My sense is that this assertion can be empirically falsified for all levels of abstraction below "Do what is right."
Indeed, this is one of many reasons why I am starting to think "go meta" is really, really good advice.
Edit: Clarification, what I mean is that I think virtue ethics, deontology, utilitarianism, and the less popular ethical theories agree way more than their proponents think they do. At this point this is still a guess.
I don't follow. Discussing theories of morality is already quite meta from the object level moral decisions we face in our daily lives. Going another level of meta is unlikely to illuminate - it certainly doesn't seem likely to be helpful in doing the impossible.
I figure morality as a topic is popular enough and important enough and related-to-rationality enough to deserve its own thread.
Questions, comments, rants, links, whatever are all welcome. If you're like me you've probably been aching to share your ten paragraph take on meta-ethics or whatever for about three uncountable eons now. Here's your chance.
I recommend reading Wikipedia's article on meta-ethics before jumping into the fray, if only to get familiar with the standard terminology. The standard terminology is often abused. This makes some people sad. Please don't make those people sad.