TORT 035 Res Ipsa Loquitur Nature Essentials and Distinctions — Law of Torts Notes for Judiciary

Res Ipsa Loquitur: Nature, Essentials, Effect on the Burden of Proof, and How It Differs from a Presumption and from Strict Liability

Res ipsa loquitur means that the thing speaks for itself. It is a rule of evidence, not a rule of liability, and it exists because in a whole class of case the plaintiff has no means of knowing what went wrong while the defendant has. He was unconscious on the operating table, or walking past a building, or on the pavement when a vehicle mounted it. The maxim lets him prove negligence from the accident itself, provided three conditions are satisfied: the thing was under the defendant's exclusive control, the accident is one that does not ordinarily happen if proper care is used, and there is no evidence of the actual cause. It raises an inference and shifts the evidential burden; it does not reverse the legal one.

The three essentials, what the maxim does and does not do, and two distinctions

1. Meaning and Nature

The phrase is Latin for "the thing speaks for itself", and it describes a situation in which the facts of the accident are themselves evidence of negligence.
It is a rule of evidence. It does not create a duty, it does not define the standard of care, and it does not alter the substantive law of negligence in any way.
It is not a rule of liability. A defendant against whom it is invoked is not liable because of it; he is liable only if the court, having considered his explanation, concludes that he was negligent.
It is not a doctrine and not a presumption. It is better described as a convenient label for a process of reasoning which the law permits.
It reflects a practical reality, that in certain accidents the means of knowledge are all on one side, and it would be unjust to require the plaintiff to prove what he cannot possibly know.

2. The Classic Statement

📖 Scott v. London and St Katherine Docks Co. (1865) 3 H & C 596

Facts The plaintiff was a customs officer. He was passing in front of a warehouse belonging to the defendants when six bags of sugar fell upon him from a crane by which the defendants' servants were lowering them. He could give no evidence of how or why they fell.

Held The facts afforded reasonable evidence of negligence, and a new trial was ordered so that the question could go to the jury.

Ratio Erle CJ stated the rule in the terms in which it is still quoted. There must be reasonable evidence of negligence. But where the thing is shown to be under the management of the defendant or his servants, and the accident is such as in the ordinary course of things does not happen if those who have the management use proper care, it affords reasonable evidence, in the absence of explanation by the defendants, that the accident arose from want of care.

📖 Byrne v. Boadle (1863) 2 H & C 722

Facts The plaintiff was walking in a public street past the defendant's flour warehouse when a barrel of flour fell from an upper window and struck him. He could not say how it came to fall.

Held The defendant was liable, and the plaintiff was not bound to prove how the barrel came to fall.

Ratio Pollock CB observed that a barrel could not roll out of a warehouse without negligence, and that to say that a plaintiff who is injured by it must call witnesses from the warehouse to prove negligence seemed to him preposterous. The case is the origin of the maxim in its modern form.

3. The Essentials

1. The thing causing the harm was under the exclusive control or management of the defendant, or of those for whom he is responsible. Where several independent parties had access to the thing, the condition fails.

2. The accident is such as does not in the ordinary course of things happen if those who have the management use proper care. This is the heart of the maxim, and it is a question of common experience.

3. There is no evidence as to the actual cause of the accident. Where the facts are fully known, the court decides on the evidence and there is nothing for an inference to do.

4. The plaintiff himself did not contribute to the occurrence. Where his own act may have caused or contributed to the accident, the inference does not arise in the same way.

5. All of these must be established by the plaintiff. The maxim is not a shortcut past the burden of proof; it is a route through it.

4. The Effect on the Burden of Proof

	The position
It raises an inference of negligence	The facts proved permit the court to conclude that the defendant was negligent, without proof of the specific act or omission
It shifts the evidential burden	The defendant must now produce an explanation or evidence of the care he took, or he will lose on the material before the court
It does not reverse the legal burden	The legal burden of proving negligence remains on the plaintiff from beginning to end
The court is permitted, not bound	It is a permissible inference and not a compulsory one. The court weighs it with the rest of the evidence
At the close of the case the question is the same	Has the plaintiff proved negligence on the balance of probabilities, on the whole of the evidence including the inference?

5. Rebutting It

The most complete answer is to show how the accident happened, and that it happened without negligence on the defendant's part.
The defendant need not do that. It is enough for him to show that he took reasonable care, even if the cause of the accident remains unexplained.
A plausible explanation consistent with the absence of negligence displaces the inference, and leaves the plaintiff where he started.
Showing that control was not exclusive defeats the first essential, and with it the maxim.
Showing that the accident is one that does happen without negligence defeats the second, and this is the commonest answer in medical cases, where a known complication may occur despite perfect care.

6. Res Ipsa Loquitur and a Presumption of Negligence

	Res ipsa loquitur	A presumption of negligence
What it is	A permissible inference of fact	A rule of law
What the court does	May draw the conclusion	Must draw the conclusion unless it is rebutted
Which burden it shifts	The evidential burden only	The legal burden
The standard the defendant must meet	Enough to displace the inference	Proof, on the balance of probabilities, that he was not negligent
Where a true presumption is found	Not here	In statutes that expressly provide for one, and in the no fault schemes
Whether the plaintiff still carries the legal burden	Yes	No: it has passed to the defendant

The distinction matters at the close of the evidence. If the maxim were a presumption of law, a defendant who left the court in doubt would lose. Because it is an inference, a defendant who leaves the court in doubt wins, the legal burden being on the plaintiff.
Some judgments use the language of presumption loosely, and the point is worth keeping clear when reading them.

7. Res Ipsa Loquitur and Strict Liability

	Res ipsa loquitur	Strict liability
What it concerns	The proof of fault	The need for fault at all
The basis of liability	Negligence, inferred from the facts	The creation of a risk, irrespective of negligence
The defendant's answer	Show that he took reasonable care, and he escapes	Showing reasonable care changes nothing
The fault principle	Preserved; the maxim only eases its proof	Displaced
Example	A barrel falling from a warehouse	The escape of a dangerous thing under Rylands v. Fletcher
Where both may be argued	A plaintiff may plead negligence with res ipsa in the alternative to a strict liability claim

8. What the Maxim Does Not Reach

⚠ It goes to breach only

Res ipsa loquitur establishes, at most, that the defendant was negligent. It says nothing about the other three ingredients of the tort. Causation must still be proved: Barnett v. Chelsea and Kensington Hospital shows that the clearest breach founds no liability where the harm would have occurred anyway. Remoteness must still be satisfied, by the Wagon Mound test of reasonable foreseeability of the kind of damage. And damage remains an essential element, because negligence is never actionable per se. A plaintiff who invokes the maxim successfully has cleared one hurdle of four, and the remaining three are unaffected by it.

9. The Position Stated Shortly

1. Res ipsa loquitur means that the thing speaks for itself, and it is a rule of evidence and not of liability.

2. Scott v. London and St Katherine Docks contains the classic statement of it, and Byrne v. Boadle is its origin.

3. The three essentials are exclusive control by the defendant, an accident that does not ordinarily happen without negligence, and the absence of evidence of the actual cause.

4. The plaintiff must also not have contributed to the occurrence, and he must establish all the conditions himself.

5. The maxim raises an inference of negligence and shifts the evidential burden to the defendant.

6. It does not reverse the legal burden, which remains on the plaintiff throughout.

7. The defendant rebuts it by showing how the accident happened without negligence, or that he took reasonable care, or that control was not exclusive.

8. It differs from a presumption of negligence, which is a rule of law obliging the court to draw the conclusion and shifting the legal burden.

9. It differs from strict liability, which dispenses with fault altogether, whereas the maxim merely eases the proof of it.

10. It goes to breach only, and causation, remoteness and damage must still be proved in the ordinary way.