The meaning of form in contemporary innovative poetry

A fun selection of topics detailing who to read and who is reading whom, completely addled for me by the introduction’s insistence that:

“To regard cognition as having independent existence outside the brain, inherent in things in general (or in an artistic form in particular) is not a metaphorical or mystical formulation.”

Of course, that is absurd if taken literally, which Shepppard certainly does seem to do, quoting approvingly Leighton’s ‘form as a way of knowing, not as an object of knowledge’. He later differentiates ‘form’ (both of individual poems and of e.g. the sonnet) from ‘forming’, but it seems muddled at best.

Forms and language aren’t real: in which case how does “cognition” have “independent existence” in its “entering” of a poetic form?

I liked the chapter on Forrest-Thompson, but felt e.g. the tonal shift of “and they love us so” says something “irrelevant” to form, just not the poem’s meaning (that the shift is being excluded, for the inattentive reader, a sort of doubling up of its formal absence), which Sheppard seemed to miss the possibility of (even-though it changes nothing but the usefulness of her theory of “relevance”). So, it seems much safer for me to think of ‘form’ as how to read the poem. The book showcases how erudition can overwhelm a reading for content only, but not how to read (especially if content is what we already knew).