My take: what we call “extortion” or “blackmail” is where agent A1 offers A2 a choice between X and Y, both of which are harmful to A2, and where A1 has selected X to be less harmful to A2 than Y with the intention of causing A2 to choose X.
“Not responding to blackmail” comprises A2 choosing Y over X whenever A2 suspects this is going on.
A1 can still get A2 to choose X over Y, even if A2 has a policy of not responding to blackmail, by not appearing to have selected X… that is, by not appearing to be blackmailing A2.
For example, if instead of “I will hurt you if you don’t give me money” A1 says “I’ve just discovered that A3 is planning to hurt you! I can prevent it by taking certain steps on your behalf, but those steps are expensive, and I have other commitments for my money that are more important to me than averting your pain. But if you give me the money, I can take those steps, and you won’t get hurt,” A2 may not recognize this as blackmail, in which case A1 can finesse A2′s policy.
Of course, any reasonably sophisticated human will recognize that as likely blackmail, so a kind of social arms race ensues. Real-world blackmail attempts can be very subtle. (ETA: That extortion is illegal also contributes to this, of course… subtle extortion attempts can reduce A1′s legal liability, even when they don’t actually fool anyone.)
(Indeed, in some cases A1 can fool themselves, which brings into question whether it’s still blackmail. IMHO, the best way to think about cases like that is to stop treating people fooling themselves as unified agents, but that’s way off-topic.)
My take: what we call “extortion” or “blackmail” is where agent A1 offers A2 a choice between X and Y, both of which are harmful to A2, and where A1 has selected X to be less harmful to A2 than Y with the intention of causing A2 to choose X.
“Not responding to blackmail” comprises A2 choosing Y over X whenever A2 suspects this is going on.
A1 can still get A2 to choose X over Y, even if A2 has a policy of not responding to blackmail, by not appearing to have selected X… that is, by not appearing to be blackmailing A2.
For example, if instead of “I will hurt you if you don’t give me money” A1 says “I’ve just discovered that A3 is planning to hurt you! I can prevent it by taking certain steps on your behalf, but those steps are expensive, and I have other commitments for my money that are more important to me than averting your pain. But if you give me the money, I can take those steps, and you won’t get hurt,” A2 may not recognize this as blackmail, in which case A1 can finesse A2′s policy.
Of course, any reasonably sophisticated human will recognize that as likely blackmail, so a kind of social arms race ensues. Real-world blackmail attempts can be very subtle. (ETA: That extortion is illegal also contributes to this, of course… subtle extortion attempts can reduce A1′s legal liability, even when they don’t actually fool anyone.)
(Indeed, in some cases A1 can fool themselves, which brings into question whether it’s still blackmail. IMHO, the best way to think about cases like that is to stop treating people fooling themselves as unified agents, but that’s way off-topic.)