Walls, no less than writing, define civilization. They are monuments of resistance against time, like writing itself … Walls protect, divide, distinguish; above all they abstract. The basic activities that sustain life … take place beyond the walls. Within the walls one is within an emporium; one is within the jurisdiction of a bureaucracy; one is within the abstract identify of race, city, and institutionalized religion; in short, one is within the lonely enclosure of history. [He] is the builder of such walls that divide history from prehistory, culture from nature, sky from earth, life from death, memory from oblivion.
Robert Pogue Harrison, Forests: The Shadow of Civilization