NEW YORK — Of all the octogenarian actors who reached the height of their fame in the 1970s, let’s assume, generously, that a third are dead. Another third are almost certainly on base for an upcoming “In Remembrance” montage at the Oscars. The final third, the lucky ones, live on – in cameos and TV ads and on the tongues of senior citizens explaining who they are to the grandkids (not that the grandkids asked).

And then there’s Alan Alda.

Eighty-four-year-old Alan Alda, who, on a recent winter day, bounds into his company’s glass-walled Manhattan offices housed in a co-working space that is otherwise occupied by start-ups, millennials and geometric sculptures stacked artfully on top of never-opened coffee-table books.

There, he momentarily confers with one of his own millennials, Sarah Hill, who runs his social media accounts. They talk about the access levels they’ll offer subscribers to his podcast, the tweets he needs to send and the smartphone app he is working on to help people increase their capacity for empathy.

“Also,” Hill adds. “One thing I’ve been meaning to tell you – ”

“This sounds bad,” Alan Alda says in Alan Alda’s voice. (Flat “A’s,” slightly nasal, yet deep and distinctly New York.)

“No, this is fun,” Hill assures him. “Laura Dern keeps writing on our Instagram.”

Silence.

“You know – Laura?” Hill says. “Laura Dern?”

“Yeah. I know Laura Dern,” Alda laughs with Alan Alda’s laugh.” (Whoever decided laughter should be written “ha ha ha” probably did so after telling Alda a joke.) Hill explains that Dern frequently posts supportive comments on Alda’s account. “Huh. So she looks at it,” Alda says. “And I don’t.” Parkinson’s makes his right hand shake, but he jabs the table decisively. “I gotta go to it. I know Twitter, but I don’t know Instagram. OK, you’ll help me learn that.”

Alda is nearing the end of an acting career that began before most households had color TV, let alone the internet. But he isn’t ready to let the world leave him behind. The six-time Emmy winner who smart-mouthed his way into American hearts as Army doctor Hawkeye Pierce on “M*A*S*H” is, according to his eldest daughter, Eve Alda Coffey, “working harder now than ever before.”

His work has become more ambitious than acting. Alda says he wants to teach people how to better communicate with one another. To that end, he’s deployed all the available tools of communication: a Twitter feed, an Instagram account, a weekly podcast called “Clear+Vivid with Alan Alda.” He’s written three books and a play and given speeches around the world.

He’s always been ready to speak, but now he’s eager to listen. Really listen. Alan Alda takes listening very seriously.

“I have this radical idea that I’m not really listening unless I’m willing to be changed by you,” he says.

Then again, by the standard of celebrity (or humanity, even) Alda is a relic – an icon, and beloved, but well past the age where anything new is expected of him.

Which leads to the question: Is anyone really listening to Alan Alda? Enough to be changed by him?

– – –

“Is this our car?” Alda asks, pointing to a black SUV waiting down the block from the co-working space. He piles in with two staffers named Sarah – Hill and Sarah Chase, chief operating officer of Alda Communication Training – and they zigzag over to the headquarters of the podcasting giant, Stitcher, where he’ll fix his own cup of tea before heading into a studio to wait for foreign affairs wonk Fareed Zakaria, today’s guest on “Clear+Vivid.”

Zakaria explains why the country feels so at odds. And how dangerous it could be if people keep talking past one another. Alda listens and nods.

He leans forward and almost never interrupts. He has no notes in front of him. Every question – about identity politics, geopolitical upheaval and Zakaria’s college days – seems to prompted by something his guest just said. And when the podcast wraps, Zakaria lingers. Neither man seems to want the conversation to end.

Alda first learned how to get and keep people’s attention from his parents, vaudeville performers who christened him Alphonso Joseph D’Abruzzo. The family traveled from town to town with a troupe of showgirls, strippers and comics who adored him, and eventually they settled in California when his father got into the movie industry. Young Alphonso’s tutelage continued with the performers who turned up in his living room. He started to consider everyone outside the entertainment world “civilians” who didn’t really know how to make one another laugh.

Alda got his first comic’s high performing in sketches with his father, whose stage name was Robert Alda. When he showed up at public school for the first time in seventh grade, he surveyed the other students on the playground and thought, “Wow, look at the size of that audience.”

“Within a few minutes I was up on a lunch table performing,” Alda writes in his memoir. “I did bits, impersonations, a little improvised tap dance. For some reason I didn’t understand, this made kids want to hit me.”

Performance and empathy have a complicated relationship.

Alda persevered, attended Fordham University and studied theater and improvisation in New York. He learned how to communicate scripted emotions to large audiences – well enough to land on the Broadway stage at age 23 – but that didn’t necessarily translate to real-world panache. When he met Arlene Weiss, after watching her play Mozart on the clarinet at an apartment party in college, all he could manage was: “Hi. You were good.”

A few weeks later they were both invited to a dinner at the same apartment. When the hostess’s rum cake fell from the top of the fridge to the kitchen floor, Alda and Arlene were the only two guests who dug in with spoons.

“So that was it,” he says. “From that time on we were almost inseparable.”

His parents’ marriage had been fraught. His mother was schizophrenic, which opened a void of trust and predictability in their home. When Alda was 6, he watched her stab his father after accusing him of an affair.

Alda and his wife’s marriage story has been far less tumultuous. This month, the couple celebrates their 63rd anniversary. He says she taught him to read the newspaper and to be a better thinker, that she held him to his values and never asked him to get a corporate job during the early years when work wasn’t steady. “I was thinking the other day she’s the soul of my soul,” he says. “Because I wouldn’t be who I am without her.”

Last year, Alda appeared opposite Laura Dern, Scarlett Johansson and Adam Driver in “Marriage Story,” playing the thrice-divorced, cut-rate lawyer who serves as the movie’s moral compass.

“Marriage Story” is actually a story about a breakup, and what struck Alda about it was that the relationship between the two main characters fell apart because they couldn’t communicate with each other. And then, to survive their eventual divorce, they had to relearn to communicate.

Performance, whether it’s a soliloquy on a Broadway stage or Mozart in a New York apartment, can be seductive and inspiring. But communication is what keeps things together, or fixes them once they’re broken.

– – –

“I’m always surprised at how I’m really tired at the end of it,” he says.

The interview with Zakaria is over, and Alda is sitting in a restaurant across the street from the Stitcher office. “You’re not only listening as deeply as you can to the person. You’re thinking, ‘What can I pick up on here to go to the next level?’ ”

Lotta effort, all this communication.

Alda is 6-foot-2, with gray hair that starts at the top of his head. His tremors are noticeable, though not as bad as those of his character on “Ray Donovan,” the Showtime series on which Alda plays a therapist with a more advanced case of Parkinson’s than his own (he embellished his symptoms accordingly). He orders a beer and places a small microphone on the table – not to record, but to amplify the sound going to his hearing aid. Over the next two hours he’ll order a second beer and a side dish of roasted Brussels sprouts.

“I’ve been eating like a pig,” he says, explaining his restraint. “I did a tweet a couple of weeks ago where I said, ‘To lose weight you have to have a goal. My goal is to lose seven or eight pounds so I can eat like a pig again.’ So that’s what I’ve been doing.” He smiles an Alan Alda smile, which stretches wide enough to reveal his farthest molars.

Alan Alda is thinking about the future.

He’s been doing that for a long time. After “M*A*S*H” ended its 11-year run, culminating in what remains the most-watched episode in television history, Alda was flush with opportunities, one of which was an offer to serve as host of a PBS documentary show called “Scientific American Frontiers.” Alda, a science buff since childhood, agreed to do the show on one condition: that he be allowed to interview the scientists, not just introduce segments about them. That’s how he realized most of them, no matter how smart and accomplished, didn’t know how to talk to people.

Alda pulled simplified explanations out of his guests on camera. Behind the scenes, he lobbied every person he knew connected to a university to set up a program to help scientists become better communicators. Finally, in 2009, administrators at Stony Brook University on Long Island took Alda’s suggestion and unveiled what would eventually be named the Alan Alda Center for Communicating Science.

Since then Alda has been giving the program, and its larger mission, most of his spare time, energy and money. In 2016, he set up Alda Communication Training, a for-profit company that offers workshops to scientists, doctors and technologists – about 15,000 so far – who get trained in some of the same improv techniques Alda learned as an actor. The goal is to help them better relate to their audiences.

Alda says years of improvising helped him become highly attuned to cues from his scene partners, which made him better able to understand the people in his real life. “It applies to every possible field, every human activity,” he says. “Parenting, loving, negotiating for hostages.”

Hostage negotiation comes up in Season 1 of “Clear+Vivid,” in an episode featuring former FBI negotiator Chris Voss, who tells Alda he uses empathy and identification to relate to the person on the other end of the line, often using phrases such as, “I completely get where you’re coming from.”

Alda likes that approach, especially when it comes to relationships.

For anyone to get where Alda is coming from, he has to get them to listen. And he has to do the same in return.

– – –

Seventeen years ago, Alda nearly died of an intestinal obstruction while traveling in Chile. In the months that followed he woke at night with a nagging question: “Are you living a meaningful life?”

He knew he was living a good life. The acting, the fans, the family and marriage. Time split between Manhattan and a house in the Hamptons. He knew he’d at least tried to do good in the world. In the 1970s and ’80s Alda spent so much time traveling the country campaigning for the Equal Rights Amendment that the Boston Globe dubbed him an “Honorary Woman.”

But meaningful? Alda agreed with the existentialists he’d studied in college: “They said the meaning of life is the meaning you give to it.” To Alda, that meant that no matter what he’d already done, he had to keep doing things and giving them meaning, too.

“Life seems to be a lot more fun if you have a purpose,” he says. These days, the meaning Alda wants to give to his life is, “to be helpful, where I can.”

It’s hard to say for certain how helpful he is being with the podcast, talking about talking. But according his company more than 7 million listeners have downloaded the show, which pulls in guests ranging from scientific experts to famous performers, including Julie Andrews, Tom Hanks and Paul McCartney. “I get early indications that the podcast is touching people, that they’re learning from the people who come on my show and talk in an honest way about what they go through,” he says. “And that makes me happy.”

He treats Parkinson’s disease like (another) part-time job, keeping up with the latest research and strategies to slow the disease’s progression. Aging gets the same emotional distance. “I think of it as an acting thing. Right now I’m playing an older guy with less hair,” he shrugs. “So, that’s fine. I’ll play that part.”

There is a video of Alda making the rounds on the internet. In it, the actor, then a young man in his 60s, performs a tap-dance routine with his 9-year-old granddaughter in a garage. It is, perhaps, the most Alan Alda thing of all time. It has a rat-a-tat-tat rhythm, showmanship and physical comedy. Plus, it ends with a hug.

Alda posted the nearly 20-year-old clip on his Twitter account last summer – a tender moment of connection that was also a performance. For Alda, performance, communication and connection can never be untangled. So he spent the bulk of his life attempting to master all three. And he’ll spend the remainder of it trying to help us do the same.

The check comes at the restaurant and it’s time for Alda to go. To get back to Arlene and his urgent emails and his plans for the future.

To keep tap-dancing with the people he loves, and for anyone else who wants to listen.