Speaking at Cadogan Hall on Friday, the self-proclaimed "radical leftist" philosopher Slavoj Žižek gave a remarkably ebullient lecture on pessimism. The Marxist intellectual sought to convince his audience in Knightsbridge that "ideology is still alive and kicking" and that history has not ended.

This year has seen a serious academic reappraisal of Marx, with Terry Eagleton and Eric Hobsbawm both publishing books on the continuing relevance of capitalism's fiercest opponent. Introduced to the 500-strong audience as "The superstar messiah of the New Left", Žižek was received with reverence. No-one was there by mistake.

A consummate performer, Žižek treated the crowd to a series of entertaining anecdotes, using references to popular culture to show how ideology is sewn throughout the fabric of our lives. "The film Black Swan", he said, "resuscitates one of the most unpleasant myths of anti-femininity. If as a woman you are to follow your career path, you will pay the price of death." Laughter rumbled through the auditorium, but Žižek was serious. "Do not concede to the enemy too much."

His analysis of contemporary ideological trends emphasises our ability to accept profound contradictions in society. What he terms the "fetishist function of ideology", the focus on a singular component of life, is explanation for our ideological delusions. Žižek cites the managers of big businesses in the US who take Buddhist meditation classes in their lunch break, before playing the stock market in the afternoon. The fetish is the delusional belief in one's "good" inner-self, despite the evidence of one's actions. "This", he said, "explains why and how most of us believe scientists, that something catastrophic is going to happen, but we are not prepared to act upon it."

Žižek is at his most urgent in his denunciation of capitalism and the dangers of allowing market forces into diverse areas of society. "We are living in a strange time, when public space for debate is becoming more privatised . . . The education and legal systems are the hegemonic organisations as the state presents itself more and more as a market oriented operation," he said. "Just as in voting we are consumers looking for the best deals."

Reflecting on the decline of sex in Hollywood movies, Žižek atttributes it to the perception of love as a dangerous ungovernable force that doesn't sit comfortably in the market. "We want love without drama." And he believes we are being sold it.

Nevertheless, "change is in the air," he said. "Greece, Spain, here a little bit." Many in the audience shifted uneasily. "It's wonderful. Spain depressed me though. Making demands of democracy from above rather than saying 'we will do it.' We live in hopeful times, but very dangerous times... But it's not the revolution, it is the day after. The left does not have one idea."