Basic Concepts of Criminal Law
Actus non facit reum, nisi mens sit rea. [The act is not criminal unless the intent is criminal.]
Criminal statutes define conduct that falls below prescribed legal and moral standards and thereby causes identifiable social harm. Not every instance of unlawful conduct is punished, however, and not every social harm is redressed. Thus, before beginning a discussion of specific criminal statutes, it is necessary to explore some fundamental concepts that are critical to an understanding of the structure and application of the criminal law. This chapter will focus on four criminal law concepts--the voluntary act, the mental state, causation and social harm--that provide the foundation for most criminal statutes and assist society in selecting those individuals who are morally blameworthy and deserving of punishment.
To secure a conviction under a criminal statute, one element the government must prove is that the defendant performed a voluntary act that resulted in a social harm. The act must be voluntary because moral blameworthiness can be more accurately assessed when there is some degree of certainty that defendants have acted according to their own free will. Furthermore, if one of the goals of punishment is deterring unlawful con-