The speaker looks back at an earlier self and compares it with the person they are now. Before, they were "an empty room with an open window": solitary, hollow, but receptive. They spent time in empty stairwells, read Jung, and daydreamed about quiet, wind-swept orchards. It's a lonely picture, though also a dreamy and searching one.
Now everything is loud. Life is "a party on the front porch," full of raucous laughter and a great family. Yet the speaker says they are "no one in particular," which sounds like a loss of identity rather than a gain. The title suggests the self has come apart, not been fulfilled.
The last lines carry the sting. The family is so wonderful that the speaker can "hardly hear / the whispers of the elms," the quiet inner and natural world they once longed for. The mood is bittersweet and a little uneasy: contentment on the surface, with a faint sense that something important has been drowned out.