In an essay on Mencius and evolutionary psychology, Donald Munro remarks that “only those [ethical rules] consistent with human nature will survive in the long term.”  The intention is to get at some basic constraints modern evolutionary biology places on moral theorizing, and in particular to use those to separate those parts of Mencius that have a future from the “dross.”  Among the latter are the “religious” claims Munro sees in Mencius along the lines of “human nature is derived from Heaven.”

I want to poke around in this a bit, not so much with a narrow focus on Mencius, but rather as a way of considering what kinds of constraints on moral thinking evolutionary biology and psychology might plausibly place on our moral thinking.

We can start with what looks to be obvious: in doing ethics we shouldn’t commit ourselves to claims known to be false.  Hence if my favorite moral theory contradicts the results of a well established science like modern biology, I’m in trouble.  But it seems to me that when something like this is invoked, as it frequently is of late, something less obvious is typically at work.  (I think it’s actually kind of rare for moral theories worth anything to get things their biology blatantly wrong in ways that really matter).  So consider again Munro: he says of Mencius’ statement about Heaven that “This claim has no Darwinian counterpart.”  The contrast is made with Mencius’ claims about human nature (ren xing), which do apparently have a Darwinian counterpart in claims about behavioral tendencies genetically hardwired into humans.  This suggests the view that it is a test of the legitimacy of claims about humans that they reduce in some sense to the claims of biology, which is surely implausible.    I don’t know what the “Darwinian counterpart” to being a Democrat would be, but that hardly suggest “X is a Democrat” is incompatible with the biological sciences.  In the appropriate contexts such a claim has explanatory force, regardless of its apparent irreducibility to biology.  At the very least biology itself delivers no such demand that our ways of explaining ourselves and our world reduce to its categories.  Biology is not in the business of dictating the proper relations between distinct explanatory schemes.  Missing here is an argument that what Menicus means in his claims contradicts, or plainly entails something that contradicts, the science, and this is I think a rather common lacuna.

What is objectionable, then, about Mencius’ claim is not that is contradicts Darwin.  Rather, it seems clear that it is the attribution of norms to the natural world—what seems to animate Mencian  invocations of Tian—that offend.  I take it that It is such an appeal that invites the “religious” appellation in the first place.  But such an invocation is objectionable only on the assumption of a naturalism that rejects natural norms, and that too is not a result of the biological sciences per se.  There may be an argument from evolutionary biology to such a naturalism, but that’s another kind of argument that is rarely provided when Darwin is said to restrain moral theory, and any such argument is surely weaker than the straightforward scientific results of the biological sciences.  Here too the appeal to evolution is a front for philosophical work that is being done off stage, and a religiously minded Mencian (if such there be) would be in her rights I think to claim critical questions are being begged.

Coming soon: must moral rules respect natural inclinations?