Mens rea and actus reus

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“Mens rea” is a “guilty mind”, from the axiomatic Latin expression which founds the English criminal law, actus non facit reum nisi mens sit rea: “An act is not guilty unless the mind is guilty”.

What counts as a sufficiently guilty mind will depend on the offence, or wrong, in question. For criminal acts, it will generally be intention or recklessness; for strict liability offences and torts, more likely no more than gross negligence or negligence. Only the blamelessly inadvertent get away unscathed, and even they can fall prey to offences of absolute liability.

See also

• degrees of liability