One sibling in my family was nearly destroyed by religion. The clergy in our diocese committed a monstrous crime, the scourge of sexual abuse known to many Catholic communities. Another sibling was made whole by religion, after losing a son to murder and finding that no one but God could salve her wounds. There are no clean lines in our clan.

On the trail, I repeatedly heard the term “deep walking.” My fellow pilgrims were an odd assortment of spiritual stragglers of a certain age. But there were also many young people. And for the young, as I heard it described, a pilgrimage is a way to “do” religion.

At a Benedictine monastery in a tiny village in northern France, it was strangely moving to eat dinner in utter silence among a handful of men who’ve shed all material comforts to engage in rigorous daily aerobics of the soul. I missed Wi-Fi, Twitter, emails and endless digital updates, until I didn’t.

At a stopover in Laon, a city of shimmering stone 300 feet above the plains of Picardy in France, I tried to fathom the power of miracles. About 80 percent of Americans believe in them. As a pilgrim, I had to dampen down my doubts, to try to see things in another dimension. “Miracles are not contrary to nature,” as St. Augustine wrote, “but only contrary to what we know about nature.”

I was less moved by one of the high shrines of atheism, in Langres, the hometown of the Enlightenment philosopher Denis Diderot. The town is just one step short of being Diderot Disneyland, which only the French could pull off. But after deep immersion in his beautiful, busy mind, I still felt a bit empty. Religion is story, a narrative about a force much greater than us, enigmatic by nature. Atheism has trouble telling a story.

In the Swiss Alps, a permanent prayer started to honor Maurice, said to be the first black saint, has been recited day after day, year after year, century after century by a rotating band of monks known as the Sleepless Ones. The martyred Maurice, who was from North Africa, is revered. His modern comeback has much to do with the vibrancy and growth of Christianity in Africa at a time when Christianity in Europe is dying off. If present trends hold, within 20 years Africa will have more Catholics than the Continent.

At Great St. Bernard Pass, the high point of the Via Francigena, at 8,114 feet, I was fascinated by a priest of 40 years who still struggled with his faith. “Doubts are allowed by God,” said this man who introduced himself as Father John of Flavigny, a onetime medical student. “It’s a bit like training for sports. If you only ride a bicycle with the wind at your back, that’s not going to help you. You need to ride your bike against the wind.”