Virginia
"Could someone please explain to me why the 1959 definition is the only acceptable definition? Who was the authority? Was it a single person or a collective?"
A collective of people already working in the field of song who based it on research work that they were involved in andwhich had been in hand since the beginning of the century. This included research by Sharp and Karpeles, Grainger, Kidson, Hammond and Gardiner and others. It would have also included the collecting project carried out by the BBC in Britain (1950-54).
This was discussed fairly comprehensively on a recent thread (I think you took part).
"It is a folk song because I heard it played in a folk club. It is a folk club because it says so on the poster."
Two reasons why this Humpty Dumpty "Words mean what I want them to mean" 'definition' makes no sense.
1. Sinister supporter knocked it on the head fairly comprehensively with his own club's definition on the above thread:
"On an average night in our Folk Club we might hear Blues, Shanties, Kipling, Cicely Fox Smith, Musical Hall, George Formby, Pop, County, Dylan, Cohen, Cash, Medieval Latin, Beatles, Irish Jigs and Reels, Scottish Strathspeys, Gospel, Rock, Classical Guitar, Native American Chants, Operatic Arias and even the occasional Traditional Song and Ballad. We once had a floor singer who, in his own words, sang his own composition which he introduced with the Zen-like "...this is a folk song about rock 'n' roll..."."
2. Folk is probably the most the most comprehensively and extensively researched and documented musical form; still being researched and documented under the widely accepted banner 'folk', as is its fellow disciplines folklore, folk music, folkdance, folktale and folk custom.
Until all these terms are re-defined the old definition remains firmly in place - live with it.
Jim Carroll