The doctrine (or principle) of double effect is often invoked toexplain the permissibility of an action that causes a serious harm,such as the death of a human being, as a side effect of promoting somegood end. According to the principle of double effect, sometimes it ispermissible to cause a harm as a side effect (or “doubleeffect”) of bringing about a good result even though it wouldnot be permissible to cause such a harm as a means to bringing aboutthe same good end.

• 1. Formulations of the principle of double effect
• 2. Applications
• 3. Misinterpretations
• 4. Criticisms
• 5. One principle or many loosely related exceptions?
• 6. End of Life Decision-making
• Bibliography
• Academic Tools
• Other Internet Resources
• Related Entries

1. Formulations of the principle of double effect

Thomas Aquinas is credited with introducing the principle of doubleeffect in his discussion of the permissibility of self-defense in theSumma Theologica (II-II, Qu. 64, Art.7). Killing one’sassailant is justified, he argues, provided one does not intend tokill him. In contrast, Augustine had earlier maintained that killingin self-defense was not permissible, arguing that “privateself-defense can only proceed from some degree of inordinateself-love.” Aquinas observes that “Nothing hinders one actfrom having two effects, only one of which is intended, while theother is beside the intention. … Accordingly, the act ofself-defense may have two effects: one, the saving of one’slife; the other, the slaying of the aggressor.” AsAquinas’s discussion continues, a justification is provided thatrests on characterizing the defensive action as a means to a goal thatis justified: “Therefore, this act, since one’s intentionis to save one’s own life, is not unlawful, seeing that it isnatural to everything to keep itself in being as far aspossible.” However, Aquinas observes, the permissibility ofself-defense is not unconditional: “And yet, though proceedingfrom a good intention, an act may be rendered unlawful if it be out ofproportion to the end. Wherefore, if a man in self-defense uses morethan necessary violence, it will be unlawful, whereas, if he repelforce with moderation, his defense will be lawful.”

The passage can be interpreted as formulating a prohibition onapportioning one’s efforts with killing as the goal guidingone’s actions, which would lead one to act with greaterviciousness than pursuing the goal of self-defense would require.

Later versions of the double effect principle all emphasize thedistinction between causing a morally grave harm as a side effect ofpursuing a good end and causing a morally grave harm as a means ofpursuing a good end. We can summarize this by noting that for certaincategories of morally grave actions, for example, causing the death ofa human being, the principle of double effect combines a specialpermission for incidentally causing death for the sake of a good end(when it occurs as a side effect of one’s pursuit of that end)with a general prohibition on instrumentally causing death for thesake of a good end (when it occurs as part of one’s means topursue that end). The prohibition is absolute in traditional Catholicapplications of the principle. Two traditional formulations appearbelow.

The New Catholic Encyclopedia provides four conditions forthe application of the principle of double effect:

1. The act itself must be morally good or at least indifferent.
2. The agent may not positively will the bad effect but may permitit. If he could attain the good effect without the bad effect heshould do so. The bad effect is sometimes said to be indirectlyvoluntary.
3. The good effect must flow from the action at least as immediately(in the order of causality, though not necessarily in the order oftime) as the bad effect. In other words the good effect must beproduced directly by the action, not by the bad effect. Otherwise theagent would be using a bad means to a good end, which is neverallowed.
4. The good effect must be sufficiently desirable to compensate forthe allowing of the bad effect“ (p. 1021).

The conditions provided by Joseph Mangan include the explicitrequirement that the bad effect not be intended:

A person may licitly perform an action that he foresees will produce agood effect and a bad effect provided that four conditions areverified at one and the same time:

1. that the action in itself from its very object be good or at leastindifferent;
2. that the good effect and not the evil effect be intended;
3. that the good effect be not produced by means of the evileffect;
4. that there be a proportionately grave reason for permitting theevil effect” (1949, p. 43).

In both of these accounts, the fourth condition, the proportionalitycondition is usually understood to involve determining if the extentof the harm is adequately offset by the magnitude of the proposedbenefit.

It is reasonable to assume that agents who regret causing harm will bedisposed to avoid causing the harm or to minimize how much of it theycause. This assumption could be made explicit as an additionalcondition on permissibly causing unintended harm:

1. 5. that agents strive to minimize the foreseen harm.

Michael Walzer (1977) has convincingly argued that agents who causeharm as a foreseen side effect of promoting a good end must be willingto accept additional risk or to forego some benefit in order tominimize how much harm they cause. Whether this kind of condition issatisfied may depend on the agent’s current circumstances andthe options that exist.

Double effect might also be part of a secular and non-absolutist viewaccording to which a justification adequate for causing a certain harmas a side effect might not be adequate for causing that harm as ameans to the same good end under the same circumstances. Warren Quinnprovides such an account while also recasting double effect as adistinction between direct and indirect agency. On his view, doubleeffect “distinguishes between agency in which harm comes to somevictims, at least in part, from the agent’s deliberatelyinvolving them in something in order to further his purpose preciselyby way of their being so involved (agency in which they figure asintentional objects), and harmful agency in which either nothing is inthat way intended for the victims or what is so intended does notcontribute to their harm” (1989, p. 343). Quinn explains that“direct agency requires neither that harm itself be useful northat what is useful be causally connected in some especially close waywith the harm it helps bring about” (1989, p. 344). He remarksthat “some cases of harming that the doctrine intuitively speaksagainst are arguably not cases of intentional harming, preciselybecause neither the harm itself (nor anything itself causally veryclose to it) is intended” (1991, p. 511). On this view, thedistinction between direct and indirect harmful agency is whatunderlies the moral significance of the distinction between intendedand merely foreseen harms, but it need not align perfectly withit.

2. Applications

Many morally reflective people have been persuaded that somethingalong the lines of double effect must be correct. No doubt this isbecause at least some of the examples cited as illustrations of DEhave considerable intuitive appeal:

1. The terror bomber aims to bring about civilian deaths in order toweaken the resolve of the enemy: when his bombs kill civilians this isa consequence that he intends. The tactical bomber aims at militarytargets while foreseeing that bombing such targets will cause civiliandeaths. When his bombs kill civilians this is a foreseen butunintended consequence of his actions. Even if it is equally certainthat the two bombers will cause the same number of civilian deaths,terror bombing is impermissible while tactical bombing ispermissible.
2. A doctor who intends to hasten the death of a terminally illpatient by injecting a large dose of morphine would act impermissiblybecause he intends to bring about the patient’s death. However,a doctor who intended to relieve the patient’s pain with thatsame dose and merely foresaw the hastening of the patient’sdeath would act permissibly. (The mistaken assumption that the use ofopioid drugs for pain relief tends to hasten death is discussed belowin section 6.)
3. A doctor who believed that abortion was wrong, even in order tosave the mother’s life, might nevertheless consistently believethat it would be permissible to perform a hysterectomy on a pregnantwoman with cancer. In carrying out the hysterectomy, the doctor wouldaim to save the woman’s life while merely foreseeing the deathof the fetus. Performing an abortion, by contrast, would involveintending to kill the fetus as a means to saving the mother.
4. To kill a person whom you know to be plotting to kill you would beimpermissible because it would be a case of intentional killing;however, to strike in self-defense against an aggressor ispermissible, even if one foresees that the blow by which one defendsoneself will be fatal.
5. It would be wrong to throw someone into the path of a runawaytrolley in order to stop it and keep it from hitting five people onthe track ahead; that would involve intending harm to the one as ameans of saving the five. But it would be permissible to divert arunaway trolley onto a track holding one and away from a track holdingfive: in that case one foresees the death of the one as a side effectof saving the five but one does not intend it.
6. Sacrificing one’s own life in order to save the lives ofothers can be distinguished from suicide by characterizing theagent’s intention: a soldier who throws himself on a livegrenade intends to shield others from its blast and merely foreseeshis own death; by contrast, a person who commits suicide intends tobring his or her own life to an end.

3. Misinterpretations

Does the principle of double effect play the important explanatoryrole that has been claimed for it? To consider this question, one mustbe careful to clarify just what the principle is supposed to explain.Three misinterpretations of the principle’s force or range ofapplication are common.

First, it is a misinterpretation to claim that the principle of doubleeffect shows that agents may permissibly bring about harmful effectsprovided that they are merely foreseen side effects of promoting agood end. Applications of double effect always presuppose that somekind of proportionality condition has been satisfied. Traditionalformulations of the proportionality condition require that the valueof promoting the good end outweigh the disvalue of the harmful sideeffect.

For example, a physician’s justification for administering drugsto relieve a patient’s pain while foreseeing the hastening ofdeath as a side effect does not depend only on the fact that thephysician does not intend to hasten death. After all, physicians arenot permitted to relieve the pain of kidney stones or childbirth withpotentially lethal doses of opiates simply because they foresee but donot intend the causing of death as a side effect! A variety ofsubstantive medical and ethical judgments provide the justificatorycontext: the patient is terminally ill, there is an urgent need torelieve pain and suffering, death is imminent, and the patient or thepatient’s proxy consents. Note that this last constraint, theconsent of the patient or the patient’s proxy, is not naturallyclassified as a concern with proportionality, understood as theweighing of harms and benefits.

We have added a fifth condition on causing unintended harm: that theagent seek to minimize the harm involved. This ensures that DoubleEffect is not misunderstood as principle issuing a blanket permissionon causing any unintended harm that yields a benefit. Whether thisfifth condition is satisfied will depend on the agent’scircumstances and the options that exist. For example, as techniquesfor managing pain, for titrating the doses of pain-relievingmedication, and for delivering analgesic medication have been refined,what might in the past have been an adequate justification forhastening death in the course of pain relief would now fail becausecurrent techniques provide the better alternative of managing painwithout the risk of hastening death. (See section 6 for a fulldiscussion of this application of double effect.)

A second misinterpretation is fostered by applications of doubleeffect that contrast the permissibility of causing a harm as a merelyforeseen side effect of pursuing a good end with the impermissibilityof aiming at the same kind of harm as one’s end. Since it iswidely accepted that it is wrong to aim to produce harm to someone asan end, to rule this out is not part of double effect’sdistinctive content. The principle presupposes that agents do not aimto cause morally grave harms as an end and seeks to guide decisionsabout causing harm while pursuing a morally good end. For example,double effect contrasts those who would (allegedly permissibly)provide medication to terminally ill patients in order to alleviatesuffering with the side effect of hastening death with those who would(allegedly impermissibly) provide medication to terminally illpatients in order to hasten death in order to alleviate suffering. Inthe allegedly impermissible case, the physician’s ultimate endis a good one — to alleviate suffering — not to causedeath.

The principle of double effect is directed at well-intentioned agentswho ask whether they may cause a serious harm in order to bring abouta good end of overriding moral importance when it is impossible tobring about the good end without the harm. A third commonmisinterpretation of double effect is to assume that the principleassures agents that they may do this provided that their ultimate aimis a good one that is ordinarily worth pursuing, the proportionalitycondition is satisfied and the harm is not only regretted butminimized. That is not sufficient: it must also be true that causingthe harm is not so implicated as part of an agent’s means tothis good end that it must count as something that is instrumentallyintended to bring about the good end. Some discussions of doubleeffect wrongly assume that it permits acts that cause certain kinds ofharm because those harms were not the agent’s ultimate aim orwere regretted rather than welcomed. The principle of double effect ismuch more specific than that. Harms that were produced regretfully andonly for the sake of producing a good end may be prohibited by doubleeffect because they were brought about as part of the agent’smeans to realizing the good end.

4. Criticisms

Those who defend the principle of double effect often assume thattheir opponents deny that an agent’s intentions, motives, andattitudes are important factors in determining the permissibility of acourse of action. If the permissibility of an action depended only onthe consequences of the action, or only on the foreseen or foreseeableconsequences of the action, then the distinction that grounds theprinciple of double effect would not have the moral significanceclaimed for it (see the related entry onconsequentialism). Some opponents of the principle of double effect do indeed deny thatthe distinction between intended and merely foreseen consequences hasany moral significance.

Nevertheless, many criticisms of the principle of double effect do notproceed from consequentialist assumptions or skepticism about thedistinction between intended and merely foreseen consequences. Insteadthey ask whether the principle adequately codifies the moralintuitions at play in the cases that have been taken to beillustrations of it. One important line of criticism has focused onthe difficulty of distinguishing between grave harms that areregretfully intended as part of the agent’s means and graveharms that are regretfully foreseen as side effects of theagent’s means. Since double effect implies that the latter maybe permissible even when the former are not, those who wish to applydouble effect must provide principled grounds for drawing thisdistinction. The application of Double Effect to explain thepermissibility of performing a hysterectomy on a pregnant woman andthe impermissibility of performing an abortion to save a woman’slife is often singled out for criticism on this score. Lawrence Masek(2010) offers a thoughtful defense of the principle of double effectthat proposes to construe what is intended by an agent as narrowly orstrictly as possible while also distinguishing between motivating sideeffects and non-motivating side effects.

In contrast, Warren Quinn’s proposal to substitute the conceptof direct agency for the concept of intending to cause harm to someoneas a means (see Section 1) would effectively broaden the category ofresults that count as cases of causing intended harm. If the soldierwho throws himself on the grenade in order to shield his fellowsoldiers from the force of an explosion acts permissibly, and if thepermissibility of his action is explained by Double Effect, then hemust not intend to sacrifice his own life in order to save the others,he must merely foresee that his life will end as a side effect of hisaction. But many have argued that this is an implausible descriptionof the soldier’s action and that his action is permissible evenif he does intend to let himself be blown up by the grenade as a meansof protecting the others from the explosion. Shelly Kagan (1999)points out that if someone else were to shove the soldier on thegrenade we would certainly say that that the harm to the soldier wasintended by the person who did the shoving. Equally, Kagan argues, weshould say that it is intended in this case (p. 145). The same kind ofargument can be made for cases of killing in self-defense whenoverwhelming and lethal force is used. If these arguments are correct,then they cast doubt on the claim that Double Effect explains thepermissibility of these actions. Double Effect is silent about casesin which it is permissible to cause a death as a means to a goodend.

Warren Quinn has argued that double effect does not rest on thedistinction between intended and merely foreseen harm, but instead isbest formulated using a distinction between direct and indirect agency(see theFormulations section). Quinn’s view would imply that typical cases ofself-defense and self-sacrifice would count as cases of direct agency.One clearly intends to involve the aggressor or oneself in somethingthat furthers one’s purpose precisely by way of his being soinvolved. Therefore, Quinn’s account of the moral significanceof the distinction between direct and indirect agency could not beinvoked to explain why it might be permissible to kill in self-defenseor to sacrifice one’s own life to save the lives of others. Butperhaps this is as it should be: double effect might be easier toexplain and justify if the range of cases to which it applies islimited in this way. If Quinn’s view is correct, and if thedistinction between direct and indirect agency can be drawn clearly,then perhaps the objections outlined above can be answered.

If we are more inclined to call a harmful result a merely foreseenside effect when we believe that it is permissibly brought about, andif we are more inclined to describe a harmful result something thatwas intended as part of the agent’s means when we believe thatit is impermissibly brought about, then there will be an associationbetween permissible harms that are classified as side effects andimpermissibly caused harms that are classified as results broughtabout intentionally, as part of the agent’s means, but thisassociation cannot be explained by the principle of double effect.Instead, independently grounded moral considerations have influencedhow we draw the distinction between means and side effects in thefirst place. Empirical research by Joshua Knobe (2003, 2006) hasdemonstrated that the ways in which we distinguish between resultsthat are intended or brought about intentionally and those that aremere side effects may be influenced by normative judgments in such away as to bias our descriptions. This was first pointed out by GilbertHarman (1976), but is now often referred to as “The KnobeEffect” or “The Side Effect Effect”. Richard Holton(2010) has observed that norm violation merely involves knowinglyviolating a norm, while complying with a norm involves an intention tocomply with it, and that this might explain the asymmetry Knobe hasdocumented in judgments about whether bad and good results are broughtabout intentionally. This discussion raises questions about thesuitability of the distinction highlighted by the principle of doubleeffect for serving as an evaluatively neutral basis for moraljudgments.

Does the principle of double effect explain the permissibility ofswitching a runaway trolley away from a track with five people on itand onto a track containing only one person? This is an allegedapplication of Double Effect in which it seems clear to many peoplethat if one were to switch the trolley, the harm to the one personwould not be intended as part of one’s means of diverting thetrolley from the five. Of course, if the harm to the one is rightlydescribed as a merely foreseen side effect of switching the trolley,then this alone does not show that it is permissible to cause it.However, if the proportionality condition is satisfied, and if theagent attempts to minimize the harm or to identify alternative meansof saving the five and fails, then these factors together might seemto imply that the principle of double effect can be invoked to explainthe permissibility of switching the trolley. Moreover, Double Effectseems to explain the impermissibility of pushing someone onto thetrack in front of the speeding trolley in order to stop it and protectthe five on the track ahead. In both scenarios, a person would bekilled as part of saving the five; the difference in permissibilityseems to depend on whether the death of that person is a means or aside effect of saving them.

Discussions of the Trolley Problem and the relevance of the principleof double effect to explaining our intuitions about it can be dividedinto three groups. First, there are consequentialists who view thewidespread reluctance people feel to push someone in the path of thetrolley in order to stop it and save the five as irrational (JoshuaGreene, 2013). Second, there are those who take the paired intuitionsin the Trolley Problem as proof of the fundamental role of DoubleEffect as an implicit principle guiding moral judgment (Philippa Foot,1985), John Mikhail, 2011). Third, some argue that it would be wrongfor a bystander to switch the trolley (Judith Jarvis Thomson, 2008)and suggest that people’s willingness to view it as permissibleis a result of inadequate reflection or insufficient emotionalengagement. This group would include those who uphold the principle ofdouble effect but deny that it provides a permission to swerve thetrolley (Elizabeth Anscombe, 1982) and those who reject the principleof double effect while conceding that the standard intuitive judgmentsabout the Trolley Problem comport with the principle as it ordinarilyinterpreted.

The contrast between the Terror Bomber and the Strategic Bomber isoften viewed as the least controversial pair of examples illustratingthe distinction between intention and foresight that underlies theprinciple of double effect. The judgment that the Terror Bomber actsimpermissibly and the Strategic Bomber acts permissibly is widelyaffirmed. Terror bombing was engaged in by both sides in World War II(see Douglas Lackey (1989) for a thoughtful historical account of thedecision process engaged in by Allied decision-makers and thecontroversy it generated at the time). The view that terror bombing isalways impermissible would condemn the kind of incendiary bombingcarried out by Allied forces in Germany and Japan.

The common judgment that strategic bombing is permissible providedthat it is proportionate also deserves more scrutiny than it usuallyreceives when it is taken to be justified by the principle of doubleeffect. How much of an obligation do military strategists have toavoid harm to civilian populations? This is a substantive issue aboutthe conventions that constrain military decision-making and theprinciples that underlie these conventions. Many relevantconsiderations depend on judgments that are far outside the ambit ofDouble Effect. For example, theRules of Customary InternationalHumanitarian Law displayed on the website of the InternationalCommittee of the Red Cross prohibit attacks targeting civilians. Theyalso include protections denied to minimize harm to civilians:

Rule 15. Precautions in Attack In the conduct of military operations,constant care must be taken to spare the civilian population,civilians and civilian objects. All feasible precautions must be takento avoid, and in any event to minimize, incidental loss of civilianlife, injury to civilians and damage to civilian objects.

Rule 20. Advance Warning Each party to the conflict must giveeffective advance warning of attacks which may affect the civilianpopulation, unless circumstances do not permit.

Rule 24. Removal of Civilians and Civilian Objects from the Vicinityof Military Objectives Each party to the conflict must, to the extentfeasible, remove civilian persons and objects under its control fromthe vicinity of military objectives.

These considerations suggest that the principle of double effect doesnot contain, even when the principle of proportionality is included aspart of its content, a sufficient condition of permissibility forbombardment that affects civilian populations. The example concerningstrategic bombing so frequently invoked by philosophers never mentionsa duty to warn or remove civilians.

5. One principle or many loosely related exceptions?

It is not at all clear that all of the examples that double effect hasbeen invoked to justify can be explained by a single principle. Theremay in fact be a variety of considerations that bear on thepermissibility of causing unintended harm.

Proponents of the principle of double effect have always acknowledgedthat a proportionality condition must be satisfied when double effectis applied, but this condition typically requires only that the goodeffect outweigh the foreseen bad effect or that there be sufficientreason for causing the bad effect. Some critics of the principle ofdouble effect have maintained that when double effect has beeninvoked, substantive independent justifications for causing the kindof harm in question are implicitly relied upon, and are in fact, doingall of the justificatory work. These independent considerations arenot derived from the distinction between intended and merely foreseenconsequences and do not depend on it (Davis (1984), McIntyre (2001)).If this criticism is correct, then perhaps the cases that havetraditionally been cited as applications of the principle of doubleeffect are united only by the fact that each is an exception to thegeneral prohibition on causing the death of a human being.

The historical origins of the principle of double effect as a tenet ofCatholic casuistry might provide a similar explanation for the unityof its applications. If one were to assume that it is absolutelyprohibited to cause the death of a human being, then it would not bepermissible to kill an aggressor in self-defense, to sacrificeone’s life to protect others, to hasten death as a side effectof administering sedation for intractable pain, or to endangernon-combatants in warfare. If one were to assume instead that what isabsolutely prohibited is to cause the death of a human beingintentionally, then these cases can be viewed as cases ofnon-intentional killing. Controversy about the principle of doubleeffect concerns whether a unified justification for these cases ofnon-intentional killing can be provided and if so, whether thatjustification depends on the distinction between intended and merelyforeseen consequences.

In an essay that develops Warren Quinn’s view that Double Effectis best understood as resting on a distinction between direct andindirect agency, Dana Nelkin and Samuel Rickless (2014) formulate theprinciple in this way: “In cases in which harm must come to somein order to achieve a good (and is the least costly of possible harmsnecessary), the agent foresees the harm, and all other things areequal, a stronger case is needed to justify harmful direct agency thanto justify equally harmful indirect agency” (2014). In harmfulindirect agency, harm comes to some victims in order to achieve agood, but “nothing in that way is intended for the victims, orwhat is so intended does not contribute to their harm.” Inharmful direct agency “harm comes to some victims, at least inpart, from the agent’s deliberately involving them in somethingin order to further his purpose precisely by way of their being soinvolved” (Nelkin and Rickless (2014), quoting Quinn(1989)).

This way of characterizing harmful direct agency and harmful indirectagency could be thought of as two possible dimensions of agency inwhich harm is not intended, rather than as a contrast within a singledimension of agency. This view would be supported if it turns out thatsome complex plans of action count as both harmful direct agency andharmful indirect agency. For example, consider the deliberations ofpublic health officials who propose to put in place a vaccinationprogram in their region in order to protect citizens from a rapidlyspreading, highly contagious, and invariably lethal disease. Theyforesee that if the program is carried out, about one in ten thousandvaccine recipients will experience adverse effects from the vaccinethat will prove fatal, and the officials have no way to identify inadvance which vaccine recipients will be susceptible to these adverseeffects in order to screen them and exclude them from receiving thevaccine. It might seem that Double Effect is designed to explain whythey may proceed with the vaccination program despite theseforeseeable, regretted, and unpreventable unintended side effects ofpromoting a good end: this might seem to be a case of indirect agency.And yet, if the officials’ desire to bring about herd immunityleads them to advocate a widespread program with incentives forparticipation or even mandatory participation, then it will be truethat harm comes to some victims that they have deliberately involved.This would make their actions in promoting the program a case ofdirect agency. Issues about consent may be relevant here as well: ifthe vaccine recipients willingly assume the risk of experiencingadverse effects, then a full description of the program must considertheir own agency in assessing the information they receive. Exampleslike these suggest that the cases Double Effect has been taken toapply to may involve many different dimensions of agency rather than asharp contrast that concerns a single dimension of agency.

Critics of the principle of double effect claim that the pattern ofjustification used in these cases has some shared conditions: theagent acts in order to promote a good end, shows adequate respect forthe value of human life in so acting, and has attempted to avoid orminimize the harm in question. However, they maintain that thejustification for causing the harm in question depends on furthersubstantive considerations that are not derived from the contrastbetween intention and foresight or the contrast between direct andindirect agency.

Some have developed this kind of criticism by arguing that the appealof the principle of double effect is, fundamentally, illusory: anagent’s intentions are not relevant to the permissibility of anaction in the way that the proponents of the principle of doubleeffect would claim, though an agent’s intentions are relevant tomoral assessments of the way in which the agent deliberated (see DavidMcCarthy (2002) and T.M. Scanlon (2008). That an agent intended tobring about a certain harm does not explain why the action wasimpermissible, but it can explain what is morally faulty about theagent’s reasoning in pursuing that line of action.

6. End of Life Decision-Making

The principle of double effect is often mentioned in discussions ofwhat is known as palliative care, medical care for patients withterminal illness in need of pain relief. Three assumptions oftenoperate in the background of these discussions:

1. The side effect of hastening death is an inevitable or at leastlikely result of the administration of opioid drugs in order torelieve pain.
2. The hastening of death is a not unwelcome side effect ofproviding pain relief in the context of palliative care.
3. It would be impermissible to hasten death intentionally in orderto cut short the suffering of a terminally ill patient.

When these assumptions are made, double effect seems to provide atleast part of a justification for administering drugs to relieve pain.

Yet the first assumption is false. Physicians and researchers haveinsisted repeatedly that it is a myth that opioids administered forpain relief can be expected to hasten death (Sykes and Thorns, 2003provide a review of a large number of studies supporting this claim).There is no research that substantiates the claim that opioid drugsadministered appropriately and carefully titrated are likely todepress respiration. In a survey of research bearing on this issue,Susan Anderson Fohr (1998) concludes: “It is important toemphasize that there is no debate among specialists in palliative careand pain control on this issue. There is a broad consensus that whenused appropriately, respiratory depression from opioid analgesics is ararely occurring side effect. The belief that palliative care hastensdeath is counter to the experience of physicians with the mostexperience in this area.” The mistaken belief that pain reliefwill have the side effect of hastening death may have the unfortunateeffect of leading physicians, patients, and the patients’families to under-treat pain because they are apprehensive aboutcausing this alleged side effect.

The appropriate conclusion, then, is that double effect plays no rolewhatsoever in justifying the use of opioid drugs for pain relief inthe context of palliative care. Why is double effect so frequentlymentioned in discussions of pain relief in the context of palliativecare if its application rests on (and thereby perpetuates) a medicalmyth? The popularity and intuitive appeal of this alleged illustrationof double effect may have two sources. First, the point of mentioningthe permissible hastening of death as a merely foreseen side effectmay be to contrast it with what is deemed morally impermissible:administering drugs that are not pain relievers to a patient with aterminal illness in order to hasten death and thereby cut short thepatient’s suffering. Second, the myth that pain relief hastensdeath might have persisted and perpetuated itself because it expressesthe compassionate thought behind the second assumption: that thehastening of death may be a welcome side effect of administering painrelief to patients at the end of life. This point of view may not beconsistent with invoking Double Effect as a justification: if, in thecourse of treating a dying patient, death is not viewed as a harm,then Double Effect does not apply (see Allmark, Cobb, Liddle, and Todd(2010)).

Furthermore, the apparently compassionate assumption that thehastening of death is a welcome result may be unduly paternalistic inthe context of end of life care in which the patient is not dying.Patients receiving palliative care whose pain can be adequatelytreated with opioid drugs may well value additional days, hours orminutes of life. It is unjustified to assume that the hastening ofdeath is itself a form of merciful relief for patients with terminalillnesses and not a regrettable side effect to be minimized. Recallthat the most plausible formulations of double effect would requireagents to seek to minimize or avoid the merely foreseen harms thatthey cause as side effects. On this point, popular understandings ofdouble effect, with the second assumption in place, may diverge fromthe most defensible version of the principle.

Some members of the U.S. Supreme Court invoked double effect as ajustification for the administration of pain-relieving drugs topatients receiving palliative care and also as a justification for thepractice known as terminal sedation in which sedative drugs areadministered to patients with intractable and untreatable pain inorder to induce unconsciousness (Vacco et al. v. Quill et al., 117S.Ct. 2293 (1997)). If artificial hydration and nutrition are notprovided, sedation undertaken to deal with intractable pain may wellhasten death. (If death is immediately imminent, then the absence ofhydration and nutrition may not affect the time of death.) The mostplausible and defensible version of the principle of double effectrequires that the harmful side effect be minimized, so the principleof double effect provides no justification for withholding hydrationand nutrition in cases in which death is not immediately imminent. Thedecision to withhold hydration and nutrition seems to depend on ajudgment that death would not be a harm to the patient who has beensedated. In circumstances in which it would not be a harm to cause aperson’s death, the principle of double effect does notapply.

Terminal or full sedation is a response to intractable pain inpatients suffering from terminal illness. It involves bringing about aset of conditions (sedation, unconsciousness, the absence of hydrationand nutrition) that together might have the effect of hastening deathif death is not already imminent. In any case, these conditions makedeath inevitable. Two important moral issues arise concerning thispractice. First, is terminal sedation appropriate if it is necessaryto relieve intractable pain in patients diagnosed with a terminalillness, even if death is not imminent? This is what Cellarius (2008)callsearly terminal sedation because it does not satisfy therequirement that death is imminent that is typically cited as acondition of the permissibility of terminal sedation. Early terminalsedation could be expected to hasten death as a side effect ofproviding palliative care for unusually recalcitrant pain. A secondissue concerns the moral significance of the fact that once sedationhas occurred, death is inevitable either because it was imminentalready or because the withholding of nutrition and hydration has madeit inevitable. Would it be permissible to increase the level ofsedation foreseeing that this would hasten the death that is nowinevitable? Traditional applications of the principle of double effectrest on the assumption that the death of an innocent human being maynever be brought about intentionally and would rule against such anaction. Yet the assumptions that inform the popular understanding ofdouble effect — that the physician’s guiding intention isto relieve pain, that the hastening of death would not be unwelcome inthese very specific circumstances, and that this course of actionshould be distinguished from a case of active euthanasia that is notprompted by the duty to relieve pain — might seem to count infavor of it. It may obscure rather than clarify discussion of thesesituations to view the principle of double effect as a clearguideline. In this discussion, as in many others, the principle ofdouble effect may serve more as a framework for announcing moralconstraints on decisions that involve causing death regretfully thanas a way of determining the precise content of those decisions and thejudgments that justify them.

Bibliography

• Allmark, Peter; Cobb, Mark; Liddle, Jane B.; and Tod, Angela M.,2010. “Is the doctrine of double effect irrelevant inend-of-life decision making?”Nursing Philosophy, 11:170–7.
• Anscombe, Elizabeth, 1982. “Medallist’s Address:Action, Intention and ‘Double Effect’”, inProceedings of the American Catholic PhilosophicalAssociation, Volume 56, Washington, D.C.: American CatholicPhilosophical Association, pp. 12–25; reprinted in Woodward(ed.), 50–66.
• Aquinas, Thomas (13^th c).Summa TheologicaII-II, Q. 64, art. 7, “Of Killing”, inOn Law,Morality, and Politics, William P. Baumgarth and Richard J.Regan, S.J. (eds.), Indianapolis/Cambridge: Hackett Publishing Co.,1988, pp. 226–7.
• Augustine (4^th c).De Libero ArbitrioVoluntatis, Charlottesville: University of Virginia, 1947, pp.9–10.
• Bennett, Jonathan, 1966. “Whatever the Consequences,”Analysis, 26: 83–102.
• –––, 1981. “Morality andConsequences,”The Tanner Lectures on Human Values,Vol. 2, Sterling McMurrin (ed.), Salt Lake City: University of UtahPress, especially Lecture III “Intended as a Means”.
• –––, 1995.The Act Itself, New York:Oxford, pp. 194–225; reprinted in Woodward, ed.:85–118.
• Boyle, Joseph, 1991. “Who is entitled to DoubleEffect?,”The Journal of Medicine and Philosophy, 16:475–494.
• Boyle, Jr., Joseph M., 1980. “Toward Understanding thePrinciple of Double Effect,”Ethics, 90: 527–38;reprinted in Woodward (ed.), 7–20.
• Cavanaugh, T.A., 2006.Double-Effect Reasoning: Doing Good andAvoiding Evil, Oxford: Clarendon Press.
• Cellarius, Victor, 2008. “Terminal sedation and theimminence condition,”Journal of MedicalEthics, 34: 69–72.
• Connell, F.J., 1967. “Double Effect, Principle of,”New Catholic Encyclopedia (Volume 4), New York: McGraw-Hill,pp. 1020–2, p. 1021.
• Davis, Nancy, 1984. “The Doctrine of Double Effect: Problemsof Interpretation,”Pacific Philosophical Quarterly,65: 107–23; reprinted in Woodward (ed.), 119–142.
• Delaney, Neil Francis, 2008. “Two Cheers for‘Closeness’: Terror, Targeting and Double Effect,”Philosophical Studies, 137(5): 335–367.
• Duff, Antony, 1982. “Intention, Responsibility and DoubleEffect,”The Philosophical Quarterly, 32 (126):1–16.
• Fitzpatrick, William J., 2009. “Thomson’s Turnabout onthe Trolley,”Analysis, 69(4): 636–643.
• Fohr, Susan A., 1998. “The Double Effect of Pain Medication:Separating Myth from Reality,”Journal of PalliativeMedicine, 1: 315–328.
• Foot, Philippa, 1967. “The Problem of Abortion and theDoctrine of Double Effect,”Oxford Review, 5:5–15; reprinted in Bonnie Steinbock and Alastair Norcross(eds.),Killing and Letting Die, 2nd ed. New York: FordhamUniversity Press, 1994, pp. 266–279; reprinted in Woodward,(ed.), 143–155.
• –––, 1985. “Morality, Action, andOutcome,”Morality and Objectivity: A Tribute to J.L.Mackie, Ted Honderich (ed.), London: Routledge & Kegan Paul),pp. 23–38; reprinted in Woodward (ed.), 67–82.
• Garcia, Jorge, 1995. “Double Effect,” entry inEncyclopedia of Bioethics, revised edition, Warren ThomasReich (ed.), New York: Simon & Schuster Macmillan, pp.636–641
• Greene, Joshua, 2013.Moral Tribes: Emotion, Reason, and theGap between Us and Them, New York: Penguin Press.
• Grisez, Germain G., 1970. “Toward a Consistent Natural-LawEthics of Killing,”The American Journal ofJurisprudence, 15: 64–96
• Harman, Gilbert, 1976. “Practical Reasoning,”TheReview of Metaphysics, 29 (3): 431–463
• Holton, Richard, 2010. “Norms and the Knobe Effect,”Analysis, 70 (3): 417–424
• International Committee of the Red Cross,The Rules ofCustomary International Humanitarian Law,available online.
• Kagan, Shelly, 1999.The Limits of Morality, New York:Oxford University Press, pp. 128–182.
• Kamm, Frances M., 1999. “Physician-Assisted Suicide, theDoctrine of Double Effect, and the Ground of Value,”Ethics, 109: 586–605
• –––, 1991. “The Doctrine of Double Effect:Reflections on Theoretical and Practical Issues,”Journal ofMedicine and Philosophy, 16: 571–585.
• Knobe, Joshua, 2003. “Intentional action and side effects inordinary language,”Analysis, 63: 190–193.
• –––, 2006. “The Concept of IntentionalAction: a Case Study in the Uses of Folk Psychology,”Philosophical Studies, 130: 203–231.
• Lackey, Douglas P., 1989.The Ethics of War and Peace,Englewood Cliffs, NJ: Prentice Hall, pp. 128–182.
• Mangan, Joseph, 1949. “An Historical Analysis of thePrinciple of Double Effect,”Theological Studies, 10:41–61.
• Marquis, Donald B., 1991. “Four Versions of DoubleEffect,”The Journal of Medicine and Philosophy, 16:515–544; reprinted in Woodward (ed.), 156–185.
• Masek, Lawrence, 2010. “Intentions, Motives, and theDoctrine of Double Effect,”The PhilosophicalQuarterly, 60 (24): 567–544; reprinted in Woodward (ed.),156–585.
• McCarthy, David, 2002. “Intending harm, foreseeing harm andfailures of the will,”Noûs, 36(4):622–642.
• McIntyre, Alison, 2001. “Doing Away with DoubleEffect,”Ethics, 111(2): 219–255.
• McMahan, Jeff, 1994. “Revising the Doctrine of DoubleEffect,”Journal of Applied Philosophy, 11(2):201–12.
• Mikhail, John, 2011.Elements of Moral Cognition: Rawls’Linguistic Analogy and the Cognitive Science of Moral and LegalJudgment, Cambridge: Cambridge University Press.
• Nelkin, Dana K. and Rickless, Samuel C., 2014.“Three Cheersfor Double Effect,”Philosophy and PhenomenologicalResearch, 89(1): 125–58.
• Quinn, Warren, 1989. “Actions, Intentions, and Consequences:The Doctrine of Double Effect,”Philosophy and PublicAffairs, 18(4): 334–351; reprinted in Woodward (ed.),23–40.
• –––, 1991. “Reply to Boyle’s Who isEntitled to Double Effect?,”The Journal of Medicine andPhilosophy, 16: 511–514.
• Scanlon, T.M., 2008.Moral Dimensions: Permissibility,Meaning, Blame, Cambridge: Basic Books.
• Steinhof, Uwe, 2007.On the Ethics of War and Terrorism,New York: Oxford University Press.
• Sykes, Nigel and Andrew Thorns, 2003. “The use of opioidsand sedatives at the end of life,”The Lancet Oncology,1: 312–318.
• Thomson, Judith Jarvis, 1985. “The Trolley Problem,”The Yale Law Journal, 94: 1395–1415.
• –––, 2008. “Turning the Trolley,”Philosophy & Public Affairs, 36(4): 201–12.
• Uniacke, Suzanne, 1984. “The Doctrine of DoubleEffect,”The Thomist, 48(2): 188–218.
• Walzer, Michael, 1977.Just and Unjust Wars, New York:Basic Books, pp. 151–9; reprinted in Woodward (ed.),261–269.
• Woodward, P. A. (ed.), 2001.The Doctrine of Double Effect:Philosophers Debate a Controversial Moral Principle, Notre Dame,IN: University of Notre Dame Press.

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Other Internet Resources

• List of References for the Principle of Double Effect [PDF], maintained by Jörg Schroth.
• Whether it is lawful to kill a man in self-defense?, St. Thomas Aquinas,Summa Theologica, Second Part of theSecond Part, Question 64, Article 7.
• Just War Theory, Internet Encyclopedia of Philosophy.
• The Rules of Customary International Humanitarian Law, International Committee of the Red Cross.
• U.S. Supreme Court decisionVacco v. Quill, concerning the challenge to laws prohibiting assisted suicide posedby Quill,et al., Legal Information Institute, Supreme CourtCollection.
• The International Association for Hospice and Palliative Care.

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