Thought Experiment · 01
The Monty Hall Problem
You are about to be wrong about probability. Don't take it personally — nearly everyone is.
the setup
Three doors. Behind one: a car. Behind the other two: goats.
You pick a door. The host — who knows where the car is — opens a different door to reveal a goat. Now two doors remain closed: yours, and one other.
He asks the question every decision theorist wants you to get wrong:
“Do you want to switch, or stay?”
Most people say stay. It's 50/50, right? You've seen this. It feels obvious. That feeling is the trap.