Immanence and Unity of Reason in Kant's Opus postumum through a Comparison with Maimon and Fichte

The aim of this project is to provide a systematic investigation of the transformations undergone by transcendental philosophy through the works of Maimon and Fichte, and to examine whether, and to what extent, similar developments can also be identified in Kant’s Opus postumum. Kant’s manuscripts are thus examined, for the first time in an extended manner, in the historical-philosophical context in which they were developed. The dissertation is structured in three parts. The first part offers a comprehensive reconstruction of Kant’s unfinished project, with particular emphasis on the significance of the so-called “Transition from the Metaphysical Foundations of Natural Science to Physics” and on the new conceptual tools that Kant develops in order to fill the gap between the two disciplines. In particular, I will focus on the meaning and on the function of the Mittelbegriffe and on the a priori proof of the existence of the ether. In the second part I identify a conceptual affinity between the problems Kant confronts in the first fascicles of the manuscripts and those Maimon attempts to address in his Versuch über die Transzendentalphilosophie. In particular, I will show that in both cases one can discern three important reformulations: (1) a new transcendental schematism; (2) a revaluation of the doctrine of the thing-in-itself; and (3) a new concept of experience. At the same time, I will point out that Kant’s project maintains its own specificity and distinguishes itself from Maimon’s philosophy insofar as it succeeds in avoiding both the dogmatic rationalism and the empirical skepticism of the latter. In the third part, I will investigate the relation between the final fascicles of the Opus postumum and Fichte’s philosophy during the Jena period. This section will begin with a general analysis of Fichte’s Grundlage, understood as an attempt to respond both to Schulze’s and Maimon’s skepticism. The primary objective will be to show that the radicalization of the structures of critical philosophy advanced by Fichte does not lead, as many interpreters claim, to a simplistic subjectivist metaphysics in which all reality is dissolved into the infinite activity of the I. At the same time, I will draw attention to the practical implications of Fichte’s operation, showing how it leads to a significant revaluation of the relation between subject, world, and God, and thus of Kant’s doctrine of the highest good. I will then proceed to examine the final two fascicles of Kant’s manuscripts. First, I will focus on the so-called Selbstsetzungslehre, showing both its coherence with the overall project of the Opus postumum and its connection with the earlier fascicles. At the same time, I will demonstrate that it exhibits not only a terminological but also a conceptual affinity with Fichte’s Grundlage. Finally, I will show that, in Kant as well, this reformulation of the doctrine of subjectivity leads, in the very last fascicle, to a significant rethinking of his moral doctrine, which no longer assigns to God the task of synthesizing subject and world, but rather to the subject the task of unifying God and the world.