A Worry re: Ideal Responder Theory

So an ideal responder would differ from me and you in various ways, while remaining similar in other ways. The ideal responder must escape our various, merely parochial, limitations if his responses are to have any normative authority. On the other hand, however, should his responses be too alien from our own, we cannot accept that his responses ground the precise values we want them to. (Evidently this responder isn't after the Tasty after all, but rather the Nasty!)

Obviously, something like an ideal responder plays a role in our thinking about value. For example, when my conscience is activated I simulate a kind of idealized version of myself to help me determine whether or not an act deserves guilt. Or when I try to determine whether or not, for example, jealousy is warranted, I try to imagine how a creature like myself -- only more sober-minded, or something -- would respond. [Shout out to Remy Debes and Rob Gressis!]

But, here is just one problem with IRTs: it can be a matter of controversy which features of myself the ideal responder must retain and which features the ideal responder must vary. Our grip on which features must vary and which must remain unchanged is to be explained by an independent grip on the values in question. Presumably, if an IRT is supposed to be a realist theory there is some fact of the matter about which features constitute the ideal responder for a given value. And these facts, if I had to guess, would require that the values in question have a status independent of the responder.