From Our Very Greatest Human Thing is Wild: Brenda Hillman in Conversation, as available in full at poets.org:

I still have the feeling that the task of artists is always going to be a matter of a seeking that is intense and is about a soul at work—"soul" being another term for the seeking of a mind. Boundary issues impact so much of that work: the ideas of shape in a piece of art, your relationship to tradition, how much you can risk, and your relationship to the mysterious and to your future readers—whether you want to call that divine or human nature or artifice. And language subverts any of our efforts to make boundaries. Our very greatest human thing—which is language to me—musicians would say it's music, but I think it's language—our very greatest human thing is wild. Uncontrollable. It is impossible to put boundaries on your words, even if you make a poem. Each word is a maze. So you are full of desire to make a memorable thing and have the form be very dictated by some way that it has to be. But the poem itself is going to undo that intention. It's almost like you're knitting a sweater and something is unraveling it on the other end. You know what I mean? In this way, it is very strange.