But this misunderstanding of Japan reveals an equally profound misunderstanding in regard to ourselves. Occidental peoples are supposed to be what they are in civilization and to have reached their high attainments in theoretical and applied science, in philosophy and in practical politics, because of their unique brain-structures, brains secured through millenniums of biological evolution. The following statement may seem to be rank heresy to the average sociologist, but my studies have led me to believe that the main differences between the great races of mankind to-day are not due to biological, but to social conditions; they are not physico-psychological differences, but only socio-psychological differences. The Anglo-Saxon is what he is because of his social heredity, and the Chinaman is what he is because of his social heredity. The profound difference between social and physiological heredity and evolution is unappreciated except by a few of the most recent sociological writers. The part that association, social segregation, and social heredity take in the maintenance, not only of once developed languages and civilizations, but even in their genesis, has been generally overlooked. But a still more important factor in the determination of social and psychic evolution, generally unrecognized by sociologists, is the nature and function of personality. Although in recent years it has been occasionally mentioned by several eminent writers, personality as a principle has not been made the core of any system of sociology. In my judgment, however, this is the distinctive characteristic of human evolution and of human association, and it should accordingly be the fundamental principle of social science. Many writers on the East have emphasized what they call its "impersonal" characteristics. So important is this subject that I have considered it at length in the body of this work. Sociological phenomena cannot be fully expressed by any combination of exclusively physical, biological, and psychic terms, for the significant element of man and of society consists of something more than these--namely, personality. It is this that differentiates human from animal evolution. The unit of human sociology is a self-conscious, self-determinative being. The causative factor in the social evolution of man is his personality. The goal of that evolution is developed personality. Personality is thus at once the cause and the end of social progress. The conditions which affect or determine progress are those which affect or determine personality.