There are, however, four different theories of punishment, viz., Deterrent, Preventive, Retributive and Reformative.
The object of criminal justice in awarding punishment, according to this theory is to deter people from committing a crime. Commission of offences must be made as a bad bargain for the offender.
The infliction of punishment serves as a check on others who are evil-minded. But this theory is not absolutely correct for a hardened criminal becomes accustomed to the severity of punishment and no amount of deterrence prevents him from indulging in crime.
It aims to prevent a repetition to the offence by the offender by such penalties as imprisonment, death and exile. This form of punishment also fails to achieve the desired end. Persons who visit jail once are habituated to it.
With the advancement of civilization death sentence has also become incongruous, for murders are in a large number of cases never premeditated.
According to it the offender should be made to suffer in proportion to the injury caused to the victim, viz., and a tooth for a tooth or an eye for an eye. It is a barbarous form of punishment and betrays an utter ignorance of the causes that lead to crime.
The object of the punishment must not be to wreak vengeance but so to reform the criminal as to prevent him from further crime. Crime like all other diseases should be properly diagnosed and treated scientifically.
Crime is a malady and the aim of every punishment should be the reclamation of the offender by prescribing proper treatment. Uninvestigated criminals are an expensive luxury. The message of Mahatma Gandhi ‘Hate the sin and not the sinner’, should guide the reformer in adopting a judicious penal policy.
For the society contains within itself the germs of all the crimes that are about to be committed, and the criminal is only the instrument which executes them. In the new era of prison reform medical treatment on the basis of the study of the causative factors of crime will play a very important part.