The essential elements constituting national unity are psychic and social, not biological.  Racial unity is biological.  The same race may accordingly separate into different social and psychic groups.  And members of different races may belong to the same social psychic group.

The so-called “race soul” of many sociologists is, therefore, a fiction and indicates mental confusion.  The term refers not to the racial unity of inherent psychic nature, but only to the social unity of socially inherited psychic characteristics.  Groups thus socially unified may or may not be racially homogeneous.  In point of fact no race is strictly homogeneous biologically, nor is any social group completely unified psychically.

In sociology as in biology function produces organism, that is to say, activity produces the organ or faculty fitted to perform the activity.[2] The psychic characteristics differentiating social groups are chiefly, and perhaps exclusively, due to diverse social activities.  These activities are determined by innumerable causes, geographical, climatic, economic, political, intellectual, emotional, and personal.

The plasticity of a psychic group is due to the plasticity of the infant mind and brain, which is wonderfully capable of acquiring the language, thought forms, and differentiating characteristics of any group in which it may be reared.  To what extent this plasticity extends only carefully conducted experiments can show.  In the higher Asiatic and European races we find it to be much greater than is generally supposed to be the case, but it is not improbable that the lowest races possess it in a much lower degree.

The relative fixity of a psychic group is due to the fact that in full-grown adults, who form the majority of every group, function has produced structure.  Body, brain, and mind have “set” or crystallized in the mold provided by the social order.  Influences sufficiently powerful to transform the young have little effect on the adult.  The relative fixity of a psychic group is also due to the difficulty—­well-nigh impossibility—­of bringing new psychic influences to bear on all members of the group simultaneously.  The majority, being oblivious to the new psychic forces, maintain the old psychic regime.  The difficulty of reform, of transforming a social order, is principally due to these two causes.

The “character” of a people (psychic group) consists of its more or less unconscious, because structuralized or incarnate, ideas, emotions, and volitions.  Chief among them are those concerning the character of God, the nature and value of man and woman, the necessary relation of character to destiny, the nature and meaning of life and death, and the nature and the authority of moral law.  In proportion as the social order incorporates high or low views on these vital subjects, is the character of the people elevated and strong, or debased and weak.