Kant's theory of cognition appeals to a host of for ms, representational contents, faculties, and synthetic acts. One thing to which Kant's interpreters aspire is a better understanding of how these various explanatory grounds relate to one another. In some cases we are given substantial hints. For instance, there can be little doubt that the fact that our understanding operates by actualizing certain "functions" – such as the disjunctive function that is used when we judge disjunctive propositions – explains our possession of the categories, in this case the category of community. Yet even here Kant is content to leave us to fill in the details. The functions are doubtless only a partial explanation of the categories and it is less clear what else is required for a full explanation. Worse, the explanatory dependence of the categories upon the functions stands out for the amount of explicit attention that Kant devotes to it. The explanatory relations between most other explananda are more obscure. For instance, how precisely does the representation relate to the functions?¹ Or what about and the concept or concepts that allow us to grasp and pursue the ideal of complete systematic unity?