Scott Alexander defends an economic principle often mocked in jokes, explaining its validity when applied to long-standing, seemingly obvious financial opportunities. Longer summary

Scott Alexander critiques a common joke about economists dismissing free money on the ground. He argues that the underlying economic principle, when phrased more realistically, is actually correct and useful. The post explains that while it's possible to find money just dropped, it's highly unlikely for a bill to remain unclaimed in a busy area for an extended period. This principle warns against seemingly easy, no-risk money-making opportunities that have been available for a while, suggesting they may be more complicated or risky than they appear. Shorter summary