ABSTRACT
An offence against the person will almost always have two elements commonly described as the actus reus and mens rea. The rough translation of these Latin tags as ‘guilty act’ and ‘guilty mind’, should not be taken as indicating their precise meaning.1 They are simply a shorthand method of describing two very complex concepts. Nor should it be assumed that they are entirely independent. At times, there is an interrelationship, or a difficulty in drawing a clear line between the two. A person who, as a result of a sudden fit, or seizure, for example, flings out an arm and strikes another, will almost certainly not commit an offence. But is this because of the absence of an actus reus, or of mens rea, or both? The issue arises because it may be argued that an actus reus requires an act that is ‘willed’ or voluntary. It becomes important in situations where the law refuses to excuse the D even though the prosecution cannot prove the relevant mens rea – for example, if this is due to the D’s voluntary intoxication.2 If the defendant can argue that there is no actus reus, however, the mens rea issue becomes irrelevant. In other offences, the actus reus may itself involve a more specific mental element. This is more often the case with offences outside the area of our discussion,3 but an example which is applicable is the offence of conspiracy. Here, the actus reus of the offence is an ‘agreement’ between two or more parties. Clearly, such an act of agreement implies a conscious decision to make it, and a particular state of mind. The notion of an unconscious agreement is meaningless. Here, then, the determination of the actus reus involves at least some consideration of the state of mind of the person concerned.
