Hello everyone,
    I didn't think this little question would generate so much discussion, but I must say I am gratified and once again must reiterate my thanks. I would like to respond to a few individual posts, but first a general comment. I would like to qualify my use of the term "generation." By that I simply meant from one person to another, not necessarily familial in the usual sense. For example, I got the tune "Munster Bacon" phrase by phrase from my fiddle teacher, who received it from his teacher the same way, hence there are three "generations" of fiddlers learning and altering, or perhaps personalizing, the tune. So I'm a little loosey-goosey with the term generation.
    This brings up Haruo's question about oral transmission. To continue the "Munster Bacon" example, my teacher played each phrase until I could adequately reproduce it. This constitutes oral, or maybe more accurately, aural transmission for instrumental music as opposed to vocal song. A little loosey-goosey once again but there it is.
    I agree with Declan's point that newly composed music within the style of Irish traditional music becomes part of the tradition. Otherwise, people wouldn't play Liz Carroll tunes at sessions with no knowledge that she composed it.
    Finally, to respond to Mooman's post that academics should investigate a wide range of opinions and this is a good place to do it, I agree wholeheartedly, though I would characterize myself as a curious student rather than an academic. Thanks again everyone. I'll keep reading posts.
    Many thanks,
    Mike