It has already been said that the materials of civilization, whether they be tools, or institutions, or inventions, or discoveries, or religious or ethical teachings, are facts that can be directly described as psychological. An institution--the Church, the Crown, the Magistracy--is not transmitted as a building or as so many sheets of paper, but as an idea or as a set of ideas. A piece of machinery is, in the same way, a mental fact, and is a physical one in only a subordinate sense. And if this be admitted, we reach the further truth that the environment to which man has to adapt himself is essentially, so far as it is a social environment, psychological. Not alone are the outward marks of social life--the houses in which man lives, the machines he uses to do his bidding--products of his mental activity, but the more important features of his environment, to which he must adapt himself, and which so largely shape his character and determine his conduct, are of a wholly psychological character. In any society that is at all distinct from the animal, there exist a number of beliefs, ideas and institutions, traditions, and, in a later stage, a literature which play a very important part in determining the direction of man's mind. With increasing civilization, and the development of better means of intercourse, any single society finds itself brought into touch and under the influence of other social groups. The whole of these influences constitute a force which, surrounding an individual at birth, inevitably shapes character in this or that direction. They dominate the physical aspect of life, and represent the determining forces of social growth. Eliminate the psychological forces of life and you eliminate all that can be properly called civilization. It is wholly the transforming power of mind on the environment that creates civilization, and it is only by a steady grasp of this fact that civilization can be properly understood.