Easter Sunday found Paris especially joyful. Even as the French mourned their wounded cathedral, they took comfort from a promise made by President Emmanuel Macron within hours of the fire. Their beloved Notre Dame, he told them, will be rebuilt. But what exactly will France be rebuilding?

Will the rebuilt Notre Dame be yet another museum? Or might the rebuilding help resurrect an appreciation for the sense of transcendence that gave this building life? The restorers may work in wood and stone, but as the French rebuild...