There are some interesting similarities between Aristotle's 'mixed actions' in Book III of the Nicomachean Ethics and the actions often thought to be justifiable with the Doctrine of Double Effect. Here I analyse these similarities by comparing Aristotle's examples of mixed actions with standard cases from the literature on double effect such as, amongst others, strategic bombing, the trolley problem, and craniotomy. I find that, despite some common features such as the dilemmatic structure and the inevitability of a bad effect, Aristotle's mixed actions do not count as cases justifiable through application of the Doctrine of Double Effect because they fail to meet the crucial necessary condition of the Doctrine according to which the bad effect can only be a merely foreseen sideeffect and not an intended means.
The Doctrine of Double Effect1 is normally traced back to Aquinas. The attribution of the Doctrine of Double Effect to Aquinas's treatment of self-defence in 1 Here I will just assume previous knowledge of the Doctrine of Double Effect, and restrict my discussion of the actual principle to this footnote with the following representative definitions: -Aquinas, which is often credited with the first explicit version of DDE: "Nothing hinders one act from having two effects, only one of which is intended, while the other is beside the intention" (Summa II-II, 64, 7); -Gury: "It is licit to posit a cause which is either good or indifferent from which there follows a twofold effect, one good, there other evil, if a proportionately grave reason is present, and if the end of the agent is honourable -that is, if he does not intend the evil effect" (Boyle's translation 1980: 528); -Mangan: "A person may licitly perform an action that he foresees will produce a good and a bad effect provided that four conditions are verified at one and the same time: 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" (1949: 43).-McIntyre in the Stanford Encyclopedia of Philosophy: "sometimes it is permissible to bring about as a merely foreseen side effect a harmful event that it would be impermissible to bring about intentionally"
