I don't think that fast intelligence explosion ---> you have to solve the kind of hard philosophical problems that you are alluding to. You seem to grant that there are no particular hard philosophical problems we'll have to solve, but you think that nevertheless every approach to the problem will require solving such problems. Is it easy to state why you expect this? Is it because approaches we can imagine in detail today involve solving hard problems?

Regarding the hardness of defining "remain in control," it is not the case that you need to be able to define X formally in order to accomplish X. Again, perhaps such approaches require solving hard philosophical problems, but I don't see why you would be confident (either about this particular approach or more broadly). Regarding my claim that we need to figure this out anyway, I mean that we need to implicitly accept some process of reflection and self-modification as we go on reflecting and self-modifying.

I don't see why a singleton is necessary to avert value drift in any case; they seem mostly orthogonal. Is there a simple argument here? See e.g. Carl's post on this and mine. I agree there is a problem to be solved, but it seems to involve faithfully transmitting hard-to-codify values (again, perhaps implicitly).