The article discusses how economic ideas change after a major crisis like the Great Recession. Different schools of thought in economics emerge or become popular in response to economic downturns. For example, after the Great Depression, Keynesian policies were favored, leading to a period of economic growth. However, after the oil shocks, Monetarist ideas gained prominence. The rise of neo-liberalism and financial market liberalization followed, leading to increased financial activity and the development of new financial instruments. Despite these changes, the global economy faced another crisis, the Great Recession, prompting a reevaluation of economic policies.