It also says that the 100% improvised music I play on folk instruments isn't Folk Music, nor yet is 97% of Kip of the Serenes by Dr Strangely Strange. How is that not a value judgement?

Not to me, it isn't. It would never have occurred to me to call either of those things folk music; I wouldn't have called them Motown, either. As far as I'm concerned, calling something 'folk' isn't a mark of approval, and it isn't anything to do with the quality of the performance. I've seen some gloriously individual, messily exuberant performances of contemporary songs, & some dull and 'professional' performances of traditional songs. So what? There's still a difference between the songs. (On the other hand, I have seen far more dull performances of contemporary songs - some of them seem to be written for a dull performance.) For as many as will is a brilliant LP; some of it's folk, some of it isn't. Rocket cottage is a mediocre LP; some of it's folk, some of it isn't. "Folk" isn't a value judgment.

Individual creativity and vernacular variation are an observable alternative to a theory which in no way can be subjected to any sort of empirical scrutiny.

The theory is based on the reality of individual creativity and vernacular variation - and it can't be observed because it's a theory about things that take a long time to happen.

People copy what they've heard; some of the time they get it wrong, or shift it around a bit, or add an extra bit. Performers have always done this to some extent, just as composers have always borrowed from one another's work to some extent. What's different about the folk process is that lots of people whose names we don't know are doing the copying and the altering - and, more importantly, that the songs get copied again, in those altered forms. And the same processes of individual creativity and vernacular variation happen again. Give it long enough and you end up with Seeds of Love/Let No Man Steal Your Thyme/When I Was In My Prime, and 20-odd versions of Child 10.

Ron:
I have no argument to the 54 definitiobn if it refers to 'traditional', but to cast songs, and music, composed in the 'folk idiom' into the outer darkness I find unacceptable.

Nobody's casting anything into the outer darkness! I'd be overjoyed if I could walk into J. Random Folk Club and hear either folksongs or songs in the general neighbourhood of folk. (Three or four people sang Ewan MacColl songs at the last mostly-trad singaround I went to, and I was one of them.) All I'm saying is that some songs are folk songs (whatever you do to them) and some aren't - and that a folk club where folk songs are the exception, not the rule, should probably call itself something less misleading.