A while back, I bought a CD called Nouveaux “Brandebourgeois,” i.e., New Brandenburgs. The conceit is that this musicalologist Bruce Haynes has grave-robbed J.S. Bach’s other works to piece together six more Brandenburg Concerti such as the man himself might have written if he had gotten the job in Brandenburg and become a court composer instead of a church composer.

A brave attempt, but fruitless. The more I listened, the less they worked. As a composer, I have found that themes know themselves what they’re for: a sonata, a choral work, a symphony, a fugue. It doesn’t do to try to force a song theme into a symphony, nor vice versa.

And so even when I didn’t know the original pieces, the fake concerti never took flight. All those cantata themes were just not agile enough to dance through the intricacies of the Brandenburgs.

A lesson to us all, I’m sure.