Explain the principle of double effect and its use in Aquinas’ Natural Law Ethics.
• The law/rule/principle/doctrine of double effect examines the effect of an action which follows the principles of Natural Law yet causes an effect which would generally be avoided: e.g. saving the life of a pregnant woman where the effect entails the death of the foetus. Aquinas discussed it in connection with selfdefence against a homicidal maniac.
• The principle is sometimes expressed by saying that so long as one follows the principles of Natural Law, one can ‘benefit’ from any unintended consequences.
• A common modern example is that strategic bombing that harms civilians with foresight but without intent is an accepted effect of destroying a legitimate military target. Conversely, intentionally bombing civilians to secure victory in war, however good that victory might be, is not legitimate.
• Four conditions have to be met in order for an act to be morally permissible: the action itself must be morally good (or at least indifferent); the good effect must not be achieved by pursuing the bad effect; the bad effect must be no more than an unintended side-effect; the good effect…