When marriage or certain sexual practices are described as “natural,” the word is being strategically deployed as a synonym for “normal” or “traditional,” neither of which carries nearly as much rhetorical weight. “Normal” is by now too obviously soaked in moral bigotry; by comparison, “natural” seems to float high above human squabbling, offering a kind of secular version of what used to be called divine law. Of course, that’s exactly the role that “natural law” played for America’s founding fathers, who invoked nature rather than God as the granter of rights and the arbiter of right and wrong.
“Traditional” marriage might be a more defensible term, but traditional is a much weaker modifier than natural. Tradition changes over time and from culture to culture, and so commands a fraction of the authority of nature, which we think of as timeless and universal, beyond the reach of messy, contested history.
Michael Pollan, “Altered States”, The New York Times Magazine (3 May 2015), 16.