I think the discussion of reversibility and molecules is a distraction from the core of Stuart’s objection. I think he is saying that a value-agnostic impact measure cannot distinguish between the cases where the water in the bucket is or isn’t valuable (e.g. whether it has sentimental value to someone).
If AUP is not value-agnostic, it is using human preference information to fill in the “what we want” part of your definition of impact, i.e. define the auxiliary utility functions. In this case I would expect you and Stuart to be in agreement.
If AUP is value-agnostic, it is not using human preference information. Then I don’t see how the state representation/ontology invariance property helps to distinguish between the two cases. As discussed in this comment, state representation invariance holds over all representations that are consistent with the true human reward function. Thus, you can distinguish the two cases as long as you are using one of these reward-consistent representations. However, since a value-agnostic impact measure does not have access to the true reward function, you cannot guarantee that the state representation you are using to compute AUP is in the reward-consistent set. Then, you could fail to distinguish between the two cases, giving the same penalty for kicking a more or less valuable bucket.
I agree that it’s not the core, and I think this is a very cogent summary. There’s a deeper disagreement about what we need done that I’ll lay out in detail in Reframing Impact.
I think the discussion of reversibility and molecules is a distraction from the core of Stuart’s objection. I think he is saying that a value-agnostic impact measure cannot distinguish between the cases where the water in the bucket is or isn’t valuable (e.g. whether it has sentimental value to someone).
If AUP is not value-agnostic, it is using human preference information to fill in the “what we want” part of your definition of impact, i.e. define the auxiliary utility functions. In this case I would expect you and Stuart to be in agreement.
If AUP is value-agnostic, it is not using human preference information. Then I don’t see how the state representation/ontology invariance property helps to distinguish between the two cases. As discussed in this comment, state representation invariance holds over all representations that are consistent with the true human reward function. Thus, you can distinguish the two cases as long as you are using one of these reward-consistent representations. However, since a value-agnostic impact measure does not have access to the true reward function, you cannot guarantee that the state representation you are using to compute AUP is in the reward-consistent set. Then, you could fail to distinguish between the two cases, giving the same penalty for kicking a more or less valuable bucket.
That’s an excellent summary.
I agree that it’s not the core, and I think this is a very cogent summary. There’s a deeper disagreement about what we need done that I’ll lay out in detail in Reframing Impact.