I must confess that I grow weary of attacking moral naturalism. Speaking as both a moral skeptic and an atheist, I find myself classifying defenders of moral realism along with apologists for theism (and I have never bothered to argue against theists). Both, to my mind, have about them an air of slightly desperate conservatism: an anxious determination to ensure that popular belief systems turn out as true. I do not accept as a general rule the orthodox methodological principles underlying such an approach; I do not think it the job of the philosopher to leave ordinary beliefs and attitudes as unruffled as he or she can. How much more invigorating philosophy might be if it ruffled us; how much more intriguing life might be if we opened our minds to the possibility that we’ve all been dramatically mistaken about the nature of the world.

Rest here. See also Guy Kahane’s response here.