The moral unity to be expected in different ages is not a unity of standard, or of acts, but a unity of tendency. . . . At one time the benevolent affections embrace merely the family, soon the circle expanding includes first a class, then a nation, then a coalition of nations, then all humanity, and finally, its influence is felt in the dealings of man with the animal world. --W. E. H. LECKY, The History of European Morals