He takes the view that morality is a human contrivance to imply that we can answer moral questions only by understanding the biology behind our moral sentiments. It is worth noticing the implications of this argument. If we could not conduct any inquiry whose object is a human contrivance without inquiring into its biological roots, we would be unable to balance our checkbooks or figure out winning moves in chess without first understanding the selection processes that led us to engage in these activities — unless, of course, we were prepared to regard truths about our bank balances or what move will mate in two as “ethereal messages awaiting revelation”. Wilson’s argument depends on the idea that these are our only alternatives. But they are not.
Suppose, for the sake of argument, that morality is a ‘contrivance of the mind’. This would not imply that we need to use biology to determine what the answers to moral questions are. Think of mathematics, which is arguably a human invention. Biology might explain why we have the ability to construct mathematical proofs, but it is not necessary to know anything about biology to construct the proofs themselves, since biological claims do not normally figure as premises in mathematical arguments. Likewise, the claim that morality is a human contrivance might imply the existence of a biological underpinning to our ability to construct moral arguments, but it does not follow from this that biological claims must figure in the arguments themselves….
The crucial issue is whether biology is relevant to ethics in a third way. If we knew which moral principles people can act on, and the consequences of adopting them, we would still have to decide which principles we should adopt. Should we adopt those that make us happiest? Those that promote human autonomy? Those that all could endorse? Professor Wilson’s central thesis is that we can use biology to answer this question. But it is not clear how biology could answer it: how, for instance, any amount of information about the processes of selection that led to altruistic behavior could license conclusions about when that behavior should be encouraged and when it should be proscribed. Wilson’s only support for the claim that it can is that the alternative is to imagine moral truths “vibrating in a nonmaterial dimension of the mind”. But if, as I argued above, this is not our only alternative — if we can hold both that morality is a human contrivance and that biology is not relevant to answering moral questions — then this is no support at all.
While I think it is interesting to determine if biology influences our ability to construct moral arguments (or for that matter, other arguments too), hilzoy is dead on target on this–things that are ‘human contrivances’ do not require biological mechanistic explanation.
Wilson conflates two things:
1) morality is a biological process in that it is the result of human cognition.
2) biological mechanism (and, in particular heritable genetic variation) is required to explain theories of ethics and morality.
That conflation is as flawed as the idea that one must explain natural selection in terms of quantum mechanics. It also is shoddy biology.