How are we to decide when an act is negligent? As is often the case with complex questions, the answer to the question may depend on the reason for asking it in the first place. If the question is asked when one is seeking to determine liability in tort, then the definition of negligence will be framed in such a way as to grasp those situations where it is thought that loss should be shifted from plaintiff to defendant. If the question is framed in the context of criminal punishment, or as part of an inquiry into moral blame, negligence may be given a very different definition. In this chapter we shall be concerned solely with civil liability and with the way in which negligence should be defined for those purposes.

A central question in tort theory in recent decades has been that of how we are to identify a satisfactory justification for transferring loss through the medium of civil liability. A prominent trend in this analysis has been the championing of economic theories which have sought to establish a broadly utilitarian theory for the attribution of liability. In these theories, the aim of the law of torts is to shift loss where to do so will satisfy the economic interests of society.