"You must know, then," he replied, "that this wonderful principle is our grand method of _directing the intention,_ a principle of great importance in our moral system. You have already seen certain examples of it. Thus, when I explained to you how servants could carry with a clear conscience certain harmful messages, you must have seen that it was by diverting their intention from the evil of which they are the bearers and by turning it to the gain which they receive for their service. This is what we call 'directing the intention.' In the same way you have seen that those who give money in return for benefices would be guilty of simony unless they diverted their intention from the transaction. But I am going to show you this grand method in all its beauty in relation to homicide, which it justifies under a thousand circumstances." "I am ready to believe," I said, "that your principle will permit everything, and that nothing will escape it." "Not at all," he replied; "you are always running from one extreme to the other. We by no means permit everything. For instance, we never permit the formal intention of sin, for the mere sake of sinning, and we will have nothing to do with anyone who persists in seeking evil as an end in itself, for that is a devilish intention, in whatever age, sex, or rank it may be found. But so long as there is no such unhappy disposition as that, we try to put in practice our method of directing intention, which consists in proposing a lawful object as the end of one's actions. In so far as it is in our power, we turn away from forbidden things; but when we are unable to prevent the action, we at least try to purify the intention, and so correct the vice of the means by the purity of the end. "That is how our fathers have been able to permit the acts of violence which are committed in the defence of honour. It is only necessary to turn away one's intention from the desire of vengeance, which is criminal, and to restrict it to the desire of defending one's honour, which is a lawful desire. It is thus that our fathers are able to fulfil their duties towards God and towards men alike. They please the world by permitting the actions, and they satisfy the Gospel by purifying the intentions. It is a method which was unknown to the ancients, and is entirely due to our fathers. Do you understand it now?" "I understand it very well," I said. "You allow to men the external and material effect of the action, and you give to God the internal and spiritual movement of intention, and thus reconcile the human with the divine law. But though I understand your principle well enough, I should like to know what are its consequences.--I should like to know, for instance, all the cases in which your method permits one to kill. You have told me that whoever receives a blow may repay it with a sword-thrust without the guilt of vengeance, but you have not yet told me how far one may go."