@Lighter. Thanks for the " Culture" was taken to be the natural expression of inherited characteristics" observation.

@Pseudonymous. I think the modes are off-topic because Harker doesn't say much. However, I find it interesting that whilst Sharp devotes a large part of his discussion of folk tunes to the modes those other than Ionian only make up about one third of his collection. That may mean he did not suffer from the 'collection bias' that others who can 'recognise a folk tune when they hear it' might be guilty of. I think modus lascivious is always worth throwing into the discussion when people seem to be forgetting that not all folk tunes are 'modal'.