Since I’ve been participating a bit in the comments, I don’t have a lengthy summative post. I just want to say a little bit about the fundamental fallout from Kant. I do focus on the first Critique, partially due to its great influence. I’m tracing the development of ideas along a path of inheritance, so what got the most attention gets most of my attention as well. Of course, the third Critique was very important for idealism, but ultimately the first represents Kant’s greatest legacy (for the issues I’m interested in) so it’s what I focus on (I also don’t know the 3rd very well). I’m sure a really interesting narrative of the descent of ideas from the 3rd Critique could be constructed and I’d like to read it; that’s just not my story. The indefinite article of my subtitle—A History—is quite intentional: other equally legitimate histories could be written. I don’t claim that mine is definitive or the R3 way things are, just that it is reasonable, grounded, and illuminating.
I don’t see Kant’s position regarding noumena as a simple contradiction, which would make it hard to acquit him of stupidity, but as something like an antinomy. The very way he sets up his ideas—that the mind organizes the data it receives—intrinsically leads us towards positing an input coming in ab extra in a strong sense. Epistemological humility also impels us to admit that our best ideas may still be wrong, requiring a reality exceeding our awareness. On the other hand, the same ideas also lead us to forbid speaking of what is fully and completely beyond our capacity to speak, at least with any. Any consideration of reality can only consider it in the terms that govern all of our thought, yet in this case we are trying to consider precisely that which escapes these terms.
As I understand him, Kant does not merely say that we can never know if our Forms & Concepts do represent reality as it really is (thus failing the verificationist criterion), but that we do in fact know that they don’t. This is where the analogy with the pink sunglasses breaks down. Someone with the glass fused onto their face from birth can never know what color the world really is, but it may very well be pink. Another metaphor would be alphabetical order. This is entirely a human product created to order things like files and paperwork (somewhat within our control, so disanalogous on this point) and there is nothing in reality that corresponds to it. So while it is as true as true gets that the name “Braver” comes before “Cogburn,” it makes no sense to ask, “yes, in our alphabet Braver does come before Cogburn, but who actually comes first? In reality? What is the arrangement that’s independent of our alphabetical ordering but which corresponds to it?”
Hitting this antinomy casts no aspersion on Kant’s intelligence; the logic of the ideas leads into it. And my reading is that a considerable chunk of the next 125 years or so are spent on finding an adequate solution to this problem. How can we talk about our A5 mind’s activity without bringing in R1 something for it to be active upon? This is a very hard question that Hegel, Nietzsche, and Heidegger all direct considerable cerebral resources towards.