Because most philosophies that frown on reproduction don't survive.

Thursday, December 07, 2006

Some Thoughts on "Double Effect"

One of the trickier concepts within traditional Catholic moral theology is that of "double effect". The basic idea here is, one may perform certain actions with a morally acceptable intent, despite that the fact that certain undesirable results are known to be almost certain to result as well.

Thus, according to classic moral teaching, it is unacceptable to will to kill another person, but it acceptable to will to stop an intruder from threatening your family by pointing a .45 automatic at him and pulling the trigger. (I'll use the example of self defense throughout, since that's one of the most classic examples of double effect.) Your will is to stop him from causing harm, while his death (if it occurs) is a foreseen but undesired consequence. (Thus, one goes from self defense to murder if the intruder is writhing helplessly on the ground after the first shot and you step over and fire a second shot to finish him off: There is no sense in which such an action is necessary for self defense, and so the only possible object of your action is to kill the now wounded assailant.)

Now, the principle of double effect clearly handles some very important moral questions, and I don't for a moment want to sound like I'm saying it doesn't make sense or should be thrown out. However, it does seem to present a certain potential for tying ones self up in mental knots.

I think the trouble area tends to be the "undesired but foreseen" element of the double effect. A lot of people seem to have difficulty with the idea of foreseeing something clearly as the result of an action without actually willing it. Thus, in cases of self defense, some err on the side of saying that one cannot justify any defensive action which one can foresee with near complete certainty will result in the death of the attacker. Others err in the other direction, believing that by virtue of being an attacker, the assailant in a self defense situation essentially cedes his life, and any action against him is justified.

The right balance, I think, is to understand that the killing of an attacker is morally justifiable only to the extent that it is necessary in order to achieve the goal of defending the innocent. One the one hand, the principle of double effect does not require that a defender hold back on the force he uses, so long as the use of greater force actually achieves defense with more certainty. And yet, once the threat is averted, further use of force is not morally acceptible.


Anonymous said...

One thing I would suggest is that the evil effect can be expected and caused by the person performing the act, yet not willed by him. The "desire" of the person performing the act is really irrelevant. A good example as far as appeals to intuition goes is performing an emergency operation on a patient without anesthetic. The pain the patient feels from the operation is foreseen and actually caused by the surgeon; but it is not chosen by the surgeon.

Anonymous said...

In the heat of the moment one does not calculate the fine points of morality.

Darwin said...

I'd say it's precisely because one doesn't have time to think in an emergency that one should think about such questions ahead of time. On the topic at hand, we actually put a lot of work into providing police and soldiers with the training to switch immediately from "take him down" mode to "take the prisoner and keep him alive" mode. And if moral training before the fact can work under that kind of pressure, I imagine it's not wholly unuseful.

bearing said...

I don't think self defense is tricky to figure out. Now apply your reasoning skill to ectopic pregnancy, in which both endangered individuals are innocent, and explain why treating it via salpingectomy (which is more hazardous to the mother), is licit and treating it via salpingostomy, or methotrexate, isn't.

I understand the difference intuitively, but I have difficulty articulating it in a way that might make sense to someone less familiar with Catholic moral theology.

Anonymous said...


Catholics United For The Faith has a "Faith Fact" (tract) on this topic which is pretty good.

Go here:

and click on "Ectopic for Discussion: A Catholic Approach to Tubal Pregnancies.

bearing said...

You're right, momlady, that is a well-written article.