I have gone so far into these questions--which might lead to a great many other problems of legal casuistry--with the desire of bringing out one essential part of the question. The difficulties which have arisen point, I think, to the impossibility of treating the problem exclusively, from a simple consideration of the deterring influence of punishment. That, however, remains an essential element. If the sole reason for punishing a sheep-stealer be not the prevention of sheep-stealing, that is, at least, a very excellent reason as far as it goes. But it seems to me an insufficient reason from the moral point of view, and, in particular, to fail in assigning a sufficiently distinct ground for determining the desirable degree of punishment. The principle was advocated as limiting the severity of the old laws; but it is not quite easy to define the limit suggested. There is a necessary clumsiness about the method. A punishment only becomes operative in the cases in which the threat has failed to deter. The fact that a man has committed a crime demonstrates the inadequacy of the system in his case; we have not given him a sufficient motive for abstaining. When Bentham says, that if a fine of five shillings would prevent a murder, you ought not to fine the murderer seven and sixpence, he says what is, in a sense, obviously true. If I could prevent a murder, or, indeed, achieve any other desirable object, for a given sum, why should I throw away another penny? But the fine is not inflicted till somebody has committed a murder, and, in that case, the threat of fining has obviously failed. The question arises, therefore, how far am I to go? Am I to go on raising the tariff till murder becomes altogether obsolete? But we have already got as far as capital punishment, without achieving that result. And, if we consider the case upon this method, we begin to find a difficulty in the method of calculation. We are to compare the pain inflicted upon the criminal with the pain saved to the victim. But the greater the pain inflicted, the smaller, according to the assumption made, will be the number of criminals, and the greater the number of victims saved. If we could adopt the Draconic system, and be sure of punishing every crime with death, crime ought to disappear; for hardly anybody would break the law if he were quite certain of the gallows. But, in that case, the pain, both of the criminal and the victim, would disappear, for there would be no one in either class. The result, therefore, would be a pure gain: no crime and no punishment. Against this practical conclusion, indeed, Bentham was one of the first to protest; and he uses one very sound argument. Punish all crime equally, he says, and you put a premium on the worst crimes. If both robber and murderer are to be hanged, the robber will have a good reason for destroying evidence, by adding the murder to the plunder of his victims.