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.
The closest point I've found to my metaethics in standard philosophy was called "moral functionalism" or "analytical descriptivism".
Cognitivism: Yes, moral propositions have truth-value, but not all people are talking about the same facts when they use words like "should", thus creating the illusion of disagreement.
Motivation: You're constructed so that you find some particular set of logical facts and physical facts impel you to action, and these facts are what you are talking about when you are talking about morality: for example, faced with the problem of dividing a pie among 3 people who all worked equally to obtain it and are all equally hungry, you find the mathematical fact that 1/3, 1/3, 1/3 is an equal division compelling - and more generally you name the compelling logical facts associated with this issue as "fairness", for example.
(Or as it was written in Harry Potter and the Methods of Rationality:
"Mr. Potter, in the end people all do what they want to do. Sometimes people give names like 'right' to things they want to do, but how could we possibly act on anything but our own desires?"
"Well, obviously I couldn't act on moral considerations if they lacked the power to move me. But that doesn't mean my wanting to hurt those Slytherins has the power to move me more than moral considerations!")
Moral epistemology: Statements can be true only when there is something they are about which makes them true, something that fits into the Tarskian schema "'X' is true iff X". I know of only two sorts of bearers of truth-value, two sorts of things that sentences can be about: physical facts (chains of cause and effect; physical reality is made out of causes a la Judea Pearl) and logical validities (which conclusions follow from which premises). Moral facts are a mixture of both; if you throw mud on a painting it becomes physically less beautiful, but for a fixed painting its "beauty" is a logical fact, the result of running the logical "beauty" function on it.
But are those truth-values intersubjectively recognizable?
The average person believes morality to be about imperative terminal goals. You ought to want that which is objectively right and good. But there does exist no terminal goal that is objectively desirable. You can assign infinite utility to any action and thereby outweigh any consequences. What is objectively verifiable is how to maximize the efficiency in reaching a discrete terminal goal.