Causation

A plaintiff’s proof of causation entails two points: cause in fact, and proximate, or “legal” cause.

(1) Cause in Fact
Cause in fact represents the quite sensible requirement that the plaintiff must prove that the defendant’s acts or omissions contributed in some substantial degree to the plaintiff’s harm. By “substantial” degree we mean that the plaintiff has to prove that the defendant was solely responsible for the harm. Rather, the defendant’s acts need only have been a “substantial factor” in the plaintiff’s injury.

As you can see, the “substantial factor” test allows for the possibility that there might be other factors contributing to the harm. Indeed, there might be multiple defendants in a tort suit, if the acts of more than one individual was a “substantial factor” in causing the plaintiff’s harm.

Where these “other” factors, by nature or by human action, are reasonably foreseeable, such foreseeable causal contributions to the plaintiff’s harm are called “intervening causes.”. Such foreseeable “intervening causes” do not break the causal relation to the defendant’s acts. Where, on the other hand, such contributing factors are not reasonably foreseeable, they may be “superseding causes.” A “superseding” cause is a cause that is so substantial as to itself become the “producing cause” of the harm. Where the defendant first commits a tortuous act, after which a “superseding cause” presents itself, the link of causation between the defendant and the plaintiff is broken.