It must, I think, be admitted that moral indignation (or, at least, that of people whose views on morals deserve respect) is much less surely aroused by the non-punishment of those who have broken the law than by the punishment of those who have not. This is perfectly intelligible, and is due partly, I think, to two reasons: (1) The law may be too severe. When the legal penalty for sheep-stealing was death, the penalty was so much more severe than the offence deserved that there was a less serious miscarriage of justice when a sheep-stealer escaped scot-free than when one was hanged. (2) Even when the law is in general just there may be extenuating circumstances (such as the almost irresistible temptation which a starving man has to steal, or the evil chance of a hopelessly non-moral or immoral education) which assure us that the guilt of the offender has been less than that which the offence usually implies. On the other hand, there can be no ground in justice for punishing a man for an act which is not illegal, or for an illegal act he has not committed. But deeper than these two reasons is (3) the fact that while we think we have a prima facie duty not to punish the innocent, we do not think we have a prima facie duty to punish the guilty (apart from considerations of deterrence and reformation), but only no prima facie duty to leave him unpunished; or, in other words, that, while we have a duty not to punish the innocent, we have only a right (apart, again, from deterrence and reformation) to punish the guilty.

(W. D. Ross, "The Ethics of Punishment," Journal of Philosophical Studies 4 [April 1929]: 205-11, at 211 [italics in original; footnote omitted])

Note from KBJ: There are three types of retributivism:

  • Minimal. Officials of the state have a prima facie duty not to punish the innocent.
  • Permissive. Officials of the state have a prima facie right to punish the guilty.
  • Maximal. Officials of the state have a prima facie duty to punish the guilty.

Ross accepts minimal and permissive retributivism but rejects maximal retributivism. Immanuel Kant (1724-1804) accepts all three. (Indeed, Kant, an absolutist, would accept all three without the words "prima facie.") Utilitarians reject all three. Please note that minimal retributivism (so understood) does not entail that it is always wrong, all things considered, to punish the innocent. There is more than one prima facie duty, according to Ross. Another prima facie duty, besides the prima facie duty of justice that prohibits punishing the innocent, is beneficence (doing good). In a given case, where punishing an innocent person is necessary to avert a great evil, it may be right to do so. Ross would describe this as a useful injustice. In more technical language, he would say that the prima facie duty of beneficence is more obligatory than the prima facie duty of justice in this case.