iii. The graduation of punishments must be almost entirely determined by experience of their operation as deterrents. It is to be borne in mind, indeed, (i.) that the “reversionary rights” of humanity in the offender are not to be needlessly sacrificed, and (ii.) that the true essence of punishment, as punishment, the negation of the offender’s anti-social will, is in some way to be secured. But these conditions are included in the preventive or deterrent theory of punishment, if completely understood; if, that is to say, it is made clear precisely what it is that is to be prevented. If we speak of punishment, then, as having for {229} its aim to be deterrent or preventive, we must not understand this to mean that a majority, or any persons in power, may rightly prevent, by the threat of penalties, any acts that seem to them to be inconvenient. That which is to be prevented by punishment is a violation of the State-maintained system of rights by a person who is a party to that system, and therefore the above-mentioned conditions, implied in a true understanding of the reformatory and retributive aspects of punishment, are also involved in it as deterrent. But, this being admitted, we may add to them the distinctive principle on which a deterrent theory insists. If a lighter punishment deter as effectively as a heavier, it is wrong to impose the heavier. For the precise aim of State action is the maintenance of rights; and if rights are effectively maintained without the heavier punishment, the aim of the State does not justify its imposition. It is well known that success in the maintenance of rights depends not only on the severity of punishments, but also on the true adjustment of the rights themselves to human ends, and on that certainty of detecting crime which is a result of efficient government. And it must always be considered, in dealing with a relative failure of the deterrent power of punishment in regard to certain offences, whether a better adjustment of rights or a greater certainty of detection will not meet the end more effectively than increased seventy of punishment. We have seen that the equivalence of punishment and offence is really a meaningless superstition. And there is no principle on which {230} punishment can be rationally graduated, except its deterrent power as learned by experience. This view corresponds to the true limits of State action as determined by the means at its disposal compared with the end which is its justification, and is therefore, when grasped in its full meaning as not denying the nature of punishment, the true theory of it.