Commenting on our argument in the Harvard Journal of Law and Public Policy that the law ought to retain (or re-establish) the conjugal understanding of marriage as the union of husband and wife, Andrew Koppelman rehearses some of the objections (to which we reply here) posed by Kenji Yoshino. But Koppelman, who had faulted Yoshino for failing to engage our arguments and had pledged to “do better,” feels compelled to take an extra step:

I have good news and bad news for Yoshino. The bad news is that he needs to get into these technical philosophical issues in order to show why his objections are effective, and because he does not do so, his argument is incomplete. The good news, much more important, is that if one digs into these philosophical recesses, it becomes clear that Yoshino has exposed to view a central reason why George’s argument is nearly impossible to believe.

So, having declared the need to do “fairly technical philosophical work” on Yoshino’s behalf, Koppelman rolls up his sleeves to dig. But what one finds in the “philosophical recesses” of our view, far from being (as Koppelman asserts) “nearly impossible to believe,” is the kind of principle cheerfully affirmed by the majority of analytic philosophers today—and ultimately relied on, we suspect, by Professor Koppelman himself. So the debate must return from those “recesses” to the open air—where we have posed numerous challenges, almost all of which Koppelman has repeatedly sidestepped in his comments on our article, including the latest.

Our article and replies to critics (including Koppelman) argued that the only account of marriage that makes sense of the institution’s widely acknowledged features allows for genuine marriage without children, but not without sexual complementarity. For it is sexual complementarity that makes possible the consummation of marriage as a true bodily union. The union of spouses in coitus, we showed, was deeply related to marital union’s widely recognized comprehensiveness and inherent orientation to children—facts without which norms such as permanence and monogamy cannot be accounted for. Thus, sexual complementarity (among other things) is necessary for marriage, but fertility (among other things) is not.

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Koppelman’s “fairly technical philosophical” move is to reject the distinction between (a) features that a thing must have to be what it is, and (b) features that the same thing may but need not have to be what it is. He erroneously calls this “Aristotle’s essence/accident distinction.” (In fact, Aristotle did not equate necessary and essential properties.) In any event, Koppelman thinks that readers should reject this distinction wholesale, and with it therefore our view of marriage. What he offers against the distinction might charitably be called an argument from befuddlement: it is, he repeatedly says, “odd,” “weird,” and “archaic”; indeed, “nearly impossible to believe.”

That will come as a surprise to contemporary analytic philosophers, the majority of whom credit just such a distinction, affirming that things can have essential properties (quite apart from any discussion of marriage). In fact, important advances in the understanding and defense of essentialism have been made by some of today’s brightest lights in philosophy: With logical positivism now reduced to an early 20th-century relic (and, in truth, nearly impossible to believe), such thinkers as Kit Fine of NYU, Saul Kripke of Princeton and CUNY, Hilary Putnam of Harvard, David Wiggins of Oxford, Stephen Yablo of MIT, and Alvin Plantinga of Notre Dame have embraced essentialism and contributed to a growing body of literature that explores (1) different versions of essentialism (e.g., “sortal” or “origins” essentialism); (2) competing ways of analyzing it (modally vs. non-modally); and (3) its implications for the natural sciences, personal identity, philosophy of mind, philosophy of science, philosophy of language, and much else.

Of course, by themselves these observations are no argument for the view that some things have some essential properties in a more than merely linguistic sense. Nor, needless to say, are they an argument for our view of marriage, which some supporters of essentialism share and others (including several named above) do not. But these considerations do make Koppelman’s dismissive rhetoric—“odd,” “weird,” “nearly impossible to believe”—seem less true of our approach than of Koppelman’s own somewhat amusingly overconfident dismissal of it. As for the idea that the distinction we (and most contemporary philosophers) draw is “archaic”: If historical pedigree undermines a view, then what should we make of the fact that Koppelman’s rejection of essential properties can be traced to a 14th-century English scholastic monk, William of Ockham? The answer is clear: Nothing. Ideas should be judged on their merits.

So consider the merits of the idea that a given reality has some of its features necessarily, and not others—not just as a matter of the language we use, but as a matter of genuine fact.

  • To be a sample of the kind of clear liquid found in lakes and rivers (i.e., water), a substance must be composed of H2O molecules—though it need not boil at 100 °C (since boiling point varies by altitude).
  • Any particular human being (say, Andrew Koppelman) could not have been born to different parents—though he could have gone into a different profession.
  • To realize the human good of friendship with each other, two people must actively will each other’s good—though they need not be bowling partners.

None of these perfectly natural statements would make sense without the idea, attacked by Koppelman but embraced by most philosophers (both historically and currently), that some things have some essential features. Nor, again, is this merely a terminological issue. It’s not just that a human being born to different parents would have been differently named or unrecognizable as Andrew Koppelman. It’s that no one born to different parents, and thus with a completely different body, could have been the very human being that Koppelman is. Likewise, two people who do not will each other’s good are not just missing out on a label, “friendship”; they are missing out on a human good whose specific benefit or fulfillment is not available otherwise.

This is the kind of principle relied on in our argument that genuine and complete marriages have certain essential features (like sexual complementarity and a pledge of exclusivity) but that actual procreation is not one. In other words, Koppelman’s “digging” into “fairly technical philosophical” terrain will turn up a bedrock distinction common to most sensible worldviews. In fact, we imagine that Koppelman himself, like the rest of us, implicitly relies on it every day.

At points, Koppelman trades his shovel for a pickaxe, to aim at the distinction’s application specifically to marriage. But even these attempts do nothing to erode the grounds of our view.

First, Koppelman rejects our argument that marriage is inherently (not just incidentally) a sexual partnership sealed in coitus, which completes marital union to include every aspect of the spouses’ beings, including their bodies. On our view, in other words, non-marital friendships are characterized by a union of hearts and minds; but marriage, being a comprehensive union of persons, extends this unity to the bodily dimension. For our bodies are integral aspects of us as persons, not merely our extrinsic instruments. And in coitus, a man and woman’s bodies unite much as a heart and lungs unite within an individual—by coordinating together toward a single biological good (here, reproduction) of the whole (here, the whole couple).

Koppelman’s objection is that the coitus of infertile couples is no more a bodily union than any other sexual activity. But three times now he has silently passed over our reply to this: that just as a person’s stomach action retains its orientation to nourishment even when nourishment doesn’t occur (e.g., because of intestinal problems), so a man and woman’s intercourse is still coordination oriented to the single biological good of reproduction even when reproduction doesn’t occur (e.g., because of ovarian problems).

Without answering this defense of the point, Koppelman lodges a new objection that fares no better: namely, that our view would also mean that people administering and receiving CPR unite biologically. But it is clear that in this case, there is no mutual coordination toward a biological good of the parts as a whole, as there is in coitus and any form of real bodily union (e.g., among an individual’s organs, coordinated together for the life of the whole organism).

Second, Koppelman argues that nothing could be a necessary feature of marriage since marriage is nothing more than a social construct, malleable enough to include whatever sorts of unions, sealed by whatever sorts of acts, we deem most socially desirable. He thinks that our law’s longstanding practice of singling out the uniquely comprehensive unions completed and sealed by coitus can be explained away as a need for bright policy lines to prevent conception out of legal wedlock. But that answer fails to account for the 2,300-year-old philosophical tradition, originating independently of such policy considerations (and of Judaeo-Christian influence), that similarly distinguished the uniquely comprehensive unions consummated by coitus from all others. Indeed, the three great philosophers of antiquity—Socrates, Plato and Aristotle—as well as Xenophanes and the Stoic Musonius Rufus defended this view amid highly homoerotic cultures.

Especially clear is Plutarch’s statement in Erotikos that marriage is a special kind of friendship uniquely embodied in coitus (and not other acts, which Plutarch regarded as intrinsically shameful). Indeed, he called coitus a “renewal of marriage.” His insight into the value of the comprehensive union of persons uniquely embodied in marital acts also allowed Plutarch to see and explicitly affirm (in his Life of Solon) what Koppelman finds so baffling: that unlike non-coital sex, intercourse with an infertile spouse also realizes the good of marriage—something that all of the other mentioned ancient philosophers seemed to take for granted, even as they denied that other sexual acts could do the same.

The key is to see that while procreation is the biological good in virtue of which a man and woman’s intercourse unites them in mutual bodily coordination, this bodily union is an aspect of a comprehensive relationship valuable in itself and not just as a means to procreation. So the ancient philosophers saw what our legal tradition has long affirmed: marriage is a procreative relationship, but its intrinsic value remains whether or not children are born as the fruit of the spouses’ union.

Koppelman’s view has no resources to make sense of the philosophical tradition. But in attempting to explain away the parallel Western legal tradition, he does concede that the original public purpose of marriage law was not to oppress or exclude anyone, but to ensure that wherever possible children were reared by their father as well as their mother. His contention is simply that we should now expand its purposes to recognize same-sex partnerships.

Note two things about this concession.

First, it shows that when Koppelman insists that “any definition of marriage that excludes same-sex couples strikes [him] as already underinclusive,” he is simply measuring marriage law against a set of purposes that, for whatever reasons, he wishes it served, and not against the purposes that he admits it has served historically. In other words, Koppelman seems implicitly to concede that there is a rational basis for current marriage law—in which case, it passes constitutional muster. He also implicitly concedes that to recognize same-sex partnerships would be not merely to expand but to change the definition and meaning of civil marriage.

Second, while urging that we expand marriage law’s understood purposes, Koppelman says nothing to answer a consideration we raise against doing so: If the law encourages people to see marriage as an essentially emotional union that has no principled connection to organic bodily union or procreation, then marital norms (e.g., permanence, exclusivity, monogamy) will increasingly be treated as optional at best, and groundlessly restrictive at worst—at great cost to children and society generally. (After all, there is no reason that essentially emotional unions like friendships should involve pledges of permanence or exclusivity.) Koppelman also completely sidesteps our specific argument that he has no ground of principle for opposing “open marriages” and legal recognition of polyamorous sexual partnerships as marriages. That only reinforces our conclusion that no answer to this objection is possible.

Thus, two interventions in this debate which began with Koppelman’s intention to “dig” into “fairly technical” matters and illuminate the “philosophical recesses” of our view, ended up breaking no ground and exposing nothing damning or even damaging. Despite his initial projection of confidence and philosophical sophistication, Koppelman ignored almost every challenge we posed to his view. And the one distinction of ours that he chose to make the focus of his attack—deriding it as “archaic” and “nearly impossible to believe”—has turned out to be widely embraced by leading contemporary philosophers and difficult to deny on the merits. Thus, shovel in hand notwithstanding, Koppelman has struck no blows against the conjugal view of marriage or our philosophical defense of it.