Adam Smith, often referred to as the Father of Modern Economics, laid the foundations of classical economics with his seminal work, "The Wealth of Nations" (1776). Smith introduced the concept of the invisible hand, emphasizing that individuals acting in their own self-interest unintentionally contribute to the overall economic well-being of society. His ideas about free markets, competition, and the division of labor have had a lasting impact on economic theory and policy.
John Maynard Keynes revolutionized economic thought with his Theory of Income, developed during the Great Depression in the 1930s. Keynes argued that aggregate demand, which is the total demand for goods and services in an economy, is the key driver of economic growth and employment. His work laid the groundwork for modern macroeconomics, advocating for government intervention in the economy through fiscal policies to manage demand and smooth out business cycles.
The four-sector model of the economy incorporates four key components: C (Consumption), I (Investment), G (Government spending), and (X – M) (Net exports, where X is exports and M is imports). The equation for the four-sector model is:
\( C + I + G + (X - M) \)
This model highlights the interactions between different sectors of the economy and shows how total economic activity is influenced by consumer spending, business investment, government expenditure, and foreign trade. It serves as a useful framework for understanding national income and macroeconomic equilibrium.