Mens rea

The mens rea is the Latin term for "guilty mind" used in the criminal law. 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 that "the act does not make a person guilty unless the mind is also guilty". Thus, in jurisdictions with due process, there must be an actus reus accompanied by some level of mens rea to constitute the crime with which the defendant is charged (see the technical requirement of concurrence). The exception is strict liability crimes (in the civil law, it is not usually necessary to prove a subjective mental element to establish liability, say for breach of contract or a tort, although if intentionally committed, this may increase the measure of damages payable to compensate the plaintiff).

Quite simply, therefore, mens rea refers to the mental element of the offence that accompanies the actus reus. In some jurisdictions, the terms mens rea and actus reus have been superseded by alternative terminology. In Australia, for example, the elements of all Federal offences are now designated as "Fault Elements" (mens rea) and "Physical Elements" (actus reus). This terminology was adopted in order to replace the obscurity of the Latin terms with simple and accurate phrasing.1

There are four general classes of mens rea (the words used may vary from one state to another and from one definition to another) but the substance is:
 * 1) Intention; (purpose)
 * 2) Knowledge;
 * 3) Recklessness sometimes termed willful blindness which may have a different interpretation in the United States; or
 * 4) Negligence.

Concepts
Each of these classes depends on the presence or absence of foresight and a second element usually expressed as "desire". In this context, the word "desire" is dispassionate. For instance, one may visit a dentist for treatment, recognising that this is necessary, yet having little or no "desire" to do so. Nevertheless, the requisite intentionality is present in the decision to seek treatment because one desires what is necessary no matter that it may be unpleasant. Hence, the essence of this second element is that, whether subjectively or objectively, the accused wishes or aims to cause the foreseen consequences to occur. As an example of the four types of mens rea, consider a person who walks into a room which is in darkness: In the first of these four instances, damaging some of the china objects would be intentional or purposeful. Example (b) shows knowledge and high probability which suggests knowingly. Example (c) is reckless while (d) illustrates criminal negligence if the reasonable man would have taken more care when entering a room with which he was not familiar.
 * Direct intention is where the accused has a clear foresight of the consequences of his actions and desires those consequences to occur.
 * Oblique intention is where the result is a virtually certain consequence of the defendant's actions. (Authority; R v Nedrick [1986], leading case; R v Matthews & Alleyne [2004]).
 * Knowingly is where the accused knows or should know that the results of his conduct are reasonably certain to occur.
 * Recklessness is where the accused foresees that particular consequences may occur and proceeds with the given conduct not caring whether those consequences actually occur or not. (Authority; R v Cunningham [1957], leading case; R v G & R [2003], reaffirmed Cunningham following the muchly criticised House of Lords decision in R v Caldwell [1982]).
 * Criminal negligence occurs where the accused did not actually foresee that the particular consequences would flow from his actions but the reasonable person, in the same circumstances, would have foreseen those consequences.
 * (a) knowing that it is full of valuable china objects, his objective or aim being to cause the maximum amount of damage;
 * (b) knowing that it is full of valuable objects, but simply blundering about rather than reaching for the light switch;
 * (c) knowing that it is full of valuable objects, but hoping to walk quickly to the centre of the room where the main light switch is located without damaging anything;
 * (d) without being aware of there being anything specifically valuable in the room, not knowing where the light switch is, and hoping to find somewhere quiet to sit.

Ignorance of the law and mens rea
The general rule under U.S. law is that "ignorance of the law or a mistake of law is no defense to criminal prosecution." See Cheek v. United States, 498 U.S. 192 (1991). There are exceptions to this rule which are sometimes referred to as crimes of "specific intent", "Specific intent crime. Crime in which defendant must not only intend the act charged but also intend to violate law. U.S. v. Birkenstock, C.A.Wis., 823 F.2d 1026, 1028. One in which a particular intent is a necessary element of the crime itself. Russell v. State, Fla.App., 373 So.2d 97, 98. See also Mens rea; Specific intent." SOURCE: Black's Law Dictionary, Sixth Edition

For example, in the case of tax evasion under the defendant must be shown to have a specific intent to violate an actually known legal duty. See Tax avoidance and tax evasion.

Subjective and objective tests
The test for the existence of mens rea may be:
 * (a) subjective where the court must be satisfied that the accused actually had the requisite mental element present in his or her mind at the relevant time (for purposely, knowingly, recklessly etc)(see concurrence);
 * (b) objective where the requisite mens rea element is imputed to the accused on the basis that the reasonable person would have had the mental element in the same circumstances(for negligence); or
 * (c) hybrid where the test is both subjective and objective.

The court will have little difficulty in establishing mens rea if there is actual evidence, say because the accused made an admissible admission. This would satisfy a subjective test. But a significant proportion of those accused make no such admissions. Hence, some degree of objectivity must be brought to bear as the basis upon which to impute the necessary component(s). It is always reasonable to assume that people of ordinary intelligence are aware of their physical surroundings and of the ordinary laws of cause and effect (see causation). Thus, when a person plans what to do and what not to do, he will understand the range of likely outcomes from given behaviour on a sliding scale from inevitable, probable, possible to improbable. The more an outcome shades towards the inevitable end of the scale, the more likely it is that the accused both foresaw and desired it, and, therefore, the safer it is to impute intention. If there is clear subjective evidence that the accused did not have foresight, but a reasonable person would have, the hybrid test may find criminal negligence. In terms of the burden of proof, the requirement is that a jury must have a high degree of certainty before convicting. It is this reasoning that justifies the defences of infancy, and of lack of mental capacity under the M'Naghten Rules and the various statutes defining mental illness as an excuse. Self-evidently, if there is an irrebuttable presumption of doli incapax or the accused did not have sufficient understanding of the nature and quality of his actions, the requisite mens rea is absent no matter what degree of probability might otherwise have been present. For these purposes, therefore, where the relevant statutes are silent and it is for the common law to form the basis of potential liability, the reasonable person must be endowed with the same intellectual and physical qualities as the accused, and the test must be whether an accused with these specific attributes would have had the requisite foresight and desire.

In English law, s8 Criminal Justice Act 1967 provides a statutory framework within which mens rea is assessed. It states:
 * A court or jury, in determining whether a person has committed an offence,
 * (a) shall not be bound in law to infer that he intended or foresaw a result of his actions by reasons only of its being a natural and probable consequence of those actions; but
 * (b) shall decide whether he did intend or foresee that result by reference to all the evidence, drawing such inferences from the evidence as appear proper in the circumstances.

Under s8(b) therefore, the jury is allowed a wide latitude in applying a hybrid test to impute intention or foresight (for the purposes of recklessness) on the basis of all the evidence.

The relevance of motive
One of the mental components often raised in issue is that of motive. If the accused admits to having a motive consistent with the elements of foresight and desire, this will add to the level of probability that the actual outcome was intended (it makes the prosecution case more credible). But if there is clear evidence that the accused had a different motive, this may decrease the probability that he or she desired the actual outcome. In such a situation, the motive may become subjective evidence that the accused did not intend, but was reckless or wilfully blind.

But, motive cannot be a defence. Say for example, an accused breaks into a laboratory used for the testing of pharmaceuticals on animals, the question of guilt is determined by the presence of an actus reus, i.e. entry without consent and damage to property, and a mens rea, i.e. intention to enter and cause the damage. That the accused might have had a clearly articulated political motive to protest such testing does not affect liability. If it has any relevance, it may be addressed in the sentencing part of the trial when the court considers what punishment, if any, it would be appropriate to impose given the degree of fault or blameworthiness in the accused.

Recklessness (willful blindness in the U.S.)
In such cases, there is clear subjective evidence that the accused foresaw but did not desire the particular outcome. When the accused failed to stop the given behaviour, he took the risk of causing the given loss or damage. There is always some degree of intention subsumed within recklessness. During the course of the conduct, the accused foresees that he may be putting another at risk of injury: A choice must be made at that point in time. By deciding to proceed, the accused actually intends the other to be exposed to the risk of that injury. The greater the probability of that risk maturing into the foreseen injury, the greater the degree of recklessness and, subsequently, sentence rendered.

Criminal Negligence


Here, the test is both subjective and objective. There is credible subjective evidence that the particular accused neither foresaw nor desired the particular outcome, thus potentially excluding both intention and recklessness. But a reasonable person with the same abilities and skills as the accused would have foreseen and taken precautions to prevent the loss and damage being sustained. Only a small percentage of offences are defined with this mens rea requirement. Most legislatures prefer to base liability on either intention or recklessness and, faced with the need to establish recklessness as the default mens rea for guilt, those practising in most legal systems rely heavily on objective tests to establish the minimum requirement of foresight for recklessness.

Mens rea under the American Law Institute Model Penal Code
Prior to the 1960s, mens rea was a very slippery, vague and confused concept. Since then, the formulation of mens rea set forth in the Model Penal Code has been highly influential throughout North America in clarifying the discussion of the different levels of mens rea.

The four levels of mens rea set forth in the MPC are:


 * 1) Purposely - Express purpose to commit a specific crime against a particular person; for example, to shoot an arrow at someone and hit him.
 * 2) Knowingly - Knowledge that one's actions would certainly result in a crime against someone, but did not specifically intend to commit that crime against the particular victim which one is accused of injuring; for example, to shoot an arrow at A but hit B.  This also covers the concept of willful blindness.  Willful blindness is where a person knows that something is very probable, but avoids investigating to gain that knowledge.  Often used against drug mules, who knew that it was highly likely that there was contraband in the vehicle, but refused to look.
 * 3) Recklessly - Knowledge that one's actions had an unjustifiable risk of leading to a certain result, but did not care about that risk ("reckless disregard"), and acted anyway; for example, to shoot an arrow in the air in a crowded place. Under the MPC, barring contradictory statutory language, recklessness is the minimum mens rea that will lead to criminal liability.  This covers the "depraved heart" state of mens rea, which is an extreme disregard for human life.  Examples include playing Russian Roulette, street racing, and other highly dangerous activities.
 * 4) Negligently - Did not intend to cause the result that happened, but failed to exercise a reasonable duty of care to prevent that result (which includes failing to become aware of the risk of that result.)  The above is the tort standard of negligence.  In general this is not enough for criminal liability.  Criminal negligence is a "gross deviation" from the standards of normal conduct and includes a substantial and unjustifiable risk.  For example, one might be negligent for failing to put up a fence to keep children away from your pool.  This will not lead to criminal charges. Criminal negligence might include keeping a vicious dog tied to a tree with twine.

Some commentators like to add on a fifth uncodified level, which exists in practice if not in the idealized Model Penal Code, which is, after all, merely a guide for states to follow in the development of their own criminal code. It should be kept in mind that the MPC is, in and of itself, not the law of the land anywhere, though many states have followed it to some degree or another.

 Strict liability - Strict liability is usually for "public welfare" offenses, like parking tickets, environmental regulations, and other such things. § 2.05(2)(a) of the Model Penal Code states where the mental state of the defendant bears no relevance to the prosecution of the offense then it is not a crime but a violation (and thus only enforceable by fine or forfeiture and not by imprisonment); the act itself is enough for conviction. Strict liabilty is rather rare in criminal law, but it does happen. For instance, statutory rape is a strict liability crime in some North American jurisdictions. Therefore even if the defendant believed the child to be over the age of consent, the defendant is still guilty of statutory rape if the child is underage even if the child lied about his or her age.

Examples of mens rea in statutes
Model Penal Code: A person commits murder if he (1) purposely or knowingly (2) causes the death of a human being.

Common Law: (a) It shall be unlawful for a person to cause the death of a human being with malice aforethought. (b) A violation of this section is murder in the second degree.