 According to causal imperialists, such as Lewis, this explanation is causal by virtue of the fact that it provides information about the causal history of a sample of metal. Does this construal of the explanation as pointing to a hidden causal structure allow us to make perspicuous its explanatory import? As we have seen, Pearl’s and Woodward’s accounts of causation emphasize two features as characteristic functions of causal notions. First, knowledge of causal structures allows us to identify relationships amenable to manipulation and control; and second, common cause reasoning enables us to draw inferences from one time to another even when we possess only incomplete knowledge of the state of a system on an initial or final value surface.