The group mind comes into being only through contact with other groups. We may go so far as to conclude that there must be two groups in order that there may be one group. If an isolated island possessed a few people so unorganized that they felt no difference of groupings among themselves, then there would be no sense of a total group, either. Under those circumstances that would be attained only in case of an invasion by people from without the land, or a rebellion within, when group unity of the islanders would at once appear. If my previous identification of mind in the individual and the group is exact, not merely an analogy, then this follows from Baldwin’s genetic study of the individual. The mind of the individual grows by constant reference to the alter—for in the thought of the child the ego and alter are one—and even in the highest reaches of moral judgment there remains an element of social approval, of what would be the judgment of the ideal group or the ideal comrade. [40]“We do right by habitually imitating a larger self whose injunctions run counter to the tendencies of our particular selves.” To quote a few applications of this viewpoint to particular problems: Sumner applies it to the primitive horde: [41]The relationship of comradeship and peace in the we-group and that of hostility and war toward others-group are correlative. War and peace have reacted on each other and developed each other, one within the group, the other in the inter-group relation. Loyalty to the group, sacrifice for it, hatred and contempt for outsiders, brotherhood within, warlikeness without—all grow together, common products of the same situation. In Ellwoods’s words: [42]While the stimuli afforded by the struggle with the physical environment are conceivably sufficient to bring about the highest degree of coordination, unity and solidarity in the larger human social groups, yet historically they have not done so. Rather, it has been the stimuli arising from the conflict and competition of one human group with another which has chiefly developed conscious social solidarity in the larger human group. Dr. George E. Vincent wrote: [43]Conflict, competition, rivalry, are the chief causes which bring human beings into groups, and largely determine what goes on within them. [44]It is in conflict or competition with other nations that a country becomes a vivid unity to the members of its constituent groups. It is rivalry which brings out the sense of team work, the social consciousness. “Races, Nations and Classes,” a recent work by Dr. Herbert A. Miller, presents a series of studies of social relations in terms of group conflicts, group oppression and group revolt, as these exist in various crucial situations today.