I think that the answer to this conundrum is to be found in Joshua Greene's dissertation. On page 202 he says:
"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 ... a piece of moral theory with justificatory force and not a piece of psychological description concerning patterns in people’s emotional responses."
When Eliezer presents himself with this dilemma, the neural/h...
see Bostrom's paper