uage, folkways, mores, conventions, and ideals
separate individuals and peoples from each other as widely as oceans and
deserts. Communication between England and Australia is far closer and
freer than between Germany and France.

Conflict groups, like sects and parties, and accommodation groups like
castes and classes depend for survival upon isolation. Free intercourse
of opposing parties is always a menace to their morale. Fraternization
between soldiers of contending armies, or between ministers of rival
denominations is fraught with peril to the fighting efficiency of the
organizations they represent. The solidarity of the group, like the
integrity of the individual, implies a measure at least of isolation
from other groups and persons as a necessary condition of its existence.

The life-history of any group when analyzed is found to incorporate
within it elements of isolation as well as of social contact. Membership
in a group makes for increasing contacts within the circle of
participants, but decreasing contacts with persons without. Isolation is
for this reason a factor in the preservation of individuality and unity.
The _esprit de corps_ and morale of the group is in large part
maintained by the fixation of attention upon certain collective
representations to the exclusion of others. The memories and sentiments
of the members have their source in common experiences of the past from
which non-members are isolated. This natural tendency toward exclusive
experiences is often reinforced by conscious emphasis upon secrecy.
Primitive and modern secret societies, sororities, and fraternities have
been organized around the principle of isolation. Secrecy in a society,
like reserve in an individual, protects it from a disintegrating
publicity. The family has its "skeleton in the closet," social groups
avoid the public "washing of dirty linen"; the community banishes from
consciousness, if it can, its slums, and parades its parks and
boulevards. Every individual who has any personality at all maintains
some region of privacy.

A morphological survey of group formation in any society discloses the
fact that there are lateral as well as vertical divisions in the social
structure. Groups are arranged in strata of relative superiority and
inferiority. In a stratified society the separation into castes is rigid
and quite unalterable. In a free society competition tends to destroy
classes and castes. New devices come into u