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