development; that reciprocity is the fundamental principle in exchange, as also in the social structure; that exchange performs a legitimate social function in creating time and place values; that industrial expansion is limited by a law of diminishing returns; that the primary purpose of exchange should not be profit, but satisfaction of economic need; that commerce merely for its own sake does not necessarily increase the national store, but may produce only economic inequalities; that extremes of wealth and poverty cause industrial inefficiency, social strife, and crime; that excessive individual wealth is not usually compatible with just acquisition or just expenditure; that it also necessarily implies corresponding extremes of poverty; that the commercial spirit in nations is the chief cause of international differences; that the goal of economics is consumption rather than production, and that foolish consumption results in great economic waste; that all economic problems are moral problems; that private property is not a natural right, but a gift of society, and therefore that society may properly control its activities; that there is a certain unity in human nature, which is opposed to the doctrine of natural slavery; that the individual should have opportunity for personal development in accord with his capacities, aside from the mere struggle for physical existence; that true economic equality does not demand equal shares for all, but shares proportioned to capacities and services; and that gifts of charity merely for consumption are fruitful causes of poverty and indolence. Besides the recognition of such principles, we have seen that many practical suggestions for the amelioration of economic and social conditions, which are being seriously presented today, were first proposed by Greek thinkers. Measures for the divorce of government from big business, state control of natural monopolies, conservation of natural resources, state supervision of trade and commerce, including regulation of prices and rates, publicity in business, pure food laws, and the socialization of industry and its products were all first proposed by Greeks. On the other hand, we have seen that practically all the modern stock arguments against socialism were long ago presented by Aristotle, and that the ideal of the Greek socialist was not primarily materialistic and selfish, as the modern, but moral and social.