A prominent contemporary of Keynes argued and empirically demonstrated that major corporations in actual practice "administer prices." What this means is that corporations determine prices based on the cost of production, plus a percentage markup to allow for profit. They do not change prices in response to changes in demand, but instead simply respond to those changes by changing how much they produce. including during times of economic downturn (they keep the same prices but reduce levels of production). How does this concept and finding support, or not support, the theories of Keynes and his neoclassical contemporaries? (Keynes called all traditional economists of the time "classical", although that term really only applies to economists prior to the 1890s. His contemporaries were what is defined as neoclassical economists.)