of the gene pool.
The explanation for the award should tell you my view of the merits of the panel’s analysis of factual causation law principles.
Some readers will know that wrote a comment on that decision. It was available elsewhere on the web for a time. I have deleted it, for now. It will eventually reappear here, within a week or so, perhaps with some additions.
In the meantime, if you really really really need that commentary in the meantime, email me.
In the meantime, those of you who have to read and consider the merits of the Sacks assertions should keep in mind these three points:
1. In January 2017 the ONCA in Surujdeo v Melady, 2017 ONCA 41 clearly, expressly, specifically, etc., dealt with the issue the Sacks panel decided, AND that earlier panel came to the opposite conclusion. (Take a look at the name of the president of the Surujdeo panel.) The judges on that panel had before them, considered, and approved the analysis of the law as set out by and applied by the trial judge in Sacks. The discussion starts at . The discussion isn’t obiter. The issue of what and how to instruct the jury on factual causation in negligence, what the questions to the jury were to be, was the issue in Surujdeo. Surujdeo is a medical malpractice action with multiple defendants tried with a jury. (The plaintiffs succeeded at trial. The appeal was dismissed.) Nonetheless, it isn’t mentioned at all in Sacks even though Sacks cites Surujdeo as authority on a separate issue. This means we have the procedural issue of whether it was open to the panel to validly undertake the analysis in the manner that it did, regardless of what the proper decision was.
2. In Benhaim v. St‑Germain,  2 SCR 352, 2016 SCC 48, a decision which the Sacks doesn’t mention at all, McLachlin CJC, speaking for a unanimous court – there was dissent on a different issue – wrote
“ As I will now explain, Snell and St-Jean held that the ordinary rules of causation must be applied in medical malpractice cases. As prime examples of how the ordinary rules of causation operate in medical liability cases, these decisions are equally relevant in Quebec.”
That comment goes right to the issue of the merits of the panel’s analysis of the law governing proof of factual causation, including the questions and instructions to be given a jury.
3. The seeming claim by the Sacks panel that, essentially, medical malpractice claims with multiple wrongdoers are somehow different in principle, not just more factually complex, requiring not just a more careful analysis but somehow a different analysis in principle than other less complex cases, medical negligence and otherwise. That claim includes this assertion.
“ However, it is worth observing that the Supreme Court has never considered cases beyond the simple.”
I think there’s room to disagree on that claim but decide for yourself. Let’s start, and stop, here, with Benhaim v. St‑Germain and Ediger v. Johnston,  2 S.C.R. 98, 2013 SCC 18 on the medical malpractice side. For other types of case, let’s use Bow Valley Husky (Bermuda) Ltd. v. Saint John Shipbuilding Ltd.,  3 SCR 1210, 1997 CanLII 307 (SCC).
When I last checked, Ontario, like Quebec and BC, was still part of Canada, both geographically and politically.
I realize I’ve yet to say what it is the panel asserted that is so wrong.
If you’re wondering what it is the Sacks panel actually said, and you need to know, it involves the meaning of the but-for test for factual causation in negligence, the proper form of the jury question(s) on factual causation, and what words to use to tell the jury about the meaning of but-for causation. The panel wrote in 
 There are three general issues:
1. Did the trial proceed on a correct understanding of causation in negligence cases?
2. Were the jury questions and the jury instructions on causation legally correct?
3. Did any legal error in the jury questions or the jury instructions deprive the appellants of a fair trial?
Beyond that? Read the decision. I’m trying to maintain some standards, here, for now.
I did write never say never.
I now return to my currently scheduled life.
I have discussed the case here and here. The SCC did not, as is its current practice, provide reasons for granting leave. However, we can glean what the parties think the issues are, or are not, from these excerpts from the Applicants’ and Respondents’ factums.