The very title of this summer's big show at the National Museum of Modern Art in Paris, which fills a floor of the cavernous Centre Georges Pompidou with 263 works by 95 artists (through Oct. 13), gives one pause: "Qu'est-ce que la Sculpture Moderne?" (What is modern sculpture?). A tendentious question, perhaps, but not without its point. Most museumgoers feel they know what modern painting is. About sculpture they care less and are less sure.
If you asked a Parisian or a New Yorker in 1886 what sculpture was, the answer (after a short blank stare) would have been: statues. Statuary,...