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Comment by jpwagner | Hacker News Reader

how are you quantifying it

It's a silly question, so I'll give a silly answer.

Suppose we have a man who, from the ages of 30 to 60, is likely to kill a person each year with probability 1/$age. Now suppose he's on trial for murder (a crime he is guilty of) and there's a 99% chance he spends life in prison and a 1% chance he spends no time in prison due to a mistrial. The overall probability he will kill again is ~ 0.7%

Suppose instead that we put him in jail for 10 years with 100% probability (ie, a deal that a logical actor would take facing life in prison with 99% probability) and each year he spends in jail his desire to kill decreases by a factor of 2. Now his overall probability of killing again is ~ 0.04%.

So the killer's situation has improved and society's situation has improved.

</silly answer>

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Perhaps silly, but let me explain a little more. Here's the scenario I envisioned after reading your original comment:

Say you have 10 people who have committed a crime and under the current system 9 get convicted and go to jail for 10 years and and 1 gets off on a technicality. So, there's collectively 90 years of prison time being served.

Now imagine we introduce plea bargaining and offer 5 years to all those accused and all 10 take it. The conviction rate goes up, but the total amount of jail time being served is drastically down.

Now I don't know what kind of "discounts" plea deals usually offer, or what it increase the conviction rate to, but I doubt it's an "obvious" win if you're counting by the number of years convicted offenders are removed from society.

Reading your silly answer, I think you're arguing something even less "obvious", which is that willingness to commit a crime is a direct function of age. And if that's the case, and if we're measuring benefit by a decrease in one's willingness to commit a crime, well then your system makes sense because any jail time is essentially better than none because the majority of the decrease in willingness to commit a crime happens at the front end of the sentence anyways. But I think that requires a broad assumption about the correlation of age and crime.

That's a fair point. I would argue that we're not trying to optimize time in prison but benefit to society. Your argument relies on a linear(ish) relationship between the two.

Your argument depends upon omniscience. It's not silly. It's absurd.

That's why the question is silly. The absurd answer illustrates a point. Fiction can illustrate a philosophy.

The question doesn't seem silly to me. I didn't see any obvious benefit.

It took a lot of work to find a possible candidate for an obvious benefit. Yet, given the recent utilitarian turn of your comments, I doubt that a Hobbesian analysis was the basis for the claim.

You're assuming that he won't murder anyone in prison.

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