I'm continually surprised that so many people here take various ideas about morality seriously. For me, rationality is very closely associated with moral skepticism, and this view seems to be shared by almost all the rationalist type people I meet IRL here in northern Europe. Perhaps it has something to do with secularization having come further in Europe than in the US?

The rise of rationality in history has undermined not only religion, but at the same time and for the same reasons, all forms of morality. As I see it, one of the main challenges for people interested in rationality is to explore how to live without morality. Many "rationalists" instead go into denial and try to construct some supposedly rational form of morality, more often than not suspiciously similar to the traditional ideas. I'm not sure whether or not Eliezer's metaethical project is an example of this, but in any case he is commendable for taking the issues very seriously. Most other LW:ers seem to be far too uncritical toward their moral prejudices.