## 1. Formulations of the principle of double effect



Thomas Aquinas is credited with introducing the principle of double
effect in his discussion of the permissibility of self-defense in the
*Summa Theologica* (II-II, Qu. 64, Art.7). Killing one's
assailant is justified, he argues, provided one does not intend to
kill him. In contrast, Augustine had earlier maintained that killing
in self-defense was not permissible, arguing that "private
self-defense can only proceed from some degree of inordinate
self-love." Aquinas observes that "Nothing hinders one act
from having two effects, only one of which is intended, while the
other is beside the intention. ... Accordingly, the act of
self-defense may have two effects: one, the saving of one's
life; the other, the slaying of the aggressor." As
Aquinas's discussion continues, a justification is provided that
rests on characterizing the defensive action as a means to a goal that
is justified: "Therefore, this act, since one's intention
is to save one's own life, is not unlawful, seeing that it is
natural to everything to keep itself in being as far as
possible." However, Aquinas observes, the permissibility of
self-defense is not unconditional: "And yet, though proceeding
from a good intention, an act may be rendered unlawful if it be out of
proportion to the end. Wherefore, if a man in self-defense uses more
than necessary violence, it will be unlawful, whereas, if he repel
force with moderation, his defense will be lawful."



The passage can be interpreted as formulating a prohibition on
apportioning one's efforts with killing as the goal guiding
one's actions, which would lead one to act with greater
viciousness than pursuing the goal of self-defense would require.



Later versions of the double effect principle all emphasize the
distinction between causing a morally grave harm as a side effect of
pursuing a good end and causing a morally grave harm as a means of
pursuing a good end. We can summarize this by noting that for certain
categories of morally grave actions, for example, causing the death of
a human being, the principle of double effect combines the claim that
it can be morally permissible to cause a death incidentally as a side
effect of pursuing a good end with a general prohibition on causing
the death of an innocent human being for the sake of a good end. The
prohibition is absolute in traditional Catholic applications of the
principle. Two traditional formulations appear below.



*The New Catholic Encyclopedia* provides four conditions for
the 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 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.
3. 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.
4. The good effect must be sufficiently desirable to compensate for
the allowing of the bad effect (see Connell, 1021).



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



> 
> 
> A person may licitly perform an action that he foresees will produce a
> good effect 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 (Mangan 1949, p. 43).
> 
> 
> 



In both of these accounts, the fourth condition, the proportionality
condition is usually understood to involve determining if the extent
of the harm is adequately offset by the magnitude of the proposed
benefit.



Peter Cataldo formulates the first condition in a way that focuses on
the "moral object" of the act:



1'.
The moral object of the act must be good or at least not be
intrinsically immoral (Cataldo 2022, 3).


Cataldo also reports that the Catholic moral tradition provides useful
clarification of the fourth "proportionality" condition by
recognizing five different dimensions of assessment: "the degree
of badness of the effect; the degree of dependence of the bad effect
on the act; the proximity of the effect to the bad act; the degree of
certainty that the bad effect will occur; and the degree of obligation
to prevent the bad act" (Cataldo 2022, 9. fn. 12).



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


5. that agents attempt to minimize the foreseen harm and consider
less harmful alternatives.



Michael Walzer (1977) has convincingly argued that agents who cause
harm as a foreseen side effect of promoting a good end must be willing
to accept additional risk or to forego some benefit in order to
minimize how much harm they cause. Whether harm has been minimized
will depend on the agent's current circumstances and the options
available.



Double effect might also be part of a secular and non-absolutist view
according to which a justification adequate for causing a certain harm
as a side effect of pursuing a good end might not be adequate for
causing that harm as a means to the same good end under the same
circumstances.


## 2. Applications



Many morally reflective people have been persuaded that something
along the lines of double effect must be correct. No doubt this is
because at least some of the examples cited as illustrations of DE
have considerable intuitive appeal.



***Terror bomber vs Tactical bomber***: The terror
bomber aims to bring about civilian deaths in order to weaken the
resolve of the enemy: when his bombs kill civilians this is a
consequence that he intends. The tactical bomber aims at military
targets while foreseeing that bombing such targets will cause civilian
deaths. When his bombs kill civilians this is a foreseen but
unintended consequence of his actions. Even if it is equally certain
that the two bombers will cause the same number of civilian deaths,
terror bombing is impermissible while tactical bombing is
permissible.



***Euthanasia vs Pain relief that hastens death*:**A doctor who intends to hasten the death of a terminally ill
patient by injecting a large dose of morphine would act impermissibly
because he intends to bring about the patient's death. However,
a doctor who intended to relieve the patient's pain with that
same dose and merely foresaw the hastening of the patient's
death would act permissibly. (The mistaken assumption that the use of
opioid drugs for pain relief tends to hasten death is discussed below
in section 5.1.)



***Abortion vs Hysterectomy*:** A doctor who
believed that abortion was wrong, even in order to save the
mother's life, might nevertheless consistently believe that it
would be permissible to perform a hysterectomy on a pregnant woman
with cancer. In carrying out the hysterectomy, the doctor would aim to
save the woman's life while merely foreseeing the death of the
fetus. Performing an abortion, by contrast, would involve intending to
kill the fetus as a means to saving the mother.



***Pre-emptive Killing vs Active Self-defense*:**To kill a person whom you know to be plotting to kill you
would be impermissible because it would be a case of intentional
killing; however, to strike in self-defense against an aggressor is
permissible, even if one foresees that the blow by which one defends
oneself will be fatal.



***Suicide vs Heroic Shielding*:** Sacrificing
one's own life in order to save the lives of others can be
distinguished from suicide by characterizing the agent's
intention: a soldier who throws himself on a live grenade intends to
shield others from its blast and merely foresees his own death; by
contrast, a person who commits suicide intends to bring his or her own
life to an end.



***The Trolley Problems, Pushing a Bystander onto a Track to
stop the trolley vs Diverting a Trolley onto a track with one person
away from a track with five:*** You are a bystander
standing near a switch watching a runaway trolley barrel down a track
on which five people who cannot escape are positioned. Pushing another
bystander onto the track to stop the trolley would be wrong, many
believe. However, many believe that it would be permissible to turn a
switch and divert the trolley onto a different track on which one
person who cannot escape is positioned (examples from Thomson, 1985,
based on examples in Foot 1967).


## 3. Misinterpretations



Does the principle of double effect play the important explanatory
role that has been claimed for it? To consider this question, one must
be careful to clarify just what the principle is supposed to explain.
Three misinterpretations of the principle's force or range of
application are common.



First, the Doctrine of Double Effect does not claim that the fact that
a harm was foreseen and not intended by an agent is sufficient to
explain the permissibility of causing it. Applications of double
effect always presuppose that some kind of proportionality condition
has been satisfied and plausible accounts of double effect require
agents to minimize harms brought about as side effects. Classifying
civilian casualties during wartime as merely foreseen but unintended
side effects of pursuing a military objective does not show that the
agents were not morally responsible for these consequences or that
they were permissibly brought about. Quite obviously, a
physician's justification for administering drugs to relieve a
patient's pain while foreseeing the hastening of death as a side
effect does not depend only on the fact that the physician foresees
but does not intend the hastening of death; that explanation could not
justify treating the pain of kidney stones with a lethal dose of
morphine.



A second misinterpretation is fostered by applications of double
effect that contrast the foreseen harms that one permissibly
*allows* to occur with intended harms that one impermissibly
*causes* by acting to promote a good end. The distinction
between causing and allowing can be distinguished from the distinction
between intended and merely foreseen consequences of acting (see
 Doing vs. Allowing Harm).



A third misinterpretation of double effect bases the impermissibility
of causing harm as a means to a good end on the fact that it is
wrongful in itself to intend to cause harm. There are many
circumstances in which agents may cause harms as a means to a good end
and in such cases, producing a harm as a means to a good end is
compatible with having an appropriate attitude toward the harm.
Surgeons may amputate limbs to save lives while regretting the damage,
the disfigurement, and the disability that their actions will cause. A
dentist may apologetically probe while instructing her patient
"tell me where it hurts". This is why plausible accounts
of double effect insist on the importance of the proportionality
condition and the requirement to minimize harm and to seek less
harmful alternatives: it is directed at agents who aim at good ends
and seek guidance about what they may do to promote them.


## 4. Criticisms


### 4.1 Consequentialist Objections



Those who defend the principle of double effect often assume that
their opponents deny that an agent's intentions, motives, and
attitudes are important factors in determining the permissibility of a
course of action. If the permissibility of an action depended only on
the consequences of the action, or only on the foreseen or foreseeable
consequences of the action, then the distinction that grounds the
principle of double effect would not have the moral significance
claimed for it (see the related entry on
 consequentialism).
 Some opponents of the principle of double effect do indeed deny that
the distinction between intended and merely foreseen consequences ever
has any kind of moral significance.



Nevertheless, many criticisms of the principle of double effect do not
proceed from consequentialist assumptions or skepticism about the
importance and moral significance of distinguishing between what an
agent intends and what an agent merely foresees. Instead, critics ask
whether the principle adequately codifies the moral intuitions at play
in the cases that have been taken to be illustrations of it.


### 4.2 The Problem of Closeness



One important line of criticism is known as the "problem of
closeness": it is difficult to distinguish between grave harms
that are regretfully foreseen as side effects of the agent's
means and grave harms that are so close to the agent's means
that it seems that they must be (regretfully) intended as part of the
agent's means. In the *Abortion vs Hysterectomy* example,
it is hard to see why the death of the fetus would not be a
regretfully foreseen side effect of saving the mother's life in
both cases (Boyle 1991). Or, alternatively, it is hard to see why the
death of the fetus would not be regretfully intended as part of the
physician's means of saving the mother's life in both
cases (Davis 1984, 110). Those who wish to apply double effect to this
example must provide principled grounds for distinguishing between the
cases in this way; no clear resolution of this problem has emerged (a
summary of proposals is discussed by Dana Nelkin and Samuel Rickless
2015).


### 4.3 The Side Effect Effect



Are we more inclined to call a harmful result a merely foreseen side
effect when we believe that it is permissibly brought about, while
also being more inclined to describe a harmful result as something
that was intended as part of the agent's means when we believe
that it is impermissibly brought about? If so, there will be an
association between permissible harms that are classified as side
effects and impermissibly caused harms that are classified as results
brought about intentionally, but this association cannot be explained
by the principle of double effect. Research by Joshua Knobe (2003,
2006) has demonstrated that the ways in which we distinguish between
results that are intended or brought about intentionally and those
that are mere side effects may be influenced by normative judgments in
such a way as to bias our descriptions: we are more likely to say a
result was brought about intentionally when we disapprove of it. This
was first pointed out by Gilbert Harman (1976), but is now often
referred to as "The Knobe Effect" or "The Side
Effect Effect". Suppose that an agent decided to swerve a
runaway trolley away from a track with a rare wildflower on it and
onto a track with one track workman on it. Would you say that the
agent intended to cause the track workman's death in order to
spare the wildflower? If you would also say that the bystander who
switches the trolley away from the track with five track workmen on it
and onto a track with one track workman on it foresees the death of
the one as a side effect of saving the five, but does not intend it,
then your judgments exemplify the Side Effect Effect. If you believe
that it is permissible to swerve the trolley onto the one to save five
but not permissible to swerve the trolley onto the one to save the
wildflower, then this moral judgment influences whether the death of
the one is intended or a merely foreseen side effect. Does the
distinction between intended and merely foreseen consequences of
action relied upon by the principle of double effect fail to serve as
an evaluatively neutral basis for moral judgments? If so, it might
guide and explain how actions are described without being a reliable
guide to evaluating actions.


### 4.4 Direct and Indirect Agency



Warren Quinn has proposed that what is valuable and correct about
applications of double effect could be formulated as involving a
distinction between direct and indirect agency. On his view, double
effect "distinguishes between agency in which harm comes to some
victims, at least in part, from the agent's deliberately
involving them in something in order to further his purpose precisely
by way of their being so involved (agency in which they figure as
intentional objects), and harmful agency in which either nothing is in
that way intended for the victims or what is so intended does not
contribute to their harm" (1989, p. 343; see also Nelkin and
Rickless, 2014). Quinn explains that "direct agency requires
neither that harm itself be useful nor that what is useful be causally
connected in some especially close way with the harm it helps bring
about" (1989, p. 344). He acknowledges that "some cases of
harming that the doctrine intuitively speaks against are arguably not
cases of intentional harming, precisely because neither the harm
itself (nor anything itself causally very close to it) is
intended" (1991, p. 511).



Quinn's reformulation of double effect is not absolutist in
character. He observes that a result brought about through direct
agency might not be impermissible; instead it would require more
offsetting benefit than the same result brought about through indirect
agency in similar circumstances.



Quinn's proposal would effectively broaden the category of
results that count as the more problematic form of direct agency in
causing harm. As a result, if we believe that some forms of direct
agency that involve causing death are permissible, we will have to
seek some other explanation than double effect's claim that the
harms are indirect or merely foreseen. The soldier who throws himself
on the grenade in order to shield his fellow soldiers from the force
of an explosion has directly involved himself in the protective
action. Shelly Kagan (1999, 145) points out that if someone else were
to shove the soldier on the grenade we would certainly say that that
the harm to the soldier was intended by the person who did the
shoving, even if the shoving was intended to promote the goal of
saving the lives of others. Equally, we should say that it is intended
in this case - not as a goal or as an end pursued for its own
sake but as a means to an end. The same kind of argument can be made
for cases of killing in self-defense when overwhelming and lethal
force is used. If these are cases of permissible direct agency, and if
Quinn is right that the distinction between direct and indirect agency
explains the intuitive appeal of double effect's contrast
between intended means and foreseen side effects, then these cases
cast doubt on the claim that double effect explains why the
life-saving actions in the Hysterectomy, Heroic Shielding and
Self-defense examples are permissible.


### 4.5 Does double effect provide an adequate explanation of the trolley cases?



It seems clear to many people that if one were to switch the trolley
from a track with five people to a track with only one, the harm to
the one person would not be intended as part of one's means of
diverting the trolley from the five to save their lives and would
therefore count as a foreseen side effect of swerving the trolley.
Quinn's proposal would not count it as a case of direct agency.
These considerations alone do not show that it is justified to switch
the trolley. Double effect might seem to explain the contrasting
impermissibility of pushing someone onto the track in front of the
speeding trolley in order to stop it in order to protect five people
who cannot escape on the track ahead. In both scenarios, a person
would be killed as part of one's plan for saving the five.
Because of this, the difference in permissibility might seem to depend
on whether the death of that person is a means to saving the five or a
side effect of doing so.



Discussions of the Trolley Problem and the relevance of the principle
of double effect to explaining our intuition that it is permissible to
swerve the trolley can be divided into three groups. First, there are
those who take the paired intuitions in the Trolley Problem as proof
of the fundamental role of the distinction between intended means and
foreseen side effects in an implicit principle guiding moral judgment
(Mikhail, 2011). Second, some argue that it would be wrong for a
bystander to switch the trolley (Thomson, 2008, contradicting Thomson
1976 and 1985) and suggest that people's willingness to view it
as permissible is a result of inadequate reflection. This group would
include those who uphold an absolutist version of the principle of
double effect and deny that it provides a permission to swerve the
trolley (Anscombe, 1982). Third, one could reject the claim that the
principle of double effect could explain the permissibility of
switching the trolley (McIntyre, 2001), while remaining neutral about
what verdict to render about such artificial cases.



Can our intuitions about the Trolley Problem be generalized to other
cases? Autonomous vehicles might be equipped with algorithms that
treat the alleged permissibility of swerving the trolley away from the
five and onto the one as an important precedent. Avoiding dangerous
collisions with other vehicles by swerving onto sidewalks where
pedestrians may or may not be be present might be viewed as ethically
similar to swerving the trolley. Or, as Patrick Lin suggests (2016,
76-7), an autonomous car driving on a cliffside roadway that
encounters a school bus with many passengers that has moved into its
lane as it rounds a sharp corner, might decide to sacrifice itself and
its passengers to avoid the more dangerous collision with a school bus
and the greater predicted loss of life. This should make us all
consider whether the highly abstract and context-less trolley problem
elicits reliable moral judgments that can be used as a precedent in
programming autonomous vehicles (see also discussion of the trolley
problem and autonomous vehicles in Nyholm and Smids 2016). You, as the
Bystander at the Switch, have no special positive duty toward the five
that requires you to assist them, and you have no special negative
duty toward the one that requires you not to harm him. What duties
does an autonomous vehicle have to its driver, other drivers, and
nearby pedestrians? Have drivers assumed a risk simply by driving that
pedestrians have not assumed by using a sidewalk? Should the
algorithms promote ethical concerns or the interests of drivers? Who
would buy an autonomous vehicle that would always sacrifice its
passengers to prevent greater loss of life?


### 4.6 Does Double Effect Explain the Permissibility of Risky Rescues and Rescue by Reducing the Extent of Harm?



Proponents of double effect have argued that agents may cause certain
and serious harm or run the risk of causing serious harm when they are
trying to prevent even greater harm that would otherwise be certain to
occur. In such cases, the harm or the risk of harm is described as
foreseen by the agent but not intended. Dangerous surgery undertaken
to save a life is one example (Anscombe 1982; Boyle 1991; Uniacke
1998). Uniacke mentions that the distinction between intended and
foreseen effects can also be applied to acts of justifiable
risk-taking in which the good effect and the bad effect are
"incompatible outcomes", noting that a parent might
justifiably throw a child out of a burning building in an attempt to
save its life (1998, s. 3). The parent intends to prevent certain
death, while foreseeing that the rescue might cause death.



Could it be claimed that the rescuing agents foresaw a risk of causing
harm as a side effect of their attempt at rescue but did not intend to
risk harm to those they were trying to rescue? Proponents of double
effect claim that the physician foresaw but did not intend that the
patient might not survive risky surgery, that the parent foresaw but
did not intend that the child could be killed by the fall, and that
the soldier foresaw but did not intend to cause his own death (Uniacke
1998). But this justification is incomplete for two reasons. First,
emphasizing that the risk of causing death is *foreseen* by the
rescuer but *not intended* by the rescuer implicitly compares
the rescuer's motives with the motives of agents who aimed to
cause death as an end, out of malice, callousness, or some other
wrongful motive. But double effect speaks only about the contrast
between harming as a side effect of promoting a good end and harming
as part of one's means of promoting a good end. Second, this
justification fails to distinguish between intending to impose a risk
of death on a person by acting in a certain way and intending to cause
death. These agents certainly did not intend to cause death, but they
did intend to impose a risk of death on a person by acting in a
certain way.



The physician who undertakes dangerous surgery in a patient who would
otherwise face certain death is attempting to reduce the risk of harm
to the patient. Undertaking the risky surgery constitutes the
physician's means of lowering the patient's risk of death.
The surgery is chosen because it imposes a lower risk of death on the
patient than what the patient faced without it. The surgeon intended
to impose a (lower) risk of death on the patient by undertaking the
risky surgery. Given that fact, it is not true that the surgeon did
not intend to impose a risk of harm. Imposing a (lower) risk of harm
in order to prevent a greater harm is exactly what the agent intended
to do. This was not a foreseen side effect of action, this was what
constituted the physician's attempt to save the patient's
life.



Similarly, the soldier who throws himself on a grenade is attempting
to reduce the extent of the harm that the explosion will cause by
attempting to absorb the force of the explosion with his body. The
heroic action is chosen because it imposes a very high risk of harm to
himself, thereby lowering the risk of harm to others nearby. Such
rescues seem to be cases in which agents act permissibly when they
choose to impose a risk of death on someone as their means of lowering
that person's risk of death (surgery, burning building) or as
their means of lowering the risk of harm to others nearby
(self-sacrifice). This involves imposing a risk of harm on a person in
order to promote a good end. It seems that the agents do intend to
impose a risk of harm on the person they involve: that is their means
to the good end. If this is permissible, double effect does not have
the resources to explain why it is permissible, since it is harmful
- but justifiably harmful - direct agency. These cases
satisfy Warren Quinn's definition of direct agency as agency in
which "harm comes to some victims, at least in part, from the
agent's deliberately involving them in something in order to
further his purpose precisely by way of their being so involved
(agency in which they figure as intentional objects)," and they
clearly do not satisfy the definition of harmful indirect agency as
agency "in which either nothing is in that way intended for the
victims or what is so intended does not contribute to their
harm" (1989, p. 343). If the risky surgery is unsuccessful and
the patient dies, the surgeon cannot say that what was intended,
dangerous but potentially life-saving surgery, did not contribute to
the harm.


### 4.7 The Role of Conventions and Norms in Warfare



The contrast between the Terror Bomber and the Tactical Bomber is
often viewed as the least controversial pair of examples illustrating
the distinction between intention and foresight that underlies the
principle of double effect. The judgment that the Terror Bomber acts
impermissibly and the Tactical Bomber acts permissibly is widely
affirmed. Terror bombing was engaged in by both sides in World War II
(see Douglas Lackey (1989) for a thoughtful historical account of the
decision process engaged in by Allied decision-makers and the
controversy it generated at the time). The view that terror bombing is
always impermissible would condemn the kind of incendiary bombing
carried out by Allied forces in Germany and Japan.



The common judgment that tactical bombing is permissible provided that
it is proportionate also deserves more scrutiny than it usually
receives when it is taken to be justified by the principle of double
effect. How much of an obligation do military strategists have to
avoid harm to civilian populations? This is a substantive issue about
the conventions that constrain military decision-making and the
principles that underlie these conventions. Many relevant
considerations depend on judgments that are far outside the ambit of
Double Effect. For example, the *Rules of Customary International
Humanitarian Law* displayed on the website of the International
Committee of the Red Cross prohibit attacks targeting civilians. They
also include protections designed 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 taken to avoid, and in any event to minimize, incidental loss
> of civilian life, injury to civilians and damage to civilian
> objects.
> 
> 
> 
> Rule 20. *Advance Warning* Each party to the conflict must give
> effective advance warning of attacks which may affect the civilian
> population, unless circumstances do not permit.
> 
> 
> 
> Rule 24. *Removal of Civilians and Civilian Objects from the
> Vicinity of Military Objectives* Each party to the conflict must,
> to the extent feasible, remove civilian persons and objects under its
> control from the vicinity of military objectives.
> 
> 
> 



These considerations suggest that the principle of double effect does
not contain, even when the principle of proportionality is included as
part of its content, a sufficient condition of permissibility for
bombardment that affects civilian populations. The example so
frequently invoked by philosophers concerning the permissibility of
tactical bombing in which civilian deaths are foreseen never mentions
a duty to warn or remove civilians.


## 5. End of Life Decision-Making


### 5.1 Pain Relief in Palliative Care



The principle of double effect is often mentioned in discussions of
what is known as palliative care, medical care for patients with
terminal illness in need of pain relief. Double effect is cited as a
justification for the view that it is permissible to administer opioid
drugs to relieve the suffering of a terminally ill patient, foreseeing
that the hastening of death will occur as a side effect. Double effect
reasoning in this context seems to express the compassionate view that
physicians may not intend to cause the death of a patient, but may
accept that actions intended to relieve pain might hasten death. Three
assumptions often operate in the background of these discussions:


1. It would be impermissible to administer an opioid drug in a dose
high enough to hasten the patient's death in order to cut short
the suffering of a terminally ill patient in the process of
dying.
2. The side effect of hastening death is an inevitable or at least
likely result of the administration of an opioid drug in order to
relieve the pain of a terminally ill patient.
3. The hastening of death is a not unwelcome side effect of providing
pain relief in the context of palliative care.



If the first assumption is not made, double effect has no explanatory
role to play. Those who appeal to double effect in this context must
also assume that it would be impermissible to hasten the death
*intentionally* of a terminally ill patient whom one was
treating with opioids for pain in order to shorten the process of
dying. If one believes that this is permissible, then double effect is
not needed to explain its permissibility.



The second assumption is false. Physicians and researchers have
insisted repeatedly that it is a myth that opioids administered for
pain relief can be expected to hasten death (Sykes and Thorns, 2003
provide a review of a large number of studies supporting this claim).
There is no research that substantiates the claim that opioid drugs
administered appropriately and carefully titrated are likely to
depress respiration. In a survey of research bearing on this issue,
Susan Anderson Fohr (1998) concludes: "It is important to
emphasize that there is no debate among specialists in palliative care
and pain control on this issue. There is a broad consensus that when
used appropriately, respiratory depression from opioid analgesics is a
rarely occurring side effect. The belief that palliative care hastens
death is counter to the experience of physicians with the most
experience in this area." The mistaken belief that pain relief
will have the side effect of hastening death may have the unfortunate
effect of leading physicians, patients, and the patients'
families to under-treat pain because they are apprehensive about
causing this allegedly inevitable side effect.



The third claim - that the hastening of death is not unwelcome
in these circumstances - ignores the role of the patient and the
patient's medical proxy in assessing whether hastening death is
a desirable result. It represents the physician's role as one
that does not require consultation with the patient or the
patient's proxy or attention to advance directives for guidance.
If hastening the death of a patient with a terminal condition is
desirable according to the patient or the patient's proxy, then
many thoughtful people would view the first assumption to be false: it
would be permissible to intend to relieve pain while also intending to
hasten the death of a terminally ill patient (see Allmark, Cobb,
Liddle, and Todd 2010; Kamm 1999; Quinn 1989, 343, n.17; McIntyre
2004). On the other hand, if the hastening of death is not desirable
according to the patient or the patient's proxy, it is not
permissible to hasten death in the course of treating pain, especially
since hastening death is neither likely nor inevitable when treating
pain. Patients receiving palliative care whose pain can be adequately
treated with opioid drugs may well value additional days, hours or
minutes of life as they look forward to meetings with family members.
A physician's duty of compassion does not override the
patient's preferences in such a weighty matter. The apparently
compassionate assumption that the hastening of death is a desirable
result when a patient is being treated for pain is unduly
paternalistic in this context.



Note that if the physician views the hastening of death as something
that would be good for the patient, and the patient or the
patient's proxy agrees, then even a secular version of double
effect does not apply to this situation: the hastening of death would
be a benefit for the patient, not a harm. As the discussion in
Section 1 (Formulations) has shown, any plausible
formulation of double effect would require agents to seek to minimize
or avoid the merely foreseen harms that they cause as side effects. On
this point, popular understandings of double effect reasoning at the
end of life, with the third assumption in place, diverge from what the
principle assumes: the popular understanding of double effect might
involve the assumption that hastening death is a merciful act and not
a harm to be avoided.



Note that a variety of substantive medical and ethical judgments
provide the justificatory context for this example: the patient is
terminally ill, there is an urgent need to relieve pain and suffering,
death is imminent, and we can now add that the condition that the
patient or the patient's proxy consents. The consent of the
patient or the patient's proxy is not naturally classified as a
concern with proportionality, understood as the physician's
weighing of harms and benefits.


### 5.2 Terminal Sedation



In a U.S. Supreme Court decision that rejected arguments for
permitting patients with terminal illness to request assistance from a
physician in ending their lives (Vacco et al. v. Quill et al., 117
S.Ct. 2293 (1997), Chief Justice William Rehnquist, writing for the
majority, invoked double effect not only as a justification for the
administration of pain-relieving drugs that might hasten death but
also as a justification for the practice known as terminal sedation or
continuous sedation. This occurs when patients with terminal
conditions who experience intractable pain that cannot be treated
effectively with opioid or other analgesic drugs are treated with
sedative drugs (which do not typically have analgesic properties) in
order to induce unconsciousness. Artificial hydration and nutrition
are not provided for patients sedated for these reasons in the context
of palliative care at the end of life. If death is not already
imminent for such a deeply sedated patient, dehydration and starvation
will make it inevitable. In such cases, withholding life-sustaining
treatment does in fact hasten death, intentionally but justifiably.
Prolonging the process of dying for a continuously sedated patient, in
whom sedation was initiated to deal with intractable pain, does not
benefit the patient.



In some cases, the patient's right to refuse life-sustaining
treatment, as expressed directly by the patient or through a proxy or
an advance directive, is the justification for withholding artificial
hydration and nutrition during terminal sedation. If a dying patient
views hastening death as a good to be pursued, then double
effect's presumption that death is a harm that a physician may
not intend to bring about is at odds with the preferences of a patient
who rejects artificial hydration and nutrition in order to hasten
death.



Timothy E. Quill, M.D., Rebecca Dresser, J.D, and Dan W. Brock, Ph.D.
argue that double effect, if applied consistently, would rule out the
practice of terminal sedation. "Unlike the use of high-dose
opioids to relieve pain, with death as a possible but undesired side
effect, terminal sedation inevitably causes death, which in many cases
is what the patient desires. Although the overall goal of terminal
sedation is to relieve otherwise uncontrollable suffering,
life-prolonging therapies are withdrawn with the intent of hastening
death. Terminal sedation would thus not be permitted under the rule of
double effect, even though it is usually considered acceptable
according to current legal and medical ethical standards"
(Quill, Dresser and Brock, 1997; see also Quill, Lo and Brock
1997).



The belief that doctors can cite double effect reasoning to justify
actions that hasten death tends to obscure rather than clarify these
important issues in palliative care. A single principle is no
substitute for the professional expertise of palliative care
specialists who seek to ensure a patient's comfort at the end of
life by using a variety of forms of care while respecting the
patient's right to refuse even life-sustaining treatment.
Standardized forms that invite patients with advanced chronic
illnesses to specify in advance their *Medical (or Physician)
Orders regarding Life-Sustaining Treatment* (MOLST or POLST form)
allow patients to request or to reject various treatments that would
extend their lives while also opting for forms of medical care that
will promote their comfort in dying (Bomba 2011). A physician
providing palliative care with the goal of promoting the
patient's comfort might provide pain relief, supplemental oxygen
or artificial hydration to a patient with the goal of increasing their
comfort, even when these treatments also have the effect of extending
life and prolonging the process of dying. The issues are complex and
cannot be resolved with a single principle that endorses a single
remedy. The compassionate ethos that the traditional application of
double effect is often understood to express is a central commitment
of palliative care, but the considerations to be taken into account go
beyond what could be explained by the principle of double effect.


## 6. One principle or many loosely related exceptions to a general prohibition on causing grave harms?



It is not at all clear that all of the examples that double effect has
been invoked to justify can be explained by a single principle, since
there may be a variety of considerations that bear on the
permissibility of causing grave harms in particular contexts. Perhaps
all of these cases have in common the feature that the agent acts to
promote a good end in a permissible manner and regrets any harms that
are involved. For some proponents of double effect, these facts are
enough to show that the harms that are caused should be described as
merely foreseen side effects.



Critics of the use of double effect as an explanatory principle point
out that the proportionality condition is vague and too general,
requiring only that the good effect outweigh the foreseen bad effect
or that there be sufficient reason for causing the bad effect. These
critics add that when substantive principles that explain the
permissibility of causing the kind of harm in question are explicitly
formulated, these principles are doing all of the justificatory work
(Davis 1984; McIntyre 2001). These substantive considerations are not
derived from double effect and in some cases do not support the
traditional applications of double effect. If this criticism is
correct, then perhaps the cases that have traditionally been cited as
applications of the principle of double effect are united only by the
fact that each is an exception to the general prohibition on causing
the death of a human being.



The historical origins of the principle of double effect as a tenet of
Catholic casuistry might explain the appearance that there is a single
principle with diverse applications. If one were to assume that it is
absolutely prohibited to cause the death of a human being, then it
would be impermissible to kill an aggressor in self-defense, to
sacrifice one's life to protect others, to hasten death as a
side effect of administering sedation for intractable pain, to
endanger non-combatants in warfare, to undertake risky surgery to save
a patient's life, to perform a hysterectomy on a pregnant woman
in order to save her life, or to swerve the trolley. However, if one
were to assume instead that what is absolutely prohibited is to cause
the death of a human being *intentionally*, then these cases
can be viewed as cases in which one might permissibly cause death
regretfully viewing the death as a "merely foreseen side
effect" of pursuing a good end.



However, as we have seen, it is hard to make sense of the idea that
the soldier who throws himself on a grenade does not view his
self-sacrifice as a means of protecting his fellow soldiers, or that
the physician who performs a hysterectomy on a pregnant woman does not
see the removal of the fetus as part of the life-saving procedure. It
is true that we could emphasize the soldier's motive by talking
about what he intended: that his intention was not to cause his own
death but to protect the lives of his fellow soldiers, or that the
physician who performs a hysterectomy on a pregnant woman to save her
life did not intend to kill the child, only to remove a cancerous
uterus containing a fetus. But in the same way we could say of someone
who ended her life: her intention was not to kill herself but to bring
her suffering to an end; and of someone who killed an enemy he
suspected of plotting against him that the did not intend to kill the
enemy but instead intended to insure his own future security. This way
of speaking amounts to saying that the harm that the agent caused was
chosen *as a means* to the agent's end and was not
pursued for its own sake. But double effect is supposed to condemn,
not to justify, grave harms intended as a means to a good end.



Some have developed this kind of criticism by arguing that the appeal
of the principle of double effect is, fundamentally, illusory: an
agent's intentions are not relevant to the permissibility of an
action in the way that the proponents of the principle of double
effect would claim, though an agent's intentions are relevant to
moral assessments of the way in which the agent deliberated (see
McCarthy 2002; Scanlon 2008). That an agent intended to bring about a
certain harm does not make an otherwise permissible action
impermissible, but it can explain what is morally faulty about the
agent's reasoning in pursuing that line of action.