Principle of double effect

The principle of double effect (PDE) or doctrine of double effect (DDE), sometimes simply called double effect for short, is a thesis in ethics, usually attributed to Thomas Aquinas. The principle seeks to explain under what circumstances one may act in a way that has both good and bad consequences (a "double effect").

It states that an action having an unintended, harmful effect (e.g., an early death) is defensible on four conditions as follows:

• the nature of the act is itself good (e.g., its nature is to relieve someone of pain or distress);
• the intention is for the good effect and not the bad;
• the good effect outweighs the bad effect in a situation sufficiently grave to merit the risk of yielding the bad effect (e.g., risking a patient's death to stop intolerable pain); and
• the good effect (relieving pain) does not go through the bad effect (e.g., death)

Intentional harm versus side-effects

Although different writers state the doctrine in different ways, it always claims that there is a moral difference between courses of action such as the following:

1. An agent that deliberately causes harm in order to promote some good.
2. An agent that promotes some good in such a way that harm is caused as a foreseen side-effect.

The doctrine of double effect stems from an application of the Hippocratic moral norm, i.e., "First, do no harm," along with Aquinas's First Precept (or Principle) of Natural Law, i.e., "Good is to be Done and Promoted and Evil is to be Avoided" [Summa Theo I-II Q94 Art 2].

Examples from medicine

A vaccine manufacturer typically knows that while a vaccine will save many lives, a few people will die from side-effects of vaccination. The manufacture of a drug is in itself morally neutral. Lives are saved as a result of the vaccine, not as a result of the deaths due to side-effects. The bad effect, the deaths due to side-effects, does not further any goals of the manufacturer, and hence is not intended as a means to any end. Finally, the number of lives saved is much greater than the number lost, and so the proportionality condition is satisfied. This is more a case of side-effects/benefit analysis than of a real Principle application and is common in medicine.

The administration of a high dosage of opioids is sometimes allowed for the relief of pain in cases of terminal illness, even when this can cause death as a side effect. This argument played a great part in the acquittal of suspected serial killer Dr John Bodkin Adams. Some, including most Catholic ethicists, hold that this concept is morally different from deliberate euthanasia for the relief of pain. Today, palliative care experience and research has shown that it is possible to manage pain or distress without hastening death (see opioids), so the debate relies on out-of-date data.

The principle of double effect is frequently cited in cases of pregnancy and abortion. A doctor who believes abortion is always morally wrong may nevertheless perform a procedure on a pregnant woman, knowing the procedure will cause the death of the embryo or fetus, in cases in which the woman is certain to die without the procedure (examples cited include aggressive uterine cancer and ectopic pregnancy). In these cases, the intended effect is to save the woman's life, not to terminate the pregnancy, and the effect of not performing the procedure would result in the greater evil of the death of both the mother and the unborn child.

War

The Principle appears useful in war situations. In a war, it may be morally acceptable to bomb the enemy headquarters to end the war quickly, even if civilians on the streets around the headquarters might die. For, in such a case, the bad effect of civilian deaths is not disproportionate to the good effect of ending the war quickly, and the deaths of the civilians are side effect and not intended by the bombers, either as ends or as means. On the other hand, to bomb an enemy orphanage in order to terrorize the enemy into surrender would be unacceptable, because the deaths of the orphans would be intended, in this case as a means to ending the war early, contrary to condition.

Whether the Principle applies to the bombing of Hiroshima and Nagasaki and the sometimes massive conventional bombing of European cities is a highly controversial question.

Controversy

Despite some apparent plausibility, the doctrine of double effect is controversial. Consequentialists, in particular, reject the notion that two acts can differ in their permissibility, if both have exactly the same consequences.

A major argument against the DDE is the hypothetical case where some evil must actively be done to bring about an enormous good. For example, suppose a nuclear bomb has been planted in a major city, and a person is held in custody who knows where it is, but who refuses to disclose the bomb's location. May the interrogators torture this person's family in front of his or her eyes, exploiting the family attachment to extract information and save millions of lives?

Even in such an extreme case, the DDE would not permit evil to be done prior to good consequences, whereas the consequentialist position states that the order of events is irrelevant. The argument against DDE thus becomes a question of how high must the stakes be before any evil is permissible for good ends, with the DDE position maintaining that evil is never permissible as an instigator to good ends.

In the past few years in the UK, at least two doctors undergoing murder trials for giving large doses of opioids to ill patients, have used the defence of double effect.

See also

• Opioids
• Trolley problem

External links

• Principle Of Double Effect
• Stanford Encyclopedia of Philosophy entry
• What is the doctrine of double effect?