stand in a specific close relation to a man and a woman.[565] The woman is invariably their own mother, who gave them birth; the man is the woman's husband. The existence of this group, which may be called the individual family, is the basis upon which kinship may be determined; it is the condition under which it is possible to speak of individual parental kinship in any given society. [565] Compare the footnote above, p. 174. But it was shown that the knowledge of these facts is not sufficient to yield a precise idea of maternal and paternal kinship, and that many of its manifold aspects of foremost sociological interest would remain unknown if the inquiry were broken off at this point. These latter aspects depend upon factors which are by no means constant in all societies, but have a very wide range of variation depending on the general social conditions. A discussion of the concept of consanguinity has shown that the variations go so far as to affect the main question of paternal kinship: "Who is the father (in the social sense) of a child, and how is he determined?" In order to indicate in which direction the varying general conditions of society must be investigated so as to yield all that is essential for the sociological knowledge of kinship, it was found most convenient to range the facts in two main lines of inquiry: (1) The different sets of facts which express the central collective idea of what fatherhood is; and the various other collective ideas--legal, customary, moral--of a normative character referring to the relation in question. The social facts in which these ideas must be looked for are: Beliefs, traditions, customs referring to the relation in question (as for instance the couvade type), and functions of kindred such as legal duties and obligations between parent and child. (2) The facts in which the expression of the collective feelings characteristic of the relation in question is to be found. The facts of daily life, as well as the dramatic expression of feelings, come in here. The emotional character of the parental kinship relation is of the highest importance in determining the social feature of this relation, and for the comprehension of its social working.