And why would a good and sane person ever want to impose costs on third parties ever except like in… revenge because we live in an anarchic horror world, or (better) as punishment after a wise and just proceeding where rehabilitation would probably fail but deterrence might work?
This paragraph sounds to me like when you say “costs” you are actually thinking of “punishments”, with an implication of moral wrongdoing. I’m uncertain that Duncan intended that implication (and if he did, I’d like to request that both of you use the more specific term).
If you continue to endorse the quoted paragraph as applied to “costs” that are not necessarily punishments, then I further contend that costs are useful in several scenarios where there is no implication of wrongdoing:
The SUPER obvious example is markets, where costs are used as a mechanism to control resource allocation.
Another common scenario is as a filter for seriousness. Suppose you are holding a contest where you will award a prize to the best foozle. If entry in the contest is free of charge, you might get a lot of entries from amateur foozle artists who know that they have negligible chance of winning, but who see no downside to entering; you will then be forced to spend resources judging those entries. If you instead charge a $10 entrance fee, then most of those people will not bother to enter, and you’ll only have to judge the foozles from artists who self-evaluate as having a real shot.
There is no implication that entering the contest is an evil thing that no one should ever do. It’s just a mechanism for transferring some of the transactional costs onto the party that is best able to judge the value of the transaction, so that we end up with better decisions about which transactions to perform.
Another use for costs is for creating precommitments. If you want to avoid a certain future action, attaching a cost to that action can be helpful both for generating the willpower to stick to your decision and also for convincing other people that you will stick to it. There exist services people voluntarily sign up for where you agree to pay money if you break a precommitment.
Additionally, I feel you are unfairly maligning deterrence. You imply it should only be used where rehabilitation would probably fail, but rehabilitation only prevents that offender from repeating the offense, whereas deterrence discourages anyone from repeating the offense; this creates many scenarios where deterrence might be desirable in addition to rehabilitation (or where rehabilitation is irrelevant, e.g. because that particular offender will never have a similar opportunity again).
You also imply deterrence should only be used after meeting an extremely high standard of evidence; most people only consider this necessary for extreme forms of deterrence (e.g. jail) but permit a much weaker standard of evidence for mild forms (e.g. verbal chastisement; leaving a negative review). I think this common view is probably correct on cost/benefit grounds (less caution is required in situations where a mistake causes less harm).
This paragraph sounds to me like when you say “costs” you are actually thinking of “punishments”, with an implication of moral wrongdoing. I’m uncertain that Duncan intended that implication (and if he did, I’d like to request that both of you use the more specific term).
If you continue to endorse the quoted paragraph as applied to “costs” that are not necessarily punishments, then I further contend that costs are useful in several scenarios where there is no implication of wrongdoing:
The SUPER obvious example is markets, where costs are used as a mechanism to control resource allocation.
Another common scenario is as a filter for seriousness. Suppose you are holding a contest where you will award a prize to the best foozle. If entry in the contest is free of charge, you might get a lot of entries from amateur foozle artists who know that they have negligible chance of winning, but who see no downside to entering; you will then be forced to spend resources judging those entries. If you instead charge a $10 entrance fee, then most of those people will not bother to enter, and you’ll only have to judge the foozles from artists who self-evaluate as having a real shot.
There is no implication that entering the contest is an evil thing that no one should ever do. It’s just a mechanism for transferring some of the transactional costs onto the party that is best able to judge the value of the transaction, so that we end up with better decisions about which transactions to perform.
Another use for costs is for creating precommitments. If you want to avoid a certain future action, attaching a cost to that action can be helpful both for generating the willpower to stick to your decision and also for convincing other people that you will stick to it. There exist services people voluntarily sign up for where you agree to pay money if you break a precommitment.
Additionally, I feel you are unfairly maligning deterrence. You imply it should only be used where rehabilitation would probably fail, but rehabilitation only prevents that offender from repeating the offense, whereas deterrence discourages anyone from repeating the offense; this creates many scenarios where deterrence might be desirable in addition to rehabilitation (or where rehabilitation is irrelevant, e.g. because that particular offender will never have a similar opportunity again).
You also imply deterrence should only be used after meeting an extremely high standard of evidence; most people only consider this necessary for extreme forms of deterrence (e.g. jail) but permit a much weaker standard of evidence for mild forms (e.g. verbal chastisement; leaving a negative review). I think this common view is probably correct on cost/benefit grounds (less caution is required in situations where a mistake causes less harm).