Imagine an urn with 90 balls. Exactly 30 are red. The other 60 are black or yellow in some unknown mix — could be all black, could be all yellow, you aren’t told. Bet A pays out if you draw red. Bet B pays out if you draw black. Most people take A. Now two new bets. Bet C pays if you draw red or yellow. Bet D pays if you draw black or yellow. Most people take D. Those two choices can’t coexist under expected utility theory, and that’s the whole point. Preferring A over B says you act as if red is more likely than black. Preferring D over C says the opposite, that black beats red. Yellow sits in both C and D, so it cancels. Strip it out and D over C reduces to black over red. You’ve contradicted yourself. Daniel Ellsberg laid this out in 1961, the same Ellsberg who later leaked the Pentagon Papers. His target was Leonard Savage’s sure-thing principle: a shared outcome common to two options shouldn’t sway your ranking between them. People break this rule reliably. The driver is amb...