Gay Marriage and Natural Kinds

by David Carlin - December 12, 2008

Reprinted with permission.

What does Aristotle have to do with same-sex marriage?

Aristotle held that the human race, in addition to being divided into male and female, was also divided into slave and free. This latter division was not merely conventional or legal; like the male-female division, it was a product of nature. Just as nature had made some humans male and others female, so it had made some free and others slave.

I mention this Aristotelian idea, not because I want to discuss slavery and freedom, but because I want address the idea that the human race can be divided up into what may be called "natural kinds."

It's an idea that has surfaced again and again in human history. Almost all ancient Greeks in Aristotle's time, and for a few centuries earlier, believed that there was a difference in nature between Greeks and those they labeled "barbarians" – that is, all non-Greeks, whether living in a pre-civilized condition (like the Scythians of the north) or living in a highly civilized condition (like the Persians and Egyptians). And this was not just a distinction in kind, it was also a distinction in rank: Nature ranked Greeks above barbarians. Greeks were superior by nature, barbarians inferior.

With only very rare exceptions, a distinction of natural kinds has always been seen as a distinction in rank between superior and inferior. Throughout the centuries, scholars may have said, "The X people are different from us because they have a different religion or different environmental circumstances or a different education," but most regular people, it is safe to say, would think, "The X people are different from us because nature (or God, the author of nature) has made them different – and made them inferior as well."

Modernization, the Enlightenment, and the growth of democracy brought a welcome decline in the idea that the human race is divided into natural kinds. "All men are created equal" – this was the new belief that was sweeping the world, and for much of the 19th century it looked as though this new belief would prevail. But it suffered a tremendous setback as the old natural-kind theory underwent a tremendous revival in the aftermath of the Darwinian revolution in biology.

A theory of nature-made human "races" emerged and became popular, especially in the countries of northwestern Europe and the United States. At first this theory was the property of gentlemanly pseudo-scientists, who used the theory to justify, for example, the social supremacy of whites over blacks, or of Englishmen over the Irish, or of Europeans generally over the peoples of Africa and Asia. But before long the theory fell into the hands of some exceedingly un-gentlemanly people, including Hitler and his fellow Nazis. The Holocaust followed, almost as a kind of logical conclusion from the theory.

In the decades since the horror of the Nazi episode, the world has turned away not just from race theories but from the whole idea that the (one and only) human race can be divided into different natural kinds. This is true even in the single case in which nature really has made an obvious and undeniable difference – as in the difference between men and women. Traditionally, this difference in kind implied a difference in rank: Nature, it was believed, made men superior and women inferior.

But we have now rejected this difference in rank. While we acknowledge that men and women have natural differences, we now insist that they are equal in rank. And we have adopted what may be called a "minimalist" idea of the natural difference between the two. No longer do we hold that women are by nature unsuited for certain careers or activities.

Yet at this moment, when the theory of natural kinds is on the verge of being thrown into the dustbin of history, along comes the gay-rights movement with its insistence that the human race is divided by nature into heterosexuals and homosexuals (not to mention bisexuals and transgender people). It is this argument that justifies the movement's demand for same-sex marriage. Gays and lesbians, it is argued, being different kinds of human beings, cannot be expected to conform to the form of marriage that has been established in response to the needs of the heterosexual kind of human being. A different form of marriage must be created in order to respond to the needs of a different kind of human being.

Supporters of the gay movement often argue that there is a strict analogy between the ban on same-sex marriage and the earlier ban in some American states of interracial marriage. But the analogy is far from strict. The ban on black-white marriage would make sense if we believed that blacks and whites are different kinds of human being. But since we have decided that they are not different kinds, the ban on interracial marriage makes no sense. Yet the promoters of same-sex marriage make an argument that is the inverse of this: Since homosexuals are, they say, a different kind of human being, the ban on same-sex marriage makes no sense.

I am unable to see the future of human society, so I am unwilling to make predictions. But I cannot avoid the ominous feeling that this reversion to the old, pernicious, and almost dead theory of natural kinds is something that we may all – and I include in this "all" homosexual activists themselves – eventually come to rue.

David R. Carlin is the author of The Decline and Fall of the Catholic Church in America.