In the preceding chapters I have endeavoured to show how, without invoking any "definitely directed variations," which we seem to have little chance of understanding, we may obtain a broad conception of the way in which the earth and its living inhabitants came to be what they are. No one is more conscious than the writer that this account is extremely imperfect. The limits of the volume have permitted me to use only a part of the material which modern science affords, but if the whole of our discoveries were described the sketch would still remain very imperfect. The evolutionary conception of the world is itself undergoing evolution in the mind of man. Age by age the bits of fresh discovery are fitted into the great mosaic. Large areas are still left for the scientific artist of the future to fill. Yet even in its imperfect state the evolutionary picture of the world is most illuminating. The questions that have been on the lips of thoughtful men since they first looked out with adult eyes on the panorama of nature are partly answered. Whence and Why are no longer sheer riddles of the sphinx. It remains to be seen if evolutionary principles will throw at least an equal light on the progress of humanity in the historical period. Here again the questions, Whence and Why, have been asked in vain for countless ages. If man is a progressive animal, why has the progress been confined to some of the race? If humanity shared at first a common patrimony, why have the savages remained savages, and the barbarians barbaric? Why has progress been incarnated so exceptionally in the white section of the race, the Europeans? We approach these questions more confidently after surveying the story of terrestrial life in the light of evolutionary principles. Since the days of the primeval microbe it has happened that a few were chosen and many were left behind. There was no progressive element in the advancing few that was not shared by the stagnant many. The difference lay in the environment. Let us see if this principle applies to the history of civilisation.