Gardner's presentation of Kant on Skepticism

Question

I am working (slowly) through the Critique of Pure Reason, reading Sebastian Gardner's Routledge Philosophy Guidebook to Kant and the Critique of Pure Reason as a secondary source (among others), and am confused about an argument he attributes to Kant concerning the viability of skepticism.

As I understand him, in Gardner's discussion of the Preface(s) he has Kant arguing that we use the same principles of reason for both metaphysical and everyday cognition, and these principles seem or are themselves unassailable (Kant says as much at Aviii); "Metaphysics simply pushes them further, in search of complete explanation..." (Gardner, 21). To reject metaphysical cognition as possible would "repudiate cognition as a rational phenomenon." (ibid.)

This stumps me because, while a priori (lol) it seems like the sort of argument Kant might make, at least to a newbie like me, I can't find him articulating anything like it in either the A/B Prefaces or the Introduction. Am I just misreading Kant, and/or am I missing something implicit? Or is this Gardner's view of the sort of argument Kant would make?

For what it's worth, I do see Kant explicitly arguing against indifferentism (saying, among other things, that indifferentists end up making and using metaphysical assumptions in their thinking even when they profess not to, and that metaphysics is driven by an "natural disposition" in humans and thus is not to be dismissed), and agree with Gardner's reading of Kant on this score.

Answer 1

I think Gardner might be referring to Aviii and explicating what is otherwise implicit when Kant writes:

Human reason has the peculiar fate in one species of its cognitions that it is burdened with questions which it cannot dismiss, since they are given to it as problems by the nature of reason itself, but which it also cannot answer, since they transcend every capacity of human reason.

Reason falls into this perplexity through no fault of its own. It begins from principles whose use is unavoidable in the course of experience and at the same time sufficiently warranted by it. With these principles it rises (as its nature also requires) ever higher, to more remote conditions. But since it becomes aware in this way that its business must always remain incomplete because the questions never cease, reason sees itself necessitated to take refuge in principles that overstep all possible use in experience, and yet seem so unsuspicious that even ordinary common sense agrees with them. But it thereby falls into obscurity and contradictions, from which it can indeed surmise that it must some where be proceeding on the ground of hidden errors; but it cannot discover them, for the principles on which it is proceeding, since they surpass the bounds of all experience, no longer recognize any touch stone of experience. The battlefield of these endless controversies is called metaphysics.

It seems to me that Gardner is expanding upon what Kant says. Where Kant writes that reason begins with principles arising from experience and necessary for it Gardner takes that as an identification of metaphysical cognition and cognition in general, so that if metaphysical cognition is rejected so is everyday cognition. Kant says, here, that metaphysical inquiries arise unavoidably from reason itself and so I think Gardner is restating the argument that to reject metaphysical inquiries would be to reject reason. I might be misunderstanding too, though!