The accumulation of knowledge and the advancement of reason are accompanied by a progressive widening of the circle of the group mind, to include an ever larger number and variety of sub-groups. Dr. Baldwin suggests this process: [53]“Group selection gives rise to what may be called the law of the widening unit, that as the circle of co-operation widens the unit of survival, the group, taken as a whole, becomes larger.” The other side of the same process is the increasing complexity of the mind of the individual and the sub-group because of the richer world in which they exist—in Dr. Vincent’s words, [54]“The person has as many selves as there are groups to which he belongs. He is simple or complex as his groups are few and harmonious or many and conflicting.” The actual growth of an international mind today is evident, through scientific, religious, artistic and economic influences; through the great alliances of the World War; through the ease of communication and the spread of news and propaganda. A world-wide group mind, if such is possible, cannot and should not eliminate its sub-groups, but include them in a wider synthesis; even enriching the complexity of the sub-groups by its further ramifications and their further imitations. But the easy and natural way for such an international group mind is by conflict with a still different outside group. The white races would easily attain unity if there were a real race conflict against the colored races of the world; differences between French and German, between Russian and American, would be swallowed up in a day. Unity of the entire human race would come instantly if we were invaded from Mars. The slogans of our earth-wide unity would be the defense of our beloved planet and the common descent of all human beings. In default of such a threat from without, is the international mind an impossible hypothesis?