§ 10.03 Rationale of the Mens Rea Requirement

§ 10.03 Rationale of the Mens Rea Requirement¹⁹

[A] Utilitarian Arguments

The mens rea requirement is sometimes explained on grounds of deterrence. A person cannot be deterred from criminal activity, it is argued, unless he "appreciate[s] that punishment lies in store" if he persists in his actions.²⁰ Therefore, punishment of one who lacks a culpable state of mind will be ineffective and, consequently, wasteful. It may also be reasoned that one who causes harm accidentally, rather than intentionally or with an "evil-meaning mind," is harmless and not in need of reformation.

These claims are only partly persuasive. Even if one acting without a culpable state of mind cannot be deterred on the present occasion, his punishment may serve as a useful warning to others to be more careful in their activities, thereby potentially reducing the number of accidentally inflicted injuries.²¹ Furthermore, although it may be agreed that one who acts with a mens rea is apt to be dangerous and in need of reformation, the accidental harmdoer may also need incapacitation or some other corrective influence. Some people are accident-prone; the criminal sanction may be a rational way to protect society from them. At a minimum, their punishment may influence them to change their lifestyle and to avoid activities that may result in injury to others.

The mens rea requirement may be counterproductive for another reason. The prosecution is constitutionally required to prove beyond a reasonable doubt every element of a criminal offense, including the defendant's mens rea. This is sometimes a difficult burden to satisfy because "[t]he bottom line is that in many cases the State is not privy to direct evidence of [the defendant's mens rea] . . . because of the impossibility of peering inside a defendant's mind."²² Consequently, some persons who are culpable are able to avoid conviction. Their acquittals send the potential counter-utilitarian message to would-be wrongdoers—those who are looking for a legal loophole—that they might also be able to escape the criminal sanction.

[B] Retributive Arguments

The Supreme Court once observed that "[a] relation between some mental element and punishment for a harmful act is almost as instinctive as the child's familiar exculpatory [statement], 'But I didn't mean to'."²³ Oliver Wendell Holmes has made the same point with animals rather than children when he suggested that "even a dog distinguishes between being stumbled over and being kicked."²⁴

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