Presumably, PB thinks that life-long prison-sentences are too cruel, since it is a “living tomb”. Capital punishment is not (or shouldn’t be). If we wish to be humane, we ought to simply execute people who do commit such crimes: not for deterrence but in terms of appropriate punishment. This is why execution should be allowed, instead of prison. I’m not sure how right this is, but it is certainly merits thoughtful attention.
I think there is merit to his/her thinking on capital punishment and I'm mostly persuaded by flogging. Furthermore the capital punishment explanation has shaken some of my own foundations for being opposed to the death penalty. I don’t think my arguments are as strong, now, given the overarching context and need for radical revision within our punishment mechanisms. Indeed, it is what PB calls a failure of the imagination that we default to imprisoning: even I, when opposing capital punishment, claim life-long imprisonment is a “better” option. It is precisely what “better” means that I need to start reconsidering.
My ambivalence hasn't really changed since the last time we kicked this topic around. What say you?