What alternative to utilitarianism are you proposing? Avoiding taking into account multiple people’s welfare? Even a perfect egoist still needs to weigh the welfare of different possible future selves. If you zoom in enough, arbitrariness is everywhere, but “arbitrariness is everywhere, arbitrariness, arbitrariness!” is not a policy. To the extent that our “true” preferences about how to compare welfare have structure, we can try to capture that structure in principles; to the extent that they don’t have structure, picking arbitrary principles isn’t worse than picking arbitrary actions.
What alternative to utilitarianism are you proposing? Avoiding taking into account multiple people’s welfare? Even a perfect egoist still needs to weigh the welfare of different possible future selves. If you zoom in enough, arbitrariness is everywhere, but “arbitrariness is everywhere, arbitrariness, arbitrariness!” is not a policy. To the extent that our “true” preferences about how to compare welfare have structure, we can try to capture that structure in principles; to the extent that they don’t have structure, picking arbitrary principles isn’t worse than picking arbitrary actions.