Polygamy and the Slippery Slope Fallacy

A couple months ago, I devoted a post to a story that was floating around the right-wing blogosphere at the time and had even been picked up by the notoriously fact-averse Bill O'Reilly. It was the story of a Dutch trio (one man, two women) who were "married" in the Netherlands earlier this year. O'Reilly and others reported that polygamy had been legalized in the Netherlands and used the story as a platform for self-righteous "I told you so" rants. There was only one problem with the story. It wasn't true. The Netherlands does not allow three-way marriages or even three-way civil unions. The people in the story had merely signed something called a samenlevingscontract, or "cohabitation contract," which is nothing more than a private contract that spells out the legal rights and obligations of people who live together. It's nothing even remotely akin to state-sponsored marriage (or civil unions). College roommates or elderly widows who live together (think Golden Girls) can and do enter into this same sort of arrangement. It is apparently true that Victor, Bianca, and Mirjam had a wedding ceremony and plan to live together as a polygamous trio, but that, in and of itself, is hardly groundbreaking news. In free societies, people can hold ceremonies celebrating whatever they choose, and they can live in any arrangement they see fit. Remember when Roseanne and Tom Arnold "married" their personal assistant? Have you ever been to Utah? Unsanctioned polygamy is hardly newsworthy. Indeed the only newsworthy elements of the story were the claims that this wedding represented the "first civil union of three partners" and that "in the Netherlands polygamy has been legalised in all but name," claims which were, of course, outright lies.

But the story refuses to die. This week Victor, Bianca, and Mirjam grace the cover of The Weekly Standard under the caption "Here Come the Brides: Plural Marriage is Waiting in the Wings." The story, written by Stanley Kurtz, is less misleading about the underlying facts of the story than the first round of articles and blog posts, but it's every bit as hyperbolic and alarmist. Kurtz discusses in some depth what he perceives to be the "slippery-slope implications" of this story. He observes matter-of-factly that "[d]espite the denials of gay-marriage advocates, in both legal and cultural terms, Victor, Bianca, and Mirjam's triple union is a serious move toward legalized group marriage in the Netherlands." Kurtz attributes particular significance to the fact that Bianca and Mirjam describe themselves as bisexual. He suggests that bisexuality will be the hook through which activists will push to have polygamy legalized. They'll argue, he predicts, that if people are born bisexual, it is not fair to make them choose one sex over the other. It's clear from the article that Kurtz thinks the legalization of gay marriage will inevitably lead to the legalization of polygamy and God knows what else.

The problem with Kurtz' reasoning is the problem inherent in nearly all slippery slope arguments. The slippery slope analogy assumes that society exists on a level plateau situated atop a giant arcing slope. If we move away from the level ground and onto the slope of the hill, the danger is that our momentum will cause us to tumble down the embankment and into anarchy. The problem with this analogy is that it's ahistorical. Society doesn't exist on a plateau but on a continuous slope, and no part of that slope is more slippery than the next.

Human society is, at its heart, an exercise in line drawing. The rules are always changing. We, as a society, decide that you can do this but you can't do that. You can marry at age 16, but not age 15. You can marry your 2nd cousin but not your 1st cousin. Moving one of these lines does not make it any harder or easier to draw other lines. Allowing interracial marriage did not plunge society into chaos. Neither will allowing gay marriage. We'll just redraw the line. Similarly, moving the minimum age of consent from 12 to 16 did not lead to the end of teenage marriage. We just moved the line. Societies always draw lines, sometimes wholly arbitrary ones. If someone comes along and points out that there's no real difference between a 15 year old and a 16 year old, we don't just throw up our hands and change the law to allow 15 year olds to marry. That's not how things work. I'm sure Kurtz is right, that someone will argue that legalizing polygamy is the next logical step, that it's not so different from gay marriage. Democratic societies will not, however, feel logically or morally obligated to do so. Kurtz and others want you to believe that societies cannot take one step down the slope without taking a few more. But that's specious reasoning.

Every step that society takes is an independent step. It's silly to argue that taking one step necessitates taking three more. That kind of reasoning would lead to societal paralysis. It's nothing more than a dodge, a way of avoiding any substantive discussion of the actual step being proposed. Opponents of gay marriage (particularly those who consider themselves enlightened intellectuals like Kurtz) like to pretend that it's not so much gay marriage itself that bothers them, but the other things that such a step would "inevitably" lead to. Of course, these concerned citizens never seem to realize that this exact same argument, if taken seriously, would have justified not taking the last few steps as well. Why should we have legalized interracial marriage, for instance, if doing so would inevitably have led to less desirable "down slope" consequences? No, this sort of reasoning is a recipe for never changing anything. It's a cop out, a way of avoiding the issue at hand.

The truth is that all of history lies on a slope. There is no plateau. No one step is more likely to send us plummeting down the hill than any other. People who say otherwise misconceive the very nature of human society.