Thanks for the explanation and examples.
In my previous comment, I started to touch on the idea of finding the right equation for calculating happiness accross a community. And ultimately, I think that concept can be used to resolve all of the challenges you mentioned.
For instance, the requirement for continuous population growth just seems silly to me. A perfect score on a test doesn't mean you got infinite number of points - it means you got a hundred percent of the points. Similarly, a universe with 100 happy people and 0 sad people is perfect - no less so than a universe with 1 million happy people. And such a universe is, in fact, better than a universe with 999,999 happy people and 1 sad person.
And the other examples are all silly as well, because, firstly, they are not considered in comparison with other worlds, and secondly, because they presume a bad utilitarian calculus - essentially acting as a straw man.
For an example of the first point, consider that Le Guin and Dostoyevsky's innocent child worlds only necessarily represent a "net win" relative to a worse world - for instance, one in which two children are slaughered. But it doesn't necessarily represent an acceptable world.
And if we are trying to define universes or univeral states that are theoretically "acceptable" or "unacceptable", we can decide and tweak what calculus we want to use. For instance, what if there were a universe with 100 billion happy people, and one person who wasn't in agony, but always felt nauseous. That's not a perfect universe, and it doesn't mean we can't try to make it a better universe. But I think a lot of people would consider that to be an acceptable universe.
The point is, though, that we can tweak our calculation however we want, for instance, so that we prioritize bringing everyone's happiness above a certain line, rather than just averaging everybody out. But we still only need to use happiness as the sole variable in the equation. And that, to me, is what Utilitarian thinking is really getting at. And to me, it's still seems unassailable, except by straw man arguments.
