I cannot provide [a murderer] compelling grounds as to why he ought not to have done what he did… [T]o punish him would be arbitrary.
If you don’t want murderers running around killing people, then it’s consistent with your values to set up a situation in which murderers can expect to be punished, and one way to do that is to actually punish murderers.
Yes, that’s arbitrary, in the same sense that every preference you have is arbitrary. If you are going to act upon your preferences without deceiving yourself, you have to feel comfortable with doing arbitrary things.
I think you missed the point quite badly there. The point is that there is no rationally
compelling reason to act on any arbitrary value. You gave the example of punishing murderers, but if every value is equally arbitrary that is no more justifiable than punishing stamp collectors or the left-handed. Having accepted moral subjectivism, you are faced with a choice between acting irrationality or not acting. OTOH, you haven’t exactly given moral objectivism a run for its money.
If you don’t want murderers running around killing people, then it’s consistent with your values to set up a situation in which murderers can expect to be punished, and one way to do that is to actually punish murderers.
Yes, that’s arbitrary, in the same sense that every preference you have is arbitrary. If you are going to act upon your preferences without deceiving yourself, you have to feel comfortable with doing arbitrary things.
I think you missed the point quite badly there. The point is that there is no rationally compelling reason to act on any arbitrary value. You gave the example of punishing murderers, but if every value is equally arbitrary that is no more justifiable than punishing stamp collectors or the left-handed. Having accepted moral subjectivism, you are faced with a choice between acting irrationality or not acting. OTOH, you haven’t exactly given moral objectivism a run for its money.