But it's only fair then to ask you how you can be so presumptuous to think you can, or even should 'rehabilitate'?
Anyway, you are missing a third option. Imprisonment does not have to be about either rehabilitation or punishment. It could also, or even instead, be about detainment and isolation. In other words, you can imprison somebody not out of some sort of desire to "get back at them", and not with any hope of correcting their behavior, but merely to make sure they cannot injure people again.
Consider the case of Charles Manson: That guy is way too far gone to ever really hope that he can be rehabilitated. There is no fixing that guy; the US prison system couldn't do it, the Norwegian system couldn't do it, no "Manhattan Project of Psychiatry" could do it. Even so, that doesn't mean that the only option left is to ensure that he lives in relative misery the rest of his nature life. We could allow him to live the rest of his life out in relative comfort, so long as we never allow him to be free to harm others again.
Where we cannot 'fix', we obviously need to detain and isolate, but doing that for the safety of the public is sufficient motivation. We don't need to do that out of a desire to 'punish'. (Unless you buy into "such punishments act as a deterrent")
Why on earth is he being locked up. Pissing away the life savings of thousands of people? Water under the bridge. Stop being so vengeful -- it's childish and unbecoming!
I think Bernie Madoff is an interesting example. He doesn't represent a threat to anybody (he is not a violent man. Furthermore we should be able to make sure he doesn't start running another scam again, even if he is free, since we know he is a con-man now), and if we discard vengeance as a legitimate reason to detain somebody, we then need to consider the value of detaining him as a deterrent to others.
If we are worried about psychopathic con-men who are incapable of experiencing fear, then detainment probably doesn't do much to deter similar crimes. I am not convinced that is an accurate representation of psychopaths though, and I certainly don't think all con-men are psychopaths anyway. Detaining Madoff probably does serve to deter similar crimes.
The question I have is if there are other punishments besides imprisonment that could fill that roll.
Basically, just like he isn't allowed to run a business or manage his own finances now, when he is in prison, he wouldn't be able to while outside either. Literal prison walls don't really add that much to our ability to control those things.
The likelihood of being caught is probably a bigger factor in deterrence than the severity of the punishment itself. White collar criminals probably get away with a lot of small crimes (I am guessing).
Madoff is a very extreme example because he was doomed to eventually be caught. But we can look at it the other direction and consider how many hundreds(?!?) of small and large crimes did he get away with before it all collapsed on him?
This is the only truly just reason for impeding anyone's freedoms. Rehabilitation is certainly a noble end, but anything else seems to be disastrously misguided, as is evidenced by the modern situation we live in. Deterrence? How do you deter someone who has no other avenue to make a living, as we have done to felons? Retribution is also a truly vulgar line of thinking, appealing to our basest instincts, and we need to grow out of it as soon as possible.
Yes, that makes sense. Rehabilitation is something that you might as well attempt while detaining somebody dangerous, but detainment is obviously the priority.
I agree that proactively making his life miserable is silly, but the question becomes "how much comfort do we provide". Different people have different ideas of how much they are willing to pay to fund this man's life in "relative comfort", and of course only naturally their desire to channel their dollars towards his comfort is lower than it probably would be for an individual who is not a convicted criminal...