 It may well be asked of Kant’s “Refutation of Idealism”, as it had already been asked of his yet-to-be-named transcendental idealism in 1770 by such distinguished contemporaries as Johann Heinrich Lambert, Johann Georg Sulzer, and Moses Mendelssohn, whether it is really compatible with the transcendental ideality of time, that is, whether it does not presuppose the reality of the temporality of the enduring object it proposes by means of which to determine the sequence of our own representations as well as of the self that has that sequence of representations (isn’t the sequence of representations, they essentially asked, really a sequence?). But we will not further pursue that question here, because all of Kant’s successors were more concerned with the viability of Kant’s general distinction between appearances and things in themselves rather than with the specifics of Kant’s argument for transcendental idealism from a priori knowledge or of Kant’s proof that we can assert the existence of things in themselves in spite of that distinction. This concern began with the famous objection of F.H. Jacobi, made in the appendix to his 1787 book on David Hume, that without the assumption of things in themselves he could not enter into the critical system, but that with it he could not remain within the system; that is, he felt that once the distinction between appearances and things in themselves was made all ground for the assumption of the existence of things other than our own representations was removed even if Kant had made no explicit argument against that existence. We will also not further explore what we have called Kant’s practical transcendental realism, that is, his argument that morality requires us to believe that we have free wills and immortal souls and that there is an omniscient, omni-benevolent, and all-wise God, thus that those constituents of reality are essentially mental in nature. Rather, we now turn to Kant’s successors to see how they tried to save Kant’s insight into the idea that the most fundamental forms of knowledge ultimately depend on fundamental operations of self-consciousness without ending up with Kant’s combination of that with indeterminate ontological realism.