"The comparative economic efficiency of capitalism and socialism remains one of the most controversial areas. The classical socialist argument is that the anarchy of production under capitalism leads to great wastage. An appeal to the virtues of the price system is, in fact, only a partial answer to this critique. The central argument, which implies the efficiency of a competitive economic system, presupposes that all relevant goods are available at prices that are the same for all participants and that supplies and demands of all goods balance. Now virtually all economic decisions have implications for supplies and demands on future markets. The concept of capital, the very root of the term “capitalism,” refers to the setting-aside of resources for use in future production and sale. Hence, goods to be produced in the future are effectively economic commodities today. For efficient resource allocation, the prices of future goods should be known today. But they are not. Markets for current goods exist and enable a certain coherence between supply and demand there. But very few such markets exist for delivery of goods in the future. Hence, plans made by different agents may be based on inconsistent assumptions about the future. Investment plans may be excessive or inadequate to meet future demands or to employ the future labor force."
Kenneth Arrow

January 1, 1970