A recent post at my blog may be interesting to LW. It is a high-level discussion of what precisely defined value extrapolation might look like. I mostly wrote the essay while a visitor at FHI.
The basic idea is that we can define extrapolated values by just taking an emulation of a human, putting it in a hypothetical environment with access to powerful resources, and then adopting whatever values it eventually decides on. You might want some philosophical insight before launching into such a definition, but since we are currently laboring under the threat of catastrophe, it seems that there is virtue in spending our effort on avoiding death and delegating whatever philosophical work we can to someone on a more relaxed schedule.
You wouldn't want to run an AI with the values I lay out, but at least it is pinned down precisely. We can articulate objections relatively concretely, and hopefully begin to understand/address the difficulties.
(Posted at the request of cousin_it.)
Another problem with this proposal: what if egoism is the right morality, or at least that our "actual" values have a large selfish component? If that is the case, then presumably the simulated humans inside the proposed AI will eventually realize it, and then cause the AI to value them (the simulations) instead of us (biological humans).
It seems difficult for approaches to FAI based on indirect normativity (e.g., CEV) to capture selfish values (with the correct indexical references), so it's not just a problem for this specific proposal, but I don't seem to recall seeing the issue mentioned anywhere before.