The Evolution of Marriage

Larry Arnhart discusses the biological roots of marriage in a recent post.  I am sorry to report that I agree with Larry on the basic issues.  I am happy to report some skepticism regarding a secondary issue. 

Larry is responding to Sherif Girgis, Ryan Anderson, and Robert George, who argue that marriage should be restricted to a monogamous, heterosexual relationship.  He tells us that the authors make two points: one, that marriage is an institution rooted in human biology and two, that if homosexual marriage is legalized this will effectively destroy heterosexual marriage. 

Larry agrees with the first point but thinks that it is inconsistent with the second point.  If heterosexual marriage is indeed rooted in nature, then it should survive any changes in legal norms.  I am inclined to agree. 

Allow me to add some of my own reflections.  Marriage is rooted in a simple biological dimorphism: women know who their children are while men do not.  When an infant issues from her mother, the mother knows that the infant is hers.  The father must rely, let us say, on less direct evidence.  How confident can he be that he is the biological father?  This has Darwinian implications, in so far as his natural instincts move him to invest in his offspring. 

The problem is widely shared among animals and has had enormous consequences for their evolution.  Males of many species try to secure paternity by keeping other males away from their mates.  Some jealously guard their harems.  Canines have evolved a mechanism called a “copulatory lock”.  When the male enters the female, his organ expands and locks him in place.  He cannot engage until sometime after ejaculation, which makes it more likely that the female will be safely impregnated.  That is the tie that binds. 

Security for paternity encourages the male to invest his time and other resources in his offspring.  Of course there is a trade-off.  If the male is fooled, he will waste his resources on the offspring of some other male.  Likewise, he will be tempted to hedge his bets by siring offspring with other females, perhaps with false promises of support.  Such is the soap opera of mammalian biology.  If male parental investment is to be maintained against or supported by selection pressure, some means of securing paternity have to be available to the male. 

The human institution of marriage was built on these biological foundations.  Marriage offers the male some assurance of paternity in exchange for his promise of investment.  That contract is reinforced by the larger community, which recognizes his authority over his sons and daughters.  See Aristophanes Clouds.  It also puts a disproportionate weight on the fidelity of the wife. 

However, marriage is not a product of biology even if it rests on biological foundations.  It arises and is maintained because it is one of the conditions for human flourishing in social conditions.  The telos, or purpose of marriage, was not reproductive success in a Darwinian sense.  It was to promote societies that are more stable and satisfying, given our evolved inclinations.  Human institutions cannot for long act against natural selection; however, they exist to serve us and not our genes. 

Given that brief consideration of the biological foundations of marriage, what does it mean to extend the institution to include homosexual couples?  It means only that an institution that has been developed for one purpose has been employed for another.  This is a commonplace in both biological and cultural history.  In the ubiquitous beetles, a second set of wings evolved into a retractable coat of armor.  Clothing likely emerges as a remedy for discomfort in hostile climates; however, it comes to serve other purposes such as displaying wealth and status, inviting seduction, providing pockets, etc. 

While heterosexual marriage evolved to serve purposes connected with biological reproduction and familial stability, there is no reason to suppose that it cannot serve other purposes.  Some have argued that same sex marriage can promote monogamy among male homosexuals, which might well be a good thing.  Whether it can really do that remains to be seen.  I have my doubts.  

I am in favor of legal same sex marriage for a rather simple reason.  When two persons of the same sex form a stable relationship, analogous to heterosexual marriage, the two partners should enjoy the same privileges as a heterosexual couple who have chosen to marry.  When one goes to the hospital, the other should have the same medical access that I and my wife have.  This strikes me as the decent thing to do. 

I see no reason to suppose that this undermines the functions of heterosexual marriage any more than wearing cloths to make a fashion statement undermines the purpose of good winter gear in these Dakotas. 

That said, I am not at all certain that I agree with Larry Arnhart regarding the privatization of marriage.  Such a step would certainly render moot the political arguments over marriage, just as the privatization of religion dramatically reduced the tendencies toward armed conflicts between sects.  However, this step clearly weakened religion as a force in secularized societies.  As I noted above, marriage is an artificial institution and it can be stronger or weaker in its effects, depending on how it is managed. 

I think that marriage is one of the most important institutions in human history.  We want to encourage it and strengthen it, in so far as we can.  I suspect that privatizing it would weaken it by placing in the category of things that are not serious enough to have legal consequences.  Because I agree with Larry that marriage has deep foundations in human biology, I don’t expect that this would kill marriage.  I do think that it might weaken it further.  If I am right, that would be a step in the wrong direction.