But if he doesn't know where the car is, how can he be sure that the door he opens is going to have a goat?
The scenario is the host doesn't know which door has the car, opens some random door, and that door happens to have a goat behind it.
If you were in this scenario, your odds of getting the car doesn't change whether you switch or not
Nobody said he can be sure.
The scenario is the host doesn't know which door has the car, opens some random door, and that door happens to have a goat behind it.
If you were in this scenario, your odds of getting the car doesn't change whether you switch or not