Interdisciplinary citation patterns and other indicators of the flow and sharing of academic knowledge suggest that economists and anthropologists do not talk to each other. Previous studies of this puzzling trend have typically attributed the problem to methodological differences between the two disciplines. Although there are significant differences between economics and anthropology in behavioral assumptions and modes of inquiry, similar differences exist between them and other disciplines (some with much heavier volumes of cross-citations with economics or anthropology), suggesting that the source of the problem lies elsewhere. This paper considers the problem at a deeper level by examining systematic differences in the preferences, capabilities, and literary cultures of economists and anthropologists. Adopting a rhetorical perspective, I consider not the firms, households, or tribes as the principal objective of analysis in the two disciplines, but the conversations between these units. These conversations (through non-verbal as well as verbal media) can be grouped into two genres, based on the type of problem they aim to solve. Those in the first genre aim to solve the problem of interest--how to align the incentives of the parties involved. Those in the second genre deal with the problem of knowledge--how to align localized, and dispersed information. Economists are interested and capable of dealing with primarily, if not exclusively, the first genre, and anthropologists focus on the second. This difference has far reaching consequences for how economists and anthropologists conduct their own scholarly conversations with their own colleagues, why they are having difficulty talking to each other across disciplinary boundaries, and what can be done to change the patterns of communication.