Sean: why is that “what utils do”? To the extent that we view utils as the semi-scientific concept from economics, they don’t “just sum linearly.” To economists utils don’t sum at all; you can’t make interpersonal comparisons of utility. So if you claim that utils sum linearly, you’re making a claim of moral philosophy, and haven’t argued for it terribly strongly.
Sean: why is that “what utils do”? To the extent that we view utils as the semi-scientific concept from economics, they don’t “just sum linearly.” To economists utils don’t sum at all; you can’t make interpersonal comparisons of utility. So if you claim that utils sum linearly, you’re making a claim of moral philosophy, and haven’t argued for it terribly strongly.