When the community is attacked from outside at least the external danger fosters solidarity within. When it is attacked from within by wanton individuals, they can be punished and the structure publicly reaffirmed. But it is possible for the structure to be self-defeating. This has long been a familiar theme for anthropologists (see Gluckman, 1963). Perhaps all social systems are built on contradiction, in some sense at war with'themselves. But in some cases the various ends which individuals are encouraged to pursue are more harmoniously related than in others.