A problem with blackmail is that it can be repeated. After you do Y (pay me money) and I don’t do X (publish letters), I can go back and once again ask you for money. With your second example, after not rejecting the offer I no longer have the MacGuffin, so I can’t repeat.
EDIT: The only way to rule out repetition is to include it in the precommitment. But note that for human agents it is impossible to precommit in an enforceable way without side-effects. They can’t self-modify, so they would need a trusted third party. Then this trusted party will get to know at least the fact that there are some juicy secrets out there about Y.
And after selling you one, I will still have one less MacGuffin. Presumably these can’t be copied easily. And if they can, e.g. if it is a digital file, then what is it that you really want to get? Access to the information in the file or preventing access to the information for others?
This made me think of some related concepts: NDAs and exclusive rights contracts.
A problem with blackmail is that it can be repeated. After you do Y (pay me money) and I don’t do X (publish letters), I can go back and once again ask you for money. With your second example, after not rejecting the offer I no longer have the MacGuffin, so I can’t repeat.
EDIT: The only way to rule out repetition is to include it in the precommitment. But note that for human agents it is impossible to precommit in an enforceable way without side-effects. They can’t self-modify, so they would need a trusted third party. Then this trusted party will get to know at least the fact that there are some juicy secrets out there about Y.
But if I give you the letters in exchange of the money, this doesn’t make it any less blackmail...
And having extra MacGuffin’s to sell shouldn’t change it, either.
You could have made copies of the letters.
And after selling you one, I will still have one less MacGuffin. Presumably these can’t be copied easily. And if they can, e.g. if it is a digital file, then what is it that you really want to get? Access to the information in the file or preventing access to the information for others?
This made me think of some related concepts: NDAs and exclusive rights contracts.