Why are 'material contribution' vs 'proximate causation' separate tests?

Question

Source: Introduction to Law in Canada (2014). pp. 252 Bottom - 253 Top.

The Elements of a Negligence Claim

The required elements of a negligence claim have been variously named, described, and numbered. There is still no consensus on terminology, although the courts in Canada today consistently refer to the five elements outlined below. The plaintiff has the burden of proof with respect to all of these elements, although in most cases the defendant will concede some of them and the litigation will focus on just one or two (most often, breach of the standard of care, and damages).

I omit 1 and 2.

3. Factual Causation.

Often simply referred to as "causation," this element concerns whether the defendant's negligent conduct has actually caused the loss. Two tests are commonly used here:

1. the "but for" test, which asks whether there would have been no loss but for—that is, in the absence of—the defendanes conduct (or, framed another way, whether the defendant's conduct was necessary for the loss to occur); and

2. the "material contribution" test, which asks whether the defendant's conduct materially contributed to the loss (this test openly recognizes that there may be other contributing causes).

     Recall, again, the sample case in Chapter 7 [on p. 201], Matthews v MacLaren [(1969), 4 DLR (3d) 557 (Ont HC). This case illustrates the duty and standard of care elements above, but was in fact decided against Matthew's estate on the basis of this third element, factual causation. Matthews would not likely have survived even if the defendant MacLaren had exercised proper care in rescuing him. Lake Ontario was very cold at the time and the evidence was that Matthews probably died shortly after hitting the water.

4. Legal Causation.

Because negligence liability concerns carelessness rather than intentional wrongdoing, the law places a limit on the extent of the defendant's liability, even when he has clearly caused the loss. For defendants to be liable there must be a sufficiently close connection between their conduct and the loss. The question here is whether the defendant's conduct was a "proximate cause" of the loss; it concerns the conduct's "remoteness"—or, more precisely, lack of remoteness—as a causal factor in the loss.
  The test used to limit liability is the "reasonable foreseeability" test; a defendant is only responsible for losses that are a reasonably foreseeable consequence of his behaviour.
  In 2008, the SCC had to decide whether a supplier of bottled water was responsible for a serious psychological illness suffered by a consumer who witnessed a dead fly in an unopened bottle. The SCC held that all of the elements of the negligence cause of action were met on these facts, except legal causation. The injury in this case was too remote to be compensable; it was not reasonably foreseeable that a person of ordinary fortitude would suffer serious injury from seeing a dead fly in a bottle of water (see Mustapha v Culligan of Canada Ltd, 2008 SCC 27).

Q1. How do these causes (greyed overhead) differ? Aren't they inexorably interdependent? I.e., how can a cause be:

Q2. materially contributive, but NOT proximate?

Q3. NOT materially contributive, but proximate?

Answer 1

Maybe, but it doesn't matter. They aren't presented in a way that would indicate an action (or a cause of some harm) is necessarily one and not the other. In fact, one would use the "material contribution" test (and/or the "but for" test) in order to establish whether there was proximate cause. So you use the first gray phrase in order to establish the second gray phrase.

Answer 2

It's easy to think of situations where there is material contribution without being proximate cause. For instance, suppose you give your friend a ticket to a concert, and while driving to the concert, someone runs a red light and hits your friend. If you hadn't given the ticket to your friend, they would not have been driving, so this is a material contribution. But the proximate cause of them getting hit is someone running a red light; you giving them the ticket is sufficiently remote of a cause that you would not be liable.

A cause that is proximate but not material would be more difficult to find. In some sense, something that caused something that would otherwise be inevitable could be considered to qualify; for instance, if a yacht has generator that catches fire due to being flooded and kills someone, but they would have died anyway because the yacht was sinking, that might considered proximate but not material. The jurisdiction's treatment of joint liability would likely affect how that's treated.

The proximate cause requirement generally is a requirement on top of the material cause requirement; material cause is required in most cases, and proximate cause is required in a subset of cases.