This is a poem to stretch the mind. It begins by stretching our imagination to a cosmic event: a “moondog,” which is a rare bright spot in the moon’s halo. It’s formed by a “mirage of light & cloud & ice”—an image which then brings the speaker down to earth, into his own life. But this life, as he sees it, is stretched among mind-bending options: for instance, he’s “not willing to lose / that which I cannot keep/ for that which I cannot lose.” Then comes what for me is the poem’s core image: “Crumb by crumb the self is whittled down.” It’s the self of the Christian classic The Cloud of Unknowing, the self that must dissolve into “a leash of longing” for God’s very being. The “leash” then leads the poet into a metaphor of himself as “stray dog,” from which more mind-bending apparent opposites follow. All are playing with the self’s “dissolutions,” until the poem’s final line: the diminishment into a mere parenthesis filled with absences.