Is Moral Nihilism a Morality?

[vulcanlogician]

There’s some weak semantics there (which no doubt Popper covers in other publications) e.g. “mind”, “thought process”, “objective”, “consciousness”, “knowledge” and there seems to be a misstep in the summary when describing World 2 as “conscious experience” when earlier it was described as “process”.

But yes, that’s the kind of thing.

So, can we label Kant’s Noumenon and Vulcanology’s Reality-reality as World 0 given that World 1 (as described) requires human lenses and filters to detect/perceive/interpretat its contents?

I'd say that all worlds together might be a good model for reality-reality... or you could say (as per strict materialist theories) world 1 is reality reality and world 2 is merely some kind of artifact of reality reality. World 3 most resembles Plato's world of forms. I rather like Popper's distinctions and they might be a good set of categories to use when addressing relevant distinctions in our little morality debate. But that's what they are to me: distinctions of a single substance... a substance which we may call reality.

One thing that jumped out at me from Popper:
"There is, secondly, the mental or psychological world, the
world of our feelings of pain and of pleasure, of our thoughts, of
our decisions, of our perceptions and our observations; in other
words, the world of mental or psychological states or processes,
or of subjective experiences. I will call it ‘world 2’. World 2 is
immensely important, especially from a human point of view or
from a moral point of view. Human suffering belongs to world 2;
and human suffering, especially avoidable suffering, is the central
moral problem for all those who can help."

If we accept human suffering as objective fact, then (to me) we can begin to formulate a moral theory that takes human suffering into account. This doesn't mean that we give an "artificial weight" to it. At this point in our conversation, the importance of human suffering is yet to be determined. Perhaps we will find, after some investigation, that only world 3 is relevant to moral theory. (I tend to think that it is world 3 because world 3 makes sense of worlds 1 and 2, and it is only after having made sense of these realities, to some degree, that moral valuation becomes possible.) But the naturalists might disagree with me there.

I think Belaqua's suggestion to use Popper's categorizations is excellent. Plato is a bit old and musty. True, he gets credit for starting Popper's project and being an all around genius when it comes to moral realism, but Popper is much more clear and also informed by modern science. So, if you agree, I say we start with his three worlds distinctions scheme to get started in our ethical discourse.