After the heartbreakingly gentle song, “John My Beloved,” ends, Sufjan Stevens takes a single audible breath. The breath, like many of Stevens’s choices on his revelatory new album, Carrie & Lowell, beckons the listener in by virtue of its strangeness. The record is a complete work of art no matter how it is viewed, but the breath suggests something unfinished. Though “John My Beloved” is a remarkable love song, Stevens leaves us wondering for whom it was written, man or deity, and if they will ever reply.