Natural Law theory might appear on first glance to be inflexible – but before we pass over hasty judgement we need to consider the doctrine of double effect. Thomas Aquinas introduced this principle when considering killing in self-defence (ST II-II, Qu. 64, Art.7). Killing an attacker is justified, he argues, as long as I do not intend to kill them. Augustine had argued (in contrast) that killing in self-defence was not moral, arguing that “private self-defence can only proceed from excessive self-love.” Notice how this makes Natural Law theory a lot more flexible than sometimes described, adding an element of intention and of proportionality to the moral decision.

Aquinas observes that “nothing stops an act from having two effects, only one of which is intended, while the other is unintended. … so the act of self-defence may have two effects: one, saving my life; the other, killing an attacker.” 

Aquinas’s appeals to the ultimate goal, the primary precept of preservation of life that defines the ‘good’.

“Therefore, this act, since my intention is to save my own life, is not unlawful, as it is natural to preserve our life as far as possible.” 

However the justification of self-defence is not unconditional: “yet, though proceeding from a good intention, an act may be immoral if it’s out of proportion to the end. So if someone uses more than necessary violence in self-defence, it will be unlawful, but if he uses moderate force, his defence will be lawful.”

Notice that Aquinas therefore introduces the idea of proportionality later developed in the twentieth century by philosophers like Bernard Hoose. Let’s apply this to euthanasia:

The action must be proportional to the cause: if I give a patient a dose of drugs so large that it is certain to kill them, and which is far greater than the dose needed to control their pain, I can’t use the Doctrine of Double Effect to say that what I did was right. In summary here are three advantages of the doctrine:

1. It is realistic (solving the problem of when two moral goods conflict). Applying this to euthanasia, I can’t always relieve suffering and preserve life – sometimes I risk end of life euthanasia in my attempts to reduce the pain a patient suffers.

2. It is proportional and so introduces flexibility and judgement (the means must be proportional to the good end) – if I am adminstering a pain relieving drug I cannot overdose the patient without risking a murder charge. I can only give them the amount of the drug necessary for the good end of pain relief.

3. It is teleological (it focuses on the good end and so reduces the moral status of the undesirable means). Applied to euthanasia this means the good result must be achieved independently of the bad one: the bad result must not be the means of achieving the good one. So if the only way the drug adminstered by a doctor relieves the patient’s pain is by killing him, the doctrine of double effect can’t apply.

Problems with the doctrine of double effect

If you want to evaluate double effect, you could do worse than start with this list of points from the BBC website and then follow them through.

1. We are responsible for all the anticipated consequences of our actions: If we can foresee the two effects of our action we have to take the moral responsibility for both effects – we can’t get out of trouble by deciding to intend only the effect that suits us.

2. Intention is irrelevant: Some people take the view that it’s sloppy morality to decide the rightness or wrongness of an act by looking at the intention of the doctor. They think that some acts are objectively right or wrong, and that the intention of the person who does them is irrelevant. But most legal systems regard the intention of a person as a vital element in deciding whether they have committed a crime, and how serious a crime, in cases of causing death.

3. Death is not always bad – so double effect is irrelevant: Other philosophers say that the Doctrine of Double Effect assumes that we think that death is always bad. They say that if continued life holds nothing for the patient but the negative things of pain and suffering, then death is a good thing, and we don’t need to use the doctrine of double effect.

4. Double effect can produce an unexpected moral result: If you do think that a quicker death is better than a slower one then the Doctrine of Double Effect shows that a doctor who intended to kill the patient is morally superior to a doctor who merely intended to relieve pain.

The Sulmasy test

Daniel P. Sulmasy has put forward a way for a doctor to check what their intention really is. The doctor should ask himself, “If the patient were not to die after my actions, would I feel that I had failed to accomplish what I had set out to do?”

source: bbc.co.uk