Editor’s note: The following contains spoilers from the first 339 episodes of Grey’s Anatomy.

Time out of mind is time nevertheless, cumulative, informing the present. —Annie Dillard, Pilgrim at Tinker Creek

If Grey’s Anatomy has a central through line, it is, funnily enough, a circle. A carousel, to be precise—the Seattle landmark where esteemed surgeon Ellis Grey (Kate Burton) once watched the love of her life walk out on her, and the symbol at the heart of the wisdom, or warning, she imparts to her daughter: “The carousel never stops turning,” Meredith Grey (Ellen Pompeo), esteemed surgeon in her own right, remembers her mother saying. “You can’t get off.” In the course of 15 seasons, the sentiment has emerged as the unifying theme of Shonda Rhimes’ primetime soap and, after a fashion, its narrative engine: We hear it from Ellis herself, stricken with Alzheimer’s, when she’s admitted to the hospital in Season Two, and then again, repeatedly, in Season 11, near the end of the series’ heyday. If Grey’s Anatomy has a theory of change, an understanding of time, a structuring principle, it’s this notion that there is no escaping life, only riding it out—and the series’ very capaciousness may be its foremost emblem. As of tonight, with its 340th episode, the longest-running medical drama in the history of television is 14 years, one month, and 5 days old, and still its carousel turns, unceasing.

As with so much of the series’ action, I confess that my fixation on this particular image is a function of timing: I came to Grey’s Anatomy belatedly (or, more precisely, returned to it), as research for a piece on the state of the medical drama, and soon found myself obsessed, though not always for the reasons I might’ve expected. To condense the entirety of Grey’s into a span of six months—six months in which I interviewed for, was offered, and accepted a new job, professed my love to a longtime crush (who later kissed me, and then thought better of it), agreed to officiate my brother’s wedding, celebrated the pregnancies of two dear friends and the marriage of two others, ran my first half-marathon (one year after quitting smoking), and marked my 10th Mardi Gras since moving to New Orleans—is to experience a strange accordion effect, a sort of chronological vertigo. For Grey’s itself is life in concentrate: a series so soaked in births, deaths, marriages, divorces, promotions, and relocations, to say nothing of ferry accidents, plane crashes, and live explosives in dying men’s chests, that its ordinary rhythm, its murmuring backdrop, is comprised of heart monitors and No. 10 blades, CT scans and blood work, IV drips, ultrasounds, and sutures in the pit. “The little joys and tragedies that make you who you are have no place in my hospital,” the demanding Dr. Miranda Bailey (Chandra Wilson) announces on this point in Season Four, and for once in her life she’s wrong on both counts. Such joys and tragedies are the very marrow of Grey’s Anatomy, its coursing lifeblood, because they rarely seem so little when they happen to us.

I don’t mean to discount the series’ penchant for dramatics. Its most gripping entries—the aforementioned human bomb, ferry accident, and plane crash; the “John Doe” twist; the patient-turned-attacker; and above all the terrifying shooter-in-the-hospital incident, a two-part episode of such awful gumption it left me shaken, spent—turn on unimaginable crises, acts of God and man for which one cannot prepare. Its most winsome—the Post-It notes and runaway brides; the first kisses and successful surgeries; Meredith winning the Harper Avery as the ghost of her mother looks down from the gallery—turn on unforgettable triumphs, moments for which you spend your days preparing and then astonish you nonetheless. Still, the lion’s share of Grey’s, as of life, occurs in the space around the disasters, between the milestones: Though it may seem to slow down for a spell, the carousel doesn’t stop turning for earthquakes, fires, or ruinous fishing trips; for scientific breakthroughs or candlelight proposals; for miscarriages or heart attacks, adoptions or affairs. Indeed, despite my recent immersion in the series, much of it is already lost to me, though long-ago details occasionally resurface. In Season 14, for instance, a former Seattle Grace nurse named Olivia (Sarah Utterback) reappears for a single episode, and though the focus is on her assessment of reformed asshole Dr. Alex Karev (Justin Chambers), watching it I found myself in a sudden skid down the rabbit hole—to George O’Malley (T.R. Knight) and the “syph nurse” subplot, to his infatuation with Meredith, to the ways in which we hurt others because we are hurt, or hurt ourselves in the false hope that it will win us affection. This is how it always goes: More of your life is forgotten than remembered, until a place, a face, brings it all rushing back.

In this, Grey’s isn’t always masterly television—it’s been more or less coasting on goodwill since the back-to-back departures of Meredith’s closest friend, Cristina Yang (Sandra Oh), and late husband, Derek Shepherd (Patrick Dempsey), in Seasons 10 and 11, though the problem has become particularly acute without Drs. Arizona Robbins (Jessica Capshaw) and April Kepner (Sarah Drew) this season. It is exemplary television, though, in the sense that it turns the medium’s defining mechanism—time—into a powerful dramatic weapon. When I say that Grey’s Anatomy unspools around the disasters, between the milestones, I don’t just mean that no series can survive long on sweeps-style “event episodes” alone. I mean that Grey’s devotes at least as much attention to untangling causes and consequences, to following the arc of life’s slower processes—trauma, treatment, healing, growth. I mean that Grey’s has the longest memory on television. That the ghost of Denny Duquette (Jeffrey Dean Morgan) appears to Izzie more than two full seasons after his death. That Cristina wrestles with post-traumatic stress disorder for the much of the two seasons following the hospital shooting. That April develops a drinking problem years after her first child dies from the birth defect osteogenesis imperfecta. That Alex’s decision to amputate Arizona’s leg inflects all that comes after, including the dissolution of her marriage to Callie Torres (Sara Ramirez) and her pursuit of a new career. That Meredith is still skittish on planes after the crash that killed her half-sister, Dr. Lexie Grey (Chyler Leigh), and Derek’s best friend, Dr. Mark Sloan (Eric Dane). That she remains uncertain whether she’s open to love again, four years on from losing her husband. That Ellis reappears from time to time to harangue and hassle and, in her own way, love: Though it carries a fatalistic edge, “the carousel never stops turning” is simply an acknowledgement that the world only spins forward, that what is behind you is what makes you you.

For all its fireworks, then, what I’ve come to appreciate most about Grey’s Anatomy is its characterization by accumulation—its careful balance of traits and experiences, the latter layered atop and always changing the former, the way rock outcroppings emerge and erode over time. In other words, it is possible to describe yourself as “a Meredith,” “a Cristina,” “an Izzie,” “a George” as if the labels are immutable, and also to see Meredith, Cristina, Izzie, and George evolve, to change and be changed with circumstance: Grey’s rejects the static characters of a certain soap-and-sitcom template and replaces them with familiar ones—characters at once recognizable and profoundly transformed, the way it often feels, as you age, to glimpse yourself in the mirror. This interest in time as TV’s unique grammar comes full circle in the series’ 300th episode, “Who Lives, Who Dies, Who Tells Your Story,” in which three surgical interns from Seattle Presbyterian, bearing an eerie resemblance to Cristina, Izzie, and George of yesteryear, arrive at Grey Sloan after a rollercoaster accident. Within the hour’s profusion of fan service, the remaining members of the original cast confront the people they are, and used to be. Bailey cries, not for George, but for the state of her marriage, and former chief of surgery Richard Webber (James Pickens, Jr.) wishes he could have saved him. Alex remembers his love affair with Izzie as his new paramour, Jo (Camilla Luddington), looks on. Meredith operates on the spitting image of her best friend as she awaits news of the award that made her mother’s name. “I don’t want to be a trigger for your memories,” Baby Cristina complains at one point, though of course memories do not heed our commands: They are the carousel’s ceaseless engine—imperfect, unutterably powerful capsules of the joys and tragedies that makes us who we are.

At a moment of great flux in my own life, then—as I prepare to leave a job in which I’ve thrived, a city in which I’ve felt at home, a group of friends in which I’ve changed more than I could have ever imagined—Grey’s offers reassurance not because it resists transformation, but because it welcomes it—because it understands, as perhaps only TV can, that even amid the disasters and milestones, our evolution remains incremental. And so I’m reminded that Meredith’s most recent consideration of Ellis’ wisdom follows in the wake of Derek’s death, and that she ends up soldiering on anyway. Indeed, she manages, eventually, to flourish: “Dr. Grey has experienced more loss in her life than I think most of us would deem fair,” as Jackson Avery (Jesse Williams) says, accepting the Harper Avery on Meredith’s behalf in that 300th episode. “And despite all that she’s lost, she continues to find joy in her work, as a surgeon, as a teacher, as a mother.”

There is, after all, no disaster, no milestone, no little joy or tragedy that solely shapes the self: As Grey’s Anatomy recognizes, perhaps as sincerely as any TV series ever has, it is the sum total of these that makes us who we are, and will be. The carousel never stops turning. So enjoy the ride.

Grey’s Anatomy airs Thursdays at 8 p.m. on ABC.



Matt Brennan is the TV editor of Paste Magazine. He tweets about what he’s watching @thefilmgoer.