A true bubble, like the dot-com crash, involves stock prices falling over 50% and staying depressed for years, with capital infusion dropping similarly. Short-term market corrections don't meet this historical definition. The current AI boom, despite frothiness, doesn't exhibit these signs yet.

Following George Soros's theory of reflexivity, markets act like thermostats, not barometers. Rising AI stock prices attract capital, which further drives up prices, creating a self-reinforcing loop. This feedback mechanism detaches asset values from underlying business fundamentals, inflating a bubble based on pure belief.

The dot-com era was not fueled by pure naivete. Many investors and professionals were fully aware that valuations were disconnected from reality. The prevailing strategy was to participate in the mania with the belief that they could sell to a "greater fool" before the inevitable bubble popped.

Widespread public debate about whether a market is in a bubble is evidence that it is not. A true financial bubble requires capitulation, where nearly everyone believes the high valuations are justified and the skepticism disappears. As long as there are many vocal doubters, the market has not reached the euphoric peak that precedes a crash.

During the dot-com bubble, Howard Marks used second-order thinking to stay rational. Instead of asking which tech stocks were innovative (a first-order question), he asked what would happen *after* everyone else piled in. This focus on embedded expectations, rather than simple quality, is key to avoiding overpriced, crowded trades.

A market enters a bubble when its price, in real terms, exceeds its long-term trend by two standard deviations. Historically, this signals a period of further gains, but these "in-bubble" profits are almost always given back in the subsequent crash, making it a predictable trap.

In a late-stage bubble, investor expectations are so high that even flawless financial results, like Nvidia's record-breaking revenue, fail to boost the stock price. This disconnect signals that market sentiment is saturated and fragile, responding more to narrative than fundamentals.

Marks emphasizes that he correctly identified the dot-com and subprime mortgage bubbles without being an expert in the underlying assets. His value came from observing the "folly" in investor behavior and the erosion of risk aversion, suggesting market psychology is more critical than domain knowledge for spotting bubbles.

A macro strategist recalls dot-com era pitches justifying valuations with absurd scenarios like pets needing cell phones or a company's tech being understood by only three people. This level of extreme mania highlights a key difference from today's market, suggesting current hype levels are not unprecedented.