Why do people make such claims? Why would anyone ever suggest that our emotions could act as an objective ground for morality, much less that they should?
Our emotional responses play a mere supporting role to our attempts at morality. Psychologists and philosophers have long run studies and conducted thought-experiments that have confirmed that our emotions are a fickle guide to questions of morality. There is a whole set of situations described as "the trolley problem."
The trolley problem illustrates that we have very different emotional responses to different situations that appear morally equivalent. It doesn't mean we abandon the project.
Rosenberg used the example of honor killing in his article. If we don't have a universally consistent emotional response to honor killings, he asks, how can a claim that "honor killing is wrong" be right, correct or well justified? This non-problem leaves me cold.
We have a strong emotional reactions to soldiers lining up a group of women and children in front of a ditch and shooting them in the woods. On the other hand, our blood does not boil at the thought of flyers in the Enola Gay dropping an atomic bomb on women and children. That's a trolley problem. It doesn't mean that (despite our different emotional responses) we can't bring legal, religious, or philosophic reasoning to bear on these different atrocities. Within our legal, religious, philosophic and cultural traditions we can find well justified reasons to say that--despite our different emotional reactions--executing women and children with machine guns in the woods and dropping an atomic bomb on women and children from an airplane are equally wrong. Through moral reasoning we can reflect on how we would want to behave when confronted with similar problems, what behaviors we should tolerate, encourage, or prohibit and punish as a society... and why.
In the trolley problem we are asked to make on the spot hypothetical moral calculations. Neuroscientists can tell us which parts of our brain are stimulated as we make such calculations, and what the probability distributions are. But probability distributions of our emotional reactions to described situations do not answer how we would want to behave when confronted with a given situation, what behaviors we should tolerate, encourage, or prohibit as a society, ... and why.
Is an honor killing worse than President Truman authorizing the dropping of atomic bombs on Hiroshima and Nagasaki? Talk to me. That's the essence of moral reasoning.
When we reason to determine how we would want to behave in a given circumstance, what behaviors we should tolerate or encourage as a society, and which we should prohibit and punish... and why, we look to our traditions: legal, religious, communal, social, moral. And in our modern world, our ethical judgments will undoubtedly be informed by a combination of these overlapping traditions.
And our traditions and our emotions, of course, speak to each other. In the United States we have a traditional food chain that is built around inhumane treatment and killing of animals. Because that is our tradition, most of us are not affected emotionally by this practice. But there are people who look to different religious or philosophic traditions to reach the conclusion that the inhumane treatment and killing of animals on an industrial scale is not right, correct, or well justified. A person who has formed that view may start to have an emotional reaction to our inhumane treatment and killing of animals on an industrial scale.
Should same sex partners have the right to marry? That is a moral question. The Supreme Court recently examined this question in light of our two hundred year plus legal tradition. We've been having a public discussion about it. Within that tradition the court found well justified reasons to rule that "Yes, they have that right." That ruling is right and correct in light of the legal tradition in question and the reasons stated therein.
"Right, correct, and well justified," is not the same thing as undisputed and incontestable. Morality is not like that. And emotions are an uncertain guide. But bring on an enlightened legal culture; bring on thoughtful social policies; bring on education; bring on kind and wise priests, rabbis, pastors, qadhis and imams; bring on non-corrupt politicians; bring on public sector workers dedicated to serving the public; bring on citizens committed to the common welfare. Somewhere in all of that we'll find our morality.