So here's my argument against amputating jaywalkers.
1. If an action causes one to lose one or more limbs/organs, and that action has no sufficient purpose, then that action is immoral.
2. The "jaywalking penalty" does have those qualities.
C. Therefore, the jaywalking penalty is immoral. (modus ponens
WP)
This is pretty simple. Most everyone would agree that in some cases, amputating a limb can be justified, such as when it involves saving someone's life. It's important to note here that jaywalking is fairly irrelevant to the above argument. It just so happens to be that "because they jaywalked" does not suffice as a reason to do them any harm. If anyone wanted to argue that it did, then I would be forced to inquire just what that reason is.
At this point, you may have some idea how this relates to the topic at hand. All I'm going to do is switch some words around.
1. If an action causes one to die, and that action has no sufficient purpose, then that action is immoral.
2. The death penalty does have those qualities.
C. Therefore, the death penalty is immoral. (modus ponens
WP)
Now, I wouldn't blame you if you weren't so willing to accept this argument, so I'll go over it in more detail this time around.
Logically, the conclusion does follow from the premises, if they are true. Let's take a look at them.
Premise 1 is very easy. When one kills another for a bad reason, we call that murder, and we all agree that murder is wrong.
I should point out that this raises the question over whether or not there is such a thing as a good reason to kill another person. I would say that there is, such as in cases of self defense (and if need be, I will illustrate why). However, that's not terribly relevant to the argument, here. Even a hardcore pacifist would agree with premise 1.
So that only leaves us with premise 2 to contest. Obviously, capital punishment does cause death (it is not called the death penalty for ironic reasons). So is there sufficient reason? The one that's currently being tossed around in the thread is that the person in question has killed another. I'm willing to accept that as true, but it is insufficient, because it cannot possibly be sufficient. This is because
it is not possible for statements of facts, in and of themselves, to provide sufficient reason for proper behavior. Hume referred to this as the is-ought gap
WP. If this last part seems confusing, or even downright absurd, I wouldn't blame you for seeing it that way. I'm willing to go into more detail if necessary.
Another possible reason that you mentioned is that you might get some degree of satisfaction out of knowing that the individual is no longer alive. When one kills another for the pleasure of it, we call that murder, and we all agree that murder is wrong.