Supply creates its own demand
"Supply creates its own demand" is the formulation of Say's law. The rejection of this doctrine is a central component of The General Theory of Employment, Interest and Money and a central tenet of Keynesian economics.
Keynes's rejection of Say's law has on the whole been accepted within mainstream economics since the 1940s and 1950s in the neoclassical synthesis, but debate continues between Keynesian economists and neoclassical economists.
Keynes's interpretation is rejected by many economists as a misinterpretation or caricature of Say's law — see Say's law: Keynes vs. Say — and the advocacy of the phrase "supply creates its own demand" is today most associated with supply-side economics, which retorts that "Keynes turned Say on his head and instead stated that 'demand creates its own supply'".
The exact phrase "supply creates its own demand" does not appear to be found in the writings of classical economists; similar sentiments, though different wordings, appear in the work of John Stuart Mill, whom Keynes credits and quotes, and his father, James Mill, whom Keynes does not.Keynes's formulation
Keynes coined the phrase thus :
Keynes then restates this in the language of Keynesian economics as:
