Restatement of the Law, Second, Torts

Copyright (c) 1965, The American Law Institute

Proof of Negligence and Functions of Court and Jury

§ 328D Res Ipsa Loquitur

(1) It may be inferred that harm suffered by the plaintiff is caused by negligence of thedefendant when

(a) the event is of a kind which ordinarily does not occur in the absence of negligence;

(b) other responsible causes, including the conduct of the plaintiff and third persons, aresufficiently eliminated by the evidence; and

(c) the indicated negligence is within the scope of the defendant's duty to the plaintiff. (2) It is the function of the court to determine whether the inference may reasonably be drawnby the jury, or whether it must necessarily be drawn. (3) It is the function of the jury to determine whether the inference is to be drawn in any casewhere different conclusions may reasonably be reached.

COMMENTS & ILLUSTRATIONS: Comment:

a. The principle stated in this Section is commonly given the name of res ipsa loquitur. TheLatin phrase, which means nothing more than "the thing speaks for itself," originated in a causalword let fall by Baron Pollock in the course of argument with counsel in Byrne v. Boadle, 2 H. &C. 722, 159 Eng. Rep. 299 (1863), where a barrel of flour rolled out of the window of the defendant'swarehouse and fell on a passing pedestrian. In itself, the phrase has no more importance or virtuethan its English equivalent, and its use has from time to time been criticized as adding unnecessaryobscurity to a relatively simple problem.

In its inception the principle of res ipsa loquitur was merely a rule of evidence, permitting thejury to draw from the occurrence of an unusual event the conclusion that it was the defendant's fault. Shortly after its origin, however, it became confused, in cases of injuries to passengers at the handsof carriers, with the older rule which placed the burden of proof upon the carrier to show that itsnegligence had not caused the injury. (See § 328 A, Comment b.) This confusion resulted in a greatdeal of disagreement among the courts as to the application of the principle and its procedural effect. To some extent this disagreement still continues. The rule stated in this Section is that upon whichthe great majority of the American courts are now agreed.

b. Circumstantial evidence. Negligence and causation, like other facts, may of course be provedby circumstantial evidence. Without resort to Latin the jury may be permitted to infer, when arunaway horse is found in the street, that its owner has been negligent in looking after it; or whena driver runs down a visible pedestrian, that he has failed to keep a proper lookout. When the Latinphrase is used in such cases, nothing is added. A res ipsa loquitur case is ordinarily merely one kindof case of circumstantial evidence, in which the jury may reasonably infer both negligence andcausation from the mere occurrence of the event and the defendant's relation to it.

Some courts occasionally have applied "res ipsa loquitur," against certain defendants, as a ruleof policy which goes beyond the probative effect of circumstantial evidence, and requires thedefendant to explain the event or be liable. This has been true particularly in actions by passengersagainst carriers, where it is undoubtedly a survival of the older common law rule placing the burdenof proof upon the defendant, still followed by some courts. (See § 328 A, Comment b.) In suchcases "res ipsa loquitur" often is given a greater procedural effect, either as requiring the defendantto sustain the burden of proof or as creating a presumption of negligence rather than a mereprocedural inference. In general, such decisions have tended to be confined to defendants who haveundertaken a special responsibility toward the plaintiff, as in the case of the carrier and thepassenger. A few courts consistently define "res ipsa loquitur" as limited to such situations, and ashaving the greater procedural effect. Such courts usually have been compelled to recognize, underanother name, the principle of circumstantial evidence stated in this Section.