In general, the ethical theory that prevails here on Less Wrong is preference utilitarianism. The fundamental idea is that the correct moral action is the one that satisfies the strongest preferences of the most people. Preferences are discussed with units such as fun, pain, death, torture, etc. One of the biggest dilemmas posed on this site is the Torture vs. Dust Specks problem. I should say, up front, that I would go with dust specks, for some of the reasons I mentioned here. I mention this because it may be biasing my judgments about my question here.
I had a thought recently about another aspect of Torture vs. Dust Specks, and wanted to submit it to some Less Wrong Discussion. Namely, do other people's moral intuitions constitute a preference that we should factor into a utilitarian calculation? I would predict, based on human nature, that a if the 3^^^3 people were asked if they wanted to inflict a dust speck in each one of their eyes, in exchange for not torturing another individual for 50 years, they would probably vote for dust specks.
Should we assign weight to other people's moral intuitions, and how much weight should it have?
You're right, I'm concerned with morality as it applies to people generally.
If you are exclusively concerned with sufficiently rational people, then we have indeed been talking past each other. Thanks for clarifying that.
As to your question: I submit that for that community, there are only two principles that matter:
Come to agreement with the rest of the community about how to best optimize your shared environment to satisfy your collective preferences.
Abide by that agreement as long as doing so is in the long-term best interests of everyone you care about.
...and the justification for those principles is fairly self-evident. Perhaps that isn't a morality, but if it isn't I'm not sure what use that community would have for a morality in the first place. So I say: either of course there is, or there's no reason to care.
The specifics of that agreement will, of course, depend on the particular interests of the people involved, and will therefore change regularly. There's no way to build that without actually knowing about the specific community at a specific point in time. But that's just implementation. It's like the difference between believing it's right to not let someone die, and actually having the medical knowledge to save them.
That said, if this community is restricted to people who, as you implied earlier, care only for rationality, then the resulting agreement process is pretty simple. (If they invite people who also care for other things, it will get more complex.)
Very well put.