What if things could turn out differently? How the multiverse got into our heads and didn’t let go

“Let’s do things differently this time.”

Those are the first words you hear at the beginning of this month’s “Spider-Man: Across the Spider-Verse,” an otherworldly meditation on multiple realities and how our lives might unfold. The message is clear from the get-go: We have choices. Things could be malleable. You are you, sure. But wait — you might also be you and you and you.

The world is a stressful, sometimes lonely place — and more so at a moment when “It wasn’t supposed to be this way” has become a not-uncommon mantra. But what if things could turn out another way? What if, somewhere, they had? Enter the realm of the multiverse and alternate realities, one of the most glorified canvases in popular culture’s recent years — and a repository for the ache and longing of living in an era of uncertainty.

Alternate universes are everywhere these days, as the long-delayed opening weekend of “The Flash” attests with its regret-streaked, history-changing storyline (and its multiple variations of Batman). There is a deep hunger, it seems, for exploring possibilities — for seeing what might have been if just one thing had unfolded differently.

“The cultural assumption used to be that the world we live in is the way it is, and that’s the only way it could be,” says Douglas Wolk, who read 27,000 Marvel comics from across the decades for his book, “All of the Marvels.”

“What has happened in culture,” Wolk says, “is that people are saying, ‘Well, no. This consensus reality is not how things have to be.’”

THE MULTIVERSE HAS A RICH HISTORY — OR HISTORIES

The notion of exploring life’s twists and turns through alternate timelines has been around for a while, albeit in varying guises.

“It’s a Wonderful Life,” the quintessential Christmas movie from 1946, sent the affable George Bailey tumbling into a timeline where he’d never been born to reveal his true impact. “You’ve been given a great gift, George — a chance to see what the world would be like without you,” he’s told by his wannabe guardian angel, Clarence.

In the decades since, that notion has accelerated — a rise in stories that consider events both fictional and real, extrapolating different choices.

What if the South had won the Civil War (“CSA: The Confederate States of America”)? What if Germany and Japan had won World War II ( “The Man in the High Castle” )? What if John F. Kennedy hadn’t been assassinated ( “11/22/63” )? What if the Soviets had beaten the Americans to the moon (“For All Mankind”)? What if 9/11 had played out very differently (“The Mirage”)?

Fictional worlds are more malleable, though, and can yield more content. So it is that imaginary characters — particularly beloved ones with established stories — are toyed with in books, TV shows and movies that airlift them out of one life and into another. It’s a concept that cuts across genres, from rom-com (1998’s “Sliding Doors,” where missing a train splits a young woman’s life into diverging paths) to near-musical (2019’s “Yesterday,” where a budding musician tumbles into a universe where the Beatles never existed).

You have the reality where Spider-Man never married Mary Jane Watson (Marvel Comics’ “Brand New Day”); the universe where one variant of Doctor Strange has gone insane ( “Doctor Strange and the Multiverse of Madness” ); the universe where a Ben Affleck Batman never existed but the Michael Keaton Batman stuck around and got old ( “The Flash,” which we’re not spoiling since this was in the trailers).

And you have the “mirror universe” of “Star Trek,” whose dark and aggressive Terran Empire reveals the baser instincts of beloved characters. Not to mention the recent spate of “Trek” movies, which unfold in yet another reality, splintered when an aging Spock went back in time.

“It’s a way to explore a problem that’s never actually happened in the main story,” sums up Nic Lemire, 13, a California teenager who co-hosts an occasional podcast called “Marvel Mondays” with his mother, former Associated Press film critic Christy Lemire.

One crowning example of multiverse success: Last year’s “Everything Everywhere All at Once,” which showed all the different lives that Michelle Yeoh’s main character might have lived — with the point being that across the multiverse, her family remains a family. It won seven Academy Awards, including best picture.

Whatever the subject matter, these works are united by one theme: There are always possibilities, for better and for worse, and exploring them is entertaining, enlightening and escapist. That’s no small thing in a post-COVID world facing the ravages of extreme climate events, persistent racism, the rancor of political polarization and the rise of artificial intelligence — a planet where convulsive change can seem the only constant.

“Fictions have implicitly done what alternate universes seem to be doing more lately: letting us explore some reality that’s not actual, for the purpose of learning about the actual world,” says Hannah Kim, an assistant professor of philosophy at Macalester College who has researched why the multiverse resonates.

“We’re bombarded with things that seem arbitrary, random,” she says. “The number of difficult developments the past few years — the pandemic, political upheaval, effects of climate change, etc. — leave the anxiety-riddled person with the nagging feeling that this all could have been otherwise.”

IT’S A LUCRATIVE BUSINESS MOVE, TOO

Exploring the question of “what if” continues to be lucrative — to the point where there’s an entire Marvel show exploring alternate realities called “What If…?” And while multiple universes are starting to feel spread thin as a plot device, the trope isn’t going away any time soon in our single world, where reality is constantly called into question.

After all, if you can remix popular characters in multiple properties while retaining the potential for a reset in a “prime universe,” what is there to lose? Well, there’s one thing: If everything is reversible, unlike real life as we know it, how high can the stakes really be?

“It narratively lets you have your cake and eat it, too — you can kill off the character, have an emotional death scene and then bring the character back from another universe,” says Matt Ruff, whose 9/11 novel, “The Mirage,” posits an alternate universe that flips aggressors, victims and prejudices. In its reality, it was Christian extremists who attacked the Twin Towers of the “United Arab States” in Baghdad.

“If everything’s possible, the choices are less interesting. The consequences don’t matter all that much,” Ruff says. “Part of engaging in the real world is engaging with the fact that there’s no magical solution.”

That, though, may be precisely why the notion resonates. Human beings have always wanted to try on other outfits, other outcomes, maybe even other lives. That’s what stories are about. Could we be hurtling toward a narrative era — the immersive equivalent of choose-your-own-adventure stories — where all possibilities are on the table?

Technology has enabled people to obtain most anything — customized, to boot — from the world’s bounty within 48 hours. Who in the network television days of the 1980s could have imagined that streaming would bring thousands of television shows and movies to our eyeballs with the push of a button? So why not thousands of stories with thousands of possible endings for characters and plotlines? What does that do to our relationship with our stories?

“You are looking at a piece of a bigger cultural picture that provides a constant barrage of cultural images that reinforce this idea that we can be better versions of ourselves,” says David Newman, a sociologist at Colgate University who has written a book on second chances. “People want to believe that when we have a problem, the problem is fixable.”

There’s one Marvel Comics offshoot, something called “Marvel 1602,” which chronicles a universe in which Earth’s mightiest superheroes existed at the beginning of the 17th century. In it, Reed Richards, the leader of the Fantastic Four, proposes something.

“I posit we are in a universe which favors stories,” he says. “A universe in which no story can ever truly end; in which there can only be continuances.”

However it might play out, that’s a universe full of possibilities. And judging from the past two decades in the popular culture of human beings, it’s good business as well to keep on asking: What if?