I said that in the comments to the post below on the death penalty. In quantum physics, the Uncertainty Principle says that you cannot know to any random level of certainty both the position and the velocity of a particle. It's my assertion that most human events, murders included are "quantum" events; you cannot know everything about an event - about a murder. There are too many variables, too many uncertainties. Eye witness testimony has been proven to be untrustworthy in many instances; memories of events witnessed can be shaped and influenced by subsequent events and discussions and the way questions are posed.
In recent years, as technology has improved, evidence that once could not be gathered, much less evaluated has been used to exonerate people who've spent decades on death row. Some states have tried to limit either the number of appeals a deathrow inmate can mount, some have even tried to limit new evidence or the technology that can be brought to bear on evidence from older crimes. But as it always has, knowledge always grows over time.
Given the inability to have "perfect knowledge" about human events; given that inmates who've nearly exhausted their appeals have been exonerated by new or newly knowable evidence not available when they were convicted, how can society impose the ultimate sentence on a fellow, sentient human being; one for which there is no post facto remedy?
I'm tempted to stop there, but there remains a question or set of questions, posed admirably by my sister in the comments to the post below. What about serial killers or rapists? What about those who've confessed or for whom there is ample evidence that they actually committed the crime? What about those for whom recidivism is nearly a given? Don't those criminals cry out for the death penalty?
In that case, I believe we have to "appeal to our better angels." I have always been taught, I've always heard politicians say that the purpose of our justice system is - in the main - to rehabilitate offenders so that they can rejoin society. In fact, most modern, so-called "first world" countries' justice systems are based precisely on that proposition. They claim to have moved beyond the vengeance style of justice epitomized by "an eye for an eye."
Those who cannot be rehabilitated can surely be given life without parole. And there is ample proof - to dispel the first objection you'll hear to that sentence - that it's orders of magnitude less expensive to house an criminal for life than to run through the various mandatory and optional appeals processes that can mean decades of legal costs - always picked up by the tax payers - in addition to the day-to-day housing costs. And who would be the first to say that someone should be killed because it's too expensive to keep them alive?
So to those who would say that we should regularly put to death prisoners I would give you two questions to ask yourself - and to answer with full truthfulness to yourself:
1. Is it really possible to have full and complete knowledge of any human event that is as physically and emotionally complex as a murder?I think the answers to those questions should inform your opinion of the death penalty in a supposedly civilized society. Let me know your thoughts in the comments - oh, and read those in the post below, too... they are a great place to start.
2. What is the purpose of our justice system: rehabilitation or vengeance?