It is a statement that poetry should not be "didactic" but should be for no other purpose than aesthetics. Simply said, a poem shouldn't teach, it should only be beautiful. Edgar Allen Poe supported this view in his lecture titled The Poetic Principal. He referred to didactics in poetry as "The didactic heresy". However, Ralph Waldo Emerson, in his essay on Poetry, insists that poetry must be didactic. Different strokes for different folks as they say.