When John Rawls, leading political philosopher and Fulbright Fellow at Christ Church, Oxford, died in 2002, the Guardian’s obituary had this to say about his most important book, A Theory of Justice: “At heart, A Theory of Justice is concerned with what its author called the classical problems of modern political theory – problems about the grounds of basic civil liberties, the limits of political obligation, and the justice of economic and other inequalities.”

Major topics indeed. But material for a musical? Three Oxford students, Eylon Aslan-Levy, Ramin Sabi and Tommy Peto thought the idea could possibly have legs.

“We started playing around with a couple of tunes on the piano, and having some ideas about the plot,” Eylon explains when he and Tommy meet me at the Turl Street Kitchen. “We knew from very early on that we wanted a barbershop quartet, and a rap battle between [philosophers] Thomas Hobbes and John Locke. But could we pull it off, would a musical about philosophy really work?”

Doubts overcome, the trio was soon sucked into the subject matter. But to many people, surely, philosophy simply means a dry academic book containing acres of footnotes? “Some of it has got more exciting recently,” Tommy laughs. “Certainly when you’ve got people rapping about with it, there’s fewer footnotes and more foot tapping!”

“That’s where a lot of the humour comes in the show,” Eylon adds. “It’s very irreverent and self-deprecating: we’ve added Broadway-type musical numbers to bring that out. We’ve written a parody of Broadway musicals, but about philosophers: they do explain about philosophy along the way, but you don’t need to understand that to enjoy the show. There’s a hero yearning for recognition, there’s a villain and his accomplice, and there’s a love interest. But people who know about political philosophy will get a couple of laughs on top of that.”

“Most of our cast aren’t political philosophers,” Tommy says. “They’re mainly English students, or studying languages. When we did the read-through, they all laughed, which was a bit of a relief to us writers.”

Besides being one of the writers, Tommy is also appearing on stage: “I’m playing Karl Marx. “He’s a slightly crazy, homeless man. He goes around shouting that the end is nigh. “He comes across a bemused John Rawls, who doesn’t quite know how to react to him. We’re also featuring Jean-Jacques Rousseau, who tries to chat up a beautiful student, Fairness.”

None of the writers has any previous experience of musicals, although, Eylon says with great enthusiasm: “Writing a musical has always been on my list of 100 things to do before I die: it’s always been a dream.” How did they go about constructing the score?

“Mostly we worked with Ramin sitting at the piano,” Eylon replies. “We would play around with some ideas, and think what we wanted the tunes to sound like. Very often the music sprang out of the philosophy itself. For instance, the first line of Jean-Jacques Rousseau’s The Social Contract: ‘Man was born free, but everywhere he’s in chains’. We listened to the rhythm of that [here Eylon bursts into song to the slight surprise of students drinking coffee around us] and the tune just came. We very much found we had to write the music and the words together. We’ve used a whole range of musical styles.”

At this point it’s time for the writers to set off for the cinema – to see the musical of the moment; Les Misérables. “Here’s to A Theory of Justice running for 27 years in the West End like Les Mis,” Eylon says. “One can but hope!” Meanwhile, he adds, tickets for Justice are going fast here in Oxford.

O’Reilly Theatre, Keble College, Oxford January 30 until February 2 Tickets: atojtm.com