FYI, if people want to look into what aliens might value, an interesting direction might be to think about convergent evolution. One (the only?) existing book on the topic: The Zoologist's Guide to the Galaxy/ Quanta magazine article. Geoffrey Miller mentioned related work in a comment a few months ago.
Is this pointless speculation? I suspect knowing about what aliens might value would be useful in understanding how to better implement Evidential Cooperation in Large Worlds (ECL) (right now, right here, on Earth) although some people may disagree with me on that.
I've also encountered thinking that this could help avoid/reduce conflicts with aliens (which may motivate work on it from various longtermist perspectives).
I guess this kind of stuff would be particularly suited for people with an evolutionary biology/related field background but it also seems like people can pick these things up quickly/use AI assistants to help out.
What if exact copies don't matter but future experiences still do?
I think an ethics resulting from the following two premises is worth exploring:
P1: The total moral value of subjectively indistinguishable observer-moments doesn't scale with the number of copies, i.e. they sum to a constant value.
P2: What matters, and can be changed, for each type of observer-moment is the distribution of its subjectively "future" experiences.
Using these lenses, the moral situation of the world looks like:
In conclusion... well, I'm still thinking about what the objective function might look like.
There's some scale invariance here. E.g. suppose you duplicated the world. That duplication would multiply all token observer-moments by the same factor. This leaves you with the same types and the same distributions for future observer-moments.
In a small enough world, you can create or prevent the existence of new types of observer-moment. I think it's unlikely (30%) that we live in a small enough world.
On the other hand, in a large enough world, all possible types of observer-moments exist. The only thing you can change is adjusting the distributions for future observer-moments for each type of observer-moment. Try to lead types of observer-moments down paths of non-suffering etc. So, this seems like an ethics of flow (rather than stock).
In the case of finite trajectories, the objective function can be the sum of value functions across all states, with each state weighted equally - where states are types of observer-moments, and each state's value function is its immediate valence plus the expected value of its continuations. This is total utilitarianism with two modifications. 1) aggregate over types instead of tokens, and 2) sum trajectory welfare instead of immediate welfare.