In the 18th century, the Scottish social philosopher and political economist Adam Smith, in "The Wealth of Nations" (1776) proposed that the "truck, barter, and exchange" activities of the market were corresponding economic representations of human nature, that is, the buying and selling of commodities were activities intrinsic to the market, and thus are the "natural behaviour" of the market. Hence, Smith proposed that a market economy was a self-regulating entity that "naturally" tended towards economic equilibrium, wherein the relative prices (the value) of a commodity ensured that the buyers and sellers obtained what they wanted for and from their goods and services.