Barring a major collapse of human civilization (due to nuclear war, asteroid impact, etc.), many experts expect the intelligence explosion Singularity to occur within 50-200 years.
That fact means that many philosophical problems, about which philosophers have argued for millennia, are suddenly very urgent.
Those concerned with the fate of the galaxy must say to the philosophers: "Too slow! Stop screwing around with transcendental ethics and qualitative epistemologies! Start thinking with the precision of an AI researcher and solve these problems!"
If a near-future AI will determine the fate of the galaxy, we need to figure out what values we ought to give it. Should it ensure animal welfare? Is growing the human population a good thing?
But those are questions of applied ethics. More fundamental are the questions about which normative ethics to give the AI: How would the AI decide if animal welfare or large human populations were good? What rulebook should it use to answer novel moral questions that arise in the future?
But even more fundamental are the questions of meta-ethics. What do moral terms mean? Do moral facts exist? What justifies one normative rulebook over the other?
The answers to these meta-ethical questions will determine the answers to the questions of normative ethics, which, if we are successful in planning the intelligence explosion, will determine the fate of the galaxy.
Eliezer Yudkowsky has put forward one meta-ethical theory, which informs his plan for Friendly AI: Coherent Extrapolated Volition. But what if that meta-ethical theory is wrong? The galaxy is at stake.
Princeton philosopher Richard Chappell worries about how Eliezer's meta-ethical theory depends on rigid designation, which in this context may amount to something like a semantic "trick." Previously and independently, an Oxford philosopher expressed the same worry to me in private.
Eliezer's theory also employs something like the method of reflective equilibrium, about which there are many grave concerns from Eliezer's fellow naturalists, including Richard Brandt, Richard Hare, Robert Cummins, Stephen Stich, and others.
My point is not to beat up on Eliezer's meta-ethical views. I don't even know if they're wrong. Eliezer is wickedly smart. He is highly trained in the skills of overcoming biases and properly proportioning beliefs to the evidence. He thinks with the precision of an AI researcher. In my opinion, that gives him large advantages over most philosophers. When Eliezer states and defends a particular view, I take that as significant Bayesian evidence for reforming my beliefs.
Rather, my point is that we need lots of smart people working on these meta-ethical questions. We need to solve these problems, and quickly. The universe will not wait for the pace of traditional philosophy to catch up.
This is actually a useful way of looking at what metaethics (decision theory) is: tools for self-improvement, explaining specific ways in which correctness of actions (or correctness of other tools of the same kind) can be judged. In this sense, useless metaethics is one that doesn't help you with determining what should be done, and wrong metaethics is one that's actively stupid, suggesting you to do things that you clearly shouldn't (for FAI based on that metaethics, correspondingly doing things that it shouldn't).
In this sense, the injunction of doing nothing in response to failed assumptions (i.e. no coherence actually present) in CEV is not stupid, since your own non-extrapolated mind is all you'll end up with in case CEV shuts down. It is a contingency plan for the case it turns out to be useless.
(I find new obvious things everywhere after the recent realization that any explicit consideration an agent knows is subject to whole agent's judgment, even "preference" or "logical correctness". This also explains a bit of our talking past each other in the other thread.)
I don't have much idea what you mean here. This seems important enough to write up as more than a parenthetical remark.