Obviously, major value conflicts preclude co-existence.
Not obvious. (How does this "preclusion" work? Is it the best decision available to both agents?)
Well, if I don't include that sentence, someone nitpicks by saying:
How does one tolerate Hitler McHitler the murdering child-molester?
I was trying preempt by making it clear that McH gets imprisoned or killed, even by moral anti-realists (unless they are exceptionally stupid).
Do you believe in an objective morality capable of being scientifically investigated (a la Sam Harris *or others*), or are you a moral nihilist/relativist? There seems to be some division on this point. I would have thought Less Wrong to be well in the former camp.
Edit: There seems to be some confusion - when I say "an objective morality capable of being scientifically investigated (a la Sam Harris *or others*)" - I do NOT mean something like a "one true, universal, metaphysical morality for all mind-designs" like the Socratic/Platonic Form of Good or any such nonsense. I just mean something in reality that's mind-independent - in the sense that it is hard-wired, e.g. by evolution, and thus independent/prior to any later knowledge or cognitive content - and thus can be investigated scientifically. It is a definite "is" from which we can make true "ought" statements relative to that "is". See drethelin's comment and my analysis of Clippy.