The Doctrine of Double Effect

Sometimes doing the right thing involves a morally bad consequence. For instance, if someone is about to murder your family, and the only thing you can do to stop him is to yourself kill that person, it certainly seems that the right thing to do is to kill the murderer. And yet there is the morally bad consequence of killing someone at play here.

It’d be great for moral philosophers if we could adopt simple moral rules that apply in every situation, like “thou shalt not kill”. But situations like the above make it clear that the world is seldom so kind to those of us who would plumb the depths of ethical reality. So, if you’re looking to create a coherent moral system, you’d better be able to explain why it is that you are justified in killing a murderer who is intent on killing you and your family. Under what circumstances is killing okay?

Perhaps if we view the killing in this situation as a regrettable consequence of doing the right thing… That is, perhaps the moral action of saving your family — even if it results in the killing of someone — is the real action that you are undertaking. And perhaps the killing of the murderer is a tangential, unavoidable, bad moral consequence. In this analysis, we might be able to work things out to the effect that you are not a killer — you are a family-saver whose actions led (regrettably) to an unintended killing.

Aquinas

Aquinas, back in the 13th century, was thinking of a similar situation, and came up with four conditions that he thought must be met for acting morally with a tangential bad moral consequence:

  1. The Nature-of-the-Act Condition. The action itself cannot be morally wrong.
  2. The Means-End Condition. The bad effect must not lead directly to the good effect.
  3. The Right-Intention Condition. The intention must be the achieving of only the good effect with the bad effect being only an unintended side effect. The bad effect may be foreseen, but not desired.
  4. The Proportionality Condition. The good effect must be at least as morally good as the bad effect is morally bad.

If Aquinas’ analysis is on the money, then you can save your family with a clear moral conscience, despite the fact that you wound up killing someone in order to do it.

Unfortunately, in the case of killing the murderer, we hit a pretty significant problem right off the bat with condition one. The action itself here seems to be one of killing. Isn’t this almost definitionally morally wrong? To get himself out of this fix, Aquinas argues that the actual action undertaken here is saving one’s family, and that the killing is the bad but unintended side effect: “Accordingly, the act of self-defense may have two effects: one, the saving of one’s life; the other, the slaying of the aggressor.” I’m not sure I buy that, but let’s step through the other conditions…

Actually, condition two seems problematic as well. Indeed, the saving of your family’s lives seems to be a direct consequence of you killing the murderer. But Aquinas would argue that actually the bad effect of killing the murderer somehow comes later in the chain of cause-effect than the good effect of saving your family. Honestly, this seems like complete bullshit to me, but let’s keep riding this train to the station and see where we end up.

Condition three seems really to get at the heart of the matter. You don’t first and foremost intend to kill the murderer; you intend to save your family. Perhaps this is really the keystone of moral goodness. If you don’t intend to kill the murderer, then you’re not committing murder yourself. But if killing the murderer is something that has to happen in order for you to save your family, then so be it.

Condition four is also conceivably well-met by our case. Saving your family, ceteris paribus, is arguably at least as morally important in the positive as killing the murderer is in the negative.

Abortion and Euthanasia

The Catholic Church has used Aquinas’ thoughts on double effect to weigh in on two weighty moral issues of our time: abortion and euthanasia.

Many have argued that even if abortion is immoral, it is morally permissible to perform an abortion to save the life of the mother. The Church, contrary to this, has argued that saving the life of the mother in this sort of case would fail to meet both criteria one and two above.

But you can apply this same reasoning to the case of self-defense above. I’ll leave it to the reader to cogitate on this further. (Hint: If saving-your-family is the true and moral act in the first case, then why isn’t saving-the-mother the true and moral act in this case? In both cases, then, the killing would be consequent to the saving.)

The Church meant to draw a distinction between plain abortion and, for instance, performing a hysterectomy on a pregnant woman with uterine cancer. In the case of our cancerous woman (so goes the Church’s logic), the result of the hysterectomy would be an abortion, but the actual intention of the doctors is to save the woman from cancer, not to kill her fetus. This is a nifty bit of face-saving, but, again, isn’t the real intention of the doctors in the abortion case to save the woman’s life? And thus the abortion is secondary to the life-saving, and should be morally acceptable.

There’s a similar Church line taken on euthanasia. A doctor killing a patient with an overdose of morphine is (argues the Church) unacceptable, because it fails conditions one and two again. That is, even if the desired end-result is that of mercy, getting to that end via a morally bad act (killing) is wrong.

However, the Church allowed for doctors overdosing patients on morphine under the circumstance where the intention is to prevent pain. That is, if the act in question is the morally good one of pain prevention, then the unintended consequence of death is morally okay.

We’ll leave it to another day to discuss the absurdity of the presumed immorality of euthanasia, but note again that these two situations are really not that different. No doctor (or no doctor I’ve ever met, anyway) outright intends to kill her patients. They intend to ease suffering, and they know that death is often the ultimate and only suffering-ender that will work in some unfortunate circumstances.

Trolley Cases and Double Effect

Are you up to speed on philosophical trolley problems? If not, take a quick look at our primer on the subject. In fact, it was the publishing of two recent books on trolley problems in philosophy that got me thinking about double effect for this post. (Both are excellent little books, by the way, and well worth a read: Would You Kill the Fat Man, by David Edmonds, and The Trolley Problem, or Would You Throw the Fat Guy Off the Bridge? by Thomas Cathcart.)

Some will use the doctrine of double effect to justify their intuitions about trolley cases. For instance, in the standard case, a driver of a train with no brakes can either continue down his track and kill five unsuspecting workers, or divert the train down a spur and kill one unsuspecting worker. It turns out that most people believe that killing the one worker is the right thing to do in this situation. And often people will cite utilitarian reasoning here: ‘Well, one life isn’t as valuable as five, so it’s the right thing to kill one if you can save five.’

But if we change the circumstances of our thought experiment, the utilitarian justification loses some weight. Say the only way to save the five workers is to push a heavy object in front of the train. But the only object heavy enough is a fat man who happens to be above the tracks on a bridge. Would it be the right moral thing for you to push the fat main off the bridge and let the train run over him, saving the five lives further down the tracks? Well, it turns out that the general moral intuition here is that it’s actually not the right thing to do. And, if this intuition is correct, utilitarianism fails here. But the doctrine of double effect could be used to explain things! In the first trolley case, you don’t intend to kill the one worker on the spur. And your action isn’t really killing that worker — the action is saving the five workers by steering the train down a different track. The killing of the one worker that results from your action is regrettable, but is not the intended effect of the whole affair. But in the case of the fat man, you have to take direct action against the one person in order to save the five. Your action is directly killing the fat man.

As with the above analyses, I think there’s something actually amiss here. If you put an intermediate step in between your action and the fat man dying, that wouldn’t make it any more or less acceptable. There has got to be another analysis that we can apply.

And, in the spirit of cliffhanger serial short movies from the golden age of Hollywood, I’ll leave you with the promise that we’ll explore this different analysis in a future post…

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