Abstract

In tort and contract law, we calculate the harm a defendant caused a plaintiff by examining the plaintiff’s condition after an injury relative to his baseline condition. When we consider the severity of prison sentences, however, we usually ignore offenders’ baseline conditions. We deem inmates as receiving equal punishments when they are incarcerated for the same period of time under the same conditions, even though incarceration does not change their situations equally (unless they started out in identical circumstances). It is the amount by which we change offenders’ circumstances that determines the severity of their sentences. We calculate the severity of some punishments, like fines, comparatively. Fines specify an amount by which to change an offender’s wealth relative to his baseline. We never use fines to equalize the net worth of offenders, but we do use prison to equalize the liberties of prison inmates. When we recognize the comparative nature of punishment, we see that, by putting two equally blameworthy offenders in prison for equal durations, the offender with the better baseline condition is likely punished more severely than the offender with the worse baseline condition. We must attend to the differences in their baselines or else we will fail to justify some of the harsh treatment that we knowingly impose. If we insist on giving both of these offenders equal prison terms, we cannot justify doing so on the grounds of proportional punishment.