Amity-enmity complex

Amity-enmity complex is a term that was introduced by Arthur Keith in his work, A New Theory of Human Evolution (1948). The book posited that humans evolved as differing races, tribes, and cultures, exhibiting patriotism, morality, leadership, and nationalism. Those who belong are part of the in-group and are tolerated; all others are classed as out-group and are subject to hostility. "The code of enmity is a necessary part of the machinery of evolution. He who feels generous towards his enemy..