Judi Dench
Judi Dench
© Dan Wooller for WhatsOnStage

Et tu, Judi? Last week, unveiling a blue plaque in John Gielgud's honour, Judi Dench became the latest stage veteran to take a pop at young actors. It's the fashionable thing, after all. Ian McKellen's forever lamenting the loss of rep and muttering about a lack of diction. Peter Hall and Antony Sher were saying similar things a decade ago. It's always been an easy headline: 'Fings Ain't What They Used to Be,' says theatrical treasure.

But Dench's complaint is more interesting than that, and only partly about declining standards or shifting styles. She accused young actors of not respecting their roots - that is, of ignoring the shoulders on which they stand. "What is so shocking now is that young actors don't want to find out about the legacy that we left," she said. "They don't want to know about Garrick and Irving and Peggy Ashcroft and Edith Evans. That seems to me a terrible shame."

Plenty of others, it seems, agree. When I tweeted the story with a virtual sigh, Sam West and Malcolm Sinclair spoke of similar experiences. Michael Simkins backed Dench up in the Guardian: "For many, it seems, acting was invented in 2004." Not long ago, Stephen Berkoff was hammering the exact same point home: "You say what do you think of Gielgud – who's that? What do you think of Trevor Howard? - Oh, I dunno. What do you think of Edmund Kean? - I've never heard of him."

This isn't Mastermind, after all. It's theatre.

Is that a shame? I'm not entirely convinced. Knowing your Ashcroft from your Evans has no bearing whatsoever on an actor's ability. We don't go to the theatre to appreciate someone's detailed knowledge of the Life and Times of John Philip Kemble, but to see a present-tense performance, here and now – the more live, the more truthful, the better. This isn't Mastermind, after all. It's theatre.

Acting styles change, as Dench herself concedes, but her point is that the past can still inform the present. In other words, it's not simply a question of knowing your heritage, but of applying it in practice. "How can you become a better actor if you don't study and learn from the greats?" asks Simkins.

Well, by acting, for one thing, and taking on feedback. Of course one gains from going back to the past, but there are limits of the learning in that. Today's actors exist in an entirely different context to their predecessors. It's not just the acting style that's changed.

For starters, the fashion today is to scrub classics clean – that is, to strip away the conventions and assumptions that accumulate around a play or a part, and instead seek its truth afresh. That means actively turning away from stage history, and instead looking out at the world. To cycle through past performances – Donald Sinden did this, Ian Holm did that – is to get hung up on history at the expense of the truth here and now, even where an actor's seeking their own stamp. Over-emphasise that and theatre ends up in conversation with itself: one production bouncing ideas off another. There's no faster route to irrelevance.

Curiosity doesn't start and end in the archives

"It's not laziness," said Dench. "It's non-curiosity." Oh, puh-lease. Today's actors are no less curious than their forebears. They can't afford to be. A theatre that actively addresses the world needs its actors actively engaged. If it's to keep up with other art-forms, it needs actors with wide frames of reference: television, film, pop culture and more. Curiosity doesn't start and end in the archives. It means more than soaking up the stories of stalwarts. It extends beyond theatre and explores the world.

Theatre, today, requires different priorities. Its actors have a different job. Rather than rolling through the classics, double-speed, in weekly rep, they're much more likely to find themselves working on a new play. The range of work is more varied too, with actors requiring versatility as par for the course. Puppetry, movement, blank-verse and clown all come into play. They have to step from big stages to studio spaces via site-specific shows and one-on-one work. Look at the five actors in Nuclear War at the Royal Court, throwing themselves into contemporary dance. Sarah Siddons won't help with that, will she? Nicol Williamson's no use to the War Horse puppeteer.

Dench's comments also ignore the question of cultural access. To insist every actor arrives in the industry with a sense of stage history is to put up barriers around the profession. Not only is that knowledge the product of particular experience or education, for many it's actively alienating. Look down through the annals, the long list of greats, and plenty of actors won't see themselves reflected. Set those actors up as exemplary and you quash diversity and individuality. Try telling a young black actor that he should be more like John Gielgud and see how that goes down.

Actors learn not from dead legends, but from watching living greats at work

Beneath this is a question of what actors leave behind - and the truth is, onstage at least, very little. That's the nature of the beast: theatre's ephemeral nature. Individual performances survive somehow in reviews or recordings, but presences inevitably fade over time. What, really, does anyone know of David Garrick as an actor beyond the fact that he was David Garrick? Yes, he pushed realism forwards – the Marlon Brando of his day – but how exactly, who knows? What of Edmund "flashes of lightning" Kean or Ellen 'Queen of the Stage' Terry? Actors live on in the memory for a while, then in recollections handed-down. In time, they twist out of shape and become little more than a name. That's their legacy.

That belies the misty nostalgia in the way Dench and co frame the issue. Actors learn not from dead legends, but from watching living greats at work. You don't download the Gielgud extension pack. You pick up techniques and craft here and there: the way Maggie Smith lands a joke, the way Mark Rylance plays with a crowd, the way Hans Kesting warps a role out of shape.

I'll bet those new drama school grads lucky enough to work with Judi Dench are watching her every bit as closely as she might have watched Laurence Olivier or Joan Plowright in her time, and they the greats before them. To say young actors lack curiosity is, therefore, to hold them in contempt.