[Jueqelyl]

First, congratulations for having laboured through to page 188. I can only tell you my understanding without any guarantee that this is what Bikkhu Bodhi (or respectively Nara Maha Thera - difficult to tell) had in mind: it's a sort of compromise between the extremes of metaphysical realism and metaphysical idealism. There is neither an outer world completely independent of consciousness as in Kant's noumenon, nor is there an inner world completely independent of the outer world. The outer world may be a reflection of the inner world in the sense of being conditioned by it and vice versa, but not a projection in the sense of being totally constructed from scratch. That's how I interpret this.

The Kaccayanagotta Sutta makes a similar point, but instead of employing the Western antithetical notions of realism vs. idealism is employs the Indian antithetical notions of existence vs. non-existence. The essence is in the first paragraph you quoted, which is quite terse, but seems to convey the idea that the extremes should be avoided, as they are wrong views. Which means the view that the outer world ultimately doesn't exist is wrong, as well as the view that the outer world ultimately does exist (at face value). Both are expressions of a middleway teaching that runs counter to classical (Western) binary logic.

Cheers, Thomas