What - exactly - is consumerism? I've been bumbling along for ages, too embarrassed to ask, but this morning, as the City protesters search the hall cupboard for their missing balaclavas and prepare to set off, I feel I need to know. It must mean something, mustn't it, since so many people seem to be against it.

I know what a consumer is, obviously. And consumption (it's what Keats died of). But consumerism? I have never heard anyone say that they believe in consumerism, only people who say that they don't. If there really is such a thing as consumerism, where are the consumerites with their placards and seaside conferences?

So when people - archbishops, G20 demonstrators, the preposterous psychologist Oliver James - attack consumerism, and as the credit crunch brings them bigger audiences and more credibility, I think they are really attacking something far more banal. I think they are dressing up their assault in fancy language - like undergraduates who get involved in college politics and start calling themselves student unionists - to make a prosaic idea sound impressive.

I think that they have looked back at 5,000 years of human history - at pestilence and famine and disease and degradation, at genocide and civil war, at fear and loathing, at bigotry and ignorance, chauvinism and dictatorship - and concluded that our biggest problem is... shopping.

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Extraordinarily, the problem is not that we aren't doing enough shopping - thus leaving people poor - but that we do too much. I have struggled to get to grips with the idea - and maybe I am doing them a disservice - but I really think the notion that they are advancing, once stripped of all their posh words, is this. I go to the shop and buy a new television. The archbishops think that this impoverishes my soul, the G20 protesters think I am destroying the planet and exploiting the workers, and Oliver James thinks that I am making myself mentally ill.

The purchase of the TV makes me, I guess, an unbridled market force and these people want me to be, I don't know, bridled. Somehow. Although how, they always seem to reach the end of their opinion article without quite revealing.

As the protesters gather they seem to know with great confidence what they are against, but what they are in favour of is maddeningly elusive. They articulate much that is wrong with modern capitalism and imply that, just over the brow of the hill, a shining idea is to be found. But it always remains there, just out of sight and far from our grasp.

Let me explain why this matters. It is a complete dead end for progressive politics. A vague attack on consumerism, coupled with anti-capitalist rhetoric, is a complete dead end for all who want to relieve poverty, increase security, reduce the number of wars, increase social cohesion and help to reduce climate change. And we don't need a crystal ball to see that it is a dead end because we have history books.

Last weekend marked the 30th anniversary of one of the most gripping episodes in modern politics - the fall of the Callaghan Government. Sunny Jim lost a vote of confidence in the Commons by one vote. The story of that night is not merely colourful but also symbolic. Roy Hattersley signing a pact with two Ulster Unionists then having to sign it again because he used a green Biro the first time, the ludicrous arrival of an independent MP who owned a pub in Tyrone and drank the Labour Whips under the table before heading home without having cast a vote, the poignant determination of a dying MP to make a vote for his party a final act. It was somehow fitting that in this atmosphere of high farce, hardnosed politics and tragedy, a brave idea should sputter to its end.

That brave idea that expired that night was democratic socialism. In his wonderful book A Strange Eventful History, Callaghan's Trade Secretary, Edmund Dell, tells the story of a 100-year-long struggle to turn the ideals of the socialist movement into a practical programme for government.

The main protagonists of the movement are convinced that there is a form of economic organisation that is based on co-operation, can be rationally planned, abolishes war, is commonly owned and ensures social equality. But they can't quite work out what their rhetoric means. Every step they take towards their goal, sees it move further away. They try nationalising things and discover that this isn't any more co-operative or equal or rational.

They hit on the idea that the solidarity of the working class would allow them to plan and then discovered that the unions wanted to protect their own members, even at the expense of other unions or the unemployed. Human nature - the way we protect ourselves, our family and our friends against the claims of strangers - proved a constant disappointment. In the end they tried to run the economy at full tilt to avoid unemployment, with the result that inflation soared. Instead of helping, the unions went on strike.

Dell's tale is tragic. All that idealism, all that talent, in pursuit of a will o'the wisp. Surely progressives can't want to repeat that?

Instead they should start (as, in fairness, many modern Labour people do, with James Purnell giving a particularly fine lecture last week) with an acceptance that in the long violent saga of mankind we have rarely done anything as benign as going shopping, rarely devised anything as socially advantageous as property rights and the rule of law, rarely enriched the poor or enhanced lives as we did by creating capitalism.

Nobody serious believes that this capitalism should be unregulated. Nobody serious believes in complete laissez faire. But nobody serious can really believe any more that there is some brilliant alternative we haven't thought of. Can they?

daniel.finkelstein@thetimes.co.uk

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