Actus reus
Actus reus, sometimes called the external element or the objective element of a crime, is the Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 term for the "guilty act" which, when proved beyond a reasonable doubt
Beyond a Reasonable Doubt
Beyond a Reasonable Doubt is a 1956 film directed by Fritz Lang and written by Douglas Morrow. The film, considered film noir, was the last American film directed by Lang.-Plot:...

 in combination with the mens rea
Mens rea
Mens rea is Latin for "guilty mind". In criminal law, it is viewed as one of the necessary elements of a crime. The standard common law test of criminal liability is usually expressed in the Latin phrase, actus non facit reum nisi mens sit rea, which means "the act does not make a person guilty...

, "guilty mind", produces criminal liability
Legal liability
Legal liability is the legal bound obligation to pay debts.* In law a person is said to be legally liable when they are financially and legally responsible for something. Legal liability concerns both civil law and criminal law. See Strict liability. Under English law, with the passing of the Theft...

 in the common law
Common law
Common law is law developed by judges through decisions of courts and similar tribunals rather than through legislative statutes or executive branch action...

-based criminal law
Criminal law
Criminal law, is the body of law that relates to crime. It might be defined as the body of rules that defines conduct that is not allowed because it is held to threaten, harm or endanger the safety and welfare of people, and that sets out the punishment to be imposed on people who do not obey...

Jurisdiction is the practical authority granted to a formally constituted legal body or to a political leader to deal with and make pronouncements on legal matters and, by implication, to administer justice within a defined area of responsibility...

s of Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

, India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...

, Pakistan
Pakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...

, South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

, New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

, England, Ireland
Ireland is an island to the northwest of continental Europe. It is the third-largest island in Europe and the twentieth-largest island on Earth...

 and the United States. In the United States, some crimes also require proof of an attendant circumstance
Attendant circumstance
Attendant circumstance is a legal concept which Black's Law Dictionary defines as the "facts surrounding an event."...



The terms actus reus and mens rea developed in English Law are derived from the principle stated by Edward Coke
Edward Coke
Sir Edward Coke SL PC was an English barrister, judge and politician considered to be the greatest jurist of the Elizabethan and Jacobean eras. Born into a middle class family, Coke was educated at Trinity College, Cambridge before leaving to study at the Inner Temple, where he was called to the...

, namely, actus non facit reum nisi mens sit rea, which means: "an act does not make a person guilty unless (their) mind is also guilty"; hence, the general test of guilt is one that requires proof of fault, culpability
Culpability descends from the Latin concept of fault . The concept of culpability is intimately tied up with notions of agency, freedom and free will...

 or blameworthiness both in behaviour and mind.


In order for an actus reus to be committed there has to have been an act. Various common law
Common law
Common law is law developed by judges through decisions of courts and similar tribunals rather than through legislative statutes or executive branch action...

 jurisdictions define act differently but generally, an act is a "bodily movement whether voluntary or involuntary." In Robinson v. California
Robinson v. California
Robinson v. California, 370 U.S. 660 , was a case in which the Supreme Court of the United States held that the use of civil imprisonment as punishment solely for the misdemeanor crime of addiction to a controlled substance was a violation of the Eighth Amendment's protection against cruel and...

, , the U.S. Supreme Court ruled that a California law making it illegal to be a drug addict was unconstitutional because the mere status of being a drug addict was not an act and thus not criminal.

An act can consist of commission, omission or possession.


See main article omission (criminal law)

Omission involves a failure to engage in a necessary bodily movement resulting in injury. As with commission acts, omission acts can be reasoned causally using the but for approach. But for not having acted, the injury would not have occurred. The Model Penal Code specifically outlines specifications for criminal omissions:
  1. the omission is expressly made sufficient by the law defining the offense; or
  2. a duty to perform the omitted act is otherwise imposed by law (for example one must file a tax return).

So if legislation specifically criminalizes an omission through statute; or a duty that would normally be expected was omitted and caused injury, an actus reus has occurred.


Possession holds a special place in that it has been criminalized but under common law does not constitute an act. Some countries like the United States have avoided the common law conclusion in Regina v. Dugdale by legally defining possession as a voluntary act. As a voluntary act, it fulfills the requirements to establish actus reus.


For conduct to constitute an actus reus, it must be engaged in voluntarily. Few sources enumerate the entirety of what constitutes voluntary and involuntary conduct. Oliver Wendell Holmes
Oliver Wendell Holmes, Jr.
Oliver Wendell Holmes, Jr. was an American jurist who served as an Associate Justice of the Supreme Court of the United States from 1902 to 1932...

, in his 1881 book The Common Law
The Common Law
The Common Law is a book that was written by Oliver Wendell Holmes, Jr. in 1881. Holmes later became an Associate Justice on the Supreme Court of the United States....

, disputed whether such a thing as an involuntary act exists: "[a] spasm is not an act. The contraction of the muscles must be willed." A few sources, such as the Model Penal Code, provide a more thorough treatment of involuntary conduct:
  1. a reflex or convulsion;
  2. a bodily movement during unconsciousness or sleep;
  3. conduct during hypnosis or resulting from hypnotic suggestion;
  4. a bodily movement that otherwise is not a product of the effort or the determination of the actor, either conscious or habitual.

Reflex or convulsion

Generally, if, during an uncontrollable flailing caused by a sudden paroxysmal episode, such as that produced by an epileptic seizure, a person strikes another, that person will not be criminally liable for the injuries sustained by the other person. However, if prior to the assault on another, the seized individual was engaging in conduct that he knew to be dangerous given a previous history of seizures, then he is culpable for any injuries resulting from the seizure. For example, in People v. Decina, 2 N.Y.2d 133 (1956), the defendant, Emil Decina, appealed a conviction under § 1053-a of the New York Penal Code. On March 14, 1955, Decina suffered a serious seizure while operating a motor vehicle. He swerved wildly through the streets and struck a group of school girls, killing four of them. On direct examination, Decina's physician testified that Decina informed him that prior to the accident "he noticed a jerking of his right hand" and recounted his extensive history of seizures, a consequence of brain damage from an automobile accident at age seven. Decina argued, inter alia
Inter Alia
-Track listing:# Inter Alia# Outfox'd # Righteous Badass # The Altogether feat. Bix, Apt, UNIVERSE ARM and Cal# The Day-to-Daily# Trouble Brewing # The Prestidigitator# The Force...

, that he had not engaged in criminal conduct because he did not voluntarily strike the school girls. The New York Court of Appeals
New York Court of Appeals
The New York Court of Appeals is the highest court in the U.S. state of New York. The Court of Appeals consists of seven judges: the Chief Judge and six associate judges who are appointed by the Governor to 14-year terms...

 disagreed and held that since the defendant knew he was susceptible to a seizure at any time without warning and decided to operate a motor vehicle on a public highway anyway, he was guilty of the offense. "To hold otherwise," wrote Froessel, J, "would be to say that a man may freely indulge himself in liquor in the same hope that it will not affect his driving, and if it later develops that ensuing intoxication causes dangerous and reckless driving resulting in death, his unconsciousness or involuntariness at that time would relieve him from prosecution[.]"

Unconsciousness or sleep

In Hill v Baxter
Hill v Baxter
The case of Hill v Baxter concerns the issue of automatism in English law. It sets out reasonably clear guidelines as to when the defence will apply, and when it will not.-Facts:...

, Kilmuir, LC, articulated the necessity of eliminating automatism, defined as "the existence in any person of behaviour of which he is unaware and over which he has no conscious control," in proving the voluntariness of the actus reus:
Thus, a person suffering from somnambulism, a fugue
Fugue state
A fugue state, formally dissociative fugue or psychogenic fugue , is a rare psychiatric disorder characterized by reversible amnesia for personal identity, including the memories, personality and other identifying characteristics of individuality...

, a metabolic disorder, epilepsy, or other convulsive or reflexive disorder, who kills another, steals another's property, or engages in other facially criminal conduct, may not have committed an actus reus, for such conduct may have been elicited unconsciously, and, "one who engages in what would otherwise be criminal conduct is not guilty of a crime if he does so in a state of unconsciousness[.]" Depending on jurisdiction, automatism may be a defense distinct from insanity or a species of it.


While the general scientific consensus is that hypnosis cannot induce an individual to engage in conduct they would not otherwise engage in, the Model Penal Code, as well as the criminal codes of Montana, New York, and Kentucky do provide hypnosis and hypnotic suggestion as negating volition, and consequently, actus reus.

Perhaps the earliest case of hypnotism as negating voluntary conduct is California v. Ebanks, . In Ebanks, the court categorically rejected Ebanks' argument that the trial court committed reversible err in denying him leave to present expert testimony concerning the effects of hypnotism on the will. The lower court bluntly remarked that "'[t]he law of the United States does not recognize hypnotism. It would be an illegal defense, and I cannot admit it.'" Nearly sixty years later, however, the California Court of Appeals ruled that the trial court did not err in allowing expert testimony on hypnosis, though it did not rule on whether hypnotism negates volition. The Supreme Court of Canada
Supreme Court of Canada
The Supreme Court of Canada is the highest court of Canada and is the final court of appeals in the Canadian justice system. The court grants permission to between 40 and 75 litigants each year to appeal decisions rendered by provincial, territorial and federal appellate courts, and its decisions...

ruled confessions made under hypnosis inadmissible because they are involuntarily given; Germany and Denmark provide a hypnotist defense.


Voluntariness includes omission, for implicit in omission is that the actor voluntarily chose to not perform a bodily movement and, consequently, caused an injury. The purposeful, reckless, or negligent absence of an action is considered a voluntary action and fulfills the voluntary requirement of actus reus.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.