ACTUAL AND PROXIMATE CAUSE

Example:  P takes her prescription for a medication to D, her local pharmacy. D mistakenly fills the prescription by giving P pills containing 30 mg of the active ingredient rather than the 20 mg called for by the prescription. After taking the pills, P suffers serious heart arrhythmia, and sues D for this harm. P can recover only if she proves that had D provided the correct, 20 mg, pills, P would not have suffered the arrhythmia. In other words, for P to recover, the trier of fact must be satisfied that the wrong pills were the “but for” cause of P’s arrhythmia. Id., Illustr. 2.

2. Broad test:  Observe that the “but for” test casts an extremely broad net. Every injury occurring to a plaintiff has thousands of causes, by this standard, since if any of a thousand things happened differently, there would have been no accident. For instance, in a nighttime automobile accident, the fact that one of the drivers worked late at the office that night would be a cause, since had he not, he would not have been at that location in time to be hit by the other car. See P&K, p. 264, fn. 6.

a. Multiple negligence:  It follows that a defendant may not claim that she is not an actual cause of the plaintiff’s injury merely because some other person’s negligence also contributed to that harm. This matter is more fully discussed in the material on joint tortfeasors, infra, p. 181; the general principle is that each of several joint tortfeasors will be held liable for the entire harm.

Example:  P is a passenger in a car driven by D1. On a stormy night, the car crashes into an unlit truck which has been parked in the middle of the road by D2. There is evidence that D1 was negligent in not seeing the truck, and that D2 was negligent in leaving it parked where and how he did.

Held, D2 should not be dismissed from the case merely because the accident would not have happened without D1’s negligence. “Where separate acts of negligence combine to produce directly a single injury each tortfeasor is responsible for the entire result, even though his act alone might not have caused it.” Hill v. Edmonds, 270 N.Y.S.2d 1020 (N.Y. App. 1966).

B. Concurrent causes:  Inclusive as the “but for” test is, it nonetheless rules out one kind of cause which the courts have generally held does constitute a true cause in fact. This is the situation where two events concur to cause harm, and either one would have been sufficient to cause substantially the same harm without the other. To provide for this case, it is generally stated that each of these concurring events is a cause of the injury, insofar as it would have been sufficient to bring that injury about. See Rest. 2d, §432(2).

Example:  Sparks from one of D’s locomotives start a forest fire. The fire merges with another fire of unknown origin, and the combined fires burn P’s property. The evidence indicates that the fire started by D’s locomotives would by itself have been sufficient to burn P’s property.