self-enclosed, self-limiting

A poem presents material so that it becomes a universe in itself…There is something self-enclosed and self-limiting in a poem, and this self-sufficiency is the reason, as well as the harmony and rhythm of sounds, why poetry is, next to music, the most hypnotic of the arts.

—John Dewey, "The Varied Substance Of The Arts," Art As Experience(Perigee/Penguin Putnam Books, 1980)