The return of the Rennaissance man

We all begin as polymaths. I mean, if you ignore the true meaning of polymath (from the Greek, 'having learned much'), put Leonardo da Vinci and Vladimir Nabokov in a holding pen, and use the term in the inaccurate sense of simply being pretty good at a lot of different things... well, we probably hit our polymathic peak at around ten years old.

Children see no contradiction between being an actor and a musician and a footballer and a spaceman. In fact, they are frequently all of these things, and a pirate, and Rastamouse, all in the space of one playtime. It's only when we become self-conscious and adult that we cease to develop these skills, and put ourselves into compartments.

That's what the modern multitasker rebels against. Ben Drew, aka Brit Award-winner Plan B, decided one career wasn't enough, and has recreated himself as alter ego Strickland Banks, as well as pursuing a sideline as an actor alongside Michael Caine in Harry Brown, while his first project as a film writer/director, Ill Manors, an episodic Hip Hopera, is in development. Meanwhile, Johnny Flynn (left), another British musician, is as celebrated for his soulful folk arrangements as he is for his theatre works - currently to be seen alongside Juliet Stephenson at the Royal Court Theatre.

For James Franco, the star of 127 Hours and Howl, simply being a handsome Hollywood star did not satisfy. He has also published a collection of short stories, is presenting the Oscars on Sunday, modelled for Gucci, developed a sideline in video art, grown a moustache and was at one point pursuing four graduate courses: creative writing at Columbia, fiction at Brooklyn College, poetry at Warren Wilson in North Carolina, and film-making at NYU. 'I didn't want to be perceived as an actor who is just dabbling, just taking a class,' he has said. The main task of his assistant, a former classmate from UCLA, is to whisper where he's going when she bustles him onto the next plane. Such a list of accomplishments seems to provoke a mocking sort of jealousy. All the reviews of Franco's book noted his film star looks disdainfully.

Recently, I was at a recital given by the classical pianist (and ex-banker) James Rhodes, who played a piece by the 18th-century Italian Alessandro Marcello, a genuine Renaissance man: composer, poet, politician, mathematician, philosopher and - Rhodes felt compelled to add - 'bastard'. Most attempts by film stars, models or writers to launch a pop career end in extreme tedium (I'm looking at you, Minnie Driver); and it was with a wariness of this that novelist and talented jazz singer Zadie Smith gave up the mic.

But perhaps we're wrong to see the people who excel in more than one area as strange and enviable. We all contain childhood multitudes after all. In most cases, polymathdom is not a question of their taking on more activities and finding extra time. From talking to our Renaissance men and women overleaf (from Polly 'math' Stenham, gallerist and playwright, to Riz Ahmed, Evening Standard Award-shortlisted actor and rather good MC), it seems more a question of having the will to let childhood interests develop in an unbroken line.

No-one thought me all that weird when I played guitar and wrote songs at school, but, oddly, people find the fact that I still do so and maintain a career in journalism the strangest thing they've ever heard. In fact, the one discipline informs the other: a few of my songs began as news stories and, conversely, it's incredibly useful to understand how a song is produced, or what it's like to perform when you're writing about other people's music. To lose the release of music would be like chopping off an arm (which Franco can probably sympathise with after 127 Hours).

For musician-artist Marcus Foster, 25, it would be bizarre to restrict his creativity. Arty musicians are not new (art school having proved the breeding ground for bands from The Who to Blur) and nor are musicky artists so unusual - the Turner Prize-winner Martin Creed regularly fronts his own band. Foster has risen in both fields discretely: his art bought by Charles Saatchi, his music signed up by Geffen UK. His father is a sculptor and painter, his mother a doctor who 'makes strange things', his best friend is Twilight's Robert Pattinson, so he has grown up in an environment where self-expression is normal. What draws him uniquely to music is live performance: 'I like the idea of controlling this unravelling moment in time,' he tells me. 'I like that element of communication, where you're standing on stage and you're not quite sure where it's going to go next.' With art, it's different: it's about making something permanent to occupy a space. It all comes from the same place.

But what of those who span science too? Take Prasanna Puwanarajah; pursuing a successful career as an actor (he's currently touring in the National Theatre production of Hamlet, playing Rosencrantz) while maintaining a sideline in directing (he's just made a short film with Harry Lloyd, and Yes, Prime Minister's Henry Goodman and David Haig), the 29-year-old happens also to be a qualified, Oxford-educated doctor of medicine. He sees no contradiction: these are all things he has always enjoyed and he will continue to pursue each as long as he gets away with it. 'Closing the door on any of medicine, directing or acting would actually be a more active decision than not. In many ways, being a ''polymath'', if you're going to call it that, is the path of least resistance,' he says.

In truth, however, these exploits are nothing compared to the polymaths of old. Take the quintessential Renaissance man, Pico della Mirandola, reputed to have read every book in existence in the Italy of his day. Or the French genius Blaise Pascal, who invented the calculator when he was a teenager (it was 1642), found a way of weighing air, rewrote the book on geometry, had a thing or two to say about theologyand altered the course of French literature. Or Denis Diderot, pioneer of the modern encyclopaedia, himself a one-man Wikipedia. Or Thomas Young, who established the wave theory of light, identified astigmatism, wrote a comparative grammar of 400 languages, pioneered child medicine, deciphered hieroglyphics and devised a new method of tuning musical instruments.