A capitalist economy has many features, including both for-profit businesses and non-profit organizations, large scale trade, and prices that fluctuate in response to changes in supply and demand. Some people consider any economy that prominently exhibits such features to be a capitalist economy, regardless of the degree of political intervention. Typically when people define capitalism in this way they are denying or not recognizing the distinction between politics and economics.
No economy in history has been purely capitalist in the sense of having a complete absence of political intervention. In fact, the idea that an economy could be free of political intervention apparently did not occur to anyone until the late 18th century. This makes capitalism one of the more radical ideas in human history.
Capitalist economic theory was first formalized by AdamSmith? in 1776, in an attempt to refute MercantilisM?. In his work, Smith first presented his idea of MarkeT?, that is central to EconomicTheory?. Other theorists who have written about capitalism include Karl Marx, DavidRicardo?, LudwigvonMises?, FreidrichHayek?, JohnMaynardKeynes?, PaulSamuelson?, and MiltonFriedman?.