Crisis. John Maynard Keynes was the founder of the modern mixed economy, his philosophies contributing to and constituting the Keynesian school of thought. Although Keynesian economists give credence to Adam Smith's work on neoclassical theory, they only endorse it to a certain extent. By which, in multiple ways, the Keynesian school can be, five positive results of Keynesian economics. British economist John Maynard Keynes (1883-1946) wrote his seminal book The General Theory of Employment, Interest and Money. Finally, post-Keynesian theory states that this can only be done at the cost of disrupting financial markets. A monetary policy based on the money supply is therefore useless or destabilizing. pp. 7-8, essay 1, Many essays in, Summary. This article presents a study of post-Keynesian economic theory and its critiques against the framework of neoclassical macroeconomics. Post-Keynesians have emphasized how the ideas of.