risk. Particularly in the United States, where the doctrine of 'proximate cause' effectively amalgamates the two-stage factual then legal causation inquiry favoured in the English system, one must always be alert to these considerations in assessing the postulated relationship between two events. Foreseeability tests Some aspects of the physical world are so inevitable that it is always reasonable to impute knowledge of their incidence. So if A abandons B on a beach, A must be taken to foresee that the tide comes in and goes out. But the mere fact that B subsequently drowns is not enough. A court would have to consider where the body was left and what level of injury A believed that B had suffered. If B was left in a position that any reasonable person would consider safe but a storm surge caused extensive flooding throughout the area, this might be a novus actus. That B was further injured by an event within a foreseen class does not of itself require a court to hold that every incident falling within that class is a natural link in the chain. Only those causes that are reasonably foreseeable fit naturally into the chain. So if A had heard a weather forecast predicting a storm, the drowning will be a natural outcome. But if this was an event like a flash flood, an entirely unpredictable event, it will be a novus actus. The question of A's beliefs is no different. If A honestly believes that B is only slightly injured and so could move himself out of danger without difficulty, how fair is it to say that he ought to have foreseen? The test is what the reasonable person would have known and foreseen, given what A had done. It is the function of any court to evaluate behaviour. A defendant cannot evade responsibility through a form of willful blindness. Fault lies not only in what a person actually believes, but also in failing to understand what the vast majority of other people would have understood. Hence, the test is hybrid, looking both at what the defendant actually knew and foresaw (i.e. subjective), and at what the reasonable person would have known (i.e. objective) and then combining the conclusions into a general evaluation of the degree of fault or blameworthiness. Similarly, in the quantification of damages generally and/or the partitioning of damages between two or more defendants, the