In this paper I argue that Kant’s doctrine of definitions, as it is developed in theTranscendental Doctrine of Method(TDM) and in the lectures on logic, lays down the semantic background of the problem of the objective reality of the categories and of the solution Kant provides for it in theTranscendental Analytic. The distinction between nominal and real definitions introduces a two-dimensional element in Kant’s theory of concepts, and this, I argue, provides a compelling explanation for the assumption Kant makes in (...) §13 that it is possible to possess a concept without knowing the conditions of its legitimate application. This view is supported by the parallels between Kant’s discussion of empirical, mathematical, and philosophical concepts in §13 and in theTDM. And, it allows clarifying the sense in which the arguments that prove the objective reality of the categories are, at the same time, counterfactual reflections that give us (incomplete) insight into their real definitions. (shrink)