> If penalties for mugging/robberies were lowered to pick pocketing levels, Paris would have muggers in every train and far fewer pickpockets.

This is a good point!

But I think this effect is less about the "incapacitation" issue discussed above (i.e. we would have muggers on every train because we wouldn't have detained the muggers for long enough), and more about deterrence (i.e. we would have muggers on every train because pickpockets would lose a disincentive from mugging).

There are multiple dimensions to picking how societies respond to crimes:

- denunciation: we publicly send the signal that your behavior was bad

- retribution: we want you to suffer

- rehabilitation: we want to help you become a better citizen

- incapacitation: we want to stop you from committing crime

- deterrence: we want other people to be afraid to commit crimes

- ...

And all of these carry different associated values. My suspicion is that when people attempt to justify the prison system based purely on the incapacitation effect, they're trying to don some faultless, sterile, harmless guise. "I'm not a bad guy for wanting people to be in prison; I just want my neighborhood to be safe!" But I think often a desire for denunciation, or retribution, or even angst about deterrence is at play.

I wasn't trying to justify the prison system based on anything. We use incapacitation, but that doesn't justify anything.

I wasn't trying to don some faultless, sterile, harmless guise. To eliminate your suspicion: my preference is for a combination of retribution, deterrence, and restitution. I'm in no way ashamed to say that I prefer those over incapacitation. Sadly, the USA mainly uses incapacitation, probably because it causes the least outrage.

BTW, you left some items off your list:

- restitution: the criminal must pay back the victim or the society for the harm caused (with money, organs, etc.)

- religion: we must do something (crucifixion, stoning, amputation, etc.) demanded by God

Perhaps it is useful to separate means from ends. Of course, we both agree that we want less crime (as an end), but I might favor rehabilitation as an end - I want prisoners to find their way back to productive society because I care - but not as a means - I might not think rehabilitating inmates reduces crime.

Do you favor retribution as a end, or a means?

When the very natural human desire for retribution is not satisfied by the law, people will obtain retribution outside of the law. This is how you get people torn apart and burned by angry mobs. Civilization thus requires that the law act to satisfy that desire for retribution.

Because the desire for retribution is nearly universal, we can tell that it is in our DNA. It clearly offers a selective advantage. It works.

Retribution is the desire, but notice how it very effectively creates both deterrence (don't want to be torn apart by a mob) and incapacitation (can't commit crime after being torn apart by a mob). This is why it has the selective advantage.

So, unless you want brutal violence as a system of justice, don't oppose making the criminals suffer. People need to see criminals punished, and they will take matters into their own hands as needed to ensure it happens.

> If penalties for mugging/robberies were lowered to pick pocketing levels, Paris would have muggers in every train and far fewer pickpockets.

Do you really believe that? I honestly think there's a fundamental difference in character between willingness to commit non-violent crime, and willingness to commit violent crime. One's just selfish, while the other is likely to be negative-sum in utility in a way that makes most people write it off as a fundamentally unsound strategy unless they're true sociopaths.

There are countries where law enforcement is weak to virtually nonexistent. They’re not desirable living locations by any means.

Deterrence is one of the main pillars of law enforcement. There are plenty of people who reach the end of their rope and act out of desperation. Deterrence is something that limits that. There is a point where that effect plateaus and people will take the risk regardless of penalty, but lowering penalties to the point of being worthless does let crime breed.

Just look at countries where corruption laws are ignored or unwritten. They’re corrupt. Countries that don’t protect women have more crimes against women. It’s how it goes.

A lot of claims without any evidence... care to provide any?

Otherwise you just sound like a person who likes to lock up people as much as possible with hope that everything will be magically allright then. Well, as history shows, crime reduction unfortunately doesn't work like that.