take the summation of their utility over time
How do you determine the utility? To be able to compute the utility of a world-state, according to someone's personal utility function, you have to know what their personal utility function is. Can you tell me what your personal utility function is? Or how we would know what it is, even if we had a complete causal model of you?
Determining the utility functions of humans - whether we mean individual humans, or a species-universal utility-function-template, the variables of which get filled in by genetics and life experience - is one of the major subproblems of the usual approach to FAI. So your approach isn't any easier in that regard.
To measure the utility (or at least approximate it), you could just ask the models.
I mean, in this case you're limited by self-deception, but it ought to be a reasonable approximation. I may not know what my personal utility function is, but I do know roughly how satisfied I am with my life right now.
I've been reading through this to get a sense of the state of the art at the moment:
http://lukeprog.com/SaveTheWorld.html
Near the bottom, when discussing safe utility functions, the discussion seems to center on analyzing human values and extracting from them some sort of clean, mathematical utility function that is universal across humans. This seems like an enormously difficult (potentially impossible) way of solving the problem, due to all the problems mentioned there.
Why shouldn't we just try to design an average bounded utility maximizer? You'd build models of all your agents (if you can't model arbitrary ordered information systems, you haven't got an AI), run them through your model of the future resulting from a choice, take the summation of their utility over time, and take the average across all the people all the time. To measure the utility (or at least approximate it), you could just ask the models. The number this spits out is the output of your utility function. It'd probably also be wise to add a reflexive consistency criteria, such that the original state of your model must consider all future states to be 'the same person.' -- and I acknowledge that that last one is going to be a bitch to formalize. When you've got this utility function, you just... maximize it.
Something like this approach seems much more robust. Even if human values are inconsistent, we still end up in a universe where most (possibly all) people are happy with their lives, and nobody gets wireheaded. Because it's bounded, you're even protected against utility monsters. Has something like this been considered? Is there an obvious reason it won't work, or would produce undesirable results?
Thanks,
Dolores