Grandma M, (may I call you "Babushka" ?) in the days before musical copyright musicians gleefully rummaged around in each others' work for musical ideas. Nowadays we can still rummage all we like after the copyrights expire. I think this would strike a reasonable balance if the term of copyright in pre-1978 published works weren't set to a ridiculously over-long 95 years.

I'm not a lawyer, and this is not legal advice, just private opinion: From what I've been able to discover, there is no "8-bar rule". Almost any copying of what is "original" might be actionable (though in some circumstances, hard to predict beforehand, it might be defensible as "fair use"). This of course, simply raises the question of what is "original". In one legal case, George Harrison was found liable for infringement because of his use of two simple musical motives in "My Sweet Lord". As I read, it wasn't the motives themselves that infringed, but his repeating them a certain number of times in a certain order which was held to infringe on a nearly identical set of repetitions in an older song, "He's So Fine". Maybe the offending passage was more than 8 bars, but the length of a bar is fairly arbitrary anyhow.

What's more, Harrison was found to have infringed unconsciously. So if you have lots of music running around in your head which you draw on, make sure it's public domain music! If it's copyrighted music, make sure you draw only on its uncopyrightable features.

Can you name some of the commercial songs you have heard that are "absolute copies" of hymns? Other than Paul Simon's "American Tune", I mean, (that is the name of the Simon tune in question, isn't it ?) which draws on Han Leo Hassler's "Herzlich tut mich verlanen" as modified by J.S. Bach. And there are the songs from the musical "Godspell" that use old words, though not old tunes: "We plow the fields and scatter", "Day by Day", "Turn back O Man", and "When wilt thou save the people." Those I know about, but if you know of others, I'd be interested in learning of them.

T.