The burning last week of Paris’s Notre Dame Cathedral stirred the emotions of people the world over, and Catholics especially, but the French, regardless of religious commitment, seemed to feel the loss most deeply. Examining this reaction in light of evidence of the rapid decline of Christianity in France, Christopher Caldwell writes:

For centuries French people revered their cathedrals, priests, and relics. But . . . they haven’t lately: just 6 percent go to Mass, down from 35 percent half a century ago. . . . The pollster Jérôme Fourquet argues in his book L’archipel français (“The French Archipelago”), published last month, that in matters of religion the country is undergoing an “anthropological shift.” As in the United States, the size of the still-religious generation born after World War II long disguised the decline. Today, as that generation ages and dies, a demographic trapdoor opens under the religious population. . . .

The alternative to Christianity, Fourquet shows in his book, has not been lucidity; it has been gaga conspiracy-theorizing. A third of French people eighteen to twenty-four years old believe that airplane contrails have been seeded with hazardous chemicals and that the United States military can provoke storms, versus only 7 or 8 percent of those over sixty-five who believe such things. The decline of religion does not seem to have grounded people in something more true.

That is partly why the fire at Notre Dame shook so many to the core. Objects and traditions bound up with religious belief lend a feeling of sense and stability. For believers they are a reinforcement. For nonbelievers they are a substitute. Notre-Dame is perhaps the greatest such object in Europe. It is a consoling relic, as surely as the crown of thorns that Reverend Jean-Marc Fournier, [the chaplain of the Paris fire department], rescued from the blaze, and this is so for believers and nonbelievers alike. . . .

The fire at Notre Dame is harrowing in a way that feels religious because it is religious: it forces us to understand France as those who created it understood it. The people weeping on the banks of the Seine must have sensed this, even if they could not put into words exactly what they were weeping over.