The effect is the same, and the doctor knows that the removed twin will die.
I understand. However, according to Catholic moral theology (and even secular ethical principles), the morality of human acts depend upon:
- the object chosen;
- the intention;
- the circumstances
Evil cannot be intended, either as a
means or an
end. However, many human acts have more than one effect. As St. Thomas Aquinas affirmed, “***the lesser evil or the greater good is always to be chosen ***” (
Summa Theologica, suppl., 47, 2). Consequently, we are permitted to tolerate evil “
for the sake of avoiding some greater evil, or of obtaining or preserving some greater good.” (Leo XIII, *Libertas, *33).
As you state, this is not “the ends justifies the means” because the evil effect CANNOT be either a “means” or an “end.”
Paul VI: "Though it is true that sometimes it is lawful to tolerate a lesser moral evil in order to avoid a greater evil or in order to promote a greater good, it is never lawful, even for the gravest reasons, to do evil that good may come of it (cf. Rom 3:8)—in other words, to intend directly something which of its very nature contradicts the moral order, and which must therefore be judged unworthy of man, even though the intention is to protect or promote the welfare of an individual, of a family or of society in general." (*Humanae Vitae, *14).
According one of the four the conditions of the principle of double effect, the evil effect cannot be intended (postively willed). Yet, ALL FOUR conditions must be met or the act is morally illicit.
The
New Catholic Encyclopedia describes the four conditions for the application of the principle of double effect:
*]The act itself must be morally good or at least indifferent.
*]The agent may not positively will the bad effect but may permit it. If he could attain the good effect without the bad effect he should do so. The bad effect is sometimes said to be indirectly voluntary.
*]The good effect must flow from the action at least as immediately (in the order of causality, though not necessarily in the order of time) as the bad effect. In other words the good effect must be produced directly by the action, not by the bad effect. Otherwise the agent would be using a bad means to a good end, which is never allowed.
*]The good effect must be sufficiently desirable to compensate for the allowing of the bad effect” (p. 1021).
In the case of surgically separating conjoined twins,
- For condition one to be met, the acts of surgically separating them is at least morally indifferent.
- For condition two to be met, the doctor must not positively will the death of either twin.
- For condition three to be met, the bad effect (death of one twin) cannot be the CAUSE (means) of the good effect.
- For condition four to be met, the good effect of the surgery must be proportionate in tolerating the potential bad effect of death of either or both twins.
One might argue that the risk of death is far greater than the benefit of surgery, therefore condition 4 fails. If so, then the surgery could not be licit. Nontheless, given that conditions 1), 3), & 4) are met, if the doctor actually intended the death of one twin, the surgery would be morally illicit. If he did not intend the death of either twin under the same conditions, the above case is morally licit.
In such a way, “intention is an element essential to the moral evaluation of an action.” (CCC 1572).
So, this kind of ethical principle of double effect is also used in determining the moral licitness of medical responses to ectopic pregnancies. This principle does not allow abortion, if abortion is defined as the intentionally and direct killing of an unborn child.