The music fails, however, to measure our lives. You may possibly remember the first time you heard “Rhapsody in Blue”, but unless you met the love of your life in the next seat or were dragged out of the concert hall to jail, it is unlikely that you will stop in your tracks each time the work is played or someone tells you George Gershwin is dead. “I don’t have to believe that if I don’t want to,” said the novelist John O’Hara, drawing a shrewd line between the immortal and the ephemeral (once hailed as “the real Scott Fitzgerald”, O’Hara sadly joined the latter category). The death of a composer or a classical pianist is not a life-halting event, and never has been since Beethoven died.

Part of this is to do with lifespan. Classical musicians tends to live longer. We remember them old rather than young. When they vanish, it seems a natural event, except in the case of those who, by some cryonic illusion, remain forever young in our minds.

In October 1982 I persuaded an editor at the Sunday Times to send me to Paris for an interview with Daniel Barenboim, who would turn 40 the following month.

“Impossible,” said the editor. “He’s a 13-year-old in short trousers.”

“Actually,” I replied, “he’s got a grown-up job as music director of the Orchestre de Paris.”

I spent an intense afternoon with Barenboim — intensity is his default mode of communication — talking mostly about his childhood, to which he seemed preternaturally close. Israel was much on his mind. “There was a quality of life there in the 1950s that I have never found anywhere else,” he enthused. “We were all committed to an idealism, to building a new country, a new society. We would laugh at girls in my class who wore make-up or high heels: it seemed irrelevant and decadent. Much of my self-confidence stems from that childhood in Israel.”

He went on to speak about the plight of the Palestinians and the hardening attitudes of successive Israeli governments, but what struck me then, and in further conversations down the years, was how resourcefully he had frozen the boy he once was into a perpetual source of strength for the great musician and public personality that he would become. Everything he has done — whether conducting at Bayreuth or being music director of the Berlin State Opera — has been built on the moral basis of the perceptions he imbibed as a child in a marginal Mediterranean country.

Barenboim will turn 75 this year — “I don’t have to believe that if I don’t want to” — and the controversies he has aroused both on the intractable Middle East conflict and Europe’s refugee crisis have tended to occlude the uniqueness of his position. He stands today as the only classical musician whose voice is heard by world leaders, the only non-pop musician of measurable consequence.

At 75, he is full of vigour and initiatives. Chancellor Merkel has just opened his Barenboim-Said Academy in Berlin — “an experiment in utopia”, bringing together young talents from around the Middle East to play an undefined pathway to peace. The late literary scholar Edward Said was the formative intellectual influence of his life. Said has been widely contested as a fantasist whose Palestinian identity was concocted. Barenboim is an artist who functions more by instinct than by rationale. His judgments are governed by a desire to achieve beauty and a recognition that, when all is said and played, it is only music that is being made, powerful but ephemeral.

The boyish naivety Barenboim has preserved — only the beloved cellist Slava Rostropovich had a comparable quality — is what makes him a musician not just of his own time, but specifically of a time in his youth when all was possible and hopeful and life-improving. He remains a believer in the possibility of good in the world. At 75, he has managed to stay forever young.