[lrc]

So you get one free murder? No, the deterrent had to be there beforehand, so that our hypothetical killer who is certain she only wants to kill one person will be exposed to that deterrence. Even if she is not thereby deterred, the fact that the punishment is applied to her will have a deterrent effect on others contemplating a similar crime. Therefore the punishment has value even if there is no need to prevent the murderer from killing again. (Edit: you did point out that the omniscience allows you to know that there will actually be no deterrent effect but that's asking a lot :)

[munk-a]

I included omniscience specifically for that reason, I agree that murders must be punished because otherwise people will see fewer downsides to committing murders themselves.

Can I push this to the concept of Botany Bay the far away prison colony - if murder results in the murderer being shipped off and everyone in society understands how terrible it is there... do you actually need to send people there? Wouldn't the effect on society be the same if you just shipped them somewhere nice and (again lots of omnipotence and omnipresence here) could ensure no one ever learned of your deception?

I'm mostly pushing this out in an effort to clarify what we as a society get out of punishment (in my opinion) we are seeking to reduce these sorts of actions we consider to be bad for society, any punishment that exists solely to inflict pain on someone (even if they're really bad) without any associated benefits to deterrence or a decrease in recidivism ... it's pointless and cruel (again, in my eyes).

And yes, I like philosophy, so this scenario is super removed from the real world.