That's what I was trying to figure out about the analogy of motion pictures in reply to my observation that universal common descent is not evidence, it is an explantion of evidence.
Cordially,
I didn't see the post this refers to, but even if you caught someone expressing the issue poorly, it is hardly worth commenting on. Common descent is as well established as heliocentrism. There is no alternative hypothesis except poofism. Common descent is accepted by most ID advocates. Behe and Denton accept it as a fact.