Samenvatting
Two models of explanation are outlined: the causal model, used in the physical sciences and in traditional behaviouristic psychology, and the purposive model, which although not strictly "scientific", is making a useful comeback in modern cognitive psychology. It is shown that both models are required to produce a satisfactory definition of the concept of accidents, four aspects of which are considered. It is shown that the two models together illuminate the notions of objective and subjective risk.