The tightrope walker crept out over the red cliffs, delicate-toed as a bride up the aisle. Nik Wallenda stepped into nothingness, small and alone, the space around him throwing his figure into relief. Clean. Pure. Single. In that moment, 13 million television viewers drew in a gasp that made us realize just what an involuntary activity breathing is.

The rocks. The stomach-plunging drop. The cable just 21 / 2 inches wide. The small river at the bottom of the canyon like a piece of dirty brown tape. The bird-like shape of the tightrope walker holding a white balancing pole, utterly insignificant compared to the vastness around him. “A hermit watched by millions,” my friend Henry, not a man easily awed, described him. The ultimate athlete, free of all law except gravity. Solely responsible for himself. Completely out of society. Beyond criticism. Committing a pointless act — yet praying.

A total of 13 million tuned into the Discovery Channel, and millions more joined the same existential living room on social media, sharing “a fascination with the unimaginable,” Discovery Channel group president Eileen O’Neill said. As she sat in a control room, her heartbeat accelerated. Two days later, she still can’t bear to see a replay. “I haven’t been able to watch it again, to be honest,” she said. “My heart is still beating.”

Wallenda took more than 23 minutes to cross the gorge, counting the occasions when he paused on a knee in the wind that buffeted him and blew red dust in his eyes. The walk lasted long enough for us to wonder why daredevils still appeal to us, even as they do something that seems almost archaic. Why did millions tune in to a seventh generation aerialist on a high wire over a gorge near the Grand Canyon without a harness?

We thought daredevils were gone — too much science had reduced them to the predictable. Wallenda’s parents washed windows because circuses were dead — they couldn’t make a living at the old family trade. The last time anyone cared about aerialists was the 1970s, when Philippe Petit walked between the World Trade Center towers and Evel Knievel bounced on pavement like a broken toy.

But along has come this new breed. In the past year we’ve been transfixed by Felix Baumgartner skydiving from a helium balloon 24 miles above the earth — watched by 7.6 million on the Discovery Channel and viewed 52 million times on YouTube — and now by Wallenda’s walk. Both events provoked stomach-flips and held us spellbound. Both stunts explored the edge of uncontrollability, margins for error and forgiveness, yet were based in expertise. Both proved the point that what separates risk takers from suicidal idiots is mastery.

Wallenda was up there long enough for us to contemplate the difference between risk and recklessness — long enough to mentally compare him to other performers and sort out the difference between Wallenda and lion tamers or motorcyclists who ride without helmets and adrenaline junkies. Wallenda, like Baumgartner, marries his dares to science. Both, in the words of O’Neill, take “spectacular events and also bake them in thermal wind discussions and wire tension and weather and all the physics and engineering.”

Wallenda climbed on a wire for the first time when he was two years old. His parents kept their tightrope gear in the backyard suspended between cement blocks. He was a hyperactive child who found concentration on the wire. He had a recurrent dream of a man in billowy satin circus clothes who told him, “Walk over the falls.” The first time he saw Niagara Falls he was just a boy, but he said, “I’ve been here before.” His father replied, “You must have seen pictures, son.” Last year he walked over it wreathed in mist and blasted by updrafts, wearing a tether harness forced on him by terrified local authorities.

He believes the satin-clothed man was his grandfather, Karl Wallenda, descendant of the Flying Wallenda family, who walked wires in a seven-person chair pyramid. Karl was killed in San Juan, Puerto Rico, in 1978 during a walk between two 10-story hotel towers when a gust of wind swept him off the cable. Karl Wallenda’s belief was that tethers and safety nets were more dangerous than helpful. They weakened the concentration — convinced you of safety and made you too relaxed. Complacent.

There was nothing tethered or complacent about the figure hovering over the canyon. But there was confidence: the confidence of seven world records and the family heritage. And the sure knowledge that gravity was as much his aide as his enemy. The basic physics kept him anchored to the wire.The balance bar engaged the two opposing forces of gravity and lift to give him stability. Gravity is a terrible constant — it always wins in the end — but it’s predictable. The real danger is chance. Once, a bird landed on his pole. Another time a bee stung him.

He has said that knowledge of craft renders his profession no more hazardous than that of a policeman: “What I do is extremely calculated. . . . I trained my entire life to catch that wire.” When he talks like that, he sounds like old Harry Houdini talking about his milk cans and manacles. “No performer should attempt to bite off red hot iron unless he has a good set of teeth,” Houdini said.

Why are we are reawakening to people like this — daredevils — after a long period of disinterest? Historically, daredevils have most fascinated us in periods of cooped-up urban boredom and cultural rot, combined with access to new media forms. Houdini flourished in an age of the new penny press when Victorians were tired of spending too much time in parlors. Wallenda and Baumgartner have surely profited from the explosive accessibility of laptops and stage-like views of hi-def — but also perhaps with the stale, stupid predictability of reality TV, the boringness of celebrity wife swaps and starlet cat fights that seem so scripted, the droning in courtrooms of murderous girlfriends mimicking sincerity through tears.

Wallenda’s meaningless act restored the meaning of real. It had an untouched simplicity. For his next trick, he wants to walk untethered on a wire between the Empire State Building and the Chrysler Building in New York. Local authorities are resisting the idea. Asked on Monday whether he would permit such a feat, New York police commissioner Raymond Kelly replied, “I would say no.” He added, “I think it’s dangerous.”