How to Solve Parfit’s Hitchhiker

Where “rational” behavior gets you in trouble

You are driving through the desert when suddenly, your car breaks down. You try your best to fix the engine, but it’s broken beyond repair. The nearest town is way to far away to reach on foot. What’s worse, it’s over 40° C and you are running out of water. Without help, you’ll soon die of dehydration.

Luckily for you, a car comes by. The driver steps out, and says to you: “I’ll give you a ride to the nearest town, but you’ll have to pay me $100 in return”. You respond you…