CULTURE SHOCKWHAT IS A CLASSIC? The most obvious answer is that it is a work of art that transcends time. It rises beyond the here and now, leaves behind everything contingent and immediate. But is this really so? Time can never be transcended: it is the air we breathe, the element in which we swim. "Where," as Philip Larkin puts it, "can we live but days?"

And the contingent and immediate are always part of the experience of any work of art. If you read Homer, look at the Sistine Chapel or listen to a Beethoven string quartet, you do so in a particular time and place, with all of their attendant assumptions, prejudices and preconceptions.

So instead of thinking of a classic as something that doesn’t change we should rather imagine it as something that changes successfully. It is, in evolutionary terms, a species with the genetic resources to adapt to almost any environment. Its point is not that it means the same thing always and everywhere but that it reveals something – perhaps something quite different – wherever it is held up to the light.

In the American theatre, the hard-core classic is Arthur Miller’s Death of a Salesman. When Philip Seymour Hoffman opened last week in the title role of Willy Loman, he was just the fourth actor to play the role on Broadway since the landmark performance of Lee J Cobb in the original production, in 1949.

The others were George C Scott, Dustin Hoffman and Brian Dennehy, a roll-call that underlines the paradox that Willy Loman, the quintessential little man, is the big beast of American theatre.

There is, in itself, something admirably democratic about this. Miller’s achievement is, in this regard, even more extraordinary than James Joyce’s.

Joyce made a hero of the common man. But Leopold Bloom is a comic hero. Miller went further and made of the common man a tragic hero. The play is not a tragedy in quite the way that King Lear is, but it is one in the way that, say, Hedda Gabler becomes.

Its plot is ultimately not so different from that of Oedipus Rex: the closing of a trap. What we experience is the process by which Willy comes to believe that he has no way out except self-destruction. But this tragedy happens to a relentlessly ignoble man.

Willy, for all his boasts about being well liked, is not even likeable. His charm is the salesman’s forced bonhomie, a sour concoction of bad jokes and backslapping. His dreams are cliches: he can imagine nothing more thrilling than being rich. He is mean, petty and unfaithful to his loving wife, Linda. He has just one friend and treats him so rudely that he scarcely deserves even that meagre share of amity.

This very ignobility is one of the things that has changed in Death of a Salesman. It has become even more extraordinary. In our cult of celebrity, when everyone can be famous and everyone should be able to buy some vicarious glamour, people like Willy are yet more invisible than they were in 1949. If you’re not rich or sexy or talented, you had better be charming or funny or engagingly eccentric. Even when a rare poor and ugly protagonist breaks through, in the film Precious for example, she or he must be striving for something more decent. But Willy isn’t striving: he’s disintegrating. He isn’t even a proper victim on whose behalf we can feel outrage: he is chewed up and discarded, but there is no heroic last stand, no great act of defiance.

The thing that really distances Death of a Salesman from our culture – the thing that suggests that if it were not a classic it would be impossible to produce on Broadway – is its treatment of dreams. In X Factor culture, “having a dream” is compulsory. It is, however deluded, unquestionably admirable. But in Death of a Salesman (as in the plays of Eugene O’Neill) dreams are toxic. They are chilling ghosts that haunt and bewilder. For behind them lies the terrible, terrifying thought that the great dream itself, the American dream, may be a nightmare.

What makes Philip Seymour Hoffman’s performance so riveting is that he turns Death of a Salesman almost entirely into a dream play. He knows that the play is stranger and darker now than it has ever been, and is fully alive to the way it has changed. In this, he actually has to work against the instincts of the veteran director Mike Nichols, whose career on Broadway is perhaps even more distinguished than his life’s work in Hollywood. There is a friction in this production: Nichols regards Death of a Salesman as a classic in the static, timeless way while Hoffman is alive to the shifts in its meaning.

Nichols’s reverence for the play goes to the extent of using not just the original incidental music from 1949 but also Jo Mielziner’s justly famous original set. The feeling is that he would have cast Lee J Cobb as Willy if he could have. The effect of this reverence could have been deadly, even with performers as wonderful as Linda Emond as Linda. But Hoffman brings something new and urgent to bear on the play: a tremendously moving and courageous attack on the most sacred of all American values: optimism.

The last Willy I saw was Dennehy’s. His huge frame and irrepressible vigour made Willy noble and gave to his destruction the feeling of a great oak being felled. The play, in his version, was about the abundant life being squeezed out of a man. Hoffman gives us almost the exact opposite. His play is all afterlife. The death has already happened. From the moment he walks on stage and slouches across from right to left, like a man in a diving suit, he is a revenant. For all his stolid bulk, he is barely present.

So where is the drama? If Willy’s already psychologically dead, what’s left to occupy three hours? What’s left are the electric shocks of hope that convulse the corpse and make it twitch as if alive. The brilliant cruelty of Hoffman’s performance lies in the bolts of feverish faith running through his despair, making him young, vivid and apparently human. But what looks like a man being galvanised is actually a man being tortured.

This makes the play savage and lacerating and brave, brave enough to disturb a culture in which optimism is virtually compulsory. Oddly enough, by playing dead, Hoffman brings the play to life, making it as disturbing as a real classic should be.