Paul Krugman
The economic panics of the twenty-first century are not unforeseen anomalies, but rather recurring features of a global system destabilized by unregulated shadow banking and speculative exuberance.
Unregulated financial entities that perform traditional banking functions without traditional safeguards are the primary architects of modern economic crashes.
Economies can easily fall into liquidity traps where zero interest rates fail to stimulate growth, requiring aggressive government spending to revive aggregate demand.
The efficient-market hypothesis is fundamentally flawed because financial markets are inherently irrational and prone to devastating speculative bubbles.