The English word "civilization" comes from the 16th-century French "civilisé" ("civilized"), from Latin "civilis" ("civil"), related to "civis" ("citizen") and "civitas" ("city"). The fundamental treatise is Norbert Elias's "The Civilizing Process" (1939), which traces social mores from medieval courtly society to the Early Modern period. In "The Philosophy of Civilization" (1923), Albert Schweitzer outlines two opinions: one purely material and the other material and ethical. He said that the world crisis was from humanity losing the ethical idea of civilization, "the sum total of all progress made by man in every sphere of action and from every point of view in so far as the progress helps towards the spiritual perfecting of individuals as the progress of all progress".