The same thing may be said of another domain of collective mentality: that is, of the feelings involved in parental kinship. The type of feelings underlying this relationship may vary with the society, in the same way as these feelings vary with each individual case in any given society. And as these feelings essentially determine the character of parental kinship in any given society, it appears that the discussion of this point cannot be omitted. Thus into the general formula of kinship there must enter also the psychological elements: collective ideas, expressing in a given society what is kinship, what are its legal, moral and customary aspects; and the collective feelings prevailing in a given society. From the interaction of these psychological elements with different variable social elements arise the more special, peculiar factors which define kinship in any given society. In other words, the variable elements in the general formula of kinship are seen to arise chiefly from the collective psychological interpretation and valuation of some of the physiological and social facts underlying parental kinship. To sum up, it may be said that parental kinship is the personal tie obtaining between members of the _parental group_ or individual _family_, and like all other personalties it must be further determined in each society by the characteristic _collective feelings_ and _collective ideas_ which in the given society give it its specific meaning.[518] This is that general formula of kinship which will yield us what we have demanded of it--that is, an indication of the facts for which to look in any given society. As the facts referred to in the first part of the above definition (the establishment of the existence of the family unit) are dealt with in the remaining chapters, it is necessary to discuss only the second part of the definition. [518] This definition may appear a commonplace and a truism, a mere formulation of what is obvious to every one at first sight. But it is liable to this objection only when taken formally, _i. e._ when only its _form_ is considered, because it contains in the words _parental group_ (individual family) the substance of all that has been said in the preceding pages about this social unit; and the other terms of the definition (_collective ideas_ and _collective feelings_) will be determined more in detail in the following discussion. The influence upon kinship of the beliefs and ideas as to procreation appears quite plainly upon an analysis of the concept of consanguinity, and to this we may devote a few words.