In the last chapter I observed that, with the rise of human intelligence, the cultural environment becomes more important than the physical. Since human progress is a progress in ideas and the emotions which accompany them, this may seem to be a truism. In point of fact it is assailed by more than one recent historical writer. The scepticism is partly due to a misunderstanding. No one but a fanatical adherent of extreme theories of heredity will deny that the physical surroundings of a race continue to be of great importance. The progress of a particular people may often be traced in part to its physical environment; especially to changes of environment, by migration, for instance. Further, it is not for a moment suggested that a race never evolves its own culture, but has always to receive it from another. If we said that, we should be ultimately driven to recognise culture, like the early Chinese, as a gift of the gods. What is meant is that the chief key to the progress of certain peoples, the arrest of progress in others, and the entire absence of progress in others, is the study of their relations with, or isolation from, other peoples. They make progress chiefly according to the amount of stimulation they get by contact with a diverse culture. Let us see if this furnishes a broad explanation of the position of the various peoples of the world. The Ethnologist tells us that the lowest peoples of the earth are the Yahgans of Tierra del Fuego, the Hottentots, a number of little-understood peoples in Central Africa, the wild Veddahs of Ceylon, the (extinct) Tasmanians, the Aetas in the interior of the Philippines, and certain fragments of peoples on islands of the Indian Ocean. There is not the least trace of a common element in the environment of these peoples to explain why they have remained at the level of primitive humanity. Many of them lived in the most promising and resourceful surroundings. What is common to them all is their isolation from the paths of later humanity. They represent the first wave of human distribution, pressed to the tips of continents or on islands by later waves, and isolated. The position of the Veddahs is, to some extent, an exception; and it is interesting to find that the latest German students of that curious people think that they have been classed too low by earlier investigators.