logic & reasoning
a million-dollar puzzle
an almost-infallible predictor, two boxes, and a clean split down the middle of rationality.
Robert Nozick wrote that to almost everyone it is perfectly clear what you should do, and that people divide almost evenly over which obvious thing it is. After fifty years the division has not healed. Here is the puzzle; choose, and then meet the argument you did not make.
one box, or two?
Before you sit two boxes. Box A is transparent and holds £1,000. Box B is opaque: it holds either £1,000,000 or nothing.
Yesterday, a Predictor that has run this game thousands of times and never once been wrong made its forecast. If it predicted you would take only Box B, it put the million inside. If it predicted you would take both boxes, it left Box B empty. The boxes are already filled and sealed; nothing you do now can change their contents.
You may take both boxes, or only Box B.
further reading
- newcomb's problem and two principles of choice original paper
- causal decision theory stanford encyclopedia of philosophy
- newcomb's paradox wikipedia