Austrian theory emphasizes the organizing power of markets. Hayek stated that market prices reflect information, the totality of which is not known to any single individual, which determines the allocation of resources in an economy. Because socialist systems lack the individual incentives and price discovery processes by which individuals act on their personal information, Hayek argued that socialist economic planners lack all of the knowledge required to make optimal decisions. Those who agree with this criticism view it as a refutation of socialism, showing that socialism is not a viable or sustainable form of economic organization. The debate rose to prominence in the 1920s and 1930s and that specific period of the debate has come to be known by historians of economic thought as the socialist calculation debate.