"Acting," said Sir Ralph Richardson, "is merely the art of keeping a large group of people from coughing." Katharine Hepburn was equally dismissive, declaring it "the most minor of gifts and not a very high-class way to earn a living. After all, Shirley Temple could do it at the age of four."

If actors themselves have such a low opinion of what they do, perhaps it's not surprising that many argue that acting is a craft, not an art. Watch film actors Colin Firth, Morgan Freeman, Nicolas Cage, Christoph Waltz and others debate the subject here in the first of a series of YouTube videos.

But is acting always merely interpretive? The increasing trend – one borrowed from the US – in which the "cast" and "creatives" are listed separately in theatre programmes, suggests a rise in the idea that actors play no role in the creative process. They are simply puppets.

That may well be true in a commercial world, where it is producers who frequently call the shots. Yet many relationships between actors and directors are collaborative, and much contemporary theatre is devised. Are the actors on a Mike Leigh or Anthony Neilson production any less creative than the designer? What do actors in a Kneehigh production bring to the table, or the rehearsal room floor? Why do playwrights sometimes write with particular actors in mind, if the actor brings little or nothing to the production?

Shakespeare, of course, was both an actor and a writer. As Nicholas Hytner – echoing Grotowski – suggested in a brilliant piece in the Guardian, his plays are incomplete and are simply instructions for performance. Hytner suggests that Shakespeare always writes from "the premise that the dots can't be joined on the page, and writes with the confidence of an actor who knows that, if they are any good, his colleagues will do the rest of his job for him." When they do, acting is more than a craft – it's real artistry.