I don't think it's a good idea to assume that only things that are reducible to physics and/or math are worth talking about. I mean it's a good working assumption to guide your search for possible meanings of "should", but why declare that you're not "interested" in anything else?

Maybe this is because I'm fairly confident of physicalism? Of course I'll change my mind if presented with enough evidence, but I'm not anticipating such a surprise.

'Interest' wasn't the best word for me to use. I'll have to fix that. All I was trying to say is that if somebody uses 'ought' to refer to something that isn't physical or logical, then this punts the discussion back to a debate over physicalism, which isn't the topic of my already-too-long 'Pluralistic Moral Reductionism' post.

Surely, many people use 'ought' to refer to things non-reducible to physics or logic, and they may even be interesting (as in fiction), but in the search for true statements that use 'ought' language they are not 'interesting', unless physicalism is false (which is a different discussion, then).

Does that make sense? I'll explain empathic metaethics in more detail later, but I hope we can get some clarity on this part right now.