I'd appreciate clarification on what you mean by "You should_me maximize my preferences."
I understand that the "objective" part is that we could both come to agree on the value of should_you and the value of should_me, but what do you mean when you say that I should_MattSimpson maximize your preferences?
I certainly balk at the suggestion that there is a should_human, but I'd need to understand Eliezer in more detail on that point.
And yes, if one's own preferences are the foundation of ethics, most philosophers would simply call this subject matter practical rationality rather than morality. "Morality" is usually thought to be a term that refers to norms with a broader foundation and perhaps even "universal bindingness" or something. On this point, Eliezer just has an unusual way of carving up concept space that will confuse many people. (And this is coming from someone who rejects the standard analytic process of "conceptual analysis", and is quite open to redefining terms to make them more useful and match the world more cleanly.)
Also, even if you think that the only reasons for action that exist come from relations between preferences and states of affairs, there are still ways to see morality as a system of hypothetical imperatives that is "broader" (and therefore may fit common use of the term "morality" better) than Eliezer's meta-ethical theory. See for example Peter Railton or 1980s Philippa Foot or, well, Alonzo Fyfe and Luke Muehlhauser.
We already have a term that matches Eliezer's use of "ought" and "should" quite nicely: it's called the "prudential ought." The term "moral ought" is usually applied to a different location in concept space, whether or not it successfully refers.
Anyway, are my remarks connecting with Eliezer's actual stated position, do you think?
but what do you mean when you say that I should_MattSimpson maximize your preferences?
I mean that according to my preferences, you, me, and everyone else should maximize them. If you ask what should_MattSimpson be done, the short answer is maximize my preferences. Similarly, if you ask what should_lukeproq be done, the short answer is to maximize your preferences. It doesn't matter who does the asking. If you ask should_agent should be done, you should maximize agent's preferences. There is no "should" only should_agent's. (Note, Eliezer calls...
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.