The more abstract sciences, just to the extent that they are abstract and exact, like mathematics and logic, are merely methods and tools for converting experience into knowledge and applying the knowledge so gained to practical uses.
IV. HISTORY, NATURAL HISTORY, AND SOCIOLOGY
Although it is possible to draw clear distinctions in theory between the purpose and methods of history and sociology, in practice the two forms of knowledge pass over into one another by almost imperceptible gradations.
The sociological point of view makes its appearance in historical investigation as soon as the historian turns from the study of "periods" to the study of institutions. The history of institutions, that is to say, the family, the church, economic institutions, political institutions, etc., leads inevitably to comparison, classification, the formation of class names or concepts, and eventually to the formulation of law. In the process, history becomes natural history, and natural history passes over into natural science. In short, history becomes sociology.
Westermarck's History of Human Marriage is one of the earliest attempts to write the natural history of a social 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]