Standing in the quiet, dim halls of the Musée Guimet in Paris, I often watch visitors pause in confusion before a statue labeled “Maitreya.” They are looking for the “Laughing Buddha”—that golden, portly fellow they’ve seen gathering dust on the counters of…

Standing in the courtyard of a temple in East Asia, the contrast is jarring. Inside the main hall sits Siddhartha Gautama, the historical Buddha—gaunt, serene, eyes half-closed in deep meditation, embodying the ascetic discipline of ancient India. But just outside,…