Causal uncertainty is a wide-spread phenomenon. Courts are often unable to determine whether a defendant's tortious conduct was a factual cause of a plaintiff's harm. Yet, sometimes courts can determine the probability that the defendant caused the plaintiff's harm, although often there is considerable variance in the probability estimate based on the available evidence. The conventional way to cope with this uncertainty has been to apply the evidentiary rule of 'standard of proof'.

The application of this 'all or nothing' rule can lead to unfairness by absolving defendants who...