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VOL. 77 PART 2 MARCH 2019
doing of each defendant alone, the harm would not have been suffered. It is
enough to show that the wrongdoing of one or more “materially contributed”
to causing the harm, each then being liable for all damage suffered
but entitled to contribution under contributory fault legislation.
In unusual cases, none it seems so far decided by the Supreme Court of
Canada, the plaintiff may be relieved of the burden of proving “but for” causation
and need only prove that the defendant’s wrongdoing materially contributed
to the risk that someone in the plaintiff’s position might suffer
harm. This test may be applied for policy reasons in a limited class of cases
to render a defendant liable without the need of proof that “but for” that
defendant’s wrongdoing, the harm would not have been suffered. This is
effectively a substitute for actual proof of causation. It may most obviously
apply to establish liability for contributing to the risk of harm where wrongdoing
on the part of two or more persons is proved that could have caused
the loss or injury, the plaintiff has established that the loss would not have
occurred “but for” the negligence of those wrongdoers, and proof of individual
“but for” causation is impossible because each can point to one another
as the possible “but for” cause of the injury.
Difficulties encountered in the causation field in recent years relate particularly
(1) to the standard of proof to be applied to hypothetical facts for
liability and damages assessment purposes, and for damages assessment
purposes as between pre-trial and post-trial damages, and (2) to the distinction
to be drawn for liability causation purposes between “material contribution
to the harm” and “material contribution to the risk”.
CLEBC has held three seminars on developments in the law of causation
in recent years. There will undoubtedly be more to come.
1. Resurfice Corp v Hanke, 2007 SCC 7 Resurfice.
2. Ibid at para 20.
3. 2017 BCCA 158 Grewal.
4. See Athey v Leonati, 1996 3 SCR 458 at para 32
5. Ibid at paras 26–27.
6. Ibid. Hypothesis not supported by evidence is sometimes
called “mere speculation”.
7. Ibid at para 28.
8. See Vaughan Black, “Decision Causation: Pandora’s
Tool-Box” in Jason W Neyers, Erika Chamberlain &
Stephen GA Pitel, eds, Emerging Issues in Tort Law
(Oxford: Hart Publishing, 2007) 309 at 318.
9. Reynolds v M Sanghera & Sons Trucking Ltd, 2015
BCCA 232; Ostrikoff v Oliveira, 2015 BCCA 351.
These decisions were rendered per incuriam and
decided without reference to the court’s earlier decision
in Smith v Knudsen, 2004 BCCA 613 Smith.
The decisions in both Grewal, supra note 3 at paras
45–46 and Smith at para 26 make it plain that the
standard of proof for liability causation purposes
remains the balance of probabilities.
10. 2005 BCCA 348, leave to app ref’d 2005 SCCA
11. See also Briante v Vancouver Island Health Authority,
2017 BCCA 148 at para 167 Briante, leave to
appeal ref’d 2017 SCCA No 207 (“to establish
causation, the appellant needed to prove on a balance
of probabilities that referring Joseph to the oncall
psychiatrist would likely have prevented his
suicide attempt six days later”).
12. See Athey, supra note 4 at para 28; Grewal, supra
note 3 at para 45; Smith, supra note 9 at para 26.
13. See Grewal, supra note 3 at para 48; Perren v Lalari,
2010 BCCA 140 at para 32. See also Rousta v
MacKay, 2018 BCCA 29 at paras 13–17; Dhaliwal
v Greyhound Canada Transportation Corp, 2017
BCCA 260 at paras 29–30; Gao v Dietrich, 2018