RES IPSA LOQUITUR
res ipsa loquitur (rays ip-s<<schwa>> loh-kw<<schwa>>-t<<schwa>>r). [Latin “the thing
speaks for itself”] Torts. The doctrine providing that, in some circumstances, the mere fact of an
accident’s occurrence raises an inference of negligence so as to establish a prima facie case. —
Often shortened to res ipsa. [Cases: Negligence 1610. C.J.S. Negligence §§ 744–748, 754–756.]
“The phrase ‘res ipsa loquitur’ is a symbol for the rule that the fact of the occurrence of an
injury, taken with the surrounding circumstances, may permit an inference or raise a presumption
of negligence, or make out a plaintiff’s prima facie case, and present a question of fact for
defendant to meet with an explanation. It is merely a short way of saying that the circumstances
attendant on the accident are of such a nature as to justify a jury, in light of common sense and
past experience, in inferring that the accident was probably the result of the defendant’s negligence,
in the absence of explanation or other evidence which the jury believes.” Stuart M. Speiser, The
Negligence Case: Res Ipsa Loquitur § 1:2, at 5–6 (1972).
“It is said that res ipsa loquitur does not apply if the cause of the harm is known. This is a
dark saying. The application of the principle nearly always presupposes that some part of the
causal process is known, but what is lacking is evidence of its connection with the defendant’s act
or omission. When the fact of control is used to justify the inference that defendant’s negligence
was responsible it must of course be shown that the thing in his control in fact caused the harm. In
a sense, therefore, the cause of the harm must be known before the maxim can apply.” H.L.A. Hart
& Tony Honoré, Causation in the Law 419–20 (2d ed. 1985).
“Res ipsa loquitur is an appropriate form of circumstantial evidence enabling the plaintiff in
particular cases to establish the defendant’s likely negligence. Hence the res ipsa loquitur doctrine,
properly applied, does not entail any covert form of strict liability…. The doctrine implies that the
court does not know, and cannot find out, what actually happened in the individual case. Instead,
the finding of likely negligence is derived from knowledge of the causes of the type or category of
accidents involved.” Restatement (Third) of Torts § 17 cmt. a (Tentative Draft No. 1, 2001).
[Blacks Law 8th]