Why do we write poems?

As soon as we write something, we are indelibly responsible to the whole community of lexical artifacts. As Nik Hoffman has formulated it, the poet is the shepherd of language. This is not a Romantical inflation of the office, but merely a consequence of the facticity of what it means to write something. We cannot be gnostical: we speak and write the way we do, today, for concrete reasons. And poetry is the alembic wherein language is most impactfully and necessarily concentrated (what percentage of our vernacular do they credit Shakespeare for, again?). A poet can simplify, vulgarize, effeminize, harden, inebriate; he can give us new lexical roads down which to walk, or burn certain bridges of the imagination.

I shall venture briefly into theological/philological water far too deep for me (and very likely step upon a sea-anemone), but which I think will be of use to the clarification of my meaning.

Insofar as I understand it, the Subject of the classical world (in the Aristotleian paradigm) had a certain desiring capacity of the will (βούλησις). This sort of desire is of a rational, pragmatic nature; it lacks beauty and flavour, eros. 

St. Maximus the Confessor introduced the now common word for will, θελεμα. It is a word originating in the writings of the poets; it connotes a yearning, a tenacity, a creativity, that the earlier word semantically excluded.

To me, poetry is a reserve of expressions of this type of will. On first reading William Blake, I became aware that it was possible to feel and desire and know things that I had never before encountered. It showed that the human soul plumbeth far deeper than common wit avers.

Now, there are reservoirs of clean water and of dirty; Traherne and Baudelaire shew both of them glimmers of a beauty, however it takes but little discernment to recognize in the former a purer font. 

C.S Lewis, for this reason, emphasized this mimetic, pedagogical responsibility that the poet bears. The introduction of a new metaphor, or the approach, lyrically, metrically, tonally, of a poem to a subject has repercussions that are genuine, at once spiritual, historical and intellectual.

So, the poet produces poetry in order to be a complete human being. I hope that this answer is not a complete dud. However, I think there is some elegance in this because it means that poetry is not optional. And for our self-understanding, whether historical or metaphysical, this has deep implications.

As I have emphasized before, the poet, more than a cultivator of language, is one that has a particular disposition towards the world (thus St. Porphyrios (and William Blake) make the mantle of the poet a requirement of the Christian). The task of human beings is, in some sense, to discern impossible purposes in things supposedly mundane, and to realize in synergy with God these purposes. The poet looks at the decaying world and sees the world transfigured in an undying light. If he is sentimental, he will retreat from himself, from his body and the world in order to preserve this homeostatic sentimentality. But if he is true, then he sings the Paschal hymn in his deep heart amidst the layered sediment of powdered bones that constitute the desert of the world, and hears the seeds of Eden as they begin to sprout in their verdure. And there are some for whom (would I were one) the world gleams in its fullness even now.

Glory to God for all things