In his eponymous museum, Albert C. Barnes (1872–1951) divided his impressive collection into small “ensembles,” juxtaposing paintings, sculptures, and decorative objects without regard for chronology or geography: a modern abstraction beside pages from a medieval Book of Hours, an African ceremonial ax suspended above a European rendering of Christ carrying the cross. As curator John G. Hanhardt writes in the catalogue for “I Do Not Know What It Is I Am Like: The Art of Bill Viola,” Barnes’s eclecticism made his museum the ideal site for this Bill Viola exhibition—the first of its size in