The species "man," can be defined not only in anatomical and
physiological terms; its members share basic psychic qualities, the
laws which govern their mental and emotional functioning, and
the aims for a satisfactory solution of the problem of human
existence. It is true that our knowledge of man is still so
incomplete that we cannot yet give a satisfactory definition of
man in a psychological sense. It is the task of the "science of
man" to arrive eventually at a correct description of what
deserves to be called human nature. What has often been called
"human nature" is but one of its many manifestations—and
often a pathological one—and the function of such mistaken
definition usually has been to defend a particular type of society
as being the necessary outcome of man's mental constitution.
Against such reactionary use of the concept of human nature,
the Liberals, since the eighteenth century, have stressed the mal-
leability of human nature and the decisive influence of environ-
mental factors. True and important as such emphasis is, it has led
many social scientists to an assumption that man's mental consti-
tution is a blank piece of paper, on which society and culture
write their text, and which has no intrinsic quality of its own.
This assumption is just as untenable and just as destructive of
social progress as the opposite view was. The real problem is to
infer the core common to the whole human race from the
innumerable manifestations of human nature, the normal as well as
the pathological ones, as we can observe them in different indi-
viduals and cultures. The task is furthermore to recognize the
laws inherent in human nature and the inherent goals for its
development and unfolding.
This concept of human nature is different from the way the
term "human nature" is used conventionally. Just as man trans-
forms the world around him, so he transforms himself in the
process of history. He is his own creation, as it were. But just as
he can only transform and modify the natural materials around
him according to their nature, so he can only transform and