At about 11pm last Friday I had a moment of self-doubt. I was about 15 hours into Christian Marclay’s The Clock and had just realized, with a start, that I had nine hours left to go. I shifted in my seat nervously, took a bite out of a smuggled-in baguette, and settled in for a long night.

Two weeks earlier, when I first resolved to see The Clock in its entirety, I was drawn mainly to the sheer daredevilry of the thing – the resolution of a movie addict who’d scaled Sátántangó and The Human Condition and needed a bigger challenge. I imagine enthusiasts of just about everything have their Clock: some daunting project meant to test the limits of their devotion. But for a cinephile, the prospect of a 24-hour-long film has special significance. The act of moviegoing is uniquely passive, and that’s much of its appeal: for a few hours, we get to inhabit a body not our own, surrender to the illusion of participation, act out whatever we’re unable to do outside the theater. It’s satisfying in small doses but oppressive over time. We need films that remind us of our status as passive spectators, and turn the act of watching itself into something active, something that demands stamina and endurance – something we can claim not merely to have observed, but to have lived. The Clock, by virtue of its length alone, does exactly that.

It also refuses us one of the basic pleasures of moviegoing: the ability to forget, for a few hours, our subjugation to the passage of time. It’s one of the great paradoxes of the cinema that a fundamentally time-bound medium, one that, at root, is simply an extended image of the present becoming past, should be so adept at placing us outside of time – often by establishing its own, separate temporal continuity. The big joke of The Clock is that it does just the opposite: it hews assiduously to the time of the outside world while delighting in the illogic of its own internal chronology. So Inspector Clouseau can debate the time with a bunch of pompous aristocrats until one of them calls a hotline to confirm – only to have Agent Mulder pick up the phone, thirty years later. Good thing we don’t need to hear the hotline’s response, because we can look at our watches to see who among the bickerers was right.

The Clock, then, had better really make us feel as if we’re really living something – it’d be unendurable otherwise to be constantly reminded of the time you’re wasting, holed up inside a screening-room for a full day (maybe most films create their own sense of time so we don’t need to hector ourselves for spending our own so passively). It does, and not just thanks to its duration. I’d be hard-pressed to think of a single facet of human experience for which Marclay couldn’t dig up a cinematic corollary – people, it seems, reveal an awful lot about the way they live by the way they interact (and, more often than not, struggle) with time. Every three or four hours I’d take a ten-minute break to wander outside, and was struck, not by how alien the world beyond the theater seemed, but how familiar – and not just thanks to the big digital clock that greets you as you leave the Lincoln Center atrium. It seemed as if what I’d been watching for the past 3, 6, 10, or 17 hours could have just as easily been happening a few blocks away, as if those people I’d seen hurrying to work or waking up at 3pm after a rough night could’ve been hastening, or stumbling, past the atrium door.

Here, too, is part of The Clock’s magic: many of these glimpses of what seem so close to real life come, we suspect, from films that have few points of contact with reality. Marclay might find a scene of a family eating breakfast in the most overblown melodrama, and, torn from its context, reduced to its innocuous self, that clip still somehow suggests its origins in something larger-than-life. Occasionally, exchanges that were once perfectly clear are reduced to brief, enigmatic short stories, imbued with a suggestive power their owners probably never could have considered. A clip of a teenage girl coming home close to midnight to find her mother washing a dish, and their brief exchange (mom: how was your night? girl: the best night of my life…) could’ve come straight out of a Chekhov story. So if The Clock affirms the cinema’s ability to accurately reflect the varieties of human experience, it also gives the movies the right to shape and direct the stuff of life in new and unexpected ways.

All of this might sound like an elaborate self-defense, a justification for why anyone would want to spend twenty-four hours watching images on a screen. Maybe it is. But why should I even feel the need to defend the experience of watching a film as alive as The Clock, or as fun? Marclay’s surprising juxtapositions are played as much for laughs as for chin-scratching, and he’s not above moments of sheer, gleeful goofiness, conducted without a hint of irony – Ice T pointing a gun at a crook and shouting “time’s up, asshole!” ranking high among them. Then there are those moments when a well-placed cut turns a deadpan moment into a farce: in a clip from The Matrix Morpheus solemnly intones something to Neo before donning his shades and turning his back. Neo’s sole response: to take a bite out of a cookie. What’s wondrous, though, is that these moments of what we might ordinarily call comic relief are given just as much attention as the more overt philosophizing around them. Here is none of the elitism that would distinguish between “high” and “low” even as it purports to blend them. In Marclay there is neither high nor low, only necessity. We need goofiness and enlightenment in near-equal measure, and so we have both The Mask and Winter Light – both to reflect those needs and to satisfy them.

As for the twenty-four hour marathon, I could say it was worth it just to witness how expertly Marclay edits and structures The Clock to reflect its viewers’ deteriorating mental state: between the hours of 4 and 6 AM, for instance, the rhythm gets looser, the shots linked seemingly by free-association alone – and then occasionally we’ll be granted a thoroughly bizarre dream sequence, laced with superimpositions and maniacally cut. At least, I think those dream scenes were in the film. Between 4:10 and 4:40 AM I fell fast asleep. It took the security guard about ten seconds to shake me awake, and then – as fellow Double Exposure editor David Beal, who braved the screening with me, later reported – I looked around with a look of utter confusion and asked “am I watching something?”

But, really – and I’m not sure yet whether this is a good thing or a bad one – it was all worth it for the sensation of walking out of the atrium at 8:02am on Saturday morning and feeling something I’ve never felt before upon leaving a film – that in my time in that theater I’d accomplished something, that I’d weathered a challenge and emerged proudly intact. I went home and slept until 2:30 in the afternoon. Upon waking up, the first thing I did was pick up my cell phone – and check the time.

The Clock is on view now through August 1 in the David Rubenstein Atrium at Lincoln Center.