Morality is good because goals like joy and beauty are good. (For qualifications, see Appendices A through OmegaOne.) This seems like a tautology, meaning that if we figure out the definition of morality it will contain a list of "good" goals like those. We evolved to care about goodness because of events that could easily have turned out differently, in which case "we" would care about some other list. But, and here it gets tricky, our Good function says we shouldn't care about that other list. The function does not recognize evolutionary causes as reason to care. In fact, it does not contain any representation of itself. This is a feature. We want the future to contain joy, beauty, etc, not just 'whatever humans want at the time,' because an AI or similar genie could and probably would change what we want if we told it to produce the latter.
Okay, now this definitely sounds like standard moral relativism to me. It's just got the caveat that obviously we endorse our own version of morality, and that's the ground on which we make our moral judgements. Which is known as appraiser relativism.
From Costanza's original thread (entire text):
Meta: