Several people commented in response that there are other slippery slopes that opponents of same-sex marriage are worried about, and which my last post failed to address. Some even suggested that it seems clear that the reasons for allowing same-sex marriage, if accepted, really would serve as equally good reasons for allowing various forms of group marriages (marriages involving a husband with several wives, a wife with several husbands, or more egalitarian groups which I'm tempted to call "cluster-nups").
So, I'm going to walk through here the case against there being a slippery slope from same-sex marriage to group marriage.
Again, let me begin with the following point about slippery slope arguments. They're not always unsound. It all hinges on the reasons why you would be taking a certain step. If those reasons work as well as reasons for stepping into the mess that the critic is worried about, then the critic has offered a legitimate slippery slope argument against treating those reasons as good ones for taking the initial step. I should point out, however, that a legitimate slippery slope argument is not always decisive. Sometimes the reasons for taking the first step are so compelling, so powerful, that even if we don't like what follows, we would be well-advised to bite the bullet and accept it.
But I don't think we have to even explore that follow-up question with respect to the various same-sex marriage slippery slopes that have been proposed--because they aren't legitimate slippery slopes at all.
To make this point, let me begin by reminding everyone of Michele Bachmann's bad case for the view that restricting marriage to heterosexual pairings is not discriminatory. What does Bachmann say? Here's how I summarized it in an earlier post:
A law that restricts marriage rights to heterosexual couples is not discriminatory at all, because everyone in society has the same rights with respect to marriage that everyone else in society has, namely to marry someone of the opposite sex. No one is excluded from marriage. It's just that everyone in society faces exactly the same constraint on who they can marry. It must be someone of the opposite sex. So: no discrimination, and hence no need to justify the discrimination by appealing to some consideration that could warrant differential treatment.And here's how I responded to that argument in the same post:
...the argument is premised on the assumption that everyone has the same sexual orientation. If everyone had a homosexual orientation, then a law restricting marriage to heterosexual couples would require that everyone marry someone they have no attraction to, cannot fall in love with, cannot sustain romantic feelings with, etc. Everyone in society would be equally denied access to a deeply valued social good, namely legal recognition and support for their intimate, romantic loving partnerships. No discrimination there--although we might wonder why the state would systematically deny everyone access to this social good...
If everyone had a heterosexual orientation, then--once again--a law restricting marriage to heterosexual couples would be unproblematic. It would preclude everyone from doing something no one had any interest in doing in any event...
And, of course, if everyone had a bisexual orientation, then a law restricting marriage to heterosexual couples would put the same limitation on everyone...We might wonder why this constraint should be imposed, but the constraint would not be discriminatory against any individuals...
But people don't all have the same sexual orientation. And so, legally limiting civil marriage to heterosexual couples means that heterosexuals are afforded access to a distinctive good (having their intimate romatic partnerships recognized and supported by the state) that is denied to those with a homosexual orientation.In short, restricting marriage to heterosexual pairings discriminates against persons with a homosexual orientation. Were there nobody whose capacity for establishing and maintaining romantic intimacy were limited to members of the same sex, a law restricting marriage to heterosexual couples would not deny to any individual a social good available to others. Same-sex couples would still be denied marriage, such that if bisexuals of the same sex happened to fall in love they'd face legal discrimination as a couple. But since each member of the couple would still have access to the social good in question--just not with each other--the discrimination against the pairing would be easier to justify for reasons less weighty than would be required in order to systematically exclude a class of people from any access to an important social good available to those who aren't of this marginalized class.
The point here is this: Michele Bachmann's case that no legal discrimination is going on might actually work if there were no such thing as a homosexual orientation.
Whatever the details of our reasons for endorsing marriage equality for gays and lesbians, the wrong of legal discrimination is front and center for all of us. And that legal discrimination arises because there is such a thing as a homosexual orientation. (And there is. Really. Deny it at the peril of being the kid at the playground who doesn't want to hear the facts and so plugs up their ears and shouts "Nya nya!" to cover up what others are saying.)
But is there such a thing as, say, a polyamorous orientation--that is, a fixed and unchosen disposition, resistant to change, such that the person is unable to develop or maintain a satisfying romantic relationship with any other single individual, but is able to develop and maintain a romantic relationship only with two or more? Put one attractive mate in the room with them and...nuthin'. Add a second, and the person's sexual interest suddenly comes alive for the pair as a pair. A desire to cultivate romantic intimacy bursts forth, complete with an interest in long conversations, personal sharing, walks on the beach, bicycle rides together on a brisk fall day...but only with the pair as a pair. Take one of them away and the interest vanishes completely.
Sure, lots of people (most? all?) have a sexuality that isn't limited to one person. But that's not the same as what I'm talking about. It's one thing to be sexually interested in both Mary and Martha. It's something else to be incapable of romantic attraction towards Mary or towards Martha unless both Mary and Martha are there with you in the bedroom. It's one thing to be able to form intimate relationships with both Mary and Martha--and to have a strong temptation to form one with Martha even though you already have one with Mary. It's something else to only be capable of forming an intimate relationship with one only on the condition that you are also forming an intimate relation with the other at the same time.
That is the kind of sexual orientation that would need to exist in order for a law restricting marriage to pairs of people (and excluding triples and quads, etc.) to be a law that discriminates against a class of people.
The fact is, while there is enormously good and compelling reason to believe in the existence of a class of people with a stable homosexual orientation, there is absolutely no good reason at all to believe that there is anything like an analogous polyamorous orientation.
Furthermore, there is good reason to suppose that polyamorous groups wouldn't be able to form the kind of relationship that civil marriage exists to cultivate and support and encourage: intimate, stable, and enduring life partnerships. It's hard enough for couples to manage the complexities of interpersonal dynamics. But--as I've pointed out before on this blog (although I can't find where at the moment)--adding a third person to a relationship multiplies those complexities enormously. When you have two people, A and B, there is one relationship to deal with. Add a third person, C, and you now have six relationships: A's relationship to B, B's relationship to C, C's relationship to A, A's relationship to the B-C pair, B's relationship to the A-C pair, and C's relationship to the A-B pair.
Of course, all of us have multiple relationships in our lives, and hence have a range of complications to face. But a life partnership--a mutual commitment to share the challenges of life together, to support one another, to be in each other's corner through the years, to divide the responsibilities of making a home, to make crucial decisions as a team--that sort of relationship involves distinctive kinds of stresses and conflicts, as well as payoffs. A three-person life-partnership faces challenges that exponentially magnify these stresses and conflicts: potential for jealousy, for playing off one partner against the other in a way that creates a kind of hierarchy and privilege, for two teaming up and browbeating the third, for alliances that disempower, etc., etc.
The kind of intimacy, of sharing oneself with a life partner, that is at the heart of the best marriages is made enormously more difficult (if not impossible given the realities of human finitude), in the face of such magnified complications and potential pitfalls.
So, not only is there no polyamorous orientation such that a class of people will be discriminated against if group marriages are disallowed; there is also good reason to wonder whether a threesome (or larger group) can even form the kind of relationship that a marriage is supposed to be, let alone sustain it in the lifelong way that is the ideal of intimate life partnership which the institution of marriage holds up.
The relationships that two people have with one another tend to be different in kind from the relationships had by groups of three or more. And it's hardly obvious that the marital kind of relationship is the sort that can be had by groups of more than two. In fact, it seems pretty obvious that it isn't--so much so that I would think the burden of proof rests with those who would argue otherwise.
If I'm right about that, then there's a second way in which it is not discriminatory for the state to preclude polyamorous marriages: Groups of more than two simply can't have the marital sort of relationship at all, so denying it to them isn't denying them anything at all.
But suppose I'm wrong about that. Suppose there is only the one reason why it is not discriminatory to rule out polyamorous marriages in the way that it is discriminatory to rule out same-sex ones--namely the first one I mentioned, having to do with sexual orientation. That would be enough by itself--but there's more to be said. Even if groups of more than two can manage to achieve the marital kind of relationship, achieving it for a larger group would be a truly monumental task given our human condition. Maybe it could be sustained for a year or two. But marriage as a life-partnership isn't realized by pulling something off for a couple of years. And failed marriages are a matter of social concern.
Since no individuals are being discriminated against (absent a polyamorous orientation), the state's burden for justifying a restriction on the number of people who can participate in a single marriage is substantially lower than would be the case were individuals being subject to discrimination by the restriction. And the fact that such a restriction promotes the stability of the marriage contracts that the state helps to create is, it seems, a sufficient reason for the state to restrict official, state-sanctioned marriage to pairs.
(I imagine that greater stability could be attainable in group marriages if there were a clear hierarchy--where, in lieu of genuine partnership, what one had was one dictator ruling it over a few subserviant helpmates. But I also take it that equitable and egalitarian relations among human beings, including between the sexes, is a good that we have a social interest in pursuing. Maybe one reason why conservatives tend to see a slippery slope to polygamy is precisely because they secretly idealize male patriarchy in which husbands lord it over their wives--and don't see a substantive difference between a husband lording it over one wife or over several. But in that case, the slippery slope exists even in the absence of the state extending marriage to same-sex couples.)
Marriage is a stabilizing force. The gay community would be stabilized by access to marriage--but far more so if same-sex marriage were restricted to pairs than if it were made available to groups. Likewise for heterosexuals. The state is in the marriage business in part for the sake of achieving that stabilizing effect, and as such has a good reason to choose that form which does the best job of promoting the stabilizing outcome. (And let me point out that I said "in part," since in the last post some people seemed not to notice this and took a passing remark about one of the state's purposes for marriage as if it were the whole thing. If you want a fuller picture of my views on why the state is in the marriage business, see here.)
If the state has good reason to promote the stabilizing outcome that marriage makes possible, the state has both a reason to make marriage available to same-sex couples (thereby extending its stabilizing effects into the gay community) and a reason to preclude group marriages. Obviously, then, this case for same-sex marriage is not a slippery slope to group marriage.
In sum: Unlike in the case of same-sex marriage, precluding group marriage does not discriminate legally against a class of individuals. Furthermore, there is good reason to suppose that, unlike in the case of same-sex marriage, precluding group marriage does not discriminate in the sense of denying marriage to sets of people who are equally capable of creating the marital kind of relationship--because sets larger than two aren't equally capable. Finally, while the state's interest in promoting social stability is served by extending marriage to same-sex couples (and harmed by precluding same-sex marriage), the reverse is true for group marriage. Thus, all the main reasons that I offered in my previous post for extending marriage to same-sex couples are reasons that just aren't reasons for extending marriage to groups.
Hence, there is no slippery slope. Not even close. Rather than a downward oil-slicked glass slide between same-sex marriage to group marriage, what we have is a series of brick walls.
Note: I haven't talked here about incestuous marriage--but I think the last two posts make the reasoning process for assessing the merits of a slippery slope argument clear enough, so that anyone can discern for themselves the absurdity of saying there is a slippery slope from same-sex marriage to parent-child or sibling marriages (or pedophelic marriages, etc.). In these cases, ask if there is a sexual orientation that makes precluding this sort of marriage discriminatory against a class of individuals. If no, then you don't have a slippery slope. And ask, furthermore, whether the kind of relationship that would (or at least could) result is the sort that legal marriage is supporting. If no, then you don't have a slippery slope. And ask, furthermore, whether there is a significant state interest by which same-sex marriage and this other kind of marriage would have to be viewed differently. If yes, then you don't have a slippery slope.