George Szpiro

But no, when you dig into it, it's actually paradoxical.

Correct that it's 33 percent and 66 percent.

Well, yes, that's how most people think about it.

But actually, it was one third behind your door and two thirds behind one of the other two doors.

And that probability distribution remains the same even after Monty Hall opened the empty door.

What he did was...

he shifted the one-third probability behind the empty door onto the other door.

So that is now a two-thirds probability that it's behind the other door.

But even after the explanation, many people don't get it, and it took me a while to understand it.

OK, a falsidical paradox is a proposition that sounds absurd and is indeed false or self-contradictory.

Like when I said I always lie, that's a falsidical paradox because it is both true and false.

So there's fallacious reasoning there.

I'm violating the law of non-contradiction.

That's a falsidical paradox.

Another falsidical paradox would be the famous barber paradox.

In the village, there are several men in the village, and some shave themselves, and all those who don't shave themselves are shaved by the barber.

Let's call him Figaro.

So Figaro shaves all men who do not shave themselves.

The question is, does Figaro shave himself, or does he not?

If he does, then he shaves somebody who shaved himself.