Modern definition of the subject

There are a variety of modern definitions of economics. Some of the differences may reflect evolving views of the subject or different views among economists. The philosopher Adam Smith (1776) defined what was then called political economy as “an inquiry into the nature and causes of the wealth of nations” in particular as: a branch of the science of a statesman or legislator a plentiful revenue or subsistence for the people... [and] to supply the state or commonwealth with a revenue for the public services.[]

J.-B. Say (1803), distinguishing the subject from its public-policy uses, defines it as the science of production, distribution, and consumption of wealth. On the satirical side, Thomas Carlyle (1849) coined 'the dismal science' as an epithet for classical economics, in this context, commonly linked to the pessimistic analysis of Malthus (1798). John Stuart Mill (1844) defines the subject in a social context as: “the science which traces the laws of such of the phenomena of society as arise from the combined operations of mankind for the production of wealth, in so far as those phenomena are not modified by the pursuit of any other object”.

Alfred Marshall (1890) pointed that economics is a study of man in the ordinary business of life. Lionel Robbins (1932) defined economics as a science which studies human behaviour as a relationship between ends and scarce means which have alternative uses.

Gary Becker, a contributor to the expansion of economics into new areas, describes the approach he favors as "combining the assumptions of maximizing behavior, stable preferences, and market equilibrium, used relentlessly and unflinchingly." The same source reviews a range of definitions included in principles of economics textbooks and concludes that the lack of agreement need not affect the subject-matter that the texts treat. Among economists more generally, it argues that a particular definition presented may reflect the direction toward which the author believes economics is evolving, or should evolve.