Noah Millman has a sensible post up at the American Conservative criticizing natural law. He begins with the definition:
“If I understand the way natural law is supposed to work, it’s supposed to be an instance of deriving social “oughts” from a natural “is.” Human beings have to some degree immutable natures, natures we can comprehend with reason, and these natures determine, to a considerable degree, what social arrangements will “work” and what arrangements won’t – in the sense of contributing to human flourishing.”
And then goes on to criticize how an understanding of natural law is implemented. (Rod Dreher tries to argue that natural law is necessary for morality, which Razib Khan criticizes.) What both Millman and Dreher miss, I think, is how ambiguous the question “What is Human Nature?” is. (Millman has the right instinct but doesn’t take his analysis to its logical end.) Let me explain.
The entire natural law tradition, although it is supposed to based on some Aristotelian understanding of man, is a massive structure of centuries of Thomistic scaffolding upon scaffolding, where the original structure is no longer recognizable. (It’s like this rendition compared to the original Mona Lisa.)
Back to the source. Aristotle was primarily a biologist, whose understanding of biology influenced the rest of his philosophy. His writings on ethics and politics are secondary to his writings on natural science. Like Charles Darwin, Aristotle examined the natural world and drew empirical conclusions. For instance, in politics Aristotle takes a rather relativistic stance that different forms of government are better suited for different groups of people. If Aristotle were alive today, he most certainly would be influenced by evolutionary theory. Who knows, his views on ethics and politics might dovetail E.O. Wilson’s Sociobiology. (I know, I know, I unfairly summarize Aristotle in three sentences what a book could be written on.) But this is not the case with natural law theory, which which now survives in some a priori stratosphere wholly removed from any biological understanding of men. (There I go again…)
Look at almost any modern natural law theory and you will find a theory either wholly ignorant of or implicitly hostile toward evolutionary theory. And on what are these natural law theories based? What is their view of “human nature” upon which this law is supposed to rest? A bunch of a priori assumptions that probably have little resemblance to reality.
As those of us who are part of the “Dark Enlightenment / Anti-Enlightenment” already know, there really isn’t a “human nature.” It’s an oversimplification. As Johan Bolhuis, Peter Frost, Cochran & Harpending and others have recently noted, humans have undergone more selection in the past 10,000 years than in the previous 40,000 years. In short, there are “human natures” (plural), and these “natures” largely correspond to what we think of as continental races – discrete groups of people who underwent natural and sexual selection to adapt to particular circumstances. (Heck, we’re now learning that different races aren’t even completely the same species.)
Thus, natural law theory is, in many respects, anti-nature in that it doesn’t wholly incorporate a realistic understanding of human biodiversity. If there is a true “natural law,” it’s the recognition of HBD.
Here are two clear-cut examples to demonstrate that natural law theory does not have a natural appreciation of human nature.
Monogamy: Usually within the context of the gay marriage debate, natural law theorists tend to argue that the “natural” order of things is monogamy among a man and a woman. While “gay marriage” might be a new invention, the scope of monogamy is limited. Throughout human history, the norm has been polygyny (which actually accelerates selection). Most of human history has been a history of hunter-gatherers and among hunter-gatherers polygyny is the norm. In fact, the fragile institution of monogamy seems to only be strong among Europeans and North Asians (and even there it has its limits — e.g. Chinese emperors taking multiple concubines, 1/4 of the Irish descended from Niall of the Nine Hostages, etc.) who switched over to agriculture approximately 10,000 years ago. So, while monogamy might be the natural current norm of North Asians and Europeans, is it for everyone?
The Abortion Debate: There’s a tendency of many natural law theorists to be obsessed with a “right to life,” which somehow is supposed to be grounded in nature. A quick survey of human history, however, shows otherwise. While the popularization of abortion might be fairly recent, the exposure of defective or unwanted infants has been the norm throughout human history — continuing even up until the 19th century. This practice was so widespread that it baffles the modern mind. While pro-life advocates today cite “high” numbers of abortions, these numbers are dwarfed by the numbers of infants routinely exposed throughout history.
While I’m not advocating a return to infant exposure or polygamy for Westerners (there are other reasons to reject these institutions), my point is that “natural law” seems to have no basis in a nature. Again, many natural law theorists seem wholly ignorant of any naturalistic understanding of human nature.