th social and psychical, the offspring necessarily develop psychic
and social characteristics similar to those of the parents.

Evolution takes place through the transformation of inheritance. The
evolution of _innate_ physiological, anatomical, and psychical
characters takes place through the transformation of biological
inheritance; and the evolution of society and of _acquired_ characters
chiefly through the transformation of social inheritance.

Nearly all biologists admit that change in the form of natural
selection is one of the principles transforming biological
inheritance; but whether the _acquired_ characters of parents are even
in the least degree inherited by the offspring, thus becoming _innate_
characters, is one of the important biological problems of recent
years. Into this problem we have not entered, though we recognize that
it must have important bearings on sociological science. Briefly
stated, it is this: Do social and psychic characteristics, acquired by
individuals or by groups of individuals, affect the intrinsic
inherited and transmissible psychic nature in such ways that
offspring, by the mere fact of being offspring, necessarily manifest
those characteristics, regardless of the particular social environment
in which they may be reared? Into this problem, thus broadly stated,
we do not enter. Limiting our view to those advanced races which
manifest practically equal physiological development, we ask whether
or not their differentiating psychic characteristics are due to
modifications of their inherited and intrinsic psychic nature, such
that those characteristics are necessarily transmitted to offspring
through intrinsic biological heredity. Current popular and scientific
sociology seems to give an affirmative answer to this question. The
reply of this work emphasizes the negative. Although it is not
maintained that there is absolutely no difference whatever in the
psychic nature of the different races, or that the psychic differences
distinguishing the races are entirely transmitted by social heredity,
it is maintained that this is very largely the case--far more largely
than is usually perceived or admitted. Such inherent differences, if
they exist, are so vague and intangible as practically to defy
discovery and clear statement, and may be practically ignored.

The only adequate disproof of the position here maintained would be
about as follows. Let a Japanese infant be reared in an Americ