We are now ready to define group mind in the sense in which it will be understood in this essay. A group mind is the common purpose of two or more persons, which they accept as their own purpose. The mode of this acceptance or identification is in behavior, which includes the reasons given by the individuals—their rationalizations—as well as their overt acts. The test of this in any particular case is the test of sacrifice, whether the man acts as a self-preserving being, an individual pacifist, or as a citizen and soldier, a member of a group at war; whether the church member acts as an individual thinker, or subordinates his judgment to the interpretation and the practice of the church; whether the son acts as a loyal son, a member of the family, to his own hurt, or goes off to marry against his parents’ will, leaving them perhaps to suffer want. I have purposely taken examples where opinion may be divided, as it is not my purpose to attach moral right or wrong to either group loyalty or individual freedom; either may be right under given circumstances, or judged by certain standards. The group mind may be conscious, as a deliberative assembly; or instinctive and unconscious, as the racial group or the partly hypnotized mob. The ancient Israelite identified himself with his people; he did not even expect personal immortality, but desired sons to carry on his name so that his family and his people might be immortal. Parents are willing sacrifices for their children, but sacrifices nevertheless. The patriot volunteers for dangerous duty consciously, or leaps over the parapet in the blind enthusiasm of a charge; whether conscious or unconscious of the meaning of his act, he acts as a soldier, not a self-seeking person. The varieties of the group mind are almost innumerable. The group mind may be as instinctive and unorganized as a religious revival, as natural as a nation with its bonds of language, land, custom and government, as artificial as a military company without even a name, with only a number, and yet with a definite morale, a tradition, a personality of its own. The theater audience has a group mind, while the restaurant crowd has not; for it is an axiom in the theater that each audience has a character of its own, that only a full house really abandons itself at a comedy, while even a smaller crowd may be carried away by a tragedy, and so on; the individual abandons his own judgment and his inhibitions at least in part, to react to the performance as a member of the group.