A spike in my otherwise flatlined traffic alerts me to the fact that Bill Vallicella has breathed some new life into an old post of mine which connects the same-sex marriage debate with postmodernist anti-realism. Check out Bill’s commentary and then consider the following:
1. I think Bill may have misunderstood the purpose and target of my post. I agree with him that in a debate one shouldn’t invoke premises which one’s opponent doesn’t accept. But in that post I wasn’t offering an argument against SSM, still less an argument that might be persuasive to non-Christians. Rather, I was addressing fellow Christians and making the point that some responses to SSM proposals give away the store by conceding that marriage could in principle be redefined by us.
2. Bill suggests, following his Fox News namesake O’Reilly, that appealing to the idea that marriage is a divine institution would amount to “Bible-thumping”. I don’t think appeals to the Bible are out of place in the public square, even when directed at unbelievers, but I won’t argue the point here. (Such appeals may not have argumentative traction, but rational persuasion isn’t the only respectable kind of persuasion.)
Instead I’ll observe that one could argue for the divine institution of marriage on the basis of natural theology and natural law. If there is a Creator who intended for humans to exist, and to exist as males and females in procreative relationships, then natural law arguments for marriage lead naturally (!) to the conclusion that marriage is a divine institution. If God is the author of human nature, and human marriage is grounded in human nature, God must also be the author of human marriage; in which case, we’re in no position to change it.
3. I agree that the question of whether marriage has a nature is distinct from the question of whether marriage is divinely ordained. Still, it’s hard to see how marriage could have much of a nature apart from divine ordination. Suppose marriage is neither a divine institution nor a human institution (i.e., a social convention or construction). By who or what would it be defined? Bill offers an argument to the effect that marriage is grounded in human nature and human procreative powers. But armadillos have procreative powers too. So why don’t armadillos have marriage?
Marriage has to be grounded in something more than procreative powers and opposite-sex unions. (Bill seems to grant this when he says that “there are social and cultural factors in addition to this natural substratum.”) And if that “something more” isn’t divinely ordained, it’s hard not to conclude that it arises out of human social conventions.
But perhaps Bill’s point is that this “natural substratum” is a necessary component of marriage; thus, while we might be able to change some aspects of marriage, we cannot change it in such a way as to eliminate its grounding in opposite-sex procreative unions. I think this is a good argument. However, it still depends on the notion of a biological human nature, and I’m persuaded (though again, I won’t argue the point here) that Darwinian naturalism is incompatible with biological essentialism. So it seems we’re still driven toward a theistic grounding for marriage.
4. Finally, I agree with Bill that advocates of SSM don’t have to adopt anti-realism — but it helps enormously. My observation, for what it’s worth, is that the cutting edge of the LGBT movement is closely allied with postmodernist anti-essentialism and social constructivism. (If you don’t believe me, just do some research on “queer theory”.) So the connection I’m making is a sociological one rather than a logical one.