On this approach, the structure of marriage derives from the behaviorneeded to maintain such a relationship. Thus marriage involves acommitment to act for the relationship as well as to excludeincompatible options—although there is controversy over whatspecific policies these general commitments entail. To take anuncontroversial example, marriage creates obligations to perform actswhich sustain love, such as focusing on the beloved's good qualities(Landau 2004). More controversially, some philosophers argue thatsustaining a love relationship requires sexual exclusivity. Thethought is that sexual activity generates intimacy and affection, andthat objects of affection and intimacy will likely come intocompetition, threatening the marital relationship. Another versionfocuses on the emotional harm, and consequent damage to therelationship, caused by sexual jealousy. Thus, due to thepsychological conditions required to maintain romantic love, marriage,as a love-protecting institution, generates obligations to sexualexclusivity (Martin 1993, Martin 1994, Scruton 1986, Chapter 11,356–361, Steinbock 1986). However, philosophers dispute thepsychological conditions needed to maintain romantic love. Some arguethat casual extra-marital sex need not create competing relationshipsor trigger jealousy (Halwani 2003, 235; Wasserstrom 1974). Indeed,some have even argued that extra-marital sex, or greater socialtolerance thereof, could strengthen otherwise difficult marriages(Russell 1929, Chapter 16), and some polyamorists (those who engage inmultiple sex or love relationships) claim that polyamory allowsgreater honesty and openness than exclusivity (Emens 2004). Otherphilosophers have treated sexual fidelity as something of a redherring, shifting focus to other qualities of an ideal relationshipsuch as attentiveness, warmth, and honesty, or a commitment to justicein the relationship (Martin 1993, Kleingeld 1998).
A second widespread (though less unified) institutional approach tomarriage appeals to the ideal marital love relationship to define thestructure of marriage. This approach, in the work of differentphilosophers, yields a variety of specific prescriptions, on, forexample, whether marital love (or committed romantic love in general)requires sexual difference or sexual exclusivity (Scruton 1986,305–311, Chapter 11, Halwani 2003, 226–242, Chartier2016). Some, but not all, proponents explicitly argue that the maritallove relationship is an objective good (Scruton 1986, Chapter 11,356–361, Martin 1993). These views, however, all take theessential feature, and purpose, of marriage to be protecting a sexuallove relationship. The thought is that marriage helps to maintain andsupport a relationship either in itself valuable, or at least valuedby the parties to it.
A first reason for recognizing marriage should be set aside. This isthat the monogamous heterosexual family unit is a natural,pre-political structure which the state must respect in the form inwhich it finds it (Morse 2006; cf. new natural lawyers, Girgis etal. 2010). But, whatever the natural reproductive unit may be,marriage law, as legislation, is constrained by principles of justiceconstraining legislation. Within most contemporary politicalphilosophy, the naturalness of a given practice is irrelevant; indeed,in no area other than the family is it proposed that law should follownature (with the possible exception of laws regardingsuicide). Finally, such objections must answer to feminist concernsthat excluding the family unit from principles of justice, allowingnatural affection to regulate it, has facilitated inequality and abusewithin it (see section 5).
Before exploring some common rationales, it is worth noting thatcritics of the social contract model of the state and of freedom ofcontract have used the example of marriage against contractualprinciples. First, Marxists have argued that freedom of contract iscompatible with exploitation and oppression—and Marxistfeminists have taken marriage as a special example, arguing againstcontractualizing it on these grounds (Pateman 1988,162–188). Such points, as we will see, suggest the need forrules governing property division on divorce. Second, communitarianshave argued that contractual relations are inferior to thosecharacterized by trust and affection—again, using marriage as aspecial example (Sandel 1982, 31–35, cf. Hegel 1821, §75,§161A). This objection applies not only to contractualizingmarriage, but more generally, to treating it as a case for applicationof principles of justice: the concern is that a rights-basedperspective will undermine the morally superior affection betweenfamily members, importing considerations of individual desert whichalienate family members from their previous unselfish identificationwith the whole (Sandel 1982, 31–35). However, although marriagesare not merely an exchange of rights, spousal rights protect spouses'interests when affection fails; given the existence of abuse andeconomic inequality within marriage, these rights are especiallyimportant for protecting individuals within, and after, marriage(Kleingeld 1998, Shanley 2004, 3–30, Waldron 1988).
Let us then begin with the question of why marriage should berecognized in law at all. One answer is that legal recognition conveysthe state's endorsement, guiding individuals into a valuable formof life (George 2000). A second is that legal recognition is necessaryto maintain and protect social support for the institution, a valuableform of life which would otherwise erode (Raz 1986, 162, 392–3; Scruton1986, 356–361; see discussion in Waldron 1988–89). Butthis prompts the question as to why this form of life is valuable.
As Finnis emphasizes, one feature of the new natural law account ofmarriage is that the structure of marriage can be fully explained byits purpose. Marriage is between one man and one woman because this isthe unit able to procreate without third-party assistance; permanenceis required to give children a lifelong family. Finnis charges, asnoted above, that accounts which do not ground marriage in this purposehave no theoretical reason to resist the extension of marriage topolygamy, incest, and bestiality (Finnis 1995). As all non-marital sexfails to instantiate basic goods, there is no way morally todistinguish these different relations.
Like Kant, the new natural law account of marriage focuses on thepermissible exercise of sexual attributes; following Aquinas, itemphasizes the goods of marriage, which new natural lawyers, notablyJohn Finnis (cf. George 2000, Grisez 1993, Lee 2008), identify asreproduction and fides—roughly, marital friendship(see entry on The Natural Law Tradition in Ethics). Marriage is heretaken to be the institution uniquely apt for conceiving and rearingchildren by securing the participation of both parents in an ongoingunion. The thought is that there is a distinctive marital good relatedto sexual capacities, consisting in procreation and fides, andrealizable only in marriage. Within marriage, sex may be engaged in forthe sake of the marital good. Marital sex need not result in conceptionto be permissible; it is enough that it is open towards procreation andexpresses fides. The view does not entail that it is wrong totake pleasure in sex, for this can be part of the marital good.
The main theoretical alternatives to the contractual view hold thatmarital obligations are defined by the purpose of the institution, andthat spouses cannot alter these institutional obligations (much likethe professional moral obligations of a doctor; to become a doctor, onemust voluntarily accept the role and its obligations, but one cannotnegotiate the content of these obligations). The challenge forinstitutional views is to defend such a view of marriage, explainingwhy spouses may not jointly agree to alter obligations associated withmarriage. Kant confronted this question, arguing that special maritalrights were morally necessary for permissible sex. His account ofsexual objectification has influenced a prominent contemporary rival tothe contractual view—the new natural law view, which takesprocreation as essential to marriage. A second widespread approachfocuses solely on love as the defining purpose of marriage.
One objection to the contractual account is that, without appeal tothe purpose of the institution, there is no reason why not just any setof promises count as marriage (Finnis 2008). The objection continuesthat the contractual account cannot explain the point of marriage. Somemarriage contractualists accept this implication. According to the“bachelor's argument,” marriage is irrational:chances of a strongly dis-preferred outcome (a loveless marriage) aretoo high (Moller 2003). Defenders of the rationality of marriage havereplied that marital obligations are rational because they help agentsto secure their long-term interests in the face of passing desires(Landau 2004). From the institutional perspective, evaluating therationality of marriage thus, in terms of fulfilling subjectivepreferences, clashes with the tradition of viewing it as uniquelyenabling certain objective human goods; however, a positive case mustbe made for the latter view.
A further point concerns law: to guide citizens' judgments andchoices towards the relationship in which they can uniquely achieve themarital good, the state should endorse marriage, as understood on thisview, and not recognize same-sex relationships as marriages. However,it might be asked whether this is an effective way to guide choice, andwhether state resources might be better spent promoting other basichuman goods. Moreover, as the argument equally implies a state interestin discouraging contraception, divorce, and extra-marital sex, thefocus on same-sex marriage appears arbitrary (Garrett 2008, Macedo1995). This objection is a specific instance of a more generalobjection: this account treats sex and the marital good differentlythan it does the other basic human goods. Not only is less attentionpaid to promoting those goods legally (and discouraging behaviorcontrary to them), but the moral principle forbidding action contraryto basic human goods is not consistently applied elsewhere—forexample, to eating unhealthily (Garrett 2008).
There are many reasons that women might have gravitated more toward the latter. It’s easy to imagine why, for example, Jane Eyre’s needs might be different from Moses Herzog’s. Herzog is a world-renowned scholar with a seemingly endless list of wealthy and successful friends; he has ample opportunity to express himself in writing, and to engage with peers. (Whether Ramona is an idiot or a savant, he won’t want for intellectual companionship.) Jane, on the other hand, is a lowly and lonely governess without any claims to status in the eyes of the world; her wit and originality of mind are entirely unrecognized until Rochester comes along and offers her the outlet she has long yearned for. For centuries, men have had far more opportunities to find intellectual outlets outside the romantic sphere—they’ve been able to travel more, to meet a broader range of people, to have professions, to win the respect of peers. Women, on the other hand, were forced to lean more heavily on love and marriage, for intellectual recognition and companionship as for everything else.