Re: whose CEV?
I’m certain this was explained in an OB post (or in the CEV page) at some point, but the notion is that people whose visions of the future are currently incompatible don’t necessarily have incompatible CEVs. The whole point of CEV is to consider what we would want to want, if we were better-informed, familiarized with all the arguments on the relevant issues, freed of akrasia and every bad quality we don’t want to have, etc.; it seems likely that most of the difference between people’s visions of the future stems from differing cultural/memetic backgrounds, character flaws, lack of information and time, etc., and so maybe the space of all our CEVs is actually quite small in configuration-space. Then if the AI steered towards this CEV-region in configuration space, it would likely conform to many people’s altruism, and hence be beneficial to humankind as a whole.
I agree with cumulant. The mathematical subject of probability is based on measure theory, which loses a ton of convergence theorems if we exclude 0 and 1. We can agree that things that are not known a priori can’t have probability 0 or 1, but I think we must also agree that “an impossible thing will happen soon” has probability 0, because it’s a contradiction. An alternate universe in which the number 7 (in the same kind of number system as ours, etc.) is prime is damn-near inconceivable, but an alternate universe in which impossible things are possible is purely absurd.
If our mathematical reasoning is coherent enough for it to be meaningful to make probability assignments then certainly we are not so fundamentally flawed that what we consider tautologies could be false. If you are willing to accept that maybe 0 is 1, then you can’t do any of your probability adjustments, or use Bayes’ Theorem, or anything of the sort without having a (possibly unstated) caveat that probability theory might be complete nonsense. But what’s the probability that probability theory is nonsense (i.e. false or inconsistent)? What does that even mean? We can only assign a probability if that makes sense, so conditioned on the sentence making sense, probability theory must be nonsense with probability 0, no? So averaged over all possible universes (those where probability theory makes sense, and those where it doesn’t) the sentence “probability makes sense with probability 1” better approximates the truth value of probability making sense than “probability makes sense with probability p” for p0. If it’s not, it’s still not worse, but what the hell are we even saying?