Taken from some old comments of mine that never did get a satisfactory answer.
1) One of the justifications for CEV was that extrapolating from an American in the 21st century and from Archimedes of Syracuse should give similar results. This seems to assume that change in human values over time is mostly "progress" rather than drift. Do we have any evidence for that, except saying that our modern values are "good" according to themselves, so whatever historical process led to them must have been "progress"?
2) How can anyone sincerely want to build an AI that fulfills anything except their own current, personal volition? If Eliezer wants the the AI to look at humanity and infer its best wishes for the future, why can't he task it with looking at himself and inferring his best idea to fulfill humanity's wishes? Why must this particular thing be spelled out in a document like CEV and not left to the mysterious magic of "intelligence", and what other such things are there?
I am honestly not sure what to say to people who ask this question with genuine incredulity, besides (1) "Don't be evil" and (2) "If you think clever arguments exist that would just compel me to be evil, see rule 1."
I don't understand your answer. Let's try again. If "something like CEV" is what you want to implement, then an AI pointed at your volition will derive and implement CEV, so you don't need to specify it in detail beforehand. If CEV isn't what you want to implement, then why are you implementing it? Assume all your altruistic considerations, etc., are already folded into the definition of "you want" - just like a whole lot of other stuff-to-be-inferred is folded into the definition of CEV.
ETA: your "don't be evil" looks like a confusion of levels to me. If you don't want to be evil, there's already a term for that in your volition - no need to add any extra precautions.