Hi. In his book A Short Critique of Kant's Unreason, dr. Avi Sion has made the following suggestion: "Kant’s dichotomy between the world apparent to us and some unknowable more really real world beyond is based on and buttressed by his peculiar theory of logic. I refer especially to his analytic-synthetic dichotomy."

I would be glad if the author, or somebody else, clarifies what precisely this grounding consists in since there can be numerous suggestions on this point. Thus, it would not be unnatural to suppose that the grounding was presumed to work in the opposite direction, that is, the dualism between the noumenal and the phenomenal actually grounds the analytic-synthetic dichotomy (or, at least, its synthetic a priori part), not vice versa. I personally believe that Kant indeed at least tried to argue from and adhere to the logico-epistemological viewpoint but I cannot fully explicate the connection in question. It would be natural to suppose that synthetic a priori judgments ensure both the so-called Copernican turn and the dualism at issue if there were not a possibility that they themselves were deduced based on the ready-made dualism.

Thanks in advance.

You quote the introduction to chapter 2: "Kant’s dichotomy between the world apparent to us and some unknowable more really real world beyond is based on and buttressed by his peculiar theory of logic. I refer especially to his analytic-synthetic dichotomy." This was intended to link this chapter with the previous, in which I discussed Kant's fanciful claim to a transcendental reality.

In the conclusion of chapter 2, I wrote: "The logic proposed by Kant does not correspond to the logic of actual human discourse; it is a mere incoherent invention of his. He may have pretentiously called it a critique of pure reason, but I would call it an impure critique devoid of reason. If he describes reason erroneously, he is logically bound to end up with absurdities like the unbridgeable gulf between things-in-themselves and things-as-they-appear. But such difficulties are not the fault of reason; they are the fault of (his own) unreason."

Through that chapter, I describe aspects of how humans actually develop knowledge and show that this method does not correspond to the one erroneously proposed by Kant (notably, the analytic-synthetic dichotomy). The connection between these two chapters is the workings of Kant's own mind - in the same way as he lacks logical acumen in his proposed theory of knowledge, so he lacks intellectual skill in his proposed theory of twofold reality. The same amateur mind is at work, producing both of these silly theories of his.

Still, I would place the analytic-synthetic dichotomy as logically underlying the things-apparent or in-themselves dichotomy, for the following reason. Call these his epistemological and metaphysical claims, roughly speaking. His metaphysical claim is essentially imaginative, whereas his epistemological claim is a more intellectual construct. The metaphysics he proposes is not historically new - all religions have used similar ideas; whereas, his epistemology constitutes a novel attempt to intellectually justify that metaphysics by laying claim to possibilities of a priori knowledge, i.e. knowledge quite independent from experience.

Something about you (optional) logician-philosopher

This is precisely the point I try to catch. To begin with, the contrary picture is not uncommon — that Kant's analytic/synthetic distinction is quite traditional (being a kind of reinterpretation of the classical distinction between necessity and contingency), whereas his metaphysical dualism between the noumenal and the phenomenal is quite new. I strongly disagree at least with the first assertion, but all this is just by the way. The main question is about the (inter)connection between the kinds of knowledge allegedly exempt from experience and the dualism at issue. It is quite clear that Kant's aim behind formulating the new logical dichotomy is to define a class of synthetic a priori truths. However, if we remember his main question — on how they are possible — we rather have to answer it in the following fashion: they are possible because all knowledge is about mere appearances, not vice versa. Therefore, given that the dualism in question constitutes the inherent part of the so-called Copernican turn, and synthetic a priori truths do not ground this dualism, it is not clear how the truths in question can ground the Copernican turn. But if they cannot do this, it is not clear what else can ensure this so-called turn and what does it consist in if it cannot justify the metaphysical dualism at issue.

The situation becomes more complicated if we consider those philosophers who accept the analytic/synthetic dichotomy but reject synthetic a priori judgments. Indeed, "positivists" should adhere to the Copernican turn since their theories depend on postulating the "subjective" character of linguistic conventions and meaning. This suggests that the turn at issue can be ensured merely by the so-called analytic truths. But this makes the situation even more mysterious — we are left with a plain circularity between the truths allegedly exempt from experience and the dualism between the noumenal and the phenomenal. And what could such philosophers say about the epistemological and ontological status of things-in-themselves?