Mag Uidhir on performance

Christy Mag Uidhir has recently argued (a) that there is no in principle aesthetic difference between a live performance and a recording of that performance, and (b) that the proper aesthetic object is a type which is instantiated by the performance and potentially repeatable when recordings are played back. This paper considers several objections to (a) and finds them lacking. I then consider improvised music, a subject that Mag Uidhir explicitly brackets in his discussion. Improvisation reveals problems with (b), because the performance-event and the performance-type are distinct but equally proper aesthetic objects.