For a more parable-ic version of this, see here.
Suppose I make a precommitment P to take action X unless you take action Y. Action X is not in my interest: I wouldn't do it if I knew you'd never take action Y. You would want me to not precommit to P.
Is this blackmail? Suppose we've been having a steamy affair together, and I have the letters to prove it. It would be bad for both of these if they were published. Then X={Publish the letters} and Y={You pay me money} is textbook blackmail.
But suppose I own a MacGuffin that you want (I value it at £9). If X={Reject any offer} and Y={You offer more than £10}, is this still blackmail? Formally, it looks the same.
What about if I bought the MacGuffin for £500 and you value it at £1000? This makes no difference to the formal structure of the scenario. Then my behaviour feels utterly reasonable, rather than vicious and blackmail-ly.
What is the meaningful difference between the two scenarios? I can't really formalise it.
It does not make them worse off than if the negotiation had never been opened.
I don't see where the difficulty is in distinguishing "I have $OBJECT for sale at $MONEY. Interested?" and "Nice operation you've got here, you wouldn't want anything to happen to it, would you? Just see that you do some business with me from time to time, and I can guarantee there won't be any trouble."
I dare say there are some radicals who see all free exchange of value as an act of violence, each party viciously withholding the good they could do for the other in order to extort a price from them, and in a virtuous society all would freely, selflessly work for the benefit of everyone but themselves without even the very idea of a return for their labour. But the world contains all manner of madness.
The difference there seems to be the default (or disagreement) point: the assumed zero of the transaction. Then any deviation from the default is seen by whether it's positive or negative. It's the difference between "pay your ta... (read more)