Causation - General. Khan v Allstate Insurance Company
In Khan v Allstate Insurance Company (Div Court, 2023) the Divisional Court considered an appeal from a LAT SABS auto insurance ruling "that the Appellant was not catastrophically impaired due to mental behavioural impairments". In these quotes the court considered causation:
Did the LAT apply the wrong causation test?. Burr v. Tecumseh Products of Canada Limited
 According to the Appellant, this was a case that required the LAT to apply the “material contribution” causation test. This is because determining the cause of the March 9, 2017 fall was a complex matter. As put by the insurer’s own neurologist, Dr. Soric, [the Appellant] subsequently experienced neurological events which were subsequently investigated. Based on a review of the available documentation, the cause/etioloty of these neurological events and subjective symptoms has never been established.” In other words, according to the Appellant, Dr. Soric acknowledged that the etiology or cause of the March 9, 2017 fall has never been established. In such a situation, the Appellant argues, the law requires the use of the material contribution test.
 In Clements v. Clements, 2012 SCC 32,  2 S.C.R. 181, the Supreme Court of Canada stated the following at para. 13:
To recap, the basic rule of recovery for negligence is that the plaintiff must establish on a balance of probabilities that the defendant caused the plaintiff’s injuries on the “but for” test. This is a factual determination. Exceptionally, however, courts have accepted that a plaintiff may be able to recover on the basis of “material risk of contribution to risk of injury”, without showing factual “but for” causation. The LAT applied the normal test for causation. The Appellant is asserting that this case falls within that exceptional class of cases where the “material risk of contribution” test should be applied.
 The material risk of contribution test is to be applied “only where it is impossible to say that a particular defendant’s negligent act in fact caused the injury. It imposes liability not because the evidence establishes that the defendant’s act caused the injury, but because the act contributed to the risk that injury would occur”: Clements at para. 15. Because eliminating the necessity to prove causation as an element of negligence is a “radical step” that goes against a fundamental principle that a wrongdoer is only a wrongdoer in respect of the damage they actually cause, the material contribution to risk test is only employed very rarely.
 In Clements, the Supreme Court summarized the state of the law in Canada at para. 46 as follows:
The foregoing discussion leads me to the following conclusions as to the present state of the law in Canada: This is not a case involving sorting out causation in a situation where there are multiple tortfeasors, with the attendant risk that they can escape liability by pointing the finger at each other. Therefore, the LAT was correct in law when it applied the “but for” test.
(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 acts of the defendant….
(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 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 Burr v. Tecumseh Products of Canada Limited (Ont CA, 2023) the Court of Appeal considered basics of causation:
 ... The test for showing causation is the “but for” test. The plaintiff must show on a balance of probabilities that “but for” the defendant’s negligent act, the injury would not have occurred. Inherent in the phrase “but for” is the requirement that the defendant’s negligence was necessary to bring about the injury ― in other words that the injury would not have occurred without the defendant’s negligence. This is a factual inquiry: Clements v. Clements, 2012 SCC 32,  2 S.C.R. 181, at para. 8. The determination of the standard of care and whether there is a breach is a question of mixed law and fact: Housen v. Nikolaisen, 2002 SCC 33,  2 S.C.R. 235, at paras. 31, 70. The standard of review is correctness for questions of law, and palpable and overriding error for findings of fact, mixed fact and law, and inferences of fact: Housen, at paras. 8, 10 and 19-20.. Sajid v. Certas ['direct cause']
In Sajid v. Certas (Div Ct, 2022) the Divisional Court considered an issue of 'direct cause' in a MVA insurance case:
 The Appellant relies on North Waterloo Farmers Mutual Insurance Co. v. Samad (Samad), in which the Divisional Court held:
 A “direct cause” is a cause or an act that sets in motion an uninterrupted chain or train of events or the first in a row of blocks after which the rest fall down without the assistance of any other act or intervention of any other force. If an unbroken chain of events involving the use or operation of an automobile leads to an injury, the injury can be said to have been directly caused by the incident. (Chisholm v. Liberty Mutual Group, 2002 CanLII 45020 (ON CA),  O.J. No. 3135 (C.A.) at para. 27 and Petrosoniak and Security National Insurance Co. (FSCO A98-000198, November 2, 1998), at p. 7.)
 There need not be one direct cause, and a direct cause need not be the most immediate cause. (Wawanesa Mutual Insurance Company and Webb (FSCO Appeal P11-00015, July 18, 2012), p. 6.)