If we can’t use preference to determine ethical utility, it makes ethical utilitarianism a lot harder [...]
The way “preference” tends to be used in this community (as a more general word for “utility”, communicating the same idea without explicit reference to expected utility maximization), this isn’t right either. The actual decisions should be higher in utility than their alternatives, it is preferable if they are higher utility, but the correspondence is far from being factual, let alone “by definition” (Re: “By definition, if you choose X over Y, then X is a higher utility option than Y”). One can go a fair amount from actions to revealed preference, but only modulo human craziness and stupidity.
The way “preference” tends to be used in this community (as a more general word for “utility”, communicating the same idea without explicit reference to expected utility maximization), this isn’t right either. The actual decisions should be higher in utility than their alternatives, it is preferable if they are higher utility, but the correspondence is far from being factual, let alone “by definition” (Re: “By definition, if you choose X over Y, then X is a higher utility option than Y”). One can go a fair amount from actions to revealed preference, but only modulo human craziness and stupidity.