As in an orchestra, every type of instrument has its specific timbre and tonality, founded in its substance and form; as every type has its appropriate theme and melody in the whole symphony, so in society each ethnic group is the natural instrument, its spirit and culture are its theme and melody, and the harmony and dissonances and discords of them all make the symphony of civilization, with this difference: a musical symphony is written before it is played; in the symphony of civilization the playing is the writing, so that there is nothing so fixed and inevitable about its progressions as in music, so that within the limits set by nature they may vary at will, and the range and variety of the harmonies may become wider and richer and more beautiful.