In discussions about the justification of punishment, six aims of punishment are typically described. We will be examining which of these aims we consider valid.
The functions of punishment
The idea is to discourage wrongdoing by making the consequences for the perpetrator so unpleasant that they choose not to re-offend. It is also intended that when others, who have not yet offended, consider undertaking a criminal act they will see those who have been punished previously and reconsider their decision in order to avoid the punishment. You might think, therefore, that the harsher the punishment the better as the desire to avoid the pain and suffering involved will be even stronger. Why not threaten to hang the offender for stealing a loaf of bread? Wouldn't it concentrate the mind wonderfully?
For deterrence to work it is important that the crime be detected. No one is likely to be deterred if the chances of getting caught are slim. It is also important that the punishment must follow quickly upon the crime, otherwise the psychological connection between offence and consequence are weakened.
While deterrence is essentially utilitarian, in that it is justified by considering its overall good consequences, retribution has no good consequences at all. Punishment is meted out simply because it is 'deserved' regardless of the outcome. Perhaps it satisfies an atavistic desire for revenge in the victim, but is that the kind of emotion we want to encourage in citizens in a modern society. It is over the retributive function of punishment that the fault line between liberal and conservative attitudes tends to open up.
Restitution, or restorative justice, involves bringing victim and offender together so that the latter can be confronted with the human consequences of their crime. It also tries to create a situation in which the offender can recompense the victim in some substantial way. Obviously, this is limited in application as there is no way that anyone can make restitution for, say, murder. Although confronting the family of the victim might have a useful effect on the offender by bringing home to them the suffering they have inflicted. In other cases, such as abuse or rape, being confronted with the perpetrator may be the last thing in the world that the victim wants.
Perhaps the most important element in modern notions of punishment is reform of the offender. The aim is to cause a change in attitude so that the offender no longer desires to engage in criminal activity and to provide them with the skills and knowledge so that they can earn a living by non-criminal means. How far reform works, when judged by recidivism rates, is a moot point. It is also appears to conflict with the deterrence aim of punishment as reform is an educative process and education is more effective using carrot than stick.
(5) Societal protection
Putting offenders in prison has the effect of simply incapacitating their criminality. This is a pretty uncontroversial effect of punishment and clearly works (for the duration that the offender is “banged up”). However, the cost of keeping someone in prison is very high and so there is strong political pressure to find alternative means.
(6) Societal disapproval
A function of punishment often overlooked in these discussions is what we might call the 'signaling' function. By setting the tariff of punishment for, say rape, quite low, a society is in effect saying that this crime is less serious than burglary. By increasing the sentence a rapist gets in a court, the law is signalling to society in general the relative seriousness of this offence.
Another important aspect of punishment, which is less to do with justification than the 'fairness' of the sentence, is 'proportionality'. It is generally felt that the type punishment should be appropriate to the crime and that it should not be unduly harsh for minor crimes. This is critical if the law is to accepted as legitimate by the society at large.