  (2) The same objection can be generalized in terms of the relation that obtains in Kant’s Critique between ‘reason’ and ‘understanding’. It is the task of reason, according to Kant, to define the extra-systemic conditions that make the system of experience possible. But, ex hypothesi, reason has no knowledge of these conditions. As defined by it, they are empty conceptual constructs that acquire meaning only to the extent that they are used by the understanding in its endless work of systematizing experience. To this extent, reason is totally subordinated to the understanding. Yet the latter needs reason. To the extent, therefore, that reason does satisfy this need with its ideas, it cannot help creating the illusion that, through them, it yields genuine knowledge — that, logically, its conceptions are prior to those of the understanding. Now, Jacobi objected to what he took to be the existentially impossible requirement thus being imposed on reason, namely, that it should generate illusions for the sake of the understanding, yet be fully aware that such illusions are just that (Jacobi, 1812–25: vol. 2, 81, 100–01, 115).