"I was picking out salient features (actually identified by Brian) SPECIFIC to folk songs; very distinct identifying features IMO a good deal more unique to folk songs than having four legs and a tail is to a cat."

I can't help thinking that this is similar to the way you picked songs that you liked or approved of to put in your big "Folk Songs" box, Gene. This is not logic as we know it - it is selection. You remind me of a boss I had once, in my 'working-in-a-laboratory' days, who thought that it was OK to pick out the data which supported his preconceived ideas and to discard the rest (he eventually got fired - I wonder why?).

And what does happen to those features that you don't believe are "salient"?

I was going to go on and labour the analogy by rambling about Tasmanian Tigers and Marsupial Lions ... bit I think I'd better stop there ...