I have been wondering about this quality for some time, an aspect of writing/language which I can only call poetic intelligence, a something far more than ‘intelligence’ normally accounts for… and yet it is a kind of mental accuracy of skill and knowingness. An ability to understand and almost calculate language and knowledge – but also allow the aleatory interventions that ‘work’.

Wallace Stevens, 1948. Photo by Sylvia Salmi. Details

John Ashbery, 1975. Photo by Michael Teague. Details
It is normal intelligence in reverse – it happens as answer before the question is consciously put. And may never be put. It invents responses from within which the ‘problems’ are seen. Poetry as speculation. This might be as different as that line from Stevens, to Ashbery to Jorie Graham.
I suspect PI is the stuff in all good poetry. It’s practically impossible to define because it manifests so variously: blindingly theatrical in one poet (say, early Lowell) and subtle in another (and brittle, as in Louise Gluck). One poet has plain diction and weird logic, another a packed-up density of encountering effects, both high in PI.
The nuance of language-perception; the acuity of awareness of the physical, or the feeling, worlds; psychological observation and insight; unexpected language kick and spin; philosophical interrogation; trance-making; trouble-making; comic inventiveness; the ability to mix and jolt between registers in ways that increasingly balance the rope-walk rather than fall from it… the intelligence in language and mood of some poetry is hot, some cold.
It can seem present in the mystic sense (?)… as of a blur of states, not all the same, but in overlap and with different centres or means (as in statistics, graphs), for each of us. Not enough of ‘it’ and you feel the lack, something that is clearly apprehended but less clear/easy to identify in the actual poem…

Jorie Grahams, 2007. Image in public domain. Details

Peter Porter, 2007. Photo by Simon James. Details
I don’t mean rational either, or only. Sometimes poetic intelligence is more emotional, sometimes more ‘feeling’, deeply interior and meditative, its wit more ‘intellectual-erudite’ and resourceful (eg: Peter Porter, Gwen Harwood, Peter Steele) or more intuitive and insightful of where worldly and inner perceptions overlap, etc. Lovely subtlety. It is a crazy head-trip in Ted Berrigan and its rhyzomic extension in John Forbes. The deliberate language interventions of Language Poetry. And yet, Robert Frost is a dour, wise-like-old-trees stoical member of it. It is a tight cry of controlled awareness in Sylvia Plath and an elegant, resistant lyricism in that other stoic Anna Akhmatova. In psychological prose, Janet Frame is as poetically intelligent as any poet. The opening pages of Faces in the Water are embarrassingly good, as are the opening pages of Jazz, by Toni Morrison.
And even if we have enough of it to successfully ‘be’ the poet we are, (each different, each a provisional version of it) it may desert us sometimes, which could explain those infuriating poems which do not work. Unless we can see the reason, the lack… and re-phase (not re-phrase) them with shocks of the right stuff, they do not have the charge, the potential, etc, of the good poem, ie: ‘having’ poetic intelligence. (Sorry for electrical metaphors).

Portrait of Gwen Harwood, West Hobart, 1988, by Alec Bolton (National Library of Australia; nla.pic-vn3119883 used with the kind permission of Dr Caren Florance on behalf of the Bolton Family)
In some of the less successful poems I’ve read, quite oblique associations and deferred meanings are used when dealing with moral and political topics. They take the poet beyond what I’d call the taste of plausible and even moral association. Such a poem uses us, ie: the poet tries to make us follow in with their gratuitous reaching into empathy/towards suffering/ when the ask is too great (and for nothing). Moral messiness results in presumptuous poetry. I am not convinced. Such tricks of syntax are formulaic and predictably ‘inventive’ based on imitation or formula – formulae masquerading as avant-garde. This often is merely rated by inclusion in the politics of avant-gardism, despite its paucity; merely the equal and opposite of traditionally formal poets who get a rhyme scheme and a rhetorical fineness-of-feeling into essentially mundane poems. Who cares? Simplistic.
But in these poems of both kinds we are missing the form and finding ‘the person’, the one who is felt-speaking there, the moral being, then, and if we get it awkwardly we will not like the poem.

Anna Akhmatova by Kuzma Petrov-Vodkin,1922. Photo in public domain. Details
For this reason, perhaps, readers are obsessed with lyric poetry – they crave the person within the poem (even if it’s false, ie: not real) because the desire for the person is desire for moral connection, and it is more powerful than the form, the content, the brilliance, even, of the poem – when thus reduced these readers want the illusions of autobiography. But that may be nothing other than tone and tone can just as easily be said to be part of form, not content at all, and certainly not person. The intelligence in this, then, is the sentimental: a person-sounding presence IS the (moral) intelligence the reader discerns.
Some poems have a fluency of phrase-making which is astonishing, some observe with an accuracy that is visually brilliant (Murray) or psychologically astute, some both, some both in the same phrase; other poems are rogue poems; some are bloody funny, are delightful in fresh ways; some are deeply moving, sad, or satiric or politically powerful.

Toni Morrison, 1970. Photo by Bert Andrews. In public domain. Details
Poems where the attention to sound and form and the line is irresistible, where the radical over-turning of conventions is invigorating. Different qualities, various effects, but within the poems overall there is a blend of these elements that feels and stays with us by the power of being… well, convincing. They feel right. Insightful. Persuasive (even if you are not inclined to ‘believe’ them). Inventive.
And, the oddest one of all – a quality of ‘just so’. As if that really means, and it does feel as if it really means, the ‘right’ words, in the ‘right’ order (even if this is the most collage-y, cut-up passage of bricolage), the telling phrase, the fine judgment of tone or manner, voice (or deliberate disordering of any single voice), the timely attack, the bravura… announces to us as readers, yes, this is sui generis, it is itself and it is fully, (as if) knowingly itself. I suggest these are the markers of poetic intelligence, in the poems, in the readers.