3. Value is not a ratio of exchange, or "purchasing power," but is an absolute quantity, prior to exchange. It is the fundamental and essential attribute or quality of wealth, the common or homogeneous element present amidst the diversities of the physical forms of wealth, by virtue of which comparisons may be instituted among different kinds of wealth, and different items of wealth may be added to make a sum, put into ratios of exchange, and so on. 4. Economic value is a _species_ of the _genus_, _social value_, cooerdinate with legal value, and moral value. It is part of a system of social motivation and control.[454] Psychological in character, it none the less presents itself to an individual as an objective, external force, to which he must adapt himself. 5. Individual prices have two cooeperating causes: (a) the social economic value of the money-unit, and (b) the social economic value of the unit of the good in question. 6. The average of prices, or the "price-level," is a mere mathematical summary of the particular prices. The causation involved in the average of prices is nothing more than the causation involved in the particular prices. 7. The value of money is to be distinguished from the "reciprocal of the price-level," or the "purchasing power of money." The value of money is an absolute quantity, one of the factors, determining each particular price. Particular prices and general prices may change because of changes in the values of goods, with no change in the value of money. Or, particular prices and general prices may change because of changes in the value of money, with goods remaining constant in value. 8. The absolute value of money, assumed constant, is presupposed by the great body of present day price theory, as supply and demand, cost of production, and the capitalization theory. These theories are, therefore, inapplicable to the problem of the value of money. 9. But supply and demand, cost of production, the capitalization theory, and other laws concerned with the concatenation and interrelations of prices, being applicable to the problem of particular prices, are also applicable to the problem of general prices. (Chapter on "The Passiveness of Prices.") 10. The general price-level, as a consequence of changes in particular prices, growing out of changes in the values of goods, may rise or fall, without antecedent changes in the value of money, or the quantity of money, or the volume of credit, or the volume of trade, or in the "velocities of circulation" of money or credit. (Chapter on "The Passiveness of Prices.") 11. The general laws of prices, supply and demand, cost of production, the capitalization doctrine, the imputation doctrine, etc., conflict with the quantity theory. In the cases where they conflict, the first named doctrines are correct, and the quantity theory is wrong. (Chapter on "The Passiveness of Prices.")