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by bigstrat2003 976 days ago
I don't see how a new contestant has less information, though? They know that one of the two doors contains the prize, which is all the previous contestant knows either.
2 comments

The crucial bit of information that the new contestant doesn't have is that there was a door that was ineligible to be eliminated (the door chosen by the original contestant).

If the game had different rules, it would work like you are imagining. Specifically, if Monty randomly eliminated one of the two doors, meaning there was a chance for Monty to reveal the prize instead of a goat. If Monty has the chance to eliminate the prize before giving the contestant a chance to switch, then switching does not give you an advantage.

When one door was opened it revealed information about the other two doors.
But it didn't. Before, we knew that one of those two doors could contain either a prize or a goat. After, we know the same exact thing. No information was gained there.
As a result of how the doors were selected one of them is more likely to contain the prize. That is information.