It is gone now, but the image from a billboard in my New York City neighborhood haunts me. It was an advertisement for fashion designer Alexander McQueen and, like many ads these days, it showed no product. Instead, rising above the pavement was a supersized portrait of a street protest. It’s a particular moment: Paris in May of 1968, when students and workers took to the streets in a fit of imagination and fury. They seized the city and brought down the French government. But you don’t need to know the particulars to be moved by the image.

It’s a close-up of a handful of young protesters standing in the middle of the street. To the left is a row of attractive women in their early 20s, dressed with the careless elegance that Parisian women are known for. They hold red flags. Some of the poles point forward and some back. The flags fill and billow out beautifully, as they often do in socialist realist paintings. Two young men stand with their backs to the women. They too are stylish, wearing black leather jackets. They raise megaphones to their lips, speaking not to the group of spectators we see lining the sidewalk, but to a larger, invisible audience down the street and presumably around the world.

It’s a striking image – both aesthetically and historically – which is no doubt why the agency selected it. It bespeaks hip rebellion, today’s lingua franca of mass consumption. It is the old alchemy of advertising: buy this product and you will magically become someone else. McQueen’s last design collection and ad campaign drew upon the imagery of mods and rockers. To move from images of mid-’60s subcultural rebellion in Britain to late-’60s political rebellion in France is just a few short years and a hop across the Channel. Time and space and ideology are easily transcended by the advertisements’ appropriation; only the image of rebellion remains constant.

This is nothing new. The culture of rebellion has been embraced by the very culture being rebelled against for quite some time. Arguably the first cultural artifact of modern bohemia, Henri Murger’s La Vie Bohème (1849), along with its operatic reincarnation as Giacomo Puccini’s La Bohème (1896), was, and still is, wildly popular with the very bourgeoisie it criticizes. By 1968 Columbia Records was selling music with an image of young protesters in a jail cell with the tagline “But the man can’t bust our music,” and today the image of Che Guevara sells everything from T-shirts to Swatch watches to Smirnoff vodka. Co-opting rebellion is an old story.

But there is something new about the McQueen advertisement. What’s being appropriated is not just the external image of rebellion, but the rebel’s inner passions. What makes the billboard so alluring is that these young protesters believe in something. I don’t know exactly what they believe – they might be chanting Maoist or situationist slogans – but the details of what they are saying and protesting are largely immaterial. They believe. It’s hard to say how I know this. There are signs: the paradisiacal smile that lights up the face of the woman to the far left; the simultaneously intense and vacant eyes of the young woman in the middle whose mouth is open mid-chant; the cool confidence of the young man in front holding the megaphone like a jazz soloist and clearly knowing that what he has to say is bigger than he is. But it’s something more than these visual markers. It’s a presence permeating the whole image. A presence that reaches out through history, past its present appropriation on this billboard, and confronts me where I stand. I can feel that they believe.

Advertising – consumer capitalism – desperately needs belief. Consumption in this overdeveloped world is carried out largely as custom rather than the result of any real belief in anything. This is the price a system pays for hegemony: once an ideology is routinized into everyday behavior, belief is no longer an issue. Kevin Roberts, the CEO of advertising giant Saatchi & Saatchi, recently called for companies to move from trademarks to what he calls “lovemarks.” According to Roberts, it is only by creating brands with “emotional resonance” that foster “loyalty beyond reason” that companies can hope to stir the sedated psyche of the contemporary consumer. Advertisers fear, with reason, that we have become like the zombies in George Romero’s classic horror flick, Dawn of the Dead, who return to wander the shopping mall by sheer force of habit. By appropriating the political passion of the Parisian protesters, Alexander McQueen is attempting to animate dead desire.

The billboard’s expression – and appropriation – of political belief confronts me with my own faith. Not my convictions as a consumer (I’m more or less a zombie) but my belief as a political citizen. I’ve been an activist my entire adult life. I’ve built houses in Nicaragua, walked union picket lines, organized community activist groups and shut down cities with mass protests, but I can’t honestly say that I’ve ever really believed. My activism, like that of so many of my generational comrades, was more a reactive, or even existential, activism. We acted to hold on to what little things we had: community gardens, affordable rent and the right to unionize. Or we acted because to not act was simply inconceivable, it would mean accepting things as they were, and we knew something was wrong with the way things were. But believe, truly believe, in something? I’d be lying if I said I did.

I don’t think I’m alone on the left. Ask liberals in the United States today what they believe in. They might tell you they want an end to the war in Iraq, that they desire universal health care or are inspired by Barack Obama. But these aren’t beliefs, they’re actions, policies and politicians. A belief is something like universal peace or a caring society or a world with great leaders (or no leaders at all). It is only by believing in such grand impossibilities that small accomplishments are possible. This is why liberals, for nearly two decades now, have accomplished nothing. Many contemporary radicals are little better. They have grand beliefs but little desire to realize what they believe. Doing so would jeopardize their outsider status as rebels. As such, their belief is in bad faith.

Believing is what the other side does: the Christian fundamentalists who believe in the rapture and the righteousness of their cause, the Muslim radicals who dream of a Caliphate and a return to Islamic law or even the neoconservatives in Washington who fantasize about exporting free markets and Western culture by force. Belief is also part of the uncomfortable heritage of my own side. It was a sort of utopian faith that led to the forced collectivization and brutal public projects that marked Stalin’s Soviet Union and Mao’s China.

It was a belief in the inevitability of a new world that animated the students who protested in Paris and so many other places in 1968. Yet when this new world failed to appear, that faith passed into the illusion of victorious armed struggle in the West (the Weather Underground, Brigada Rosa or Baader-Meinhof gang) or a pacific retreat to the commune. In all these historical narratives, belief leads to heaven, the gulag, delusion or isolation. This is a history from which I am desperately trying to awake.

Yet without belief can there be any progress? For as much as I detest the religious right, I have to admit that they’ve gotten results: their agenda, be it family values or the War on Terror, is now America’s agenda. We might debate it, fight it or try to redefine it, but Ralph Read and Osama bin Laden are the ones who have defined the “it” we react to. And the left at its strongest was also the left with the strongest beliefs. It was the ’30s that realized the ideal of a modern society that cared for all its citizens and the ’60s that conjured up a culture of individual liberty. Belief motivates. It gets you up in the morning and headed toward the horizon; it makes you act to bring about what you know is impossible.

I know that belief is necessary to inspire and motivate, this is what makes it such a hot property for advertisers and activists alike, yet I still find it hard to believe. Too many of the most atrocious, and just plain stupid, events in history have been initiated by those who truly believe. Belief is blind. I prefer acting in the world with my eyes wide open.

Can belief and skepticism, rationality and faith, be reconciled? I don’t think so, for each cancels the other out. Belief is an edifice built upon ephemeralities like hopes and dreams. Rationality demands a firm foundation that is constantly tested through inspection and deconstruction. Philosopher René Descartes found this centuries ago when he fruitlessly tried to prove that God exists. It’s also why the “logic” of creationists today is so weak when presented in an academic debate or courtroom (though a majority of people in the US still believe in creationism or its variants). Combine the fiery flames of faith and the icy waters of calculation and you get a sodden pile of ashes.

Yet every day I carry this warring opposition within me. I know, for instance, that I am determined by my biology, history and ideology, yet I act as if I were fully responsible for my actions. When I watch reality TV or visit Las Vegas, for example, I know that what I am seeing is a staged representation of real people or landmarks, but my enjoyment is contingent on my feeling as if they are real. I think the trick is to possess both belief and skepticism, simultaneously, without trying to reconcile the two. That is, to exist somewhere in between, resonating with both yet never being wholly subsumed by either.

This isn’t as impossible as it sounds. Irony, for example, works this way: it makes a statement of belief that can only be understood by not believing it. And while irony leads most often to a smirking, knowing distance, it does suggest that there may be ways to be suspended between the poles of belief and disbelief: a critical, provisional and ironic belief.

We need to believe, but we also need to remember that we are the ones who have constructed (and can thus deconstruct and reconstruct) the objects and rituals of our belief. This critical belief is the nightmare of politicians and advertisers, both of whom would rather have us feel loyalty beyond reason or express cynical skepticism, as neither of these subjectivities demand a self-conscious awareness that we are the architects of our own ideals.

I’ll probably never have the beatific look of conviction that lights up the faces of those young protesters on the streets of Paris. Nor will I ever share the certainties of the skeptic who points out that this billboard image is really just an ad campaign and that the photo was probably faked anyway. The belief I want to believe in is not easily reducible to a political slogan and doesn’t translate well into religious dogma. It’ll make a lousy billboard. Maybe for that reason alone it’s worth trying.