Classicals, Keynesians, and Bastard Keynesians.
Macroeconomics is a child of the Great Depression. Before the publication of Keynes’ book, The General Theory of Employment, Interest and Money, macroeconomics consisted primarily of monetary theory.
Economists were preoccupied with price stability, as we are today, but the idea that government should control aggregate economic activity through active fiscal and monetary policy was absent.
There is no self-correcting market mechanism to return the boat to a safe harbor. We must rely on political interventions to maintain full employment. That is the essential insight of Keynes’ General Theory.
Hicks embraced the Keynesian idea that mass unemployment is caused by insufficient aggregate demand, and he formalized that idea in the IS- LM model.
The program that Hicks initiated was to understand the connection between Keynesian economics and general equilibrium theory. But, it was not a complete theory of the macroeconomy because the IS- LM model does not explain how the price level is set. The IS- LM model determines the unemployment rate, the interest rate, and the real value of GDP, but it has nothing to say about the general level of prices or the rate of inflation of prices from one week to the next.
To complete the reconciliation of Keynesian economics with general equilibrium theory, Paul Samuelson introduced the neoclassical synthesis in 1955. According to this theory, if unemployment is too high, the money wage will fall as workers compete with each other for existing jobs. Falling wages will be passed through to falling prices as firms compete with each other to sell the goods they produce. In this view of the world, high unemployment is a temporary phenomenon caused by the slow adjustment of money wages and money prices. In Samuelson’s vision, the economy is Keynesian in the short run, when some wages and prices are sticky. It is classical in the long run when all wages and prices have had time to adjust.
In Keynes’ vision, there is no tendency for the economy to self- correct. Left to itself, a market economy may never recover from a depression and the unemployment rate may remain too high forever. In contrast, in Samuelson’s neoclassical synthesis, unemployment causes money wages and prices to fall. As the money wage and the money price fall, aggregate demand rises and full employment is restored, even if government takes no corrective action. By slipping wage and price adjustment into his theory, Samuelson reintroduced classical ideas by the back door— a sleight of hand that did not go unnoticed by Keynes’ contemporaries in Cambridge, England. Famously, Joan Robinson referred to Samuelson’s approach as “bastard Keynesianism.”
The New Keynesian agenda is the child of the neoclassical synthesis and, like the IS- LM model before it, New Keynesian economics inherits the mistakes of the bastard Keynesians. It misses two key Keynesian concepts: (1) there are multiple equilibrium unemployment rates and (2) beliefs are fundamental. My work brings these concepts back to center stage and integrates the Keynes of the General Theory with the microeconomics of general equilibrium theory in a new way.