Punishment at the Speed of Light

I have written before about why it's a mistake for theorists to measure the severity of incarceration in objective terms, like months in prison. Here's a new argument adapted from Against Proportional Punishment (Vand. L. Rev., forthcoming 2013):

Special relativity teaches us that even if we wanted to resort to objective measurements of time, there is no observer-independent rate at which time passes. To illustrate, assume that in the distant future, we develop spaceships that travel at speeds approaching the speed of light. Due to the effects of special relativity, a person on such a ship will age slowly on average from the perspective of people on Earth. For example, a space traveler might age four years but come back to a planet whose inhabitants are eight years older.

Now suppose that twin brothers, alike in virtually all respects, commit crimes of equal blameworthiness. The only pertinent difference in their circumstances is that one is incarcerated on Earth while the other is incarcerated on a spaceship traveling near the speed of light. Assuming the twins deserve equal treatment, is it more accurate to measure the duration of their sentences based on an Earth clock or a spaceship clock? The answer is neither. As a first approximation, the duration of each twin’s confinement depends on the clock in the twin’s frame of reference.

But if we ought to individualize time measurements based on frames of reference, why stop there? Just as one person’s clock might appear to tick slower than another’s because of special relativity, one person might experience time moving slower than another because of his unique brain chemistry. When assessing the severity of harms associated with confinement, there is no obvious moral reason to consider the ticking of their clocks but not the ticking of their brains, so to speak.

Importantly, experiencing the passage of time is not itself a harm. But it is closely related to harmful experiences, like the distress and boredom associated with confinement. These experiences are clearly relevant to our assessments of how harshly offenders are treated by confinement. (There may be room to consider objective measurements of time when calculating the societal benefits of incapacitating offenders, but objectively measured elapsed time is not directly relevant to our assessments of sentence severity.)

Of course, it is extremely difficult to measure the experiences I'm discussing. In the real world, we have to settle for rough proxies, at least for the near future. But if you're a punishment theorist, you should care about figuring out what really matters in the absence of cost and technological constraints. After you've done that,  you can better return to real world problems by trying to approximate, as best we can, the things we really care about.