At present, Copyright Law views each work as a sacred whole, complete and indestructable by itself. While one can make live version or a cover, it is almost impossible to use a piece or two of said work to make a new work.
In other words, if someone can declare that you used something of theirs in your work and can prove it (in however tenuous ways), they own you.
Another way to look at it: George Harrison's "My Sweet Lord" was judged to be a copy of "He's So Fine." While the judge agreed that Harrison had no intention of copying the work, the fact that there were enough aspects of "My Sweet Lord" similar to "He's So Fine" that the Chiffons could use Harrison's words to their music meant that Harrison ripped off their song without intending it.
Of course, why the hacks who wrote the song to "Gilligan's Island" didn't sue Led Zeppelin for making "Stairway to Heaven" I'll never know. Probably because they were 2-bit writers and the Zep was a band known for Multi-media bullying (lawsuit plus actual fisticuffs (by paid goons, natch) plus bad words all around). At least now one of the surviving band members likes the song enough to welcome its release.
But anyway, this viewing of each work as an organic whole that can't be touched or used (even if accidentally) except as a complete piece of work is very much limiting as a whole. You use even an identifiable note of the other work, you're stuck with paying for the whole
Is it any wonder rap went from a wonderfully dense soundscape to what now passes as simple noodling over a keyboard? Is it any wonder The Wind Done Gone had to be passed off as a parody when it was a serious work of alternative history (and let's not forget: Sally Hemmings and Thomas Jefferson's progeny was long considered a bit of alternative history
Copyright laws at present threaten to freeze people's creative juices at a time when more people are able to create art than before. What was once considered an act of ownership over a piece of
I believe the Creative Commons idea is many steps in the right direction. It allows for ideas to become warped and expanded in a way that keeps the rights to the whole work intact. I don't think that Sony, the MPAA or The Margaret Mitchell Society will abide by it, but they're dinosaurs who're waiting for their time to die.
Copyright Law needs changes. Maybe this time change will come on its own, despite the laws.