we might have to conclude that there are actually millions of incommensurable 'axes' of utilitarian experience.

Yeah, I guess I more or less take this for granted. Or, rather, not that they're incommensurable, exactly, but that the range of correspondences -- how many Xs are worth a Y -- is simply an artifact of what set of weighting factors was most effective, among those tested, in encouraging our ancestors to breed, which from our current perspective is just an arbitrary set of historical factors.