The preceding three chapters have offered an account of the physical expansion of the vocabulary and of some of the physical changes it has undergone. They have shown how words are increased in numbers by new creation and by varied combinations. They have shown how words are modified in form so as to fit in with the existing order and how they are brought into varied relations with each other. But these physical modifications go only a short way in the explanation of how language has been able to accomplish its function, the task little short of the miraculous, of making the limited variety of sounds producible by the organs of the human voice serve to express the almost infinite variety and complexity of human thought. The achievement of this function has been possible only through an inner or psychical expansion, a true evolution of the powers of expression. In this evolution much has been accomplished by a variety of shifts in meaning, by which a single word has been made to express not one meaning alone, but a remarkable variety of meanings. "It is thanks to the metaphor," according to the remark of Quintilian (VIII, 6), "that each thing seems to have its name in language."1 In order to avoid the ambiguity connected with the name metaphor, in the present discussion the shifts in meaning will be referred to collectively as tropes.
In the development of language it is well established that the things first to receive names were the definite, tangible things coming most close in everyday experience.____________________