institution. It is
based upon a comparison and classification of marriage customs of widely
scattered peoples, living under varied physical and social conditions.
What one gets from a survey of this kind is not so much history as a
study of human behavior. The history of marriage, as of any other
institution, is, in other words, not so much an account of what certain
individuals or groups of individuals did at certain times and certain
places, as it is a description of the responses of a few fundamental
human instincts to a variety of social situations. Westermarck calls
this kind of history sociology.[16]

It is in the firm conviction that the history of human
civilization should be made an object of as scientific a
treatment as the history of organic nature that I write this
book. Like the phenomena of physical and psychical life those
of social life should be classified into certain groups and
each group investigated with regard to its origin and
development. Only when treated in this way can history lay
claim to the rank and honour of a science in the highest sense
of the term, as forming an important part of Sociology, the
youngest of the principal branches of learning.

Descriptive historiography has no higher object than that of
offering materials to this science.[17]

Westermarck refers to the facts which he has collected in his history of
marriage as phenomena. For the explanation of these phenomena, however,
he looks to the more abstract sciences.

The causes on which social phenomena are dependent fall within
the domain of different sciences--Biology, Psychology, or
Sociology. The reader will find that I put particular stress
upon the psychological causes, which have often been deplorably
overlooked, or only imperfectly touched upon. And more
especially do I believe that the mere instincts have played a
very important part in the origin of social institutions and
rules.[18]

Westermarck derived most of his materials for the study of marriage from
ethnological materials. Ethnologists, students of folklore (German
_Voelkerkunde_), and archaeology are less certain than the historians of
institutions whether their investigations are historical or
sociological.

Jane Harrison, although she disclaims the title of sociologist, bases
her conception of the origin of Greek religion on a sociological theory,
the