Somebody is holding two envelopes, one with some amount of money, the other with twice as much.
He hands you one envelope, you open it and see there is 10 dollars. He asks you if you want to switch envelopes.
One envelope has x dollars and the other has 2x dollars. If you get the x dollar envelope, you stand to gain x dollars if you switch. If you get the 2x dollar envelope, you stand to lose x dollars if you switch.
But why then, if you do this experiment over and over again, will you make more money in the long-run by switching?
Not as tricky as picking goats, but a little weird nonetheless. It seems logical that you should switch, but if you try to explain why… it gets a little tricky.
So do you switch or not?