Descriptivist theories of belief content (for example those of Quine, Lewis, Braddon-Mitchell, and Jackson) imply that ordinary agents do not often have beliefs with the same content. Common complaints made against descriptivism concern communication, agreement, disagreement, and the norms of belief change. The natural explanation of these phenomena, the complaints run, requires that agents often have beliefs with the same content, so accepting descriptivism compromises our ability to correctly explain these phenomena. In this paper I spell out these complaints and consider how the descriptivist should respond to them. Descriptivists incur an explanatory debt. If communication, agreement, disagreement, and the norms of belief change are not to be explained in the natural way, descriptivists must give an alternative account of these phenomena. I argue that this explanatory debt can be paid with the help of a theory of sameness of subject matter. I consider some accounts of sameness of subject matter in the literature and present and defend my own account of sameness of subject matter.