In the decades since The Beatles’ break up and John Lennon’s death, Paul McCartney has never lost the value he placed on his bandmate’s opinion. While Lennon and McCartney’s relationship wasn’t always perfect, they had a successful working partnership for years. McCartney revealed that even to this day, he considers what Lennon would think of a song before he releases it.

Paul McCartney said he still considers what John Lennon would think about a song

In the four decades since Lennon’s death, McCartney has released a good deal of music. Lennon, of course, did not contribute to these albums, but McCartney said his opinion still mattered. If McCartney can imagine his former bandmate rolling his eyes at an overly sentimental lyric, he’ll rewrite it.

“Often I’ll sort of refer… ‘What would John think of this? He’d have thought it was too soppy,’” McCartney said on the iHeartPodcast McCartney: A Life in Lyrics (via NME). “So I’ll change it.”

McCartney explained that he doesn’t want to lose Lennon’s outlook on songs, so he inserts it himself.

“That interplay was miraculous,” he explained. “You don’t have this opposing element so much [now]. I have to do that myself.”

Paul McCartney spoke about the excitement of writing with John Lennon

When writing songs, McCartney’s approach to the lyrics often clashed with Lennon’s. This was, McCartney said, the most exciting part about writing with Lennon.

“If I were saying, ‘It’s getting better all the time,’ John might easily say, ‘It can’t get no worse,’” McCartney said in the book The Lyrics: 1956 to Present.

He believes that this dynamic is what has given their songs lasting success.

“Mine would be doing this, his would be doing that, and the interplay was just miraculous,” he explained. “And that’s why people are still listening to the songs we wrote. They didn’t just go away like your average pop song. The climate that the two of us created in writing wasn’t a soppy pop song climate. We created an environment in which we might grow, try new things, maybe even learn a thing or two.”

John Lennon wasn’t as kind about his former bandmate

While McCartney still speaks about the influence Lennon has had on his songwriting, his songwriting partner wasn’t as complimentary. In the years immediately following The Beatles’ break up, Lennon often spoke critically about McCartney in the press. He insulted the work they did in The Beatles and McCartney’s solo career. He also said that he never felt a loss when he stopped writing with McCartney.

“I never actually felt a loss,” he said in the book All We Are Saying: The Last Major Interview With John Lennon and Yoko Ono by David Sheff. “I don’t want it to sound negative, like I didn’t need Paul, because when he was there, obviously, it worked. But I can’t — it’s easier to say what my contribution was to him than what he gave to me. And he’d say the same.”

According to the people who worked closely with McCartney and Lennon, though, they needed each other in equal measure.