It admits the reality of death, of human finitude and failure, it admits that the world is not us and that we do not control it. In poetry, or any art, it is impossible to talk of form and content as if they are two separate qualities. But most discussion about art, and much art, implicitly makes this distinction. A formless poem is an oxymoron. A poem is not a vessel from which a subject can be poured out, any more than the human body is a container for the soul.
Poetry is about nothing except itself.
A way of happening, a mouth. The fact that poetry has no justification is a sore trouble to many people and is why it is so often asked to be something else. It can matter only on its own terms, which are radically without use. If it incorporates the terms of other agendas, they must be secondary to the imperatives of the poetic. Poetry requires the courage to believe in nothing except the infinite possibilities of the poetic.