The Vizzini Effect

This is a principle I discovered from playing social deduction games, but I’ve found it helpful in everyday reasoning as well.

I call it the ‘Vizzini Effect”, named after Wallace Shawn’s character from The Princess Bride.  For the very few of you who have not memorized every line from this brilliant film, here’s the scene I’m referencing:

As it turns out, both glasses were poisoned, and the man in black(the Dread Pirate Roberts) has spent the last few years building up an immunity to Iocane powder.

What In the World is That?

The Vizzini Effect is the stipulation that you can never draw a conclusion based off what a person would or would not do, given that the person in question is, or might be, clever, because the same argument can be used as proof of nearly any theory.

So how does it work?  Let’s take for example the case of Abel, Baker, Charlie, and Dennis.  They’re playing a game of Werewolf/Mafia, and they’ve just finished first night, during which Dennis was killed.  

Now, Baker knows that Abel had always had a grudge against Dennis, and so he suspects Abel as the killer.

Charlie, however, knows Abel to be a very crafty player who would suspect that Baker would point to him(Abel) if Dennis died first, and thus he clearly cannot be the killer.

But wait!  Baker points out that Abel, being as clever as he is, would know that Charlie would say it wasn’t him because Baker said it was him, and therefore would choose Dennis as his first target.  So it was Abel!

I Clearly Cannot Choose…

Just before votes are cast, Abel makes the case that, if he was as clever as the others supposed, he certainly would suspect that Baker would assume that he was the killer because he would know that Charlie would conclude, based on the fact that Baker assumed that Abel would kill Dennis, that he could not be the killer, and therefore he would not kill Dennis.  In fact, he would depend on it, so Abel cannot be the killer.

Charlie then attempts to refute this argument, but he messes up the pronouns and accidentally says that he, himself, is the killer, and Abel and Baker vote for Charlie.

Inconceivable!

It gets somewhat convoluted, and this example is a bit exaggerated, but I think you can see what I’m getting at here;  though it may seem helpful, any evidence based solely on tendencies or preferences is utterly useless, as it is evidence both for and against your argument.

The Vizzini Effect is mostly useful as a logical fallacy;  When you notice it in action, call it out, explain what the it means, and get past the infinite loop of ‘he must, he must not’ and get back to real reasoning.  It can save you a lot of time and energy, which is especially crucial when you’re on a timer.

Am I Finished?  Not Remotely!

That’s about all I have for today, but I’d like to know what you guys think about this principal.  Have you ever seen it in action?  Do you have something to add or change about the principle?  and do you have some potent stratagems to fight it?  If you do, feel free to comment below.  So thanks, and as always, keep on geekin’ on!