[akvadrako]

I disagree. should is only relevant when there is a choice. Under the MUH, it's like saying 1+1 should = 3, which is fairly meaningless. Basically, the MUH answers the should question which is why it qualifies as religion. It's answer is "it's irrelevant".

[pron]

Well, people have literally spent millennia arguing over this. I doubt this could be resolved in a HN comment :)

Anyway, even a deterministic universe (mathematical, i.e. monistic Platonistic, or otherwise) is still undecidable/intractable, and so normative prescriptions may well serve an important role as you don't know their place in the causal chain.

Of course, you could argue that "importance" is also a subjective measure in a deterministic universe, and an irrelevant one, but then so is "relevance" itself.