“Day after day,” the French-German artist Jean Arp once said, man “invents machines and devices that increase noise and distract humanity from the essence of life: contemplation, meditation.” The fluid, mysteriously figurative sculptures for which Arp is known, on display in Greater China’s first exhibition of his work, certainly do invite contemplation, asking us to decide when an object begins to be abstract. Likewise his earlier, lesser-known works, also included in this retrospective: woodcuts, drawings, cardboard collages, and wood reliefs, which add geometrical forms to his artistic equation. —J.V.