Scenario A:
>you chose door 1
>Monty opens door 3
Switching now increases probability from 1/3 to 2/3 according to "mathematics".

Scenario B:
>you are presented three doors
>before you can choose a door, Monty opens door 3 and reveals the goat
>now you can choose between the remaining two doors
>you choose door 1
Again according to " mathematics" the probability is now 1/2.

What the fuck, guys? It's the exact same result in the end, i.e. door 3 is open and you choose between the others. The only valid conclusion is that probability is absolute bullshit without any logical basis.