not do evil that good may come; the end does not justify the means. [1] Lastly, there must be such a proportion between the good and bad effects that right reason tells me that I am not forbidden to forego the good effect of the action on account of the bad being inextricably bound up with it.
The question as to whether a general is justified in ordering his army to take a stronghold by assault in war will serve to illustrate the principle and its use. In the first place, the assault must be justified by itself, apart from the cost in human life. The assault will be justified in itself if the war is just and the stronghold belongs to the enemy; it will not be justified if the war is one of unjust aggression, or if the general has been expressly ordered by his Government not to take the place. Moreover, the general must not directly intend the necessary loss of life among the innocent non-belligerents. He foresees and deplores it; he is said in the technical language of theology to permit the evil effect, not to intend it. The slaughter of innocent non-belligerents must not be the means chosen to capture the stronghold; evil may not be done that good may come. Finally, the capture of the place must be a matter of sufficient importance in the war to warrant the shedding of innocent blood in the bombardment, and the other evils necessarily entailed in an assault. The question as to when the good result is sufficient to outweigh the evil is largely a matter of sound judgement after a careful examination of all the circumstances. If the successful storming of the place would only add to the personal reputation of the general without bringing the end of the war any the nearer, the assault would be a crime; if it would compel the enemy to sue for peace, it would usually be justified.
This principle is of great importance in Moral Theology; it has in its support the common consent of divines, and is expressly used by St Thomas. [2]
5. If I am not justified, according to the foregoing principle, in performing an action which causes some evil effect, that evil effect is imputable to me though I did not intend it in itself; it is not indeed voluntary in itself, but it is voluntary in its cause, and I am bound to avoid evil even though only voluntary in its cause.
When, however, evil is not voluntary in itself, but only voluntary in its cause, a question arises concerning the degree of moral guilt which is contracted when such a cause of evil is posited unwarrantably. The case arises especially when
