A kid’s baseball goes through a bakery window, and someone in the crowd shrugs that at least the glazier gets paid. In 1850 the French economist Frédéric Bastiat took that reflex apart in his essay That Which Is Seen and That Which Is Not Seen. His shopkeeper, James Goodfellow, spends six francs replacing a pane his careless son broke, and those six francs never reach the cobbler or the bookseller. Nothing new was created. A window that already existed was simply bought back.

This episode follows the idea from Bastiat to Henry Hazlitt, who named the broken window fallacy in his 1946 book Economics in One Lesson, and then tests it against bigger wreckage: the Great Fire of London, hurricanes and earthquakes, cash for clunkers, and the old belief that war is good for business. Along the way it separates GDP, which measures flow, from wealth, which is the stock that destruction drains, and explains why economies recover from lost buildings far more easily than from lost people.

• Bastiat imagined the glazier secretly paying a boy one franc per smashed window, then showed the economic math is identical whether the breakage is an accident or a racket.
• He mocked a protectionist journal by following its logic to the conclusion that burning Paris to the ground would be a boost for national trade.
• A bathtub analogy explains post-disaster booms: a hurricane blows a hole in the tub, insurance money turns the faucet on full, and GDP spikes while the region only refills what it lost.
• Geological disasters like the 1995 Kobe earthquake do more lasting economic harm than climate disasters, because they destroy human capital along with property.
• About a tenth of the economic cost of the United Kingdom’s 2007 summer floods was attributed to public health effects, spending that raises GDP while only healing a wound.