§ 12. #Social welfare as the aim.# The conflicting interests of the various classes of taxpayers in each period are to some degree softened by the prevailing public opinion, sometimes called the social conscience, and taxes are adjusted according to a vaguely held ideal of the social welfare. Social expediency, more or less broadly interpreted, determines who shall be taxed and what social results are to be sought. The exemptions from taxation in feudal times were great and, viewed from our standpoint, were inequitable, for the upper classes escaped while the peasants bore most of the burdens. The landlords and nobility, who were assumed to be performing important social functions, generally had outgrown their usefulness in the period preceding the French Revolution, which swept away many of these abuses. Exemptions from taxation are granted liberally in most states to-day on some kinds of wealth and to some classes of citizens, because of their supposed relations to the public interest. Real estate and equipment devoted to educational, religious, and charitable purposes, the homes of priests and ministers, homesteads purchased with pension money, as well as all public lands, buildings, and equipment are exempt. The social interest requires that taxes be both elastic and productive, so that the needs of the government shall be amply provided for. The harmonizing of these needs in the laws of taxation requires a high degree of wisdom, of foresight, and of integrity in the legislator and in the citizen. No hard-and-fast rule for the apportioning of taxes can be laid down. The decision must be made in each generation by the public opinion as to what is most expedient for the general welfare.