But like other innate predispositions the parental bent continually reasserts itself in its native and untaught character, as an ever resilient solicitude for the welfare of the young and the prospective fortunes of the group. As such it constantly comes in to reënforce the instinct of workmanship and sustain interest in the direct pursuit of efficiency in the ways and means of life. So closely in touch and so concurrent are the parental bent and the sense of workmanship in this quest of efficiency that it is commonly difficult to guess which of the two proclivities is to be credited with the larger or the leading part in any given line of conduct; although taken by and large the two are after all fairly distinct in respect of their functional content. This thorough and far-going concurrence of the two may perhaps be taken to mean that the instinct of workmanship is in the main a propensity to work out the ends which the parental bent makes worth while. It seems to be these two predispositions in conjunction that have exercised the largest and most consistent control over that growth of custom and conventional principles that has standardised the life of mankind in society and so given rise to a system of institutions. This control bears selectively on the whole range of institutions created by habitual response to the call of the other instincts and has the effect of a “common-sense” surveillance which prevents the scheme of life from running into an insufferable tangle of grotesque extravagances. That their surveillance has not always been decisive need scarcely be specifically called to mind; human culture in all ages presents too many imbecile usages and principles of conduct to let anyone overlook the fact that disserviceable institutions easily arise and continue to hold their place in spite of the disapproval of native common sense. The selective control exercised over custom and usage by these instincts of serviceability is neither too close nor too insistent. Wide, even extravagant, departures from the simple dictates of this native common sense occur even within the narrow range of the domestic and minor civil institutions, where these two common-sense predispositions should concur to create a prescriptive usage looking directly to the continuation and welfare of the race. Considerations, or perhaps rather conventional preconceptions, running on other grounds, as, for instance, on grounds of superstition or religion, of propriety and gentility, of pecuniary or political expediency, have come in for a large share in ordering the institutions of family and neighbourhood life. Yet doubtless it is the parental bent and the sense of workmanship in concurrence that have been the primary and persistent factors in (selectively) shaping the household organisation among all peoples, however great may have been the force of other factors, instinctive and habitual, that have gone to diversify the variegated outcome.