From the earliest times man has bought and sold all things that he needed, and he seldom considers the real value of what he buys, but he fixes a price by the degree of his need and by his difficulty in satisfying it. For instance, in wealthy European cities one has seen the working day of workmen, and even of children, sold For next to nothing, so that the misery of their conditions cried aloud; and again at another time they have received a wage for the same work, that enabled them to lift their heads with some of the dignity that human kind should show; or again, at the other extreme, children have been paid a wage that could have supported a whole family. And these differences in money paid for the same working lives depended on no other fact than the supply of hands in the world of industry. Thus most unnatural customs appear natural to man, who still prides himself on the thought that mankind is always evolving, and that the latest phase of civilization is the best from all points of view.