In his recent book, Explaining Behavior: Reasons in a World of Causes, Fred Dretske develops at length a conception of behavior as part of an ingenious attempt to display the causal relevance of intentional states, qua intentional, to behavior. So-called folk-psychological explanations of intentional human behavior accord central explanatory roles to beliefs, desires, reasons, intentions, and the like. But how, Dretske asks, do the distinctively psychological features of such items figure in the etiology of behavior - how, for example, do (...) reasons qua reasons contribute to human behavior? My primary concern here, however, is with a significant portion of the ground work that Dretske lays for the answer -specifically, his conception of behavior. (shrink)