[rewgs]

Composer here. This is a terrible analogy. Whether or not a composer can/does perform a piece has absolutely nothing to do with authorship -- do we expect a writer to read aloud their novel?

A better question to ask is, "If the composer merely told others what to write, is it actually the composer's music?" This is an unbelievably common practice, and IMO, the answer to the question is no.

[nine_k]

What listeners get is not sheet music, it's performed music.

To me it's like an artist provides a detailed plan of how to build a monument, and then certified builders actually construct it.

Of course if an artist just gives a few rough sketches, and then a civil engineer provides the detailed drawings, and the builders construct the monument by them, then the artist is a co-author at best.

I don't know how specific D. Chihuly was in his instructions. I just think that such a separation of labor is possible, when the artist does the artistic stuff, and a performer follows on with the technical execution. In an extreme case, a machine (such as a music box) can play Bach, but that machine can't play without Bach having written the notes.