Defendants, mental illness and negligence law: a critique

Abstract

At common law, liability in negligence is based generally on an objective standard of reasonable care. As a consequence of this idea those who possess reduced capacities, as compared to the ordinary reasonable person, may be held to standards which they are incapable of reaching. Yet there are exceptions to this general rule. Children are not required to behave the way reasonable adults behave. Rather, when the defendant is a child, courts take into account the capabilities which are a concomitant of the defendant’s age. A defendant’s mental illness, on the other hand, is not considered by courts in Australia (or elsewhere) to be relevant when determining liability in negligence. It has been argued that in this regard the common law is incoherent and unfair. This thesis considers whether these claims of incoherence and unfairness can be substantiated. In so doing, it considers the philosophical underpinnings of tort law in order to explore possible bases for the current law. It also examines a number of more specific accounts which attempt to justify the present law as it relates to mental illness. It is argued that none of these discussions provide a convincing basis for the different treatment in law between child defendants and defendants with a mental illness. The discussion extends beyond the confines of tort law to criminal law for explanations for the apparent incoherence. It notes the suggestion that the criminal law’s response to defendants with a mental illness has been fuelled to some extent by a misunderstanding of mental illness and a fear of those suffering from such illnesses. The thesis examines whether this negative attitude towards mental illness, which some scholars have referred to as ‘sanism’, is at work in the few Australian decisions which have considered the common law position in relation to mentally ill defendants. Possible changes to this area of law are then outlined and considered.