What is Keynes' Law?

Keynes’ law:, was proposed by John Maynard Keynes, and states  “Demand creates its own supply.” 

The alternative to Say’s law, which states that Supply creates Demand. 

Keynes law is a simplification of principles espoused by Keynes in his influential work The General Theory of Employment, Interest, and Money, written during the 1930s Great Depression.

Keynes argued that the Great Depression—and many ordinary recessions as well—were not caused by a drop in the ability of the economy to supply goods as measured by labor, physical capital, or technology. He argued the economy often produced less than its full potential, not because it was technically impossible to produce more with the existing workers and machines, but because a lack of demand in the economy as a whole led to inadequate incentives for firms to produce. In such cases, he argued, the level of GDP in the economy was not primarily determined by the potential of what the economy could supply, but rather by the amount of total demand.

Criticism of Keynes Law

Keynes law cannot tell the whole macroeconomic story, either. After all, if demand was all that mattered at the macroeconomic level, then the government could make the economy as large as it wanted just by pumping up total demand through a large increase in the government spending component or by legislating large tax cuts to push up the consumption component. 

Economies do, however, face genuine limits to how much they can produce, limits determined by the quantity of labor, physical capital, technology, and the institutional and market structures that bring these factors of production together. These constraints on what an economy can supply at the macroeconomic level do not disappear just because of an increase in demand.

Related Topics

• Supply-Side Economics
• Say's Law
• Laffer Curve
• Neo-Classical Economics
• New Keynesian Economics
• Classical Economics
• Supply-Side Economics
• Keynesian Economics
• Keynes' Law
• Keynesian Analysis
• Demand Side Theory
• Market Forces
• Aggregate demand
  
• Aggregate Demand Curve (and shifts)
• Aggregate supply
• Aggregate Supply Curve (and Shifts)
• Aggregate Demand / Aggregate Supply Models
• Potential GDP
• Aggregate Supply and Demand Equilibrium
• Aggregate Supply and Aggregate Demand in Macroeconomics and Microeconomics
• Input-Output Model
• Stagflation
• Growth and Recessions in the Aggregate Demand - Aggregate Supply Model
• Unemployment in the Aggregate Demand - Aggregate Supply Model
• Inflation in the Aggregate Demand - Aggregate Supply Model
• Keynesian, Intermediate, and Neoclassical Zones