Précis of Depth

Many scientic explanations have the form of deductive derivations from laws or other generalizations. Hempel and Oppenheim’s (1948) equation of explanation with law-involving deduction is stymied, however, by cases such as the žagpole and the shadow: two deductions, formally almost identical, have quite dišerent explanatory properties. e length of the žagpole’s shadow can be explained by deriving it from the height of the žagpole and the position of the sun, but the height of the žagpole is certainly not explained by deriving it from the length of its shadow. e former derivation owes its explanatoriness, apparently, to something that goes beyond mere logical deduction. e modern reaction to this case (not so dišerent from that insinuated by Aristotle in Posterior Analytics 1.13) is that the deduction is only a representational instrument: the meat of the explanation inheres in what the deduction stands for, which is almost universally taken to be a causal relation. A deduction of the length from the height, if done right, represents the causal process by which the žagpole and sun together cause the shadow. e reverse deduction fails to represent a causal process, because there is no such process running from shadow to pole. What explains, in short, are the causal facts—the facts that constitute the process causing the explanandum