Theories of punishment have significant role to play in the ongoing debate on capital punishment, especially for murder. Some retributivists appeal to the lex talionis, the law of retaliation, to determine the appropriate amount of punishment . This principle specifies that the punishment should inflict on offenders what they have done to their victims; “an eye for an eye, a tooth for a tooth”, and “a life for a life”. Capital punishment is therefore the only appropriate punishment for murder. But the lex talionis is deeply flawed. It focuses on the harm done by offenders without regard to their mental states.
A life may be taken intentionally or accidentally; a person may be killed for personal gain or in order to relieve him or her of the agony of a terminal illness. Even if we restrict the scope of the lex talionis to cases in which the wrongdoing is fully intentional, there is still the problem about the level at which the punishment should imitate the crime (Singer, 1993). Should murderers be killed in exactly the manner that they killed their victims? In any case, it is impossible to apply the lex talionis to many offenders; the penniless thief, the tooth assailant who knocks out his victim’s teeth, the tax evader, etc.
If conscious of the defects of the lex talionis, retributivists merely insist that the punishment should be appropriate to the moral gravity of the offence, then this requirement can be satisfied so long as the murderer is punished more severely than less serious offenders. There is no need for capital punishment. From the utilitarian point of view, capital punishment can only be justified if it produces better consequences than less severe forms of punishment. This condition would be satisfied if capital punishment is a superior deterrent to alternative forms of punishment such as long periods of imprisonment.
So a utilitarian will try to settle the issue on the basis of the evidence about the effects of capital punishment. The statistical evidence is based on comparisons of murder rates in countries where there is capital punishment with those in socially similar countries where there is no capital punishment, and no comparisons of the murder rates in one and the same country at different times when it had capital punishment and when it later abolished it, or when it restored capital punishment after a period of abolition.
The evidence does not show that capital punishment is a superior deterrent. However, the utilitarian approach is rejected by those who wish to place greater value on the lives of the innocent victims of murder than on the lives of convicted murderers. It is suggested that the evidence does not conclusively rule out the superior deterrence of capital punishment, and in the presence of such uncertainty, it is better to have capital punishment.
If there is capital punishment, and it turns out that capital punishment is not a superior deterrent, then convicted murderers have been unnecessarily executed. If, on the other hand, we abolish capital punishment, and it turns out that it is a superior deterrent, then there would be additional victims of murder.
But this argument is unacceptable because where there is capital punishment, it is certain that convicted murderers will die, but in the absence of capital punishment and in the light of available evidence there is only a remote probability that there would be more innocent victims of murder (Conway, 1974). In any case, there is a risk of a few innocent people being wrongly convicted of murder and executed if there is capital punishment. This has to put on the scales against capital punishment.