My mother was Jewish. Her mother was Jewish. And her mother was Jewish. My father was Jewish. His mother was… and so on. Shouldn't this be enough to encourage me to think I'm Jewish? Orthodox Jewry wouldn't think so. Only those, say the Orthodox, who adhere to the prescribed rituals and laws of the Torah can claim the mantle of Jewishness.

When Max Stafford-Clark was artistic director of the Royal Court Theatre, from 1979-1992, he was asked why he wasn't producing more of Arnold Wesker's plays. He replied that the problem with Arnold is that he can't be objective about his Jewishness.

Stafford-Clark would never have dared say such a thing of an Irish, Asian or West Indian playwright. What could he have meant? That I shouldn't have written Shylock, offering an alternative portrait of a Jew more sympathetic than that of Shakespeare? He would seem, on the surface, to be offering the kind of advice given to students on a creative writing course: don't become emotionally swamped by your material.

But did he mean something else? Not Arnold can't be objective about his Jewishness, but Arnold can't be objective about the Arab/Israeli conflict. But it is not the purpose of this article to argue the sad complexities of that conflict but rather to enter the old debate that frequently erupts when Jews assemble round a card game or a Shabbat table or a Seder night: what is it to be Jewish?

In an exchange with the playwright, Sir David Hare, the Israeli novelist, David Grossman, said: "I don't think you have to be religious to be a Jew. There is no God in my life, and I'm as Jewish as it's possible to be." He went on to argue that the 1967 Six-Day War changed the nature of Jewishness because "up until then places and building and stones didn't mean anything to us… what mattered to us were ideas." Ah! Ideas. We're getting nearer to what I think makes me Jewish.

Not long ago I came across an early work that surprised me. In 1949, when I was 17, I wrote an essay called Faith and Reason, under the pseudonym of Jon Smith, for a competition organised by the New Statesman.

"We are men of passions," I wrote, "filled with emotions we cannot always understand, harbouring hates and desires which confound, and vanities that disgust us. Cowardly reactions in some situations contradict strange dignities and courage in others. We are complex creatures."

Humans as complex creatures - the taste for an intellectual life began at an early age and has never left me. What, however, struck me was that the essay argued neither for faith nor reason but for "behaviour".

More than that, I realised that before I wrote my first play, Chicken Soup with Barley, in 1957, I had, eight years earlier, explored elementary philosophy. It continued into my plays. For example, to the optimistic brother, Manny in The Old Ones, written 22 years later, I gave a quotation to hurl at his pessimistic brother with whom he is constantly battling: "Boomy! You listening? I'm reading from Martin Buber again. 'Rabbi Leib, son of Sarah, used to say about those rabbis who only expound the Torah that: a man should see to it that all his actions are a Torah and that he himself becomes so entirely a Torah that one can learn from his life'."

When that essay was written, aged 17, I had not read Martin Buber, or any of the learned rabbis. From whom, then, did I inherit this view that how people conduct their lives is more important than what they say? I edge nearer to what I believe permits me to claim Jewishness.

George Steiner, the Cambridge academic, posed one of his provocative questions at a colloquium on "The Impact of the Jewish Nature on Jewish Writing" in March 1984. "Is it at all natural for a Jew to be a writer?" he asked, continuing: "We have an enormous tradition against it… I believe it is natural for a Jew to be a scholar."

He named Kafka, Proust, Hofmannsthal, Pasternak as writers who "always felt deeply ill at ease with their being writers".

Only commentary on Torah was, thought Steiner, to be taken seriously - thoughts which will "become part of the living eternity of Judaism which is Midrash, the continued argument, the re-thinking of what was given us in the Torah… if you could add to that one opinion, one question, one insight, you are inside Judaism, living Judaism, for ever".

In later years I, too, began to feel ambivalent about that part of art which is artificial, and found myself turning again and again to the extended essay or lecture in an attempt to understand what it was I had written.

More, I was interested in philosophical speculation for its own sake, unrelated to those plays and stories, hoping to add that one opinion, one question, one insight.

Jonathan Miller, interviewed in The Independent in 1993, complained about his role as a theatre director. "There's a terrible, ghastly moment at the end of Jude The Obscure, when Jude is dying in Oxford, never having got into the university, and he hears the applause and the noise of the people receiving their degrees in the Sheldonian. Well, that's the sort of feeling I have at the moment, as I reach the end of my life. I can hear the din of the real action going on in the area of the brains' sciences, and I'm outside it… It's terribly sad."

I am a bit like Jude, regretting never having gone to university; and like Jonathan, wondering are my plays and stories the work of a writer who would rather have been a scholar? This reverence for the power of intellect is not exclusively Jewish but it is a very Jewish inclination. Was it handed down to me in ways I failed to recognise? Was the simply-argued essay Faith and Reason the direction I should have taken? When I compare the intellectual experience to the theatrical one it is often like moving from the adult world to kindergarten.

What I'm saying is, Max, you got it wrong; it's not that I couldn't be objective about my Jewishness, but rather that I chose to explore ideas through characters who happen to be Jewish because those are the ones I grew up with, know, love and admire.

The King's Head Theatre in north London is celebrating Arnold Wesker's 80th birthday with a mini-season of three of his little known works from May 14 (www.kingsheadtheatre.org). Also as part of the celebrations, a production of 'Roots' will tour Colchester, Stoke-on-Trent, Hull and the Nottingham Playhouse