determinative of all the rest. We know as yet little of the development
of industry in antiquity. What little we do know, however, furnishes
good ground for claiming that changes in the methods of getting a living
are among the most influential causes of social change in general; but
there is nothing which warrants the sweeping generalization of Karl Marx
and his followers, "that the method of the production of the material
life determines the social, political, and spiritual life process in
general." On the contrary, the evolution of the Roman family clearly
shows moral and psychological factors at work quite independent of
economic causes. The decay of ancestor worship, for example, cannot be
wholly attributed to the change in the method of getting a living. The
very growth of population and accompanying changes in political
conditions probably had quite as much to do with the undermining of
ancestor worship. Moreover, while religion may not be an original
determining cause of social forms, it is, nevertheless, as we have
already seen, especially that which gives them stability and permanency,
so much so that the life history of a culture is frequently the life
history of a religion. The decay of religious ideas and beliefs,
therefore, from any cause, frequently proves the important element
working for social change in all societies. So, too, changes in
political conditions, especially changes in law through new legislation,
frequently prove a profound modifying influence in societies. Lastly,
there are certain moral causes inherent in the individual, oftentimes
involving perverted expressions of instinct, which lead to profound
social changes. Such was the vice which Rome copied very largely from
Greece, but which proved the final solvent in its family life.

In general we may say, then, that there is no single principle which
will explain the evolution of the family from the earliest times down to
the present. Any attempt to reduce the evolution of the family to a