"This Time Is Different" — The Four Most Dangerous Words

"The four most dangerous words in investing are: 'this time it's different.' When you hear them — worry." — Howard Marks

Every major bubble in history was justified by a story claiming the old rules no longer applied:

• In 1999, that traditional valuation didn't apply to internet companies because it was "a new economy".
• In 2006, that national house prices had never fallen, so property was different.
• In 2021, that near-zero interest rates justified almost any multiple.

The narratives change; the human psychology underneath does not. Greed, the habit of extrapolating recent trends, and the urge to rationalise high prices are as old as markets.

The practical signal is this: when you find yourself inventing a new framework to justify a price the old framework cannot support — stop. That moment of reinvention is itself the warning sign. The new framework is usually the risk, not the safety net.

Illustrative example: the dot-com bubble

As earnings-based valuation produced "wrong" answers, analysts invented new yardsticks like price-to-clicks. When the cycle turned, the technology-heavy Nasdaq index fell sharply from its peak, and conventional measures of value reasserted themselves — as they tend to do.