The trial judge wrote in
Skrepnek v Krochak, 2014 ABQB 358
 Sopinka J. for the Supreme Court in Snell held that factual uncertainty in that case did not automatically defeat the claim but that a “robust and pragmatic approach to the facts” could enable an inference to be drawn even though medical or scientific expertise could not arrive at a definitive conclusion: Snell at para 22. He continued at para 32, stating that “[w]hether an inference is or is not drawn is a matter of weighing the evidence”. This does not negate, however, the “but for” test. It still applies but can be satisfied by the drawing of a causal inference to a balance of probabilities from the circumstances in which risk arose and harm materialized: Clements v Clements, 2012 SCC 32 at para 8,  2 SCR 181. See also Brown J. (as he then was), “Cause-in-Fact at the Supreme Court of Canada: Developments in Tort Law in 2012-2013” (2014) 64 SCLR (2d) 327 at 337.
[Emphasis in bold added].
Your assignment, if you chose to read the case, and comment, here, is to decide whether the trial judge identified “the circumstances” other than (1) “the risk” and (2) the fact that the “harm materialized” which made this case one in which “the circumstances,” other than the fact of the risk and that it materialized, together with the facts that there was a risk of harm and that it materialized – that the plaintiff was injured from that risk – were sufficient to support an inference made on the balance of probability that the negligence was a necessary cause of the injury.
That’s because, if what the trial judge relied on was merely the fact of the risk and that it materialized, then the trial judge was wrong.
That’s because, if that’s enough in this case, it’s enough in every case, which results in causation being equated with breach of duty, which isn’t the law. Brown J.A., as he now is, made that explicitly clear writing, as he then was, as (merely) Prof. Russell Brown in “Material Contribution’s Expanding Hegemony: Factual Causation after Resurfice v. Hanke (2007) 45 C.B.L.J. 432.
That’s also because, in every case that’s sued where there was negligence – that is, breach of duty – there’s going to have been risk and actionable injury, or else there wouldn’t be (or at least ought not to) an action at all; unless somebody has decided that the facts warrant an extension of the law.
I expect that, in due course, I’ll get to biting hands that generally work a bit farther to the east, but not yet.