I'm over a year late responding to this one, but Computational Truth had an interesting post about whether disagreements over well-being are substantive. Suppose that we all agree on the empirical facts: Alan experiences more pleasure, but Betty has fulfilled more of her heartfelt desires. What are hedonists and desire theorists disagreeing about, then, when they dispute which of the two is "better off"?
The problem: According to analytical reductionism (or "descriptivism"), normative terms like 'wellbeing' simply mean whatever wellbeing reduces to -- happiness, desire fulfilment, or whatever the case may be. This would seem to suggest that the dispute is merely terminological. Either one of the theorists is confused about what their words mean, or else they're speaking subtly different idiolects. In that case, we can translate the apparent dispute:
H. "Alan is better off!"
D. "No, Betty is better off!"
H. "Alan is happier!"
D. "No, Betty has fulfilled more of her desires!"
so that they're not really in disagreement at all. (At most, they disagree about what the term 'better off' means. But words aren't worth arguing over. It's the proposition, or what is said with the words, that really matters. We mean to argue about the world, not just the language used to describe it.)
This seems like a pretty good reason to reject analytical reductionism. Normative disputes, e.g. between theories of wellbeing, are surely more substantive than is allowed for by this account.
A proposed solution: recall my recent claim that philosophical truth just is the idealized limit of a priori inquiry. If we grant this rational normativity as primitive, I've previously suggested that we can use this to define our other normative terms. So, for example, 'wellbeing' means something like "what it is ideally rational to value for a person's own sake".
This yields the happy result that disagreements about wellbeing can be substantive after all. Hedonists and desire theorists disagree about what to value (or what it would be ideally rational to value for a person's own sake). That sounds right to me, at least.