  Vaihinger does little to assuage these problems in (1876). Sometimes he suggests that they are rooted in the fact that the very notion of a thing in itself involves a contradiction, albeit one which is “grounded in the contradictory constitution of our cognitive faculty itself” (1876, 34). In other words, Vaihinger seeks to view the issue of things in themselves along the lines of a Kantian antinomy—a conflict which arises necessarily from the nature of our reason, but which can at least be recognized as such. This, however, is of little help. For one, it is questionable whether the basic epistemological standpoint of (1876) can even be coherently stated without commitment to things in themselves. For another, a crucial feature of Kant’s antinomies is that they are resolved by his transcendental idealism, thus lending that doctrine an indirect proof (KrV, A 506/B 534). If the critical philosophy itself were to generate insoluble contradictions, that would be reason to reject, not accept, it. Vaihinger would continue to struggle with these issues in the PAO, which still aims to advance the broadly Langean project of naturalizing Kantianism. As we shall see in §6, however, Vaihinger’s conception of Kantianism undergoes a considerable shift, now taking the form of what he calls “idealistic positivism”, “positivist idealism”, or even (in what is evidently the first use of the phrase) “logical positivism.” For more on Vaihinger’s debt to Lange, see (Ceynowa 1993, 133–72; Heidelberger 2014).