Sitting inside her office at New York's Dakota apartments, a stone's throw from where her husband was murdered two decades earlier, Yoko Ono considers the question:
Imagine Lennon at 60?
There's a pause. A long pause.
"I think he was always innovative," she finally says. "I think he would have jumped into the internet. Also, his music was very funky and punky - the rap kind of thing."
There's a shorter pause and her voice grows lively.
"You can almost see that John would have done that," she continues. "I'm sure he would have been the first white rapper. Or the second, maybe."
Lennon as Eminem? A bespectacled Lennon downloading MP3s from the internet? Lennon, grey-haired and grey-bearded, dueting with Fred Durst?
It's pure speculation 20 years after a demented Beatlemaniac killed Lennon with five gunshots on 8 December, 1980. It's also something that Ono, who watched in horror as her dying husband collapsed, lives with every day.
"I miss the laughter, you know?" the 67-year-old widow reflects. "He made me laugh, especially at times when things were difficult."
To the world at large, John was never the funny Beatle - that title belonged to Ringo. Paul, even at 58, remains the cute Beatle, while George in his English mansion is ever the quiet Beatle.
Lennon, paradoxically, lives as the dead Beatle - fascinating but forever frozen in time: house-husband, father, reluctant rock star who spent five years watching the wheels go round with his new son Sean.
This year, when Lennon would have turned 60, his work was ubiquitous. Nine Beatles related books were introduced in 2000 - from the authorised The Beatles Anthology, to a reissue of Lennon's verse In His Own Write, to a tome on the Beatles' dalliance with the Maharishi Mahesh Yogi.
A compilation of the Beatles' 27 No. 1 hits, released in time for Christmas shoppers, is top of the charts in 19 countries including Australia and the United States, where almost 600,000 copies were sold in its first week.
Ono supervised re-releases of the first and last solo albums of his life, Plastic Ono Band and Double Fantasy.
There was even a book from Lennon about Lennon - a 151 page pressing of his revealing 1970 interviews with Rolling Stone founder Jann Wenner.
"The dream's over," Lennon warned 10 years before his death. "And I have personally got to get down to so called reality."
The blood spattered glasses that Lennon wore on the night of his murder. And a hospital bag containing his clothes, riddled with bullet holes.
Ono explains: "In John's spirit, it was very important to have a strong message: 'Let's not kill each other any more'. John was always trying to send a message about world peace."
"I felt it was appropriate."
Even now, Ono cannot utter the killer's name. She refers to him only as 'that guy'.
Mark David Chapman came from Hawaii to Manhatten in search of Lennon.
The chubby, deranged fan settled into a hotel just a 20 block walk from the Dakota.
On the night of his death, Lennon and Ono were headed home from a Manhatten recording studio where they had worked on her Walking On Thin Ice single.
A white limousine deposited the pair on 72nd St off Central Park, and they moved towards the Dakota's gated entrance.
It was almost 11pm and Chapman was waiting.
Chapman now clutched a .38 calibre revolver.
Once Lennon passed, Chapman pumped five bullets into his back.
As Lennon lay dying on the pavement, Chapman dropped the gun and produced a paperback novel, The Catcher In The Rye, from his pocket. He opened the book and waited for the police.
Lennon, 40, was dead.
So imagine John Lennon, on the cusp of social security, smoking an unfiltered Gitane and sipping a cup of tea.
Lennon, during his 1970 interview with Wenner, was asked to conjure his vision of the Liverpool kid at age 64.
It included Yoko, but made no mention of Paul, George or Ringo. He was far from the craziness of Manhatten.
"I hope we're a nice old couple living off the coast of Ireland or something like that," he said. "Looking back at our scrapbooks of madness."
A visit to the Rock and Roll Hall of Fame provides a stark dose of reality. When the Cleveland building unveiled a Lennon tribute in October the first items on the display reinforced his violent absence.
That day, Chapman had greeted Lennon with a copy of the rocker's new Double Fantasy album. Lennon signed and dated it.