§ 14. #Various ideal standards suggested.# It may, perhaps, be agreed that the ideal standard of deferred payments is one that would insure justice between borrower and lender. Yet different views may be and have been taken as to what constitutes justice in this matter. The suggestion is attractive that repayment should involve the return of enjoyment equal to that which could be purchased with the sum at the time of the loan. Such a standard is impossible of perfect realization in any general way, for men's circumstances are constantly changing. To insure even to the average man the same amount of enjoyment is only roughly possible. The same goods do not afford the same enjoyment when conditions, either subjective or objective, have changed. Another suggestion is that the goods returned should represent the same sacrifice as those loaned. Here again the difficulty is in the lack of a standard applicable to all men. Whose sacrifice? That of the lender, who may be rich, or that of the borrower, who may be poor? Some have supposed that the condition of equal sacrifices was met by the labor standard, according to which the sum returned should purchase the same number of days of labor as when borrowed. But what kind of labor is to be taken, that of the lender or that of the borrower or that of some one else? Labor is of many different qualities, which can be exactly compared only through their objective value in terms of some one good.[20] It must be recognized that any possible concrete standard of deferred payments will sometimes work hardship in individual cases. The best average results for justice and social welfare will be secured by measuring debts in some standard that will change least often, and least rapidly, in relation to the great majority of people of all classes in the community. § 15. #The tabular standard.# Apart from the difficulties of its practical operation, a standard better than a single metal and more stable than a single commodity would be a _tabular standard_, consisting of a number of leading commodities in fixed proportions, such as is used in calculating index numbers expressing the general scale of prices. Such a standard averages the fluctuations of particular goods and would give a fair approximation in practice to the ideals of equal sacrifice and equal enjoyment (on the average tho not in individual cases). While some natural materials are growing more scarce and call for more sacrifice, other products are by industrial progress becoming more plentiful. This kind of standard has been viewed with favor by many monetary authorities, and despite the administrative difficulties ways may yet be found for putting it into practice.