In a previous post entitled: “Clear as Mud: The Supreme Court of Canada to Clarify the Law of Causation“, I noted the Supreme Court of Canada’s latest opportunity to clarify the law of causation following the BC Court of Appeal decision in Clements v. Clements. The analytical confusion stemmed from the conflicting application of “but-for” test and “material contribution” test by various trial and appellate courts, following the Supreme Court of Canada’s decisions in Fullowka v. Pinkerton’s of Canada Ltd., 2010 SCC 5,  1 S.C.R. 132 and Resurfice Corp. v. Hanke, 2007 SCC 7,  1 S.C.R. 333.
David Cheifetz over at slaw.ca valiantly attempted to sort out this mess before the Supreme Court of Canada released its decision today. Frankly, my head hurts after reading his post.
Anywho, here’s a link to the Supreme Court of Canada’s decision released this morning: Clements v. Clements, 2012 SCC 32 (S.C.C.).
The majority opinion written by the Chief Justice (Deschamps, Fish, Abella, Cromwell, Moldaver and Karakatsanis JJ concurring; LeBel and Rothstein JJ. dissenting), is summarized as follows:
 The foregoing discussion leads me to the following conclusions as to the present state of the law in Canada:
(1) As a general rule, a plaintiff cannot succeed unless she shows as a matter of fact that she would not have suffered the loss “but for” the negligent act or acts of the defendant. A trial judge is to take a robust and pragmatic approach to determining if a plaintiff has established that the defendant’s negligence caused her loss. Scientific proof of causation is not required.
(2) Exceptionally, a plaintiff may succeed by showing that the defendant’s conduct materially contributed to risk of the plaintiff’s injury, where (a) the plaintiff has established that her loss would not have occurred “but for” the negligence of two or more tortfeasors, each possibly in fact responsible for the loss; and (b) the plaintiff, through no fault of her own, is unable to show that any one of the possible tortfeasors in fact was the necessary or “but for” cause of her injury, because each can point to one another as the possible “but for” cause of the injury, defeating a finding of causation on a balance of probabilities against anyone.
In other words: The “but for” test is the default test for causation in negligence, “but for” [pun intended] multiple tort-feasors, when, exceptionally, the “material contribution” test otherwise applies.