=Summing Up.=—We have, then, passed from Happiness to Satisfaction of Wants and Desires, and from Satisfaction to the Goods which condition it. From this emerges Utility, and the analysis of Utility yields up Total Utility and Marginal Utility. With Marginal Utility we identify Value. Then we found Value naming itself in something given up; that something, in developed civilisations, is Money, and Price becomes the universal expression of Value. When we conceive of Price as the sum of money seeking after goods, it is Demand or Demand Price. =Demand and Supply.=—The above is the Theory of Value from one side, that of Demand, _i.e._, of Utility expressed and measured in money figures, and offering itself as demand for other utilities. It accounts for our willingness to pay certain prices. But although the tap root of value is Utility—for there can be no value in the absence of Utility—there is another side. The sum we are willing to offer—our Demand Price—is confronted with, and at all times affected by, another sum, which seems independent—Supply Price, and this latter sum seems determined by Cost of Production. These two sides and their mutual relations are necessary for any complete Theory of Value. Hence Marshall’s words: “There has been a long controversy as to whether Cost of Production or Utility governs Value. It might as reasonably be disputed whether it is the upper or the lower blade of a pair of scissors that cuts a piece of paper.” INDEX Adam Smith, 1, 8, 18, 20. Aristotle, 3, 47. Austrian School, 5, 27, 30, 55, 85. Böhm-Bawerk, 7, 32, 37, 40, 45, 47, 55, 60, 61. Complementary goods, 42. Consumption goods, 68. Cost of production, 67; conduction of value from marginal products to, 74; from, to products, 78. Demand Side of the Theory of Value, Appendix II., 91. Desirable and desired, 10, 11. Exchange, 56; motives of, 56; isolated, 57; no one-sided competition, 58; ordinary, 58. Goods, 11, 16; economic, 17; classification of, 21; complementary, 42; stand midway between production and consumption, 68. Illustrations: sailor and his dog, 30; Crusoe and his sacks, 32; housewife and her butter, 39; silk substitute, 76. Jevons, 6, 8, 11, 32, 85. Life, 4, 10. Marginal buyer, 64; marginal pair, 60, 64. Marginal products, conduction of value to productive goods, 74. Marginal utility, 29; level of, 40. Menger, 11, 15, 17, 42, 45, 68. Mill, 2. Neumann, 7. Political Economy, based on economic conduct, 9. Price, 55; assumptions of the law, 56; based on subjective valuations, 61; determined by the marginal buyer, 64. Ricardo, 12, 18. Roscher, 68. Ruskin, 4.