single principle, or to show that it has been controlled by a single set
of causes, must inevitably end in failure. The economic determinism of
Marx and his followers, the ideological conceptions of Hegel, the
geographical influences of Buckle and his school, and like explanations,
are all found wanting when they are applied to the actual history of the
family. It is not different with the theories of recent sociologists,
who would strive to explain all social changes through a single
principle. Professor Giddings' principle of "Consciousness of Kind" and
Tarde's principle of "Imitation" will not go further in explaining the
changes in the family life than some of the older principles that we
have just mentioned. Human life is, indeed, too complex to be explained
in terms of any single principle or any single set of causes. The family
in particular is an organic structure which responds first to one set of
stimuli and then to another. Now it is modified by economic conditions,
now by religious ideas, now by legislation, now by imitation, and so on
through the whole set of possible stimuli which may impinge upon and
modify the activity of a living organism. So it is with all
institutions.

The Influence of Christianity upon the Family.--While we cannot study
further the evolution of the family in any detail, still it is
necessary, in order to avoid too great discontinuity, to notice in a few
sentences the influence of Christianity upon the family in Western
civilization.

Early Christianity, as we have already seen, found the family life of
the Greco-Roman world demoralized. The reconstruction of the family
became, therefore, one of the first tasks of the new religion, and while
other circumstances may have aided the church in this work, still on the
whole it was mainly the influence of the early church that reconstituted