Computerizing criminal law: Problems of evidence, liability and mens rea

This paper evaluates the computability of law by considering whether legal rules have the necessary precision. The ‘open texture’ of law which Professor Hart describes is revisited, and against this background two substantive topics of criminal law are considered as illustrating the problem: both the process of developing the law, and of applying definitions to particular cases, require mechanisms which Hart envisages and which any attempt to make law machine‐readable must cope with. The two areas are, firstly, recent changes to the law governing the criminal liability of children and the now‐obsolete requirement that not only must the child be proved to have had the necessary mens rea but must in addition have known that the conduct was seriously wrong; and secondly, the definition of recklessness as applied in practice by the Civil Aviation Authority to the offence of what might be loosely described as dangerous flying.