Source: https://davidcheifetz.ca/2012/12/14/stumping-the-great-karnak-even-were-he-still-alive/
Timestamp: 2019-04-25 00:59:15+00:00

Document:
If a responsible judge finds for the plaintiff, it must be accepted that the evidence was sufficiently clear, convincing and cogent to that judge that the plaintiff satisfied the balance of probabilities test.
Trial judges are presumed to know the law with which they work day in and day out.
 Causation is established where the plaintiff proves to the civil standard on a balance of probabilities that the defendant caused or contributed to the injury: Snell v. Farrell,  2 S.C.R. 311; McGhee v. National Coal Board,  3 All E.R. 1008 (H.L.).
 The general, but not conclusive, test for causation is the “but for” test, which requires the plaintiff to show that the injury would not have occurred but for the negligence of the defendant: Horsley v. MacLaren,  S.C.R. 441.
 The “but for” test is unworkable in some circumstances, so the courts have recognized that causation is established where the defendant’s negligence “materially contributed” to the occurrence of the injury: Myers v. Peel County Board of Education;  2 S.C.R. 21, Bonnington Castings, Ltd. v. Wardlaw,  1 All E.R. 615 (H.L.); McGhee v. National Coal Board, supra. A contributing factor is material if it falls outside the de minimis range: Bonnington Castings, Ltd. v. Wardlaw, supra; see also R. v. Pinske (1988), 30 B.C.L.R. (2d) 114 (B.C.C.A.), aff’d  2 S.C.R. 979.
 In Snell v. Farrell, supra, this Court recently confirmed that the plaintiff must prove that the defendant’s tortious conduct caused or contributed to the plaintiff’s injury. The causation test is not to be applied too rigidly. Causation need not be determined by scientific precision; as Lord Salmon stated in Alphacell Ltd. v. Woodward,  2 All E.R. 475, at p. 490, and as was quoted by Sopinka J. at p. 328, it is “essentially a practical question of fact which can best be answered by ordinary common sense”. Although the burden of proof remains with the plaintiff, in some circumstances an inference of causation may be drawn from the evidence without positive scientific proof.
 It is not now necessary, nor has it ever been, for the plaintiff to establish that the defendant’s negligence was the sole cause of the injury. There will frequently be a myriad of other background events which were necessary preconditions to the injury occurring. To borrow an example from Professor Fleming (The Law of Torts (8th ed. 1992) at p. 193), a “fire ignited in a wastepaper basket is … caused not only by the dropping of a lighted match, but also by the presence of combustible material and oxygen, a failure of the cleaner to empty the basket and so forth”. As long as a defendant is part of the cause of an injury, the defendant is liable, even though his act alone was not enough to create the injury. There is no basis for a reduction of liability because of the existence of other preconditions: defendants remain liable for all injuries caused or contributed to by their negligence.
It has always been the law that a pursuer succeeds if he can shew that fault of the defender caused or materially contributed to his injury. There may have been two separate causes but it is enough if one of the causes arose from fault of the defender. The pursuer does not have to prove that this cause would of itself have been enough to cause him injury.
 The law does not excuse a defendant from liability merely because other causal factors for which he is not responsible also helped produce the harm: Fleming, supra, at p. 200. It is sufficient if the defendant’s negligence was a cause of the harm: School Division of Assiniboine South, No. 3 v. Greater Winnipeg Gas Co.,  4 W.W.R. 746 (Man. C.A.), at p. 753, aff’d  6 W.W.R. 765 (S.C.C.),  S.C.R. vi; Ken Cooper-Stephenson, Personal Injury Damages in Canada (2nd ed. 1996), at p. 748.
 This position is entrenched in our law and there is no reason at present to depart from it. If the law permitted apportionment between tortious causes and non-tortious causes, a plaintiff could recover 100 percent of his or her loss only when the defendant’s negligence was the sole cause of the injuries. Since most events are the result of a complex set of causes, there will frequently be non-tortious causes contributing to the injury. Defendants could frequently and easily identify non-tortious contributing causes, so plaintiffs would rarely receive full compensation even after proving that the defendant caused the injury. This would be contrary to established principles and the essential purpose of tort law, which is to restore the plaintiff to the position he or she would have enjoyed but for the negligence of the defendant.
 The Supreme Court of Canada re-affirmed these principles in Clements v. Clements, 2012 SCC 32, 346 D.L.R. (4th) 577. Applying these principles to this case, I am satisfied, based on all of the evidence, that the plaintiff suffered soft tissue injuries to her neck, shoulders, mid- and upper-back which were caused by the accident. These injuries have resulted in chronic pain as described in detail in Dr. Armstrong’s report. Ms. Clark has suffered headaches, emotional and cognitive distress and sleep disorder as a result of the persistent pain. Overall I found Dr. Armstrong’s report and evidence of great assistance in assessing the impact of the accident on Ms. Clark’s life.
If we gave the reasons to a first year law student, after he or she has taken torts, could he or she identify what test for factual causation the trial judge applied? He or she would know what test the judge was supposed to have applied, but that isn’t my question.
Could a member of the public reading the decision understand why the judge made the decision she did, beyond understanding that the judge believed the plaintiff and preferred the evidence of the plaintiff’s physicians?
We – meaning the part of the profession who practices in the area – can make informed assumptions as to the principles the trial judge must have had in mind, and then decide from the evidence recounted in the reasons, but is that enough?
If we assume (as we are required to, absent some indication to the contrary) that the judge knew the applicable law, that the evidence was as the trial judge recounts, that it was admissible, and that the trial judge did not make any relevant errors accepting it – something none of us can decide without reading the transcript – then the decision is correct in law (meaning that it cannot be successfully appealed).

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