Mens rea means criminal intent. An act must be blameworthy. It must be done with criminal intent or be an act of gross negligence or recklessness. Mens rea is one of two components of a crime, the other being actus reus.
Mens Rea, Concurrence,
A criminal offense requires a criminal intent. The requirement of a criminal intent is based on moral blameworthiness, a conscious decision to intentionally or knowingly engage in criminal conduct or to act in a reckless or negligent fashion. Mens rea consists of four states of mind. The most serious or culpable is purposely, and then knowingly, recklessly, and negligently.
Strict liability offenses require an actus reus, but do not incorporate a mens rea requirement. These typically are public welfare offenses or crimes that protect public safety and security by regulating food, drugs, and transportation.
On Culpability and Crime: The Treatment of Mens Rea in the Model Penal Code - Herbert Wechsler, Columbia Law School, ANNALS of the American Academy of Political and Social Science, Vol. 339, No.1 - When conduct has the external attributes of a crime, should further mental elements be required for conviction, and, if so, what should they be?
Decisions have too frequently been imprecise in analysis and inconsistent in re sults, yielding a multitude of single instances which in the ag gregate dilute the moral force that should attach to condemna tion of behavior considered criminal.
Criminal liability may justly be based only upon conduct which includes a voluntary act or the omission to perform an act which the actor was physically able to perform. Act or omission are essential pre requisites to liability, but they are not sufficient to establish culpability.
The Model Penal Code proposes four concepts to describe the kinds of culpability which are sufficient to es tablish liability: purpose, knowledge, recklessness, or negli gence. The doctrine of strict liability, ignorance and mistake of fact, intoxication, and ignorance and mistake of law are pertinent to establishing liability. One of the most conten tious problems of the penal law concerns the criteria that should determine when individuals whose conduct would otherwise be criminal ought to be exculpated on the ground that they were suffering from mental disease or defect when they acted. The Model Penal Code would exculpate the person who, as a re sult of mental disease or defect, lacked substantial capacity either to appreciate the criminality of his conduct or to con form his behavior to the requirements of law.