And now we come to the final step in the making of language. By the conventionalization of sound in oral speech, which is the actual language, man accomplished two things. First, he changed the vague suggestiveness of natural sounds into perfectly defined, articulated, limited sound symbols, that can be clearly differentiated from one another by the ear, as ‘rat,’ ‘cat.’ Second, by conventionalization he transformed the pure time symbols into space-time symbols, as in the sentence, ‘The bird sings,’ where ‘bird’ is a representation of space, ‘sings’ of time, though both are carried from the lips of the speaker to the ear of the listener upon the common substratum of sound, that is, time.

It may be worth while now to summarize in a page or two the view of world evolution as outlined above, a spiral structure of which man’s created language forms the final story. In this summary I adopt the organic hypothesis, which assumes that mind is a basic and permanent element in the world, self-determining and purposive in its nature, and the directing agency in the evolutionary process throughout its history. While the acceptance or rejection of this metaphysical hypothesis is not essential to the acceptance or rejection of the scientific exposition of the birth and structure of language given in the preceding pages, the choice of one or other hypothesis does, of course, make a rather complete difference in the diction and phraseology chosen to set out the specific exposition. To a mechanist many of the terms which I have used may appear altogether unwarranted or quite wrong.