"Now and then I miss you," sing John Lennon and Paul McCartney, 45 years apart. Artificial intelligence has "lifted" Lennon's voice from a 1978 cassette to create the last song from the Fab Four. McCartney calls the result "magical".¹

The music video dropped on Friday. It features the earliest known footage of The Beatles, recorded in a church hall in 1962. Eight months later, they released their first single, Love Me Do. The foursome went on to make pop history.

Ringo Starr and George Harrison complete the band. Harrison died of cancer in 2001, and Lennon was murdered in 1980. But new technology and old demo tapes mean all four are together again on this final recording.

The Beatles are the best-selling band of all time, shifting 600 million records.² On tour, they were met with a fan frenzy dubbed Beatlemania. They explored new sounds and worked classical, Indian and psychedelic music into their repertoire.

But can we compare McCartney's melodies to Mozart or Lennon's lyrics to Shakespeare? Popular music, by definition, has mass appeal. But, critics and experts disagree on whether we should take it seriously.

Musicologist Simon Frith says pop music is "designed to appeal to everyone" and is a commercial "enterprise not art".³ The purpose of pop music is to make you feel and dance - not think. And there is evidence that it is getting louder and dumber.⁴

The philosopher Theodor Adorno criticised popular music for sticking to a formula. Pop music is "catharsisOriginally used by the Ancient Greek philosopher Aristotle to explain the power of art to dispel strong negative emotions. The term is used in psychotherapy to describe how patients can overcome difficulties by expressing and facing their fears. for the masses", a product of capitalismA form of economy characterised by private property and competition between companies. that does not challenge society or its listeners.⁵ Writing in 1941, Adorno was thinking of jazz and swing.

But what would he have thought of Rubber Soul? The Beatles' rule-breaking 1965 album that inspired Bob Dylan, The Beach Boys, The Who and The Kinks. Expert James Decker wrote that it made listeners "desire and expect" more from music.⁶

McCartney says they try to "spread love" with their music. The former spy Leslie Woodhead believes The Beatles infected SovietRelating to the Soviet Union, a powerful group of communist republics, the biggest being Russia, that existed from 1922 to 1991. youth with a "spiritual energy" that hastened the fall of communismThe system of organising society so that all property is owned by the community and everyone receives things according to their needs. in Europe.⁷ Lennon's Imagine made "catchy pop ... unabashedly utopian and deeply moral," says sociologist Phil Zuckerman.⁸

What is pop music anyway? When musician Richard Thompson was asked for his favourite popular tunes of the "millennium", he volunteered Sumer is icumen in, a medieval hit from the 13th Century.⁹

Popular music may be powerful in the moment - but trivial and fleeting over time. Great art communicates enduring truths about human nature.

But then, 15 billion miles from Earth, the Voyage 1 probe is the furthest human-made object from Earth. It contains a "golden record" for aliens to learn about humanity. Alongside Bach and Beethoven is Chuck Berry's 1958 hit Johnny B. Goode.

Critics told astronomist Carl Sagan this "adolescent" music did not belong on this serious mission.¹⁰ Sagan replied we want to tell aliens who we are, and "there are a lot of adolescents on the planet".

Yes: Something does not need to be complex to be serious. The power of pop is its universality. It brings people together in a shared appreciation of music. Only snobs would think that wasn't serious.

No: Pop is mindless rubbish. The music is predictable, and the lyrics are glib and unimaginative. They are made to stick in our heads at the cost of thinking about anything serious or meaningful.

Or... The Beatles were not serious, and that was the point. They were irreverent, silly buffoons who mocked social conventions. We cannot always be serious, and we should enjoy the simple pleasures of pop.

Catharsis - Originally used by the Ancient Greek philosopher Aristotle to explain the power of art to dispel strong negative emotions. The term is used in psychotherapy to describe how patients can overcome difficulties by expressing and facing their fears.

Capitalism - A form of economy characterised by private property and competition between companies.

Soviet - Relating to the Soviet Union, a powerful group of communist republics, the biggest being Russia, that existed from 1922 to 1991.

Communism - The system of organising society so that all property is owned by the community and everyone receives things according to their needs.