In the same way, if we take a larger view and consider the life of a social group, we see that communication, including its organization into literature, art, and institutions, is truly the outside or visible structure of thought, as much cause as effect of the inside or conscious life of men. All is one growth: the symbols, the traditions, the institutions are projected from the mind, to be sure, but in the very instant of their projection, and thereafter, they react upon it, and in a sense control it, stimulating, developing, and fixing certain thoughts at the expense of others to which no awakening suggestion comes. By the aid of this structure the individual is a member not only of a family, a class, and a state, but of a larger whole reaching back to prehistoric men whose thought has gone to build it up. In this whole he lives as in an element, drawing from it the materials of his growth and adding to it whatever constructive thought he may express. Thus the system of communication is a tool, a progressive invention, whose improvements react upon mankind and alter the life of every individual and institution. A study of these improvements is one of the best ways by which to approach an understanding of the mental and social changes that are bound up with them; because it gives a tangible framework for our ideas—just as one who wished to grasp the organic character of industry and commerce might well begin with a study of the railway system and of the amount and kind of commodities it carries, proceeding thence to the more abstract transactions of finance. And when we come to the modern era, especially, we can understand nothing rightly unless we perceive the manner in which the revolution in communication has made a new world for us. So in the pages that follow I shall aim to show what the growth of intercourse implies in the way of social development, inquiring particularly into the effect of recent changes. FOOTNOTES: [22] The Story of My Life, 316, 317. CHAPTER VII THE GROWTH OF COMMUNICATION PRE-VERBAL COMMUNICATION—THE RISE OF SPEECH—ITS MENTAL AND SOCIAL FUNCTION—THE FUNCTION OF WRITING—PRINTING AND THE MODERN WORLD—THE NON-VERBAL ARTS.