  The kernel of Jacobi’s argument was in fact still the same as the one presented in his earlier Kant essay (1802). The point there was that Kantian reason, though transcending the understanding, was none the less restricted in its knowledge to the limits of the latter and even subservient to it in the exercise of its powers. As a result, reason found itself in the strange situation of spontaneously generating belief that we have knowledge of transcendent realities, while at the same time having to recognize that any such knowledge is illusionary. Jacobi now further develops this point by arguing that Kant’s critical system was explicitly intended from the start to serve the interests of science — where by ‘science’ Kant meant first and foremost a cognition of the understanding directed at the objects of the senses. The understanding, however, despite its earth-bound nature, cannot help falling under the influence of the higher faculty of reason. It is caught up in reason’s desire to behold all things under a transcendent single principle. And reason — as a matter of fact, according to Jacobi — does have an intuitive knowledge of things transcendent. But since the understanding cannot allow this knowledge, yet still needs reason as a higher regulative principle, it substitutes for reason’s knowledge ideal constructs that are indeed also the products of reason, but are made up, however, of abstractions derived from the understanding. These abstractions then hide from the understanding and reason itself the transcendent knowledge that the latter enjoys de facto. For since reason naturally begins with the assumption of such a knowledge, yet cannot recognize it in the abstractions construed for the sake of the understanding, it ends up treating it as mere illusion (Jacobi, 1812–25: vol. 3, 372–94).