It is wrong to portray university as the peak of aspiration for school leavers, a world-renowned academic and lawyer has said.

The most important consideration for young people should be a “joyful and fulfilling life”, wherever they can find it, said John Sexton, who compared the world to an orchestra where everyone has a valuable role to play.

Professor Sexton, who was interviewed by former prime minister Gordon Brown at the Edinburgh International Book Festival, advised school leavers to “go to the section of the symphony orchestra which will give them the most joyful and fulfilling life - and that is not college or university for everyone”.

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The former president of New York University said: “I’m from a family of carpenters and electricians. The men in our family did not go to college in the generation before my sister and me…my uncles didn’t want to go to college and developed joyful and fulfilling lives for themselves, in which they felt dignity.”

Professor Sexton, also a former president of the Association of American Law Schools, added that it was “extremely important that we not make this a two-tribe system”, with supposed “people of thought” on one side and everyone else on the other.

“My cousins and my uncles who have not gone to college are smart, worthy, virtuous and joyful and fulfilled people,” he said, during the book festival event organised by the Open University.

Professor Sexton stressed, however, that not enough young people from certain social backgrounds were going to university, which was a “disgrace”. He added that “the thing is to make sure that joyful and fulfilling lives are not allocated by zip code or primogeniture”.

He said: “Of the students in the United States that place in the national exam, in the top 15 per cent, one out of four in the bottom income quintile never apply to college. They’ve taken the [school leavers’ exam] and they’ve gotten a very good score - whereas only 4 per cent of the students from the top quintile don’t apply to college”.

He added: “I always thought the most important thing that I do in a classroom is the expectation I set for my students: I believe in them, I demand a lot of them, my courses are noted as the hardest ones they take.

“I think that the expectation we set in society is very important, for our citizens and making access available.”

Professor Sexton also encouraged students to come out of their comfort zones, in all areas of life, as “there is a joy in difference”.

He said: “My greatest teacher had a phrase: play another octave on the piano. The notes you haven’t touched, reach out and touch them. If there’s a food you haven’t tasted, a music you haven’t heard, if there’s a kind of person you haven’t met - and it’s legal and moral - try doing some.

“Now, that’s had me do all kinds of things, like skydiving, like jumping into the ocean at the North Pole.”

Professor Sexton, who is in his mid-seventies, also said he feared that the standard of primary and secondary education had fallen over the past 60 years - from a point when a high standard of education was widely available for free - with particular reference to his own country.

He also feared that the status and perception of teachers in society had fallen, adding: “I was taught by a great high-school teacher that the most worthy thing you could do on Earth was be a teacher.”

Professor Sexton said: “We’ve done a pretty good job of destroying the quality of primary and secondary education…We in America are disinvesting in education, generally.”

Professor Sexton’s new book is called Standing for Reason: The University in a Dogmatic Age - for which Gordon Brown wrote the foreword - and during his interview in Edinburgh yesterday he also touched on Donald Trump’s presidency.

He believes that a decline in education standards helped Trump to come to power.

“If we were more robustly supporting education in general in the United States, you make demagogues less likely,” said Professor Sexton.