 However, further difficulties beset the positing of abstract artifacts. It is commonly thought that abstract objects are not just non-spatiotemporal, but non-causal. Our causal commerce is with their instances, not with the abstract objects themselves. But this makes it hard to understand how abstract objects could possibly be created. Erik Satie could certainly create an instance of his Gymnopédies by playing it on his piano, but it is unclear in what sense he could be the author of this musical work as an abstract object separate from its instances. According to Jerrold Levinson (1980), the last decades of the 20th century saw a near consensus that musical works are abstract objects of a more familiar sort—structural types that exist eternally and without change, independent of their instances in the causally governed, spatiotemporal realm. A leading objection to this consensus is that composers cannot then bring their works into existence, contrary to common sense. So the music ontologist faces a dilemma—give up on the idea that musical works are abstract structural types, or explain how the composer can reasonably be said to create musical works even though the abstract structural types that comprise them are already in existence. This difficulty generalizes to other repeatable types of artworks that are held to be abstract objects. But most importantly, characterizing repeatable artworks as abstract artifacts does not allow the ontologist to escape this difficulty. Abstract artifacts do not belong to the causal realm of space and time any more than their eternal and changeless cousins do. So simply saying that they are artifacts, and therefore created and destroyed like all other artifacts, does not by itself explain how this creation and destruction is possible.