Economics, as we know it, is the social science concerned with the production, distribution, exchange, and consumption of goods and services. Economists focus on the way in which individuals, groups, business enterprises, and governments seek to achieve efficiently any economic objective they select. (46) {{U}}Other fields of study also contribute to this knowledge: Psychology and ethics try to explain how objectives are formed, history records changes in human objectives, and sociology interprets human behavior in social contexts.{{/U}}
Standard economics can be divided into two major fields. (47) {{U}}The first, price theory or microeconomics, explains how the interplay of supply and demand in competitive markets creates a multitude of individual prices, wage rates, profit margins, and rental changes. {{/U}}Microeconomics assumes that people behave rationally. Consumers try to spend their income in ways that give them as much pleasure as possible. As economists say, they maximize utility. For their part, entrepreneurs seek as much profit as they can extract from their operations.
The second field, macroeconomics, deals with modern explanations of national income and employment. Macroeconomics dates from the book, The General Theory of Employment, Interest, and Money (1935), by the British economist John Maynard Keynes. His explanation of prosperity and depression centers on the total or aggregate demand for goods and services by consumers, business investors, and governments. (48){{U}} Because, according to Keynes, inadequate total demand increases unemployment, the indicated cure is either more investment by businesses or more spending and consequently larger budget deficits by government.{{/U}}
Economic issues have occupied people's minds throughout the ages. (49) {{U}}Aristotle and Plato in ancient Greece wrote about problems of wealth, property, and trade, both of whom were prejudiced against commerce, feeling that to live by trade was undesirable.{{/U}} The Romans borrowed their economic ideas from the Greeks and showed the same contempt for trade. (50){{U}} During the Middle Ages the economic ideas of the Roman Catholic church were expressed in the law of the church, which condemned the taking of interest for money loaned and regarded commerce as inferior to agriculture.{{/U}}
Economics as a subject of modern study, distinguishable from moral philosophy and politics, dates from the work, Inquiry into the Nature and Causes of the Wealth of Nations (1776), by the Scottish philosopher and economist Adam Smith. Mercantilism and physiocracy were precursors of the classical economics of Smith and his 19th-century successors.