Some of my picking at definitions is because I am not entirely convinced about the research practices of the past. It appears that others are not happy with practices espoused by more recent workers (such as Steve Roud).

The word I had been avoiding, because is quite a 'long' one was https://en.wikipedia.org/wiki/Paradigm I had only come across it in a science. However, the Wikipedia page has an interesting section on its use in the social sciences, which I think is more like what we are talking about here.

As I read it, Jacobs (in his discussion on the 'the Folk') and Harker (in the introduction and final paragraphs of Fakesong) were both challenging current paradigms relevant to 'folk song'.

That's why I am 'poking a stick' at the use of phrases that carry meaning, or baggage, amongst a specific group of researchers. I know that some people with a lot of experience have challenged them and think others use them simply as a shield when challenged.