What is the test for determining whether a defendant’s negligence caused a plaintiff to suffer loss of consciousness?

The defendant argues the “but for” test is the appropriate test and that the “robust and pragmatic approach” suggested by the plaintiff is not a test of causation but is an approach to “enable the court to assess the plaintiff’s evidence in a less circumspect and more liberal way”. But it is still essential that for the plaintiff to be granted relief, the evidence must be of sufficient weight to meet the ultimate burden of demonstrating, on a balance of probabilities, that the defendant’s want of care caused the loss. (Koch J. para. 61 of Scharnagl v. Stimpson, supra).