Allow me to offer further clarifications; I think our intuitions about metaethics may diverge less than you think.
One. Pluralistic Moral Reductionism is not the "right track." In that post I write:
But one must not fall into the trap of thinking that a definition you've stipulated (aloud or in your head) for 'ought' must match up to your intended meaning of 'ought' (to which you don't have introspective access). In fact, I suspect it never does, which is why the conceptual analysis of 'ought' language can go in circles for centuries, and why any stipulated meaning of 'ought' is a fake utility function. To see clearly to our intuitive concept of ought, we'll have to try empathic metaethics...
Plualistic moral reductionism is merely a way of dissolving some common debates in philosophical metaethics, so they don't waste our time and we can move on to tackle the hard problems of metaethics.
Two. I agree that human neuroscience may not turn out to be relevant for metaethics, but it seems plausible that it will turn out to be relevant because (1) perhaps the only value in the universe is the type created when sentient beings value things, and hence we can learn about what has value by studying how sentient beings value things, and (2) if CEV is a good plan for Friendly AI, then we'll be extrapolating human values, and thus it'll be worth knowing what the heck we're extrapolating. And thus, in the spirit of exploring multiple approaches simultaneously, I'm trying to make sure we all have a cursory understanding of the neuroscience of human values.
Three. I don't consider human neuroscience to be "a clear and stable platform from which to solve the hard questions of morality." That phrase was meant to talk about the 'dissolving away' of common metaethical debates (e.g. moral realism vs. antirealism) so that they don't confuse us when we're trying to solve the harder problems of metaethics.
Do you still think we disagree on much? If so, I'm curious to hear what you think we disagree about.
I'll comment on the quotes Wei selected (this isn't meant to be related to anything else here, just isolated reaction to Wei's drawing attention to these things):
But whatever our intended meaning of 'ought' is, the same reasoning applies. Either our intended meaning of 'ought' refers (eventually) to the world of math and physics (in which case the is-ought gap is bridged), or else it doesn't (in which case it fails to refer).
It's easy to construct all sorts of interpretations that could be said to be referents of anything else. The question is not well...
Recently a friend of mine told me that he and a few others were debating how likely it is that I've 'solved metaethics.' Others on this site have gotten the impression that I'm claiming to have made a fundamental breakthrough that I'm currently keeping a secret, and that's what my metaethics sequence is leading up to. Alas, it isn't the case. The first post in my sequence began:
The part I consider 'solved' is the part discussed in Conceptual Analysis and Moral Theory and Pluralistic Moral Reductionism. These posts represent an application of the lessons learned from Eliezer's free will sequence and his words sequence to the subject of metaethics.
I did this because Eliezer mostly skipped this step in his metaethics sequence, perhaps assuming that readers had already applied these lessons to metaethics to solve the easy problems of metaethics, so he could skip right to discussing the harder problems of metaethics. But I think this move was a source of confusion for many LWers, so I wanted to go back and work through the details of what it looks like to solve the easy parts of metaethics with lessons learned from Eliezer's sequences.
The next part of my metaethics sequence will be devoted to "bringing us all up to speed" on several lines of research that seem relevant to solving open problems in metaethics: the literature on how human values work (in brain and behavior), the literature on extracting preferences from what human brains actually do, and the literature on value extrapolation algorithms. For the most part, these literature sets haven't been discussed on Less Wrong despite their apparent relevance to metaethics, so I'm trying to share them with LW myself (e.g. A Crash Course in the Neuroscience of Human Motivation).
Technically, most of these posts will not be listed as being part of my metaethics sequence, but I will refer to them from posts that are technically part of my metaethics sequence, drawing lessons for metaethics from them.
After "bringing us all up to speed" on these topics and perhaps a couple others, I'll use my metaethics sequence to clarify the open problems in metaethics and suggest some places we can hack away at and perhaps make progress. Thus, my metaethics sequence aims to end with something like a Polymath Project set up for collaboratively solving metaethics problems.
I hope this clarifies my intentions for my metaethics sequence.