With apologies to the green movement, "sustainability" is a myth. History and archaeology show that societies are always moving to the edge of crisis, "falling forward" through growth, but then responding often successfully to the problems created. What we can hope for is that with a somewhat more controlled level of growth, and with longer-term preparations for change, we can keep responding to the inevitable smaller crises, as they arise, and continue to postpone until later and later the, perhaps ultimately inevitable, end of our civilization.