I think that whether or not you have free will is not so important when making these considerations.
Whether or not you have a choice and free will, you can influence and be influenced by other stuff, since that is how anything is doing.
> punishment might still be justified from the point of view of reducing offending and reoffending rates, but if that is the goal then it is only justified to the extent that it actually achieves those goals
I do agree with that, and I think that whether or not you have free will is not significant. Being emotionally difficult is not what makes it good or bad in this case (and it also does not seem to be so emotionally difficult to me, anyways). Reducing reoffending rates is what is important.
(Another issue is knowing if they are actually guilty (you shouldn't arrest people who are not actually guilty of murder); this is not always certain, either.)
I also think that it should mean that prisoners should not be treated badly and that prison sentences should not be too long. (Also, they shouldn't take up too much space by the prisons, since they should have free space for natural lands and for other buildings and purposes, but that is not quite the same issue, though.)
However, there may be cases where a fine might be appropriate, in order to pay for damages (although if someone else is willing to forgive them then such a fine may not be required). This does not justify a prison sentence or stuff like that, though.
Also, some people will just not like them anymore if they are accused of murder, even if they are not put in prison and not fined. This is not the issue for police and legal things; it is just what it will be. And, if it becomes known, people who disagree with the risk assessment can try to avoid someone.
And, if someone does commit a crime again and may have opportunity to do again in future, then this can be considered as being wrong the first time and this time hopefully you can know better.
Whether or not you have a choice and free will, you can influence and be influenced by other stuff, since that is how anything is doing.
> punishment might still be justified from the point of view of reducing offending and reoffending rates, but if that is the goal then it is only justified to the extent that it actually achieves those goals
I do agree with that, and I think that whether or not you have free will is not significant. Being emotionally difficult is not what makes it good or bad in this case (and it also does not seem to be so emotionally difficult to me, anyways). Reducing reoffending rates is what is important.
(Another issue is knowing if they are actually guilty (you shouldn't arrest people who are not actually guilty of murder); this is not always certain, either.)
I also think that it should mean that prisoners should not be treated badly and that prison sentences should not be too long. (Also, they shouldn't take up too much space by the prisons, since they should have free space for natural lands and for other buildings and purposes, but that is not quite the same issue, though.)
However, there may be cases where a fine might be appropriate, in order to pay for damages (although if someone else is willing to forgive them then such a fine may not be required). This does not justify a prison sentence or stuff like that, though.
Also, some people will just not like them anymore if they are accused of murder, even if they are not put in prison and not fined. This is not the issue for police and legal things; it is just what it will be. And, if it becomes known, people who disagree with the risk assessment can try to avoid someone.
And, if someone does commit a crime again and may have opportunity to do again in future, then this can be considered as being wrong the first time and this time hopefully you can know better.