There is an unfortunate equivocation in the word theory (compare "Theory of Evolution" to "Just War Theory"). Popper says that theory can only be called scientific if it is falsifiable. Using that conceptual terminology, Freudian theory is pseudoscience, not a scientific theory. But many things that the vernacular calls theories are not falsifiable. (What would it mean to falsify utilitarian theory?)
Does that mean that we can't talk about moral theories? What word should we use instead? Because it seems like talking about moral theories is doing something productive.
For some context, I'm starting this post to separate off this conversation from a distinct conversation I'm having here
And just wait until you get to "critical theory". I fear the word "theory" in English is indeed stretched in a continuous fog from the hardest of physics to the foggiest of spurious postmodernist notions, with little in the way of joins to carve it at. Thus, cross-domain equivocation will be with us for a while yet.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
If continuing the discussion becomes impractical, that means you win at open threads; a celebratory top-level post on the topic is traditional.