Tough subject. *Long Read*
The issue of corrective justice in legal philosophy distinguishes between two principal theories of punishment: utilitarian and retributive.
Utilitarian perspective, then, capital punishment is justified if it
1.) prevents the criminal from repeating his crime;
2.) deters crime by discouraging would-be offenders. For, both of these contribute to a greater balance of happiness in society.
*For, both of these contribute to a greater balance of happiness in society.
Problems
1.) The burden of proof is on the defender of capital punishment to show that the same effects could not be accomplished with less severe punishment, such as life imprisonment. The goal of utilitarianism is to reduce as much unhappiness as possible and this entails imposing the least severe of two possible punishments when everything else is equal.
Cesare Beccaria (1738-1794) argues this point in On Crimes and Punishment, according to Beccaria, capital punishment is not necessary to deter, and long term imprisonment is a more powerful deterrent since execution is transient.
2.) A second and more basic problem with utilitarian defenses of capital punishment involves the fact gathering process. Since the utilitarian is making a factual claim about the beneficial social consequences of capital punishment, then his claim should be backed by empirical evidence.
3.) A third problem with utilitarian justifications of punishment, as pointed out by contemporary political philosopher Adam Bedeau, concerns the ratio of innocent lives saved per execution. Eventually it must be determined how many executions justify the saving of one innocent life.
The retributive notion of punishment in general is that
1.) as a foundational matter of justice, criminals deserve punishment, and
2.) punishment should be equal to the harm done.
One of the most early written statements of capital punishment from the lex talionis or "eye for an eye" perspective is from the 18th century BCE Babylonian Law of Hammurabi:
If a builder builds a house for someone, and does not construct it properly, and the house which he built falls in and kills its owner, then that builder shall be put to death. If it kills the son of the owner, then the son of that builder shall be put to death.
Problems
1.) Punishment may be inadequate. For example, if a terrorist or mass murderer kills ten people, then taking his single life is technically not punishment in kind.
2.) Foundational beliefs in general have the unfortunate consequence of appearing arbitrary.
3.) Critics of capital punishment argue that the true basis of retributive justifications of capital punishment is not at all foundational, but instead rooted in psychological feelings of vengeance.
Other Arguments
John Locke's famous defense of capital punishment has both a retributive and utilitarian component. Locke argued that a person forfeits his rights when committing even minor crimes. Once rights are forfeited, Locke justifies punishment for two reasons:
(1) from the retributive side, criminals deserve punishment, and,
(2) from the utilitarian side, punishment is needed to protect our society by deterring crime through example. Thus, society may punish the criminal any way it deems necessary so to set an example for other would-be criminals. This includes taking away his life.
Opposed to Capital Punishment
1.) Capital punishment should be abolished since it is undignified, inhumane, or contrary to love. Corporal punishment, such as flogging, and extreme types of capital punishment, such as burning at the stake, are no longer accepted practices because of their indignity. By parity of reasoning, capital punishment should be abolished too.
2.) A second direct attack on the practice of capital punishment is that, at least at present, it is virtually impossible to apply death sentences fairly. People on death row are typically poor and thus could not afford the best defense at their initial trial. They are also disproportinately Afro-American or Hispanic which raises larger issues of racial inequality in the US. As ethnic minorities, they are also likely to receive more strict judgments from juries than their white counterparts who commit the same crime.