In the movie adaptation of The Princess Bride (I haven't read the book, though apparently it's also in the book), Vizzini loses the battle of the wits by drinking a cup poisoned with iocane powder. The Man in Black then says that both cups were poisoned.
Is there anything in the wording of his challenge, if interpreted correctly, could have indicated this as a logically allowable possibility, and have a way for Vizzini to win?
Here is the exact wording of the battle of wits (Vizzini's answers removed):
In that case, I challenge you to a battle of wits. Good. Then pour the wine. Inhale this, but do not touch. What you do not smell is called Iocane powder. It is odorless, tasteless, dissolves instantly in liquid, and is among the more deadly poisons known to man... All right. Where is the poison? The battle of wits has begun. It ends when you decide and we both drink, and find out who is right... and who is dead.
I submit that under the phrasing of the challenge, Vizzini could indeed have won... had he drank out of the bottle.
He would have logically answered the question: you would not have entered a battle of wits where there was a chance of your death based on a 50/50 guess. As such, there has to be a catch, something that guarantees my death and ensures your survival. The simplest answer is that you have the antidote (or an immunity), and poisoned both glasses.
But you specifically asked me to pour the wine and never touched the bottle. If we watch the video in question, it indeed looks as though there's still wine left in the bottle based on how Vizzini pours.
Under the rules set out by the Dread Pirate Roberts, Vizzini only had to "drink," not drink from one of the glasses. By choosing the bottle, he would have saved his own life and chosen a legitimately clever solution, winning the battle of wits. At the very least, with both men alive it would have been a tie.
If he would have deduced that both are poisoned one way he could have won is to have Buttercup drink out of the same cup that Wesley drinks out of, stating that
"If I'm right and you are dead, I plan on killing her anyway and you won't be around to stop me, so it is immaterial. If I am wrong, then there is no poison in your glass and she will be fine."
Knowing that either glass would kill Buttercup Wesley would have to admit defeat and leave since Vizzini would still be in the position to cut Buttercups throat if Wesley refused to yield.
I believe that inhaling the poison is what killed Vizzini. The Man in Black plays to Vizzini's ego in order to trick him into inhaling the poison. The Man in Black sets up a battle of wits, knowing that Vizzini is so sure of his intellect. The line the Man in Black says as he hands over the poison is "Inhale this, but do not touch." By saying not to touch it after saying to inhale it tricks Vizzini into thinking it is safe to inhale it. Well, that or Vizzini is just dumb enough to inhale something that an enemy gives him. As for the pouring it into the wine and guessing which one is poisoned, that was to keep Vizzini distracted while the poison took effect. For, if Vizzini were to think something was amiss, he might have killed the princess.
