Oh, right, but it's still all preferences. I can have a preference to fulfill others' preferences, and I can have preferences for other things, too. Is that what you're saying?
Possibly, but you've said that opaquely enough that I can imagine you intending a meaning I'd disagree with. For example, you refer to "other preferences", while there is only one morality (preference) in the context of any given decision problem (agent), and the way you care about other agents doesn't necessarily reference their "preference" in the same sense we are talking about our agent's preference.
It seems to me that the method of reflective equilibrium has a partial role in Eliezer's meta-ethical thought, but that's another thing I'm not clear on.
This is reflected in the ideas of morality being an abstract computation (something you won't see a final answer to), and the need for morality being found on a sufficiently meta level, so that the particular baggage of contemporary beliefs doesn't distort the picture. You don't want to revise the beliefs about morality yourself, because you might do it in a human way, instead of doing that in the right way.
In You Provably Can't Trust Yourself, Eliezer tried to figured out why his audience didn't understand his meta-ethics sequence even after they had followed him through philosophy of language and quantum physics. Meta-ethics is my specialty, and I can't figure out what Eliezer's meta-ethical position is. And at least at this point, professionals like Robin Hanson and Toby Ord couldn't figure it out, either.
Part of the problem is that because Eliezer has gotten little value from professional philosophy, he writes about morality in a highly idiosyncratic way, using terms that would require reading hundreds of posts to understand. I might understand Eliezer's meta-ethics better if he would just cough up his positions on standard meta-ethical debates like cognitivism, motivation, the sources of normativity, moral epistemology, and so on. Nick Beckstead recently told me he thinks Eliezer's meta-ethical views are similar to those of Michael Smith, but I'm not seeing it.
If you think you can help me (and others) understand Eliezer's meta-ethical theory, please leave a comment!
Update: This comment by Richard Chappell made sense of Eliezer's meta-ethics for me.