In addition, it is plain that the purely physical desire which lies at the bottom of all human love, no matter how much sentimental considerations may obscure it, is merely a passion and so, in the very nature of things, is intermittent and evanescent. There are moments when it is overpowering, but there are hours, days, weeks and months when it is dormant. Therefore, we must conclude with Nietzsche, that the thing we call love, whether considered from its physical or psychical aspect, is fragile and short-lived. Now, inasmuch as marriage, in the majority of cases, is a permanent institution (as it is, according to the theory of our moral code, in _all_ cases), it follows that, in order to make the relation bearable, something must arise to take the place of love. This something, as we know, is ordinarily tolerance, respect, _camaraderie_, or a common interest in the well-being of the matrimonial firm or in the offspring of the marriage. In other words, the discovery that many of the ideal qualities seen in the life-companion through the rosy glasses of love do not exist is succeeded by a common-sense and unsentimental decision to make the best of those real ones which actually do exist. From this it is apparent that a marriage is most apt to be successful when the qualities imagined in the beloved are all, or nearly all, real: that is to say, when the possibility of disillusion is at an irreducible minimum. This occurs sometimes by accident, but Nietzsche points out that such accidents are comparatively rare. A man in love, indeed, is the worst possible judge of his _inamorata's_ possession of those traits which will make her a satisfactory wife, for, as we have noted, he observes her through an ideal haze and sees in her innumerable merits which, to the eye of an unprejudiced and accurate observer, she does not possess. Nietzsche, at different times, pointed out two remedies for this. His first plan proposed that marriages for love be discouraged, and that we endeavor to insure the permanence of the relation by putting the selection of mates into the hands of third persons likely to be dispassionate and far-seeing: a plan followed with great success, it may be recalled, by most ancient peoples and in vogue, in a more or less disguised form, in many European countries today. "It is impossible," he said, "to found a permanent institution upon an idiosyncrasy. Marriage, if it is to stand as the bulwark of civilization, cannot be founded upon the temporary and unreasonable thing called love. To fulfil its mission, it must be founded upon the impulse to reproduction, or race permanence; the impulse to possess property (women and children are property); and the impulse to rule, which constantly organizes for itself the smallest unit of sovereignty, the family, and which needs children and heirs to maintain, by physical force, whatever measure of power, riches and influence it attains."