In studying this anti-Semitic movement in America as a crucial example of the relations of group and sub-group, I stand in the contrary danger, that of rationalizing the inferiority complex of a persecuted group. My only justification for facing this danger is that nobody can approach this type of problem without one danger or the other, and the subject is too vital to be entirely neglected. I can only hope that my analysis of the underlying problem of the nature of human groups and of their interrelations may be made in such a scientific spirit that the application of my theory to the special problem of anti-Semitism in the United States may be of some value in the clearing up of this great field of human action. CHAPTER I. THE “GROUP MIND” A DEFINITION AND A DESCRIPTION The causes of intolerance rest, not in what men say but in what they do. The reasons alleged for dislike or suspicion of the Jew are valuable merely for showing a state of mind in the anti-Semite himself, not for revealing the actual reasons for his attitude. For that reason I shall disregard these reasons very largely in searching for the causes of anti-Semitism in America. Instead, I shall turn to the field of social study to find out how groups of men act toward one another, and why and under what circumstances intolerance is one of their by-products. I shall apply to the phenomena of group life the method of behaviorism, now being adopted by sociology from its original field of psychology, in such definitions as that of E. C. Lindeman:[3] “Sociology is the science of collective behavior.” 1. The prevailing view of students of society seems now to be that society is a natural phenomenon on the mental plane. Human society is not now regarded, as by Buckle, as a reflection of environment, even though the importance of physical background and racial constitution must be recognized. As Charles A. Ellwood says,[4] “Society is a group of psychically interacting individuals.” “The essential element in the social process is the psychical element.”[5] That is to say, mental material—instincts, emotions, feeling, and ideas—are the plane on which groups of individuals combine into social structures, operate in social functions, develop to social progress. Relations between individuals (except for the limited biological function) are mental relations, carried on through physical media such as postures, speech and writing.