Causation has always been a central topic in the history of philosophy. Many theories causation have been advanced, but not one has approached anything like general acceptance. Yet the concept of causation is prevalent in many areas of contemporary philosophy: there are the causal theories of language, of action, of personal identity, of knowledge, of perception, of scientific explanation, and of reference. If causation is doing all this philosophical work, it seems essential to strive for an intelligible account of what a 'cause' actually is. One obvious place to start is Hume's analysis...