187. It is clear, however, that this requirement, that punishment of crime should be just, may be covered by the statement that in its proper nature it is preventive, if the nature of that which is to be prevented by it is sufficiently defined. Its proper function is, in the interest of rights that are genuine (in the sense explained), to prevent actions of the kind described by associating in the mind of every possible doer of them a certain terror with the contemplation of the act,--such terror as is necessary on the whole to protect the rights threatened by such action. The whipping of an ill-behaved dog is preventive, but not preventive in the sense in which the punishment of crime is so, because (1) the dog's ill conduct is not an intentional violation of a right or neglect of a known obligation, the dog having no conception of right or obligation, and (2) for the same reason the whipping does not lead to the association of terror in the minds of other dogs with the violation of rights and neglect of obligations. To shoot men down who resist a successful _coup d'état_ may be effectually preventive of further resistance to the government established by the _coup d'état_, but it does not satisfy the true idea of punishment, because the terror produced by the massacre is not necessary for the protection of genuine rights, rights founded on public interest. To hang men for sheep-stealing, again, does not satisfy the idea; because, though it is a genuine right that sheep-stealing violates, in a society where there was any decent reconciliation of rights no such terror as is caused by the punishment of death would be required for the protection of the right. It is because the theory that punishment is 'merely preventive' favours the notion that the repetition of any action which any sufficient body of men find inconvenient may justifiably be prevented by any sort of terror that may be convenient for the purpose, that it requires to be guarded by substituting for the qualifying 'merely' a statement of what it is which the justifiable punishment prevents and why it prevents it.