As Rorty notes, "Hauser hopes that his book will convince us that 'morality is grounded in our biology.' Once we have grasped this fact, he thinks, 'inquiry into our moral nature will no longer be the proprietary province of the humanities and social sciences, but a shared journey with the natural sciences.'" Though Rorty minimizes that possibility at a very high level of generality, Mikhail moves the ball forward by pointing to the work of several experimental philosophers. This defense of X-Phi mentions one of them: "Jonathan Haidt’s discovery that low socioeconomic status (SES) individuals judge harmless actions which evoke disgust to be morally wrong, while high SES individuals do not judge them to be morally wrong."
Now my question is: what way does that observation cut, philosophically? Do we think the lower SES respondents would have a more tolerant view if, say, they were better educated (assuming a correlation between SES and education) (ala Nussbaum in Hiding from Humanity)? Or do we interpret this result as a symptom of decadence in the upper classes (perhaps ala Lasch's Culture of Narcissism)? As David Velleman notes, "real philosophizing starts after [received opinions] have been surveyed." Experiments may help us confirm positive theory like the Generalized Axiom of Revealed Preference (as this paper shows); but how do they provide a benchmark for normative theory?
To put the issue more sharply: imagine someone says "the failure of developed countries to redistibute even 3% of their resources to solve the worst privations caused by global poverty may be viewed, in 100 years, as a moral wrong as fundamental as slavery." Now I know that's a fraught and dangerous analogy...but what if someone looking at survey results said "there are few people with such an intuition. And we are biologically programmed to care almost infinitely more for those who are genetically similar to us than for distant strangers." Could an X-Phi-driven conversation end there?
I hope not. As Peter Unger observes, “all too often, our moral intuitions about cases are generated not by the basic moral values we hold, but by psychological dispositions that prevent us from acting in accord with our deep moral commitments.” Unger argues that intuitions are only valid when the intuiting person is “aware of what’s most morally relevant.” I've tried to pursue that point in a recent presentation at the APSA; I'd be happy to share it with anyone interested.