Under the heading of "The Well-Pilfered Clavier," Reason's Tim Cavanaugh lays out his argument. Bach "cribbed material, borrowed music to plug gaps in his work, and reused his own creations with an abandon that would shame a freelancer for Demand Media," argues Cavanaugh. He "recirculated other people's music--sometimes with attribution, sometimes not--with often minor changes." Cavanaugh goes into surprising detail:
[Bach] was even more aggressive in cannibalizing his own output. Music for the funeral of Prince Leopold of Anhalt-Köthen turns up later in The St. Matthew Passion. All six parts of the The Christmas Oratorio are retreads from a secular work Bach had written on commission for the Saxon court. Bach’s Mass in B Minor, described by one 19th-century musician as "The Greatest Artwork of All Times and All People," is almost entirely recycled. "Almost movement by movement you can trace the Mass in B Minor to earlier work," says Daniel R. Melamed, professor of music at the University of Indiana. "Bach was not captive to his own material."Whether Bach could properly be called, as Cavanaugh suggests, a "mash-up artist" might be up for some debate. But Cavanaugh's point is that Germany's lack of enforceable copyright code throughout the early-modern period may have had an upside, including, as historian Eckhard Höffner argues, higher German GDP growth than Britain, "which provided copyright protection beginning with the 1710 Statute of Anne."
Anyway--down with copyright. Do it for Bach--you know, that German file-sharer.