Mens rea is Latin for "guilty mind".[SUP][1][/SUP] 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 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). As a general rule, criminal liability does not attach to a person who acted with the absence of mental fault.
The exception is strict liability crimes.
In civil law, it is usually not necessary to prove a
subjective mental element to establish liability for breach of
contract or
tort, for example. However, if a tort is intentionally committed or a contract is intentionally breached, such intent may increase the
scope of liability as well as the measure of
damages payable to the
plaintiff.
Therefore,
mens rea refers to the mental element of the offence that accompanies the
actus reus.