Homo economicus, or "economic man," is the characterization of man in some economic theories as a rational person who pursues wealth for his own self-interest. The economic man is described as one who avoids unnecessary work by using rational judgment. The assumption that all humans behave in this manner has been a fundamental premise for many economic theories.
The history of the term dates back to the 19th century when John Stuart Mill first proposed the definition of homo economicus. He defined the economic actor as one "who inevitably does that by which he may obtain the greatest amount of necessaries, conveniences, and luxuries, with the smallest quantity of labor and physical self-denial with which they can be obtained."
The idea that man acts in his own self-interest often is attributed to other economists and philosophers, like economists Adam Smith and David Ricardo, who considered man to be a rational, self-interested economic agent, and Aristotle, who discussed man's self-interested tendencies in his work Politics. But Mill is considered the first to have defined the economic man completely.
The theory of the economic man dominated classical economic thought for many years until the rise of formal criticism in the 20th century from economic anthropologists and neo-classical economists. One of the most notable criticisms can be attributed to famed economist John Maynard Keynes. He, along with several other economists, argued that humans do not behave like the economic man. Instead, Keynes asserted that humans behave irrationally. He and his fellows proposed that the economic man is not a realistic model of human behavior because economic actors do not always act in their own self-interest and are not always fully informed when making economic decisions.
Although there have been many critics of the theory of homo economicus, the idea that economic actors behave in their own self-interest remains a fundamental basis of economic thought.