The mistake philosophers tend to make is in accepting rationalism proper, the view that our moral intuitions (assumed to be roughly correct) must be ultimately justified by some sort of rational theory that we’ve yet to discover.

The author seems to assert that this is a cultural phenomenon. I wonder if our attempts at unifying into a theory might not be instinctive, however. Would it then be so obvious that Moral Realism were false? We have an innate demand for consistency in our moral principles, that might allow us to say something like "racism is indeed objectively wrong, IF you believe that happiness is good."

That being said, I don't think it's enough to save moral realism. The probability that moral realism is false has been a disturbing prospect for me lately, so I'm curious how he carves out a comfortable alternative.