Doctrine of Double Effect

[toby1986]

Can you please explain the Doctrine of Double Effect? Is it a Catholic Doctrine and would this apply to ectopic pregnancies? What about a pregnancies where the life of the mother is at stake?


Thank you

[Cam42]

Hi Toby....

First, it is not a doctrine; it is a prinicple. It is not necessarily a theological priniciple, but rather a philosophical one. It can be applied in a theological manner, however it is not necessarily theological in nature.

Here it is in a nutshell:

1. that the action in itself from its very object be good or at least indifferent;
2. that the good effect and not the evil effect be intended;
3. that the good effect be not produced by means of the evil effect;
4. that there be a proportionately grave reason for permitting the evil effect

Of these four conditions the first two are general rules of morality. A person is never allowed to perform a morally bad action. Nor may one ever positively will an evil effect of an action, even though the act would otherwise be lawful.

Double effect might also be part of a secular non-absolutist view according to which a justification adequate for causing a certain harm as a side effect might not be adequate for causing that harm as a means to the same good end under the same circumstances.

The most typical example is that of pregnancy. A pregnant woman bearing a nonviable fetus is found to have a cancerous womb that will cause her death if it is not excised as soon as possible. The operation of hysterectomy is morally lawful, for this operation is permissible in itself as a normal means of saving the woman's life. She does not positively will the death of her child, but permits it as an unavoidable evil. Both the benefit to her health and the death of the child follow from the surgery with equal directness or immediacy in the order of causality, though the death of the child is prior in the order of time. The woman's chance of restoration to health (the good effect) is sufficiently desirable to compensate for the death of the fetus (the bad effect), which would probably not survive even if the operation were not performed.

Aquinas is credited with introducing the principle of double effect in his discussion of the permissibility of self-defense in the Summa Theologica (II-II, 64, 6). Killing one's assailant is justified, he argues, provided one does not intend to kill him.

Aquinas observes that:
[quote]Nothing hinders one act from having two effects, only one of which is intended, while the other is beside the intention. … Accordingly, the act of self-defense may have two effects: one, the saving of one's life; the other, the slaying of the aggressor.” As Aquinas's discussion continues, a justification is provided that rests on characterizing the defensive action as a means to a goal that is justified: “Therefore, this act, since one's intention is to save one's own life, is not unlawful, seeing that it is natural to everything to keep itself in being as far as possible.[/quote]

However, Aquinas observes, the permissibility of self-defense is not unconditional:
[quote]And yet, though proceeding from a good intention, an act may be rendered unlawful if it be out of proportion to the end. Wherefore, if a man in self-defense uses more than necessary violence, it will be unlawful, whereas, if he repel force with moderation, his defense will be lawful.[/quote]

Aquinas does not actually say that intending to kill the assailant as a means to self-defense would be prohibited. The passage can be interpreted as formulating a prohibition on apportioning one's efforts with killing as the only goal guiding one's actions, which would lead one to act with greater viciousness than the goal of self-defense would allow.

In contrast, Augustine had earlier maintained that killing in self-defense was not permissible, maintaining that:
[quote]private self-defense can only proceed from some degree of inordinate self-love.[/quote]