ut the division of labor between
psychology and sociology, it seems best to leave to the psychologist all
that goes on inside the individual and to say that the work of the
sociologist begins with the things that take place between individuals.
This principle of division is not one that can be maintained absolutely,
any more than we can hold absolutely to any other abstract
classification of real actions. It serves, however, certain rough uses.
Our work as students of society begins in earnest when the individual
has become equipped with his individuality. This stage of human growth
is both cause and effect of the life of human beings side by side in
greater or lesser numbers. Under those circumstances individuals are
produced; they act as individuals; by their action as individuals they
produce a certain type of society; that type reacts on the individuals
and helps to transform them into different types of individuals, who in
turn produce a modified type of society; and so the rhythm goes on
forever. Now the medium through which all this occurs is the fact of
contacts, either physical or spiritual. In either case, contacts are
collisions of interests in the individuals.

2. The Land and the People[122]

Every clan, tribe, state, or nation includes two ideas, a people and its
land, the first unthinkable without the other. History, sociology,
ethnology, touch only the inhabited areas of the earth. These areas gain
their final significance because of the people who occupy them; their
local conditions of climate, soil, natural resources, physical features,
and geographic situation are important primarily as factors in the
development of actual or possible inhabitants. A land is fully
comprehended only when studied in the light of its influence upon its
people, and a people cannot be understood apart from the field of its
activities. More than this, human activities are fully intelligible only
in relation to the various geographic conditions which have stimulated
them in different parts of the world. The principles of the evolution of
navigation, of agriculture, of trade, as also the theory of population,
can never reach their correct and final statement, unless the data for
the conclusions are drawn from every part of the world and each fact
interpreted in the light of the local conditions whence it sprang.
Therefore anthropology, sociology, and history should be permeated by
geography.

Most systems of sociology tre