188. But does our theory, after all has been said about the wrongness of punishment that is not just, afford any standard for the apportionment of just punishment, any criterion of the amount of interference with a criminal's personal rights that is appropriate to his crime, except such as is afforded by a prevalent impression among men as to what is necessary for their security? Can we construe it so as to afford such a criterion, without at the same time condemning a great deal of punishment which yet society could be never brought to dispense with? Does it really admit of being applied at all in the presence of the admitted impossibility of ascertaining the degree of moral guilt of criminals, as depending on their state of character or habitual motives? How, according to it, can we justify punishments inflicted in the case of 'culpable negligence,' e.g. when an engine-driver, by careless driving, for which we think very little the worse of him, is the occasion of a bad accident, and is heavily punished in consequence? 189. It is true that there can be no _a priori_ criterion of just punishment, except of an abstract and negative kind. We may say that no punishment is just, unless the rights which it serves to protect are powers on the part of individuals or corporations of which the general maintenance is necessary to the well-being of society on the whole, and unless the terror which the punishment is calculated to inspire is necessary for their maintenance. For a positive and detailed criterion of just punishment, we must wait till a system of rights has been established in which the claims of all men, as founded on their capacities for contributing to social well-being, are perfectly harmonised, and till experience has shown the degree and kind of terror with which men must be affected in order to the suppression of the anti-social tendencies which might lead to the violation of such a system of rights. And this is perhaps equivalent to saying that no complete criterion of just punishment can be arrived at till punishment is no longer necessary; for the state of things supposed could scarcely be realised without bringing with it an extinction of the tendencies which state-punishment is needed to suppress. Meanwhile there is no method of approximation to justice in punishment but that which consists in gradually making the system of established rights just, i.e. in harmonising the true claims of all men, and in discovering by experience the really efficient means of restraining tendencies to violation of rights. An intentional violation of a right must be punished, whether the right violated is one that should be a right or no, on the principle that social well-being suffers more from violation of any established right, whatever the nature of the right, than from the establishment as a right of a power which should not be so established; and it can only be punished in the way which for the time is thought most efficient