David Boonin makes a nifty argument in The Problem of Punishment to the conclusion that legal punishment — which Boonin defines as the state-authorized intentional infliction of harm on offenders for reprobative purposes *– cannot be justified by the thought that offenders deserve punishment.
The argument runs as follows. Imagine there’s only one kidney and five people who need transplants. Four of the five are villains; one is a saint. Imagine, further, that the saint clearly deserves the kidney. E.g., assume (1) that, ceteris paribus, saints deserve medical treatment more than villains do; and (2) that things are ceteris paribus, i.e. there are no countervailing facts such as that one of the villains was promised the kidney, etc. It does not follow that the saint may be forced to undergo a kidney transplant. If he refuses to undergo the transplant, for example, then the transplant may not be imposed on him.
The lesson is that the fact that A deserves x does not entail that x may be imposed on A. Thus, the fact that an offender deserves punishment (if, indeed, he does) does not entail that the offender may be punished. Something extra — e.g. the forfeiture by the offender of his right not to be punished — is needed. (A response — deserving punishment and deserving rewards are not structurally similar kinds of desert — is ad hoc.)
* A weakness of Boonin’s book is its conception of legal punishment, which imposes too heavy a burden on those who would defend the practice (to show that it is defensible for every offense).