A recent article entitled “The Importance of Your Gag Reflex When Discussing Homosexuality and ‘Gay Marriage’” has occasioned much comment in the Christian blogosphere.

In it Thabiti Anyabwile, writing for The Gospel Coalition, outlines what he thinks is a novel approach for Christians to engage the same-sex marriage question in the public square. “Most people,” Anyabwile argues, “have a visceral reaction, a gag reflex, when they think about sex between two men or two women,” and for too long professional gay activists have set the terms of the cultural debate by talking about everything except “what goes on in the bedroom.” Instead, he tells us, they have discreetly moved the discussion on to more savory topics such as love, civil rights, medical insurance, and the like.

Anyabwile’s proposed solution to this problem is that we must simply return “the discussion to sexual behavior in all its yuckiest gag-inducing truth.” At first Christians are “going to have accept the fact that we aren’t going to be liked” for doing this. But eventually the surrounding culture will, he seems to think, thank us for pointing out what they have really known all along—but were just suppressing—about how disgusting homosexuality is. To this end, Anyabwile’s article includes several graphic descriptions of homosexual sex acts intended to prove his point, and to provoke the reader’s “gag reflex.” He concludes (apparently without irony) by reminding us to engage this question with “much kindness, insight, warmth and fairness.”

Anyabwile’s no-nonsense approach to confronting sexual vice might be appealing to some embedded in the Aristotelian-Thomistic tradition. After all, we are not Kantians who care only about presenting moral arguments in cold, rationalistic syllogisms. We are interested in cultivating not just habits of right action, but a healthy moral imagination imbued with a love of the good, the true, and the beautiful. We want to train our affections (and to help others to train theirs) to love what is holy and to be repulsed by what is sinful. Judging by the lurid descriptions of gay sexual practices (and grisly statistics illustrating their medical consequences) which I’ve come across time and again in socially conservative Christian literature on homosexuality, Anyabwile is far from being the only person who thinks the best way to defend traditional sexual mores is by provoking the “gag reflex.”

But there is an insurmountable problem with using these sorts of arguments in a largely secular conversation. Though Anyabwile bills his argument as relying solely on the "gag reflex," what it actually relies on is teleology: the idea that things can be defined by the purpose for which they were created. When we argue that X body part is for this purpose, Y orifice is for that purpose, and hence combining them in Z manner violates the purposes of both, this is a statement in which every part of the description relies on a teleological understanding of the world. When we take away the assumption that we live in a meaningful universe endowed with purpose by its Creator, this argument simply falls apart. It is literally incomprehensible.

Yet it seems to me that in twenty-first century America it is this—a Christian teleological worldview in which things have purposes defined by their Creator—and not the gag reflex, that is precisely the thing we can't take for granted. I suspect Anyabwile and other social conservatives would have quite a shock if they actually tried their gross-out strategy on real people that didn’t already share their worldview. Anyabwile evidently thinks that their reaction is going to be something along the lines of, "wow, when you describe gay sex like that, it really is disgusting." Instead, in a world stripped of teleological meaning and purpose, the response is likely to be something more akin to, "well, when you describe it like that, of course it sounds gross, but I prefer to describe it differently.”

Logically speaking, one can believe in a sort of teleology without being a Christian. Aristotle believed things existed for a purpose and could be defined according to that purpose, yet he was neither a Christian nor even a theist in the modern sense. But, for Aristotle, teleology is largely assumed, not argued for. He is hardly helpful, therefore, in our present predicament. We can point to Aristotle as an example that proves non-Christians can have a teleological worldview, but not as an argument that they ought to see the world in this way. Aristotle’s thought was taken up by the medieval scholastics into a Christian synthesis, and with the rejection of that synthesis by the modern world, all notions of teleology have been junked.

This is one reason why so many attempts by Christians to present a defense of traditional marriage in “non-religious terms” fail abysmally. Arguments presented in non-religious language often still rely on a whole series of presumptions which are incomprehensible to non-Christians, and just because you’ve managed to make a case without the explicit use of theological terminology, it does not mean that a case has been made that is actually understandable and convincing to anyone except other Christians (I can’t be the only who has noticed that almost no non-religious defenses of traditional marriage are actually written by non-religious people).

Naturally, I am not arguing that the solution to this problem is to foist the entire Gospel upon non-Christians every time we wish to make a point in a public debate. St. Paul tells us that those who are “unskilled in the word of righteousness” should be fed on milk, and only those “who have their faculties trained by practice to distinguish good from evil” should be given the meat of “solid food” (Heb 5:13-14). But we can at least realize that this is a problem. Many Catholics think the best way to engage the gay marriage issue and other “culture wars” topics is not simply by not feeding people meat right now, but by hiding the meat in the cupboard and bolting the door to ensure it rots away without ever seeing the light of day, and relying instead on a jumble of sociological studies, junk science, and statistics that probably don’t even qualify as nutritious “milk.”

One of the most popular definitions of “traditional marriage” that its defenders are fond of quoting is that given by Lord Penzance in the famous English polygamy case of Hyde v. Hyde (1866). Lord Penzance defined marriage, for the purposes of Common Law, as “the voluntary union for life of one man and one woman, to the exclusion of all others.” What is usually omitted from this quotation, however, is the justification that he gave for this definition. He did not claim to be expounding the findings of the social sciences or even the natural law abstractly conceived, but the “the nature of this institution [i.e., marriage] as understood in Christendom.” It is this that Christians should be defending: Christian marriage, not “traditional” marriage, because ultimately it is God who makes the natural law law, and not merely a series of correlations. If the ultimate telos is removed from the picture, no other telos makes sense. Precisely because it is the true vision, the Christian vision of marriage has the answers to questions people are already asking. This is how Christianity shows its “reasonableness” in the public forum. Not by pretending it isn’t Christianity, but by showing that Christianity is, as Justin Martyr was fond of saying, “the true philosophy.”