The Journal of Value Inquiry
https://doi.org/10.1007/s10790-019-09727-z

Why Monogamy is Morally Permissible: A Defense of Some
Common Justifications for Monogamy
Kyle York1© Springer Nature B.V. 2019

Abstract
Harry Chalmers argues that monogamy involves restricting one’s partner’s access togoods in a morally troubling way that is analogous to an agreement between partners
to have no additional friends. Chalmers finds the traditional defenses of monogamy
wanting, since they would also justify a friendship-restricting agreement. I show
why three traditional defenses of monogamy hold up quite well and why they don’t,
for the most part, also justify friendship-restricting agreements (and why it doesn’t
seem to matter when they do). In many cases, monogamy can be justified on grounds
of practicality, specialness, or jealousy.

1 Introduction
There have been many assumptions in the philosophy of love and sex, not to mention popular culture, that monogamy is the only possible form of romantic love orat least the most ethical sexual and romantic practice.1 A growing body of literature has been calling these assumptions into question.2 Some arguments go further
and claim that monogamy or some of its components are immoral.3 I will be focusing here on one such argument about monogamy (or, more precisely, monogamous
agreements) by Harry Chalmers.4 Providing an initial pushback to Chalmers’ points,
I will conclude that, though non-monogamy may be fine, Chalmers’ argument islacking and hasn’t shown monogamous agreements to be morally troublesome.
1

For examples, see Carrie Jenkins, “Modal Monogamy,” Ergo, Vol. 2, No. 8, (2015).
E.g. Jenkins (ibid); Raja Halwani, Virtuous Liaisons, (Peru, IL: Open Court, 2003); and Elizabeth
Emens, "Monogamy’s Law: Compulsory Monogamy and Polyamorous Existence," University of Chicago Public Law & Legal Theory Working Paper, No. 58, (2004).
3
E.g. John McMurty, “Monogamy: A Critique,” The Monist, Vol. 56, No. 4, (1972): 587-599; and Hallie Liberto, "The Problem with Sexual Promises," Ethics 127, no. 2 (January 2017), pp. 383-414.
4
Harry Chalmers, “Is Monogamy Morally Permissible?” Journal of Value Inquiry Vol. 53, No. 2,(2018), pp. 225-241.
2* Kyle Yorkkylenyork@outlook.com
1

Lingnan University, Tuen Mun, Hong Kong

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Chalmers’ argument centers on an analogy between preventing one’s partnerfrom having other friends and preventing her from having other lovers. Chalmers
invites us to imagine partners who,
have agreed on a most unusual restriction: Neither is allowed to have additional friends. Should either partner become friends with someone besides theother, the other partner will refuse to support it—indeed, will go so far as towithdraw her love, affection, and willingness to continue the relationship.5
Most would judge there to be something morally troubling about such a relationship. We should want the best for our lovers. This entails wanting them to have goodthings (such as friends) in their life, or at least wanting them to be free to pursue
good things as they judge fit. As Chalmers writes, “part of letting our partner havethe freedom to pursue her own good [or good things] is to refrain from imposing
costs on her when she does so” and supporting her pursuits.6 The notion of imposing
a cost is slightly vague here, and it’s not clear whether we’re supposed to interpret it
as a putative measure, since Chalmers doesn’t describe a straying non-monogamous
partner as imposing costs on her partner, but the gist is clear enough.7 Chalmers
then points out that, “Sexual and romantic relationships are themselves an important
human good… So why not simply be happy for our partner if he found an additional
partner, much as we’d be happy for our partner if he found an additional friend?”8
Defenders of monogamy would have to find a difference between restrictions
against having friends and restrictions against having other partners. Specifically,
Chalmers thinks that we must find certain good-making features of monogamy thataren’t present in friendship-restrictions. Merely arguing that a restriction on friendships is more onerous than monogamy, Chalmers thinks, doesn’t go far enough; justbecause some x is worse than some y doesn’t mean that y is permissible. I must
briefly object to this line of reasoning before moving on. It may be true that some ycouldn’t be permissible merely by virtue of some x being worse, but x and y could
both share the same good-making feature that compensates for the bad-making feature of y but fails to compensate for that of x because x is worse. This should be kept
in mind whenever one sees an argument of Chalmers’ that examines a good-making
feature of monogamy and points out that such a feature doesn’t justify restrictions offriendships. In such cases, it could be that the more onerous restriction on additional
friendships crosses a certain threshold such that the good-making feature in question no longer compensates for the restrictions.9 More often than not, though, I shallset this point aside and assume that we must find a unique good-making property
of monogamy. Chalmers then looks through popular arguments for unique, goodmaking features of monogamy and finds them wanting. He concludes that, “by all5

Chalmers, op. cit., p. 225.
Ibid, p. 225.
7
See Liberto, op. cit., p. 409, who imagines an arrangement where, “John might decide to leave the relationship if Jane tells him she is having sex with a third party— but the decision should not be understoodas a penalty.”
8
Ibid, p. 225.
9
For a good introduction on the issue of thresholds, see Shelly Kagan, Normative Ethics (Boulder, CO:
Westview Press, 1998), pp. 78-84.
613Why Monogamy is Morally Permissible: A Defense of Some…

indications,” monogamy is “analogous to the morally troubling restriction on having
additional friends”.10
This same basic problem has also been brought up by Weaver and Woollard aswell as McKeever, all of whom find the prototypical restrictions of monogamy inneed of justification, evaluating potential candidates for the job.11 Though I will
focus on Chalmers’ argument, I will bring in McKeever and others when theirpoints are especially relevant (mostly because Chalmers doesn’t sufficiently addressthem). Before we begin, it’s worth noting that Chalmers’ argument may not justpaint monogamy as morally troubling but potentially other forms of romanticallyand sexually exclusive relationships as well. Although I won’t usually distinguishbetween monogamous and other exclusive relationships, I will actually be defending all romantically and sexually exclusive relationships, whether dyadic, triadic,
or something else.12 Though his critiques of defenses from practicality, specialness,and jealousy do not exhaust the problems in Chalmers’ essay, these each provide
full and independent grounds upon which monogamy can be defended. Thus, due tospace limitations, I will only focus on these three defenses.

2 The Practicality Defense
One extra good that monogamy offers is extra time and attention available for one’s
partner (as well as other important forms of availability). Chalmers points out that
this argument wouldn’t apply to other parts of life that take our attention elsewhere
than our partner, such as having friends and hobbies, asking, “why should it matter
if some of the time and energy one spends away from one’s partner and children
happen to involve sex and romance with others?”13
Usually, friends and hobbies don’t take up nearly the amount of time that serious relationships do, but this “hardly justifies setting the limit to one” relationship.14
This point doesn’t seem to hold when a couple is raising children or otherwise very
busy, but it may generally hold. In a committed relationship, however, partners often
end up moving for each other, and it’s important for many couples that they would
be able to if the necessity arose. Emotionally significant relationships with outside
partners greatly complicate this ability. If two or three of one’s closest lovers weremoving to different places, one may be left not knowing whom to join. Perhaps this
only justifies not dating new partners who would mind a long-distance relationship, but as I’ll later note, relationship dynamics change and can be hard to predict.
Friendships and hobbies don’t normally pose such practical problems, and it’s not
10

Chalmers, op. cit., p. 240.
Bryan Weaver and Fiona Woollard, “Marriage and the Norm of Monogamy,” The Monist, Vol. 91, No.
3-4, (2008); Natasha McKeever, “Is the Requirement of Sexual Exclusivity Consistent with Romantic
Love?” Journal of Applied Philosophy, Vol. 33, No. 2, (2015). These were also cited in Chalmers, op.
cit., p. 226.
12
This terminology comes from Jenkins, op. cit., p. 5.
13
Chalmers, op. cit., p. 232.
14
Op. cit., p. 232.
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K. York

troublesome for partners to agree to only take on careers that allow them to live
together. Thus, we already have a practical justification for restricting serious lovers.
Chalmers considers a defense of monogamy to the same effect: that to be vulnerable and concerned for others, to be “wrapped up in their world”, is an emotionallydemanding task that justifies expecting our partner to concentrate on one partner at
a time.15
Since outside sexual relationships can be quite casual, these two arguments may
fail to justify monogamy.16 However, what starts as a casual sexual relationship caneasily become something more significant, so exclusivity agreements may be needed
as a safeguard. Chalmers responds that, “surely much of the time, we can reasonably
be confident that the potential for a close emotional bond with another is low, andthat the connection is purely or primarily sexual”.17 As de Sousa adds, “both lustand intense romantic love… have relatively short shelf-lives: And both grow notoriously out of step with long term attachment.”18 Let’s call cases of sexual or romantic
affairs that don’t risk leading to emotionally close relationships ‘trysts’. It’s unclear
why we should be confident that any particular affair is only a tryst in the majorityof cases. Relationships and people are dynamic and many relationships come unexpectedly and without intentions or predictions that an emotionally weighty relationship would occur. Sex makes people more prone to behave in relationship-promoting
ways.19 There are genuine trysts, however, which we’ll return to later.
Chalmers goes on to argue that in any case we shouldn’t worry about casual sex
becoming a romantic relationship. Such a relationship need not be any more burdensome than a normal close friendship, and normal close friendships are more energizing than burdensome. The point here, however, isn’t whether romantic relationships must be emotionally burdensome but whether they tend to be, and romantic
relationships tend to contain more emotional challenge than platonic friendships.
Chalmers speculates that romantic relationships tend to be emotionally burdensome
precisely because of the expectations placed on one’s partner by monogamy to fulfill all of one’s needs. So without monogamy, new relationships wouldn’t be taxing.
Such speculation needs empirical support since it seems that even non-monogamous
relationships are taxing. After all, there are many online forums for sharing andworking through challenges in non-monogamous relationships, which regularly haveapparently little to do with such expectations. Here are just a few examples from one
thread:15

Ibid, p. 232.
Ibid, p. 233. Also see: McKeever, op. cit., pp. 356.
17
Op. cit., p. 232.
18
Ronald de Sousa, “Love, Jealousy, and Compersion”, in Christopher Grau and Aaron Smuts, ed., The
Oxford Handbook of Philosophy of Love (Oxford University Press, 2017), p. 13.
19
Birnbaum, Gurit E., Moran Mizrahi, and Harry T. Reis. “Fueled by Desire: Sexual Activation Facilitates the Enactment of Relationship-Initiating Behaviors.” Journal of Social and Personal Relationships,(November, 2018); Cindy Hazan and Lisa M. Diamond, “The Place of Attachment in Human Mating.,” Review of General Psychology 4, no. 2 (2000): pp. 190-191.
16

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Why Monogamy is Morally Permissible: A Defense of Some…

1. “I definitely don’t identify as monogamous…but I just don’t have the time andenergy for more than one serious relationship right now…”
2. “If one boyfriend gives you stress, imagine having three. If it’s hard to make time
to meet one boyfriend, imagine three… 3 people all have needs… 3 people comewith emotional labour. They are not there to overlap eachothers [sic] shortcomings.”
3. “My mom, also poly, never dated more than two and often felt exhausted…so she
was normally saturated at 1, at least in terms of spending time…”20
Moreover, many of the primary sources of trouble in relationships don’t have muchto do with monogamy at all: uncouth habits (like not grooming well), inconsiderateness (like being self-absorbed), being critical, and so on.21
Let’s return to trysts. Weaver and Woollard argue that for partners who see sex
as “conceptually inseparable from the particular kind of emotional intimacy that is
associated with erotic love,” it can make sense to restrict sex to such intimate contexts. If partners see sex acts generally (as opposed to a specific kind of sex) as connected to such intimacy, casual sex becomes a betrayal where, “the partner’s behavior ignores the tie between sex and emotional intimacy and is thus seen as a denialof the significance of sex in the relationship”.22 Thus, while trysts themselves can’tbe restricted on practical grounds, couples could have practical reasons to restrictromantically intimate relationships and in turn reasons to restrict sex to romanticallyintimate relationships.23

3 The Specialness Defense
For some, sexual and romantic (hereafter just ‘sexual’) exclusivity seem to makeromantic relationships more special. For example, Chalmers notes, “many think that
there is or can be a distinctive value in choosing, and being chosen by, just one person.”24 Chalmers sees two senses in which monogamy might make a relationshipspecial. One sense of ‘special’ is just ‘exclusive’ (as in “special seating”).25 Defending exclusivity because it is exclusive would be circular, so he disregards this sense.
The second sense of ‘special’ is that of creating additional value. Chalmers sees noreason to think that exclusivity should add additional value to a relationship. He
points out that our children or friends don’t become less special when we make new20"Anyone Else Polysaturated at 1?" Reddit. Accessed July 01, 2019. https​://www.reddi​t.com/r/polya​
mory/comme​nts/a66rz​x/anyon​e_else_polys​atura​ted_at_1/.
21
Michael R. Cunningham et al., "Social Allergies in Romantic Relationships: Behavioral Repetition, Emotional Sensitization, and Dissatisfaction in Dating Couples," Personal Relationships 12, no. 2(2005); Donald Peterson, "Conflict," in Close Relationships, ed. Harold Kelley et al. (New York, NY:
Freeman, 1983).
22
Weaver and Woollard, op. cit., p. 516.
23
Ibid, p. 516.
24
Chalmers, op. cit., p. 229.
25
Ibid, p. 229.

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ones (though I’d add that the quality of one’s relationship with each individual childor friend may lessen if one has too many).26
As for the distinctive feeling of being the one person one’s partner has chosen,
Weaver and Woollard suggest that this might simply have to do with the fact that a
relationship we make exclusive for practical reasons should be sufficiently fulfillingand significant to protect in such a way.27 It is not that exclusivity makes the relationship special; it’s that the specialness of the relationship justifies making it exclusive. This helps explain how monogamy supports the feeling that one is ‘enough’for one’s partner, a concern that Chalmers generally regards as irrational.28 It also
explains why the value of being chosen doesn’t “apply equally to the case of friendship”.29 One needn’t take such protective measures with friendships.
There are also ways in which exclusivity per se may be valuable. Firstly, exclusivity may allow for greater privacy in a relationship. Privacy, particularly in the senseof the ability to “control information about oneself”, is an important condition for
intimacy, personal integrity, spontaneity, and love.30 There are ways that privacy canbe respected in non-exclusive relationships, but it risks being a trickier business. For
example, if you spent last night doing something personally important and privatewith your lover Nia, and your other lover Sofia asks you what you did last night, you
can tell Sofia that it’s private, but this in turn seems to risk undercutting your capacity for intimacy with Sofia. Difficult situations and slipups seem likely. However,let’s assume that privacy can be adequately protected in non-exclusive relationships.
There are more ways exclusivity might be valuable. As McKeever writes, “lovers tend to show that their relationship is distinct and important through various
actions that…build, affirm and celebrate the shared identity of the lovers… If theyshare their identity exclusively then it will be important for the lovers to do somethings exclusively in order to affirm this”.31 Though sex needn’t be what some couple shares exclusively, it’s an obvious choice, being such an important act.32 Such ashared exclusive identity may also come with a special sense of intimacy.
This may beg the question; why is the exclusivity of some shared identity valuable in the first place? It might be because exclusivity is often a requirement for
intimacy, which typically involves the sharing of experiences that aren’t shared withmost others.33 But, if not for privacy concerns, why should intimacy be associatedwith exclusivity? One could provide an external (evolutionary, psychological, cultural, etc.) or internal (roughly, a reflectively justificatory) reason. McKeever gives
some reasons why this might be so. For example, exclusivity may help a couple

26

Ibid, p. 229.
Op. cit., p. 519.
28
e.g., Chalmers, op. cit., p. 235.
29
Chalmers, op. cit., p. 229.
30
See: Judith DeCew, “Privacy,” Stanford Encyclopedia of Philosophy (Stanford University, January 18,2018), https​://plato​.stanf​ord.edu/entri​es/priva​cy/#PriIn​t).
31
Op. cit., pp. 9. See also: Leslie A. Baxter, "Symbols of Relationship Identity in Relationship Cultures," Journal of Social and Personal Relationships 4, no. 3 (1987).
32
See also: McKeever, op. cit., p. 361.
33
Ibid., p. 361.
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Why Monogamy is Morally Permissible: A Defense of Some…

“make more effort sexually with each other and/or feel more relaxed and confident
knowing they are not being compared to others.”34
Chalmers might find some good arguments against these sorts of reasons. But
while reasons for our associations may be necessary if we are interrogating monogamy as a cultural phenomenon, I don’t see why they’re necessary for defending
exclusivity agreements as a practice within cultures. Chalmers’ target of analysis
is agreements, not cultures or social institutions. When considering whether sexually restrictive agreements may be bad, we wouldn’t demand an explanation of why
exactly sex is associated with “a special kind of emotional support and closeness”.35
We particularly wouldn’t demand an internal reason. We may have one, but whatmatters is simply that sexuality and exclusivity have these characteristics for somepeople.
Of course, we ought to interrogate our associations in some circumstances. To
agree only to date members of a certain ethnicity because one associates that ethnicity with purity seems wrong because that very association is objectionable.36 On
the other hand, even if we cannot find a good (internal) reason for the association
between emotional closeness and sexuality, we should still regard it as a good-making feature of sexuality. If we didn’t, we would end up with a moral theory that isn’t
appropriate for most people because it wouldn’t properly reflect what they happen to
be like.37 Seemingly, then, our associations only need to withstand such interrogation when they seem morally objectionable (at least when analyzing agreements).
So does the association in question seem immoral? Not on the face of things.
Certain associations between specialness and exclusivity doubtlessly rest uponassumptions of entitlement and ownership, but the particular association between
specialness or intimacy and shared exclusive identities seems too general to reston such assumptions. After all, it seems to underlie many cultural phenomena thathave nothing to do with entitlement or ownership, such as when friends share insidejokes and groups share special slang and fashions that distinguish them from othergroups.38 This sort of specialness, unrelated to ownership, avoids many previously
made objections to the specialness defense.39
Perhaps there is a restrictive quality to these associations that makes them seem
immoral. But while exclusivity is restrictive, to associate intimacy or specialness
and a shared exclusive identity does not seem restrictive per se. It does not follow
from this association that shared exclusive identities should be affirmed throughrestrictions, but only that certain restrictions will have at least one good-making feature if they contribute to a shared exclusive identity. Moreover, the fact that an association will attribute good-making features to certain restrictions seems unproblematic. As we saw in the last section, the association between all sex acts and intimacy

34

Ibid., p. 361.
Chalmers, op. cit., p. 225.
36
Thanks to an anonymous reviewer for bringing up this general concern.
37
Kagan, op. cit., pp. 280-294. See also: Liberto, op. cit., p. 398.
38
See also: McKeever, op. cit., p. 361.
39
For example, see Liberto, op. cit., p. 411, and Weaver and Woollard, op. cit., p. 513.
35

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K. York

may justify restrictions against casual sex, but this does not make the association
itself troublesome.
It might be pointed out that brutal hazing rituals or mutual self-mutilation could
strengthen a group’s shared identity but are not thereby morally justified. It’s simple
enough to respond here that such agreements cross a certain threshold of badness forwhich their good making features no longer compensate. This threshold could partially be explained by the fact that some restriction of goods is usually an acceptablefeature of agreements (consider religious vows, workplace contracts, and international treaties), while brutal hazing and mutilation is not. Restrictions on friendships
can also contribute to a shared exclusive identity but are likewise more onerous. For
most people, sexual relationships already have a greater association with intimacy
than friendship alone. It might be precisely the relative non-intimacy of friendshipthat makes it morally troubling to restrict the way that sex is restricted. In a world
where sex was freely shared but friendship was a particularly intimate and rarer
bond, perhaps restrictions on friendship would seem commonplace and restrictions
on sex would seem obviously wrong. Trysts may be less intimate still, but they breakthe exclusivity that makes the sex of monogamous partners contribute towards theirshared exclusive identity.
Of course, the fact that restrictions on friendships are more onerous than those on
sexual relationships does not guarantee that the value fostered by shared exclusive
identities will justify the latter restrictions. More work needs to be done to establish
whether the specialness of shared exclusive identities morally compensates for thesexual and romantic restrictions that can foster these identities. However, it should
be clear how such restrictions could be justified while leaving restrictions on friendships unjustified.

4 The Jealousy Defense, Part I: Reasons, Commitment, and Trading
Up
Monogamy ostensibly helps partners avoid painful experiences of jealousy. Chalmers notes that jealousy over a partner’s professional achievements or friendships
should not oblige her to achieve less or not have friends.40 Why then, should jealousy justify the sexual restriction of one’s partner(s)? A basic response is that jealousy in the case of romance and sexuality is usually more rational than jealousy overfriendships and professional accomplishments. Chalmers disagrees, writing, “wereit not for certain unreasonable fears and preconceptions that burden our minds, wewould react…by simply being happy” for our partner.41 These unreasonable fears
are that if our partner takes interest in another, we are not enough for her and willlose her since she will want them instead of us as opposed to in addition to us (it may
have been better to argue not that this fear is irrational, but that it only emerges in40
41

McKeever (op. cit., pp. 356-357) makes this same point with a few more examples.
Op. cit., p. 235.

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Why Monogamy is Morally Permissible: A Defense of Some…

monogamy). Being non-monogamous could fix this, since it gets rid of the requirement that we must be the best choice for our partner or she may trade up.
Even in a non-monogamous relationship, however, there is still the risk thatsomeone’s partner will trade up in some respect. She may move in with a different person or spend more time with someone else. This problem doesn’t assume
a competitive model of love wherein relationships are inherently opposed to eachother.42 In non-monogamy, while one hasn’t made her partner choose between her
and someone else, finite resources and living situations still impose choices. Jealousy may be a reasonable response to the risk or reality of these sorts of losses.43
By contrast, typically, I might temporarily lose my partner’s attention and time when
she’s with a friend, but our life together is not under threat. My lover’s accomplishments might overshadow mine, but this poses no danger to me (in typical cases, it’smore accurate to call my discomfort over my partner’s accomplishments envy rather
than jealousy).44 Still, many things that shouldn’t be restricted also carry risks, suchas friendships with attractive people, going to bars and nightclubs, and work conferences.45 One could respond that such jealousy is reasonable only if one cannot trust
one’s partner, which is (hopefully) not the case in most relationships. A new problem emerges: wouldn’t jealousy over a trustworthy partner’s other relationships also
be unreasonable?
Two responses are in order, though these will only apply to serious relationships(trysts are covered in the next section). Firstly, sexual and romantic relationships
are usually more intimate than and formally different from friendships (and certainly nightclubs). Romantic intimacy often comes with a trust based upon implicit
commitments. Trust in a relationship increases willingness for a partner to become
dependent, which in turn promotes strong commitment.46 If the connection between
lovers is serious, implicit commitments may be entered into with the new party thatmake it difficult to sustain the other relationship as it was. In such a case, trustingin one’s partner’s ability to stay true to her commitments is placing trust in the very
thing that might undermine the stability of one’s current relationship. If the preexisting commitment involves not taking on commitments that hurt the relationship,
this might undermine the capacity for trust to exist in the new relationship. Suchhierarchical non-monogamy is, for this reason, often (though not necessarily) cruelto new, secondary partners.47 There are, of course, stable non-monogamous relationships. It is only in situations where taking on new partners threatens to undermine
42

See Weaver and Woollard, op. cit., p. 513, for this accusation.
See also: Neu, op. cit., p. 452 and Leila Tov-Ruach, ‘Jealousy, Attention and Loss’ in Rorty(ed.) Explaining Emotions (Berkeley: University of California Press, 1980). These are cited in McKeever,op. cit., p. 357.
44
Daniel Farrell, “Jealousy,” Philosophical Review, 89 (1980): 527–559; Jerome Neu, “JealousThoughts,” in Rorty, op. cit.; cited in Justin D’Arms, "Envy," Stanford Encyclopedia of Philosophy,
December 22, 2016, accessed July 02, 2019, https​://plato​.stanf​ord.edu/entri​es/envy/.
45
Weaver and Wollard, op. cit., p. 513; McKeever, op. cit., pp. 357.
46
Jennifer Wieselquist et al., "Commitment, Pro-relationship Behavior, and Trust in Close Relationships," Journal of Personality and Social Psychology 77, no. 9 (1999).
47
Franklin Veaux, “Some Thoughts on Game-Changers,” Franklin Veaux’s Journal, accessed July 02,
2019, https​://tacit​.livej​ourna​l.com/32321​0.html.
43

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one’s relationship and commitments that this particular defense works, but there’s
no reason to suppose such cases are uncommon. For secondly, the risk is probably
higher for a serious relationship emerging between people who are already having
sex.48 This can more easily give rise to wants that go deeper than the fairly benign
want to sleep with someone else and into the more destructive want to have a life
with someone else.
Responding to our reasonable concerns about trading up, Chalmers implies thateven if we ran the risk of losing our partners in a significant way, this would notwork as a justification for restricting them. As he writes, “There is something puzzling, if not deeply unsettling, in the hope that your partner will remain ignorant of
options that are better for her… however much it may crush us to see our partner
leave us… [we should] want what’s best for her”.49 This is a commendable attitude.
However, it doesn’t seem that this point applies equally well to both positions thatpartners may occupy in such a situation—the straying partner and the jealous partner. Imagine that I am in a loving relationship with my partner but our life together
is contingent upon the fact that I don’t find someone who’s a better fit for me. If I
find someone else, it may crush my partner to see me go, but I’ll console myselfthat a truly loving partner would want this for me. This situation also seems deeply
unsettling. The relationship involves no commitment or loyalty on my part. It would
likewise be understandable if this disturbed my partner. If we care about loyalty andcommitment, we might not see the opportunity to trade up as a genuine good being
forsaken in monogamy.50 Like the value of friendship and promises, a fully committed relationship is the kind of good available only when refraining from weighing
its value comparatively to other potential goods.51 This outlook may help resolve
anxiety over one’s partner finding someone with whom a more fulfilling relationshipmight exist.
Very well, Chalmers could respond, but since many monogamous people trade
up and many polyamorous people value and live committed lives, commitment can’t
be used as a justification for monogamy. Additionally, sometimes opening up a relationship makes the relationship less likely to break apart.52 Still, it’s enough for myargument that for some couples, restrictions on outside relationships help avoid risksof breaking up. I’ve already given reasons why these risks would exist for many
couples.

48
Gurit Birnbaum and Eli Finkel, “The Magnetism That Holds Us Together: Sexuality and Relationship
Maintenance Across Relationship Development,” Current Opinion in Psychology 1 (2015); Hazan andDiamond, op. cit., pp. 190-191; Birnbaum, Mizrahi, and Reis, op. cit.
49
Op. cit., pp. 239.
50
For a broader discussion of problems with this attitude in contemporary culture, see Zygmunt Bauman, Liquid Love: On the Frailty of Human Bonds (Cambridge: Polity Press, 2014).
51
Philip Pettit, “How the Consequentialist Can Recognize Rights,” Philosophical Quarterly 38 (1988),
pp. 42–55; Alastair Norcross, “Act-Utilitarianism and Promissory Obligation,” in Sheinman, Promises
and Agreements (New York: Oxford University Press, 2011), pp. 217–36; cited in Liberto, op. cit., pp.,401.
52
McKeever, op. cit., p. 356.

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5 The Jealousy Defense, Part II: Painfulness and Controllability
There are nonetheless probably cases in which sexual and romantic jealousy are irrational. Some trysts may be a good example, unless the jealousy is over the breach of
exclusivity itself.53 In cases of irrational jealousy, the painfulness of jealousy is the
only factor to which one might respond. Seemingly, in cases where reasons for jealousy are lacking, a couple should make agreements accommodating such jealousy
only if the jealousy is beyond their ability to overcome (without exceedingly large
costs). I believe this is why Chalmers seems adamant that monogamy is the cause of
jealousy. He maintains that monogamy fosters an attitude of competition and capitulates to jealousy rather than facing it. If the monogamous could get over their preconceptions and behavioral responses to jealousy, he thinks, it wouldn’t pose muchof a problem. But it is not only attitude, ideology, and lifestyle that determine levelsof jealousy. Anxious attachment systems, poor mental or physical health, and low
self-esteem are all predictors of higher jealousy.54 Jealousy might take place at a
psychological level that is not always malleable by reflective, rational thought orsystematic exposure.55 Chalmers admits that being emotionally open to the possibility of one’s partner’s departure requires being comfortable and secure in oneself.
The incurably anxious and insecure must either suffer through their romantic lives
or engage in immoral acts, as they would be morally forbidden to enter into exclusivity agreements with each other, no matter how desperately they wanted to.
Chalmers counters the idea that monogamy helps avoid jealousy, quoting Conley et al.’s claim that “levels of jealousy were actually lower for those in consensually non-monogamous relationships.”56 This quote cites two studies from Pinesand Aronson.57 One study was a comparison of respondents to fifteen people surveyed in the Kerista utopian community in San Francisco. Since this community
operated according to an atypical lifestyle and principles, it’s difficult to extrapolate
this study to discussions of non-monogamy in general.58 In fact, Pines and Aronson found the Kerista community to be an “interesting exception” to their findings in a meta-study that “people who believe in monogamous relationships areless likely to be jealous.”59 The second study was a survey of swingers that merely

53

McKeever, op. cit., p. 362.
See: Leanne K. Knobloch, Denise Haunani Solomon, and Michael G. Cruz, “The Role of Relationship Development and Attachment in the Experience of Romantic Jealousy,” Personal Relationships 8,
no. 2 (2001); and Ayala Pines and Elliot Aronson, “Antecedents, Correlates, and Consequences of Sexual
Jealousy.” Journal of Personality 51, no. 1 (1983): 108-36. However, attachment studies have hitherto
taken place within a monogamous framework, so it’s possible that the correlation for anxious attachment
and jealousy will be overturned in future research that corrects for this bias, as noted in Terri Conley
et al., “A Critical Examination of Popular Assumptions About the Benefits and Outcomes of Monogamous Relationships,” Personality and Social Psychology Review 17, no. 2 (2012), pp. 10-11.
55
See also: Buss, David. “Sexual Jealousy.” Psychological Topics 22, no. 2 (2013): 155-82.
56
Conley et al., op. cit., p. 7, cited in Chalmers, op. cit., p. 237.
57
Op. cit.
58
Ayala Pines and Elliot Aronson, “Polyfidelity,” Alternative Lifestyles 4, no. 3 (1981).
59
Pines and Aronson (1983), op. cit., p. 130.
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K. York“perceived themselves as less jealous than nonswingers”.60 Conley et al. also cite acase study of a small group and a meta-study about extradyadic jealousy.61,62 Bothhold that jealousy remains in non-monogamous relationships, but that it tends tobe more manageable. As Bringle and Buunk note, “jealousy is a persistent phenomenon, even in couples who are open to extra-marital relationships”.63 Even if
a monogamous person is not as good at handling individual instances of jealousy
when they arise, these instances probably occur less often than in non-monogamous
arrangements. Moreover, non-monogamous people may experience less intense jealousy not because they are non-monogamous, but because non-monogamy is “moreappealing to people who are not predisposed to experiencing jealousy” in the firstplace.64 These points should give us reason to doubt de Sousa’s claim that jealousy
frequently can be transformed into a positive experience of ‘compersion’ merely by
adopting an alternative framing ideology.65
There are doubtlessly couples that have turned their jealousy into compersion, butwhile we would not want to adopt an uncritical attitude towards jealousy, it is unrealistic to think that anyone (or even most people) can do this. How easy it is to overcome jealousy will depend largely upon the specifics of each particular case. Just
as it’s unfair to expect the same of everyone’s ability to deal with snakes or heights,
it’s unfair to expect everyone to be able to handle jealousy in the same way. Thus, it
doesn’t even matter what is generally true of humans’ ability to handle jealousy; if
there is one couple who cannot overcome their jealousy, monogamy could be justified in their case. But, of course, even if both lovers have issues with uncontrollable
jealousy, there still seems to be a requirement that they want or usually enjoy exclusivity. The agreement should probably also increase the overall well-being of thepartners.
Chalmers can now say that all these conditions could also be met in the case of afriendship-restricting agreement. I’m ready to bite the bullet and say that in this very
unusual circumstance, the agreement is not morally troubling because they consent
to, want, and enjoy such a relationship, because their jealousy cannot be controlled,
and because their well-being is increased overall. If such an arrangement is still not
acceptable, this is perhaps just because it’s a more onerous restriction.
A final objection: even if jealousy is painful, it may still be a vicious emotion. As
such, perhaps jealousy isn’t one of those kinds of pain that morally matters in thefirst place. For example, the pain of a slaveholder at losing a slave isn’t the kind of
pain that we think should be counted as a factor in our moral decisions. De Sousa

60
Richard J. Jenks, "Swinging: A Test of Two Theories and a Proposed New Model," Archives of Sexual
Behavior 14, no. 6 (1985).
61
Richard de Visser and Dee Mcdonald, "Swings and Roundabouts: Management of Jealousy in Heterosexual ‘swinging’ Couples," British Journal of Social Psychology 46, no. 2 (2007).
62
Robert Bringle and Bram Buunk, “Extradyadic Relationships and Sexual Jealousy" in Sexuality in
Close Relationships, ed. K. McKinney and S. Sprecher (Hillsdale, NJ: Erlbaum, 1991).
63
Op. cit., p. 149. See also: Jerry Neu, "Jealous Thoughts," in A Tear Is an Intellectual Thing (Oxford
and New York: Oxford University Press, 2000), pp. 135-155, cited in de Sousa (op. cit., p. 16).
64
Conley et al, op. cit., p. 7.
65
Op. cit., p. 13-14.

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Why Monogamy is Morally Permissible: A Defense of Some…

mostly characterizes sexual and romantic jealousy as resting “on assumption of entitlement.”66 Such entitlement may be immorally objectifying. However, except inextreme cases, the positive or negative valiance of emotions is usually taken to be
morally significant, even if the emotions per se aren’t. Moreover, it doesn’t seem likemost cases of jealousy would have to be based on a sense of entitlement, given that
jealousy is often caused by things like exclusivity concerns, social rejection, andthreatened self-perception, which don’t seem related to entitled attitudes.67

6 Discussion and Conclusion
I have argued that at least three justifications for monogamy fare better than Chalmers credits them. These justifications can work together or independently. But since
I’ve been defending monogamy (and exclusive arrangements in general), it would
be a good idea to say what I’m defending. Although I have made appeals to the cultural or psychological significance of exclusivity as it relates to intimacy, I am notdefending all of the associations, agreements, or behaviors associated with monogamy. Chalmers and McKeever have mostly been interested in questioning monogamous arrangements per se, and not monogamy as a historical institution or as commonly practiced. Likewise, my interests have been in defending monogamy per se.
Monogamy (and exclusivity) per se, for our purposes, is just when lovers agree tonot engage in prototypically romantic or sexual behaviors with others.
Since romance and sexuality all come in degrees, some behaviors (like flirting or cuddling) might seem like a breach of exclusivity to one couple but not toanother. While I wish to largely leave it up to individual couples to decide what toinclude in their exclusivity agreements, I don’t think my defense will work for all
kinds of restrictions. Additionally, as was noted, there are other requirements thatmonogamous agreements may need to meet in order to be moral. Both parties seemingly need an overall desire to be monogamous. Perhaps all restrictions must apply
equally to both partners. Such details are to be worked out in the further research.
Chalmers sometimes strays from a clear and narrow critique of dyadic sexual andromantic exclusivity, and when this happens, my points no longer apply. For example, Chalmers notes that, “monogamous restrictions apply not only to sex, but toactivities like intimate dancing and outercourse, and often to emotional intimacy aswell”.68 Though outercourse is clearly sexual (and is probably just sex), I have nointerest in defending agreements to mutual restrictions upon emotional intimacy or
non-romantic and non-sexual dancing, nor perhaps even mildly sensual or flirtatious
dancing. All of these complications point to the value of Chalmers’ work in forcing

66

Op. cit., p. 5.
See, e.g., Eddie Harmon-Jones, Carly Peterson, and Christine Harris, "Jealousy: Novel Methods andNeural Correlates," Emotion 9, no. 1 (2009), pp. 114-115; Aaron Ben-Zeev, "Jealousy and Romantic
Love," in Handbook of Jealousy: Theory, Research, and Multidisciplinary Approaches, ed. Sybil Hart
and Maria Legerstee (Wiley-Blackwell, 2010); and McKeever, op. cit., p. 357.
68
Chalmers, op. cit., p. 229.
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K. York

us to find what kind of agreements are permissible. Still, more detailed arguments
against even the common justifications for monogamy are necessary for it to seem
morally troublesome.
Acknowledgements Thanks for Francesco Orsi, Derek Baker, Merily Salura, and an anonymous reviewer
for their helpful comments, notes, and conversations.
Funding Funding was provided by Hong Kong PhD Fellowship Scheme.

Publisher’s Note Springer Nature remains neutral with regard to jurisdictional claims in publishedmaps and institutional affiliations.

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