emmanuel is a performance artist. during his most recent show, instead of walking out onto the stage when the curtain came up, he sat in the audience among his fans, scrolling through his phone, unnoticed by any of the audience members. 20 minutes later, when people started getting surly that the show hadn't started yet, emmanuel walked onto the stage, picked up a sledge hammer, and smashed his phone to pieces. then he walked off the stage. suzy, age 4, used finger paint to create a rainbow on her parents' bathroom door. michelangelo took four years to create the fresco on the wall of the sistine chapel in the vatican. it is widely considered to be one of the greatest masterpieces of the renaissance period. all three of these things would be categorized as art, even though there's nothing really in common among them. according to the classical theory of categories, there should be one or more necessary and sufficient conditions for deciding whether or not something is art. but if we took a broader look at art as a category, we would find a network of overlapping similarities. this more flexible view of categories is known a