::::Please pardon me, and please delete all of my stuff, I just wanted to underline that you are right: Some presumptions show to be really ridiculous. If the car "always" is placed behind the door selected then the chance by switching of course will always be zero. Ehh? - ridiculous presumption, like Morgan; he knows: The chance of picking the winning door is exactly 1/3, so the chance of winning by switching is always 2/3, and Morgans is just wisecracking, he says: Anytime the host SHOWS that the door is behind his preferred door, i.e. if he HAS exceptionally to open "his avoided door" then everyone knows that in this case the chance by switching is exactly 3/3. Ridiculous. And every time (3/3) the host opens "his" door (the car being behind the "other" unselected door (in 1/3 chance=100%) or if he has two goats to chose from (in 2/3 chance=0%) then, in average, the door selected IS SHOWN to have a chance of 50%, and the chance by switching IS SHOWN to have a chance of 50 %. But: That does not change the overall probability that remains unchanged: Overall chance by switching remains 2/3. Morgan cannot change this overall chance, he just SHOWS whether the car actually IS behind the door selected or whether it is there with a probability of 50 %. Ridiculous. And everyone bows to him. Please Martin delete all of this. Thank you.