When the needs to be supplied are "ordinary," or "common"; that is, when they merely expose a person to considerable and constant inconvenience, without inflicting serious physical, mental, or moral injury, they do not impose upon any man the obligation of giving up all his superfluous goods. According to some moral theologians, the possessor fulfils his duty in such cases if he contributes that proportion of his surplus which would suffice for the removal of all such distress, provided that all other possessors were equally generous; according to others, if he gives two per cent. of his superfluity; according to others, if he contributes two per cent. of his annual income. These estimates are intended not so much to define the exact measure of obligation as to emphasise the fact that there exists some degree of obligation; for all the moral theologians agree that some portion of a man's superfluous goods ought to be given for the relief of ordinary or common needs. When, however, the distress is grave; that is, when it is seriously detrimental to welfare; for example, when a man or a family is in danger of falling to a lower social plane; when health, morality, or the intellectual or religious life is menaced,--possessors are required to contribute as much of their superfluous goods as is necessary to meet all such cases of distress. If all is needed all must be given. In other words, the entire mass of superfluous wealth is morally subject to the call of grave need. This seems to be the unanimous teaching of the moral theologians.[211] It is also in harmony with the general principle of the moral law that the goods of the earth should be enjoyed by the inhabitants of the earth in proportion to their essential needs. In any rational distribution of a common heritage, the claims of health, mind, and morals are surely superior to the demands of luxurious living, or investment, or mere accumulation.