I'm thinking particularly of modern poets for whom the modern world per se does not enter into the referential field, or is barely visible on the horizon. (The opposite of a poetic modernity defined by the presence of airplanes and telegraphs, the intrusion of technology.) What makes this poetry modern? It is modern by its implicit reference to something not there. That which "brilla por su ausencia" as we say. That makes it a little more interesting as a critical problem, don't you think? Modernity as an absence of modernity.