Magic.

True poetic practice implies a mind so miraculously attuned and illuminated that it can form words, by a chain of more-than coincidences, into a living entity — a poem that goes about on its own (for centuries after the author’s death, perhaps) affecting readers with its stored magic.

I believe such stored magic can author in the reader an equivalent capacity for creative wonder, creative response to a living entity. The reader completes the poem, in the process bringing to it his or her own past experiences. You are reading poetry — I mean really reading it—when you feel encountered and changed by a poem, when you feel its seismic vibrations, the sounding of your depths.

Brain Pickings has more on Edward Hirsch’s How to Read a Poem.