You may not have noticed, but The Simpsons just passed a major landmark. This past December 17 commemorated the 25th anniversary of the first broadcast of an episode of the series, the Christmas-themed "Simpsons Roasting On An Open Fire." And January 14 will mark the 25th anniversary of the show's debut proper, with "Bart The Genius." As of this month, an entire quarter century will have passed in which The Simpsons has been airing on television for at least 30 minutes a week. (The characters have been around even longer than that, having first appeared in 1987 as a series of shorts on the then-fledgling Fox network's Tracey Ullman Show.)


Long-lived shows and franchises are nothing new. Gunsmoke ran for twenty years, M*A*S*H ran for eleven, and Archie Bunker's prime time tenure spanned twelve years and two sitcoms. When The Simpsons premiered in 1989, Star Trek was still going strong after 23 years, with a third season of The Next Generation airing in syndication and a fifth movie starring the original cast just released on home video. But outside of daytime soap operas, continuously long-running shows lasting a decade or more were extremely rare, particularly in America. However, there was one program that had been around for just over a quarter-century at that time, barring a few hiccups, and it's that show with which I'd like to make parallels to the current run of The Simpsons. That series is, of course, the original Doctor Who (1963-1989).


A few years ago, Charlie Jane Anders wrote an insightful piece pointing out that the secret behind "classic" Who's longevity was that it was not one program, but at least ten, changing producers, casts, and formats to stay fresh and exciting, all the while sticking to a handful of core concepts. Borrowing the format of her article, I would like to demonstrate that The Simpsons has followed a similar pattern. Granted, unlike Who, the cast has stayed the same, and, for the most part, the types of stories have remained fairly consistent over the years; there was never a time when Homer and Marge went to work for a government agency (though Scully and Mulder did visit Springfield once), and Bart and Lisa never went on the run from a malignant demigod (Sideshow Bob notwithstanding). But like Who, the spirit and tone of the program has changed dramatically depending on the season or decade. Just as the "educational" 1960s Hartnell series about a crotchety mad scientist traveling the universe with a pair of captive humans and his granddaughter feels utterly removed from the freewheeling Time Lord sitcom of the late Tom Baker Era, it's impossible to watch an episode of The Simpsons from 1991 back to back with one from 1997, or 2007 for that matter, and feel that it's the same show. Herewith then, are the six unique shows that The Simpsons has been since 1989:


1. A Lacerating Punk Satire (1989-1990)

As everyone knows from the classic Season Seven episode "The Simpsons 138th Episode Spectacular," Matt Groening created the Simpsons when he turned the rabbit characters from his Life In Hell comic strip into humans in order to pay off his gambling debts. Okay, that's not even remotely true, but The Simpsons did start out as an animated version of Life In Hell. When Groening realized that he would lose the rights to his strip if the show got produced, he quickly sketched out a set of new characters, supposedly in the waiting room of producer James L. Brooks' office. Unlike Binky and Bongo, these were definitely humans, named mostly for members of Groening's own family. But the shorts that aired on the Brooks-produced Ullman from 1987 to 1989 definitely carried the angry, antiauthoritarian outlook of Groening's old strip, full of existential dread and resentment towards the arbitrary authority of parents, schools, and other institutions. And this attitude carried over to much of the first season of the original show, embodied by its bratty standard bearer, Bart Simpson.


If you were born after 1990, or just never watched the show during its first years, you may not realize it, but for about eight months or so, Bart Simpson was everywhere, on t-shirts, baseball caps, and bumper stickers (many of them unauthorized), in video games, and incarnated as every kind of doll or tchotchke — really, just about every conceivable media of the pre-Internet era. (He even had a hit novelty song co-written by Michael Jackson!) Bart was the show's breakout star, an "underachiever and proud of it," standing in direct contrast to the wholesome, goal-oriented kid and teen stars of Fox's live action competitors — your Theo Huxtables, Samantha Micellis, and Alex P. Keatons. This led inevitably to a backlash from educators and other cultural elites like former Secretary of Education William Bennett and President George H.W. Bush, who felt that the towheaded little scamp was demoralizing America's youth with his vandalism and prank calls.

But pay closer attention, and you'll realize that Bart isn't really much of a rebel at all. He disdains school and church attendance, but there's nothing inherently radical about his agenda. In his free time, he loves playing video games, watching the Krusty the Klown Show and Itchy and Scratchy cartoons, and eating junk food. In other words, Bart is a consumer (who ironically enough, became the show's first and most prominent consumable), bound by the whims and cycles of the marketplace, of which he himself is blissfully unaware. In that respect he's not that much different from his father, Homer. In a key first season episode, "No Disgrace Like Home," Homer gets fed up with his brood's unruly behavior, and seeking to make them more like the well-adjusted photogenic families he's seen on television, seeks out a therapist, Dr. Marvin Monroe, who himself advertises on TV. Homer is even willing to sell the family TV to pay for the treatment, which backfires spectacularly. But thanks to Monroe's refund policy, the Simpsons are able to afford an even nicer TV set ("with realistic fleshtones!"), and the episode ends with domestic bliss restored through the healing magic of consumerism. As it turned out, Homer embodied this consumerist tendency even more than Bart, and as the show transitioned into its second season, the Simpsons paterfamilias emerged as its true hero.


2. A Traditional Humanist Sitcom (1990-1993)

The Simpsons' popularity was so huge and unprecedented that it's easy to forget how much it changed in the first couple of seasons. Like a garage band that goes from playing tiny clubs to the Superbowl after a string of hit singles, The Simpsons rapidly went from being weird and radical to familiar and safe in short time. But that wasn't accidental; producer James L. Brooks had established his reputation as a writer and producer on the great sitcoms of the '70s, like The Mary Tyler Moore Show, Rhoda, and Taxi, which placed an emphasis on character development and realistic settings over "wacky" premises like magical genies or talking cars. Before returning to television with The Simpsons, he'd also written and directed ensemble-oriented movies like Terms of Endearment and Broadcast News that mixed comedy and drama. Likewise, Brooks' co-producer Sam Simon had written for character-oriented workplace sitcoms like Barney Miller and Cheers. Given their pedigrees, it's not surprising that by the second season, the show began to focus less on the characters as antisocial mutants and more as recognizable human beings, seeking dignity and belonging in a frequently mean-spirited, shallow world. Homer struggles with his appetites. Bart seeks the approval of his elders, though he can't bring himself to admit it. Marge feels trapped by her role as housewife and mother. Lisa seeks understanding and an outlet for her own frustrated ambitions. (God only knows what's going through Maggie's brain.) Flashback episodes give the family a sense of history; a burgeoning cast of supporting characters, with their own issues and backstories, creates a sense of true community. This era is best represented by "Lisa's Substitute" (1991): After years of being ignored by her peers and teachers, Lisa finally discovers an understanding soul in her substitute teacher, Mr. Bergstrom, who encourages her to give expression to her intellectual and artistic passions while finding empathy with her crude brother and slow-witted dad. When Mr. Bergstrom leaves town at the end, his parting gift is self-understanding itself, a note that reminds her "You are Lisa Simpson." This is the height of the show's humanistic period, already a million light years removed from the feral troglodytes screaming "Frosty chocolate milkshakes!" in the Ullman shorts.


This early period is also the only time The Simpsons really acknowledges the realities of middle-class family life in the US. Many episodes deal with the family's fimancial struggles, with the characters sacrificing luxuries or taking extra jobs to make ends meet. One episode in particular, "Homer's Triple Bypass" (1993), addresses the emotional and financial stresses of the American health system, as Homer's bad habits catch up with him in the form of a hilarious (and truly terrifying) heart attack. The characters deal with real and palpable fears about mortality and money that the viewers can relate to; for a brief moment, these goofy characters with bulging eyes and overbites exhibit a sense of pathos seldom seen in network comedies. It represents the apotheosis of the show's humanist phase. But it wouldn't last, and the end was fast approaching: the very next episode was "Marge Vs. The Monorail."


3. An Absurdist Thrill Ride (1993-1997)

Rubber Soul. 'Salem's Lot. Raiders of the Lost Ark. Watchmen. There's something really satisfying about seeing a popular artist or artists come fully into their own, and the fourth through roughly the eighth seasons of The Simpsons are generally seen as its high water mark, thanks largely to the lingering influence of Conan O'Brien, who wrote "Monorail" and collaborated on numerous other scripts before departing to replace David Letterman as the host of NBC's Late Night in 1993. During this period, the show gave up on any pretense of being "grounded" or "realistic" and began to focus heavily on wild, surreal adventures, often filled with allusions to movies such as Citizen Kane, 2001, It's A Mad Mad Mad Mad World, Thelma & Louise, The Birds, and Westworld. Homer goes into space, Bart becomes a superstar, Marge becomes an outlaw (and a cop), Mr. Burns and Sideshow Bob evolve into comic book supervillains, Springfield is threatened with cosmic destruction, and the characters have to cope with endless media exposure. Even the "realistic" episodes have an epic feel, like "Lemon of Troy," in which Bart and his chums travel into Springfield's rival town of Shelbyville to recover a stolen lemon tree and discover a hostile alternate universe full of doppelgängers, including a duplicate Millhouse. There had always been a fantastic strain to the show, as represented by the annual "Treehouse of Horror" Halloween specials. But now every episode was filled with fantastic elements — whether as dream sequences, half-remembered flashbacks, or actual plot elements. Killer robots and mob scenes figured heavily during this period.


And generally speaking, this is The Simpsons that everybody remembers as The Simpsons, just as The Empire Strikes Back is seen as the purest expression of Star Wars. It's also the period and style that's most widely imitated, whether by Archer, Groening's own Futurama or Seth MacFarlane's noxious Family Guy (which effectively forced the Simpsons writers to stop doing flashbacks). It's hard to imagine what the Bart-loving audiences of 1990 would have made of something like "22 Short Films About Springfield," which barely focuses on the central family. But then again, The Simpsons was the first show to really embrace the growing complexity of media in the 1990s, particularly the Internet. At first only the "nerdy" characters like the Comic Book Guy reflected the growing presence of the online world in popular discourse. But by the mid-to-late '90s The Simpsons was no longer really a family sitcom, or even a traditional comedy at all, but a kind of hypertext document assembled from other media — movies, TV shows, games, even itself. Bart or Homer's old catchphrases — "Ay caramba!" or "Why, you little..." — would be invoked to make fun of the show's earlier, simpler days. Entire episodes would satirize the show's longevity and popularity itself, like "The 138th" or "The Simpsons Spin-Off Showcase," both hosted by the series' hack actor Troy McClure. By 1997, it seemed like the show was winding down, getting ready for an end-of-decade finale. But the reality was much stranger, and more radical.


4. A Deconstructionist Self-Parody (1997-2001)

By Season Nine (1997-1998), The Simpsons had long outlasted its 1980s rivals. Entire eras of television had come and gone; wholesome sitcoms like The Cosby Show had been replaced by the likes of Seinfeld and Friends, serial shows like ER and X-Files had replaced the usual cop shows and primetime soap operas, and over on HBO, shows like Oz and The Sopranos were beginning to redefine the whole notion of what was possible with TV dramas. The Simpsons had become a staple of network TV, an institution unto itself. Having conquered a huge chunk of pop culture and defined a generation's outlook, what was left for it to do?


Simple: Deconstruction. The show had frequently parodied or satirized other beloved institutions, and now it turned its laser-like vision upon itself. The transition had arguably been long in coming. Apart from episodes like "Showcase," there were episodes that cast established characters' histories into doubt, such as "Lisa The Iconoclast" (1996), which revealed that the town's beloved founder Jebediah Springfield was really an evil pirate. But the show tended to treat the main characters as sacrosanct. This all changed with "Homer's Enemy" (1997). In it, Homer becomes rivals with his new co-worker, Frank Grimes, a hardworking, conscientious younger man who is alarmed by Homer's irresponsibility and boorishness, and more significantly, by his coworkers' inability to recognize Homer's many failings. As a peace offering, Homer invites Grimes to dinner, but the impoverished Grimes is shocked by the level of luxury and comfort that the brutish Homer enjoys in his "mansion"-like home. After suffering numerous setbacks and ignominies at work, Grimes electrocutes himself in an effort to demonstrate Homer's stupidity. The episode ends with "Grimey" being laid to rest at his funeral, with the plant's staff in attendance. But Homer is half-asleep, and cries out, "Change the channel, Marge!" Everybody bursts into laughter; "That's our Homer," shouts Homer's coworker Lenny.

Up until this point, The Simpsons had largely avoided '90s-style ironic humor of the sort practiced by Seinfeld and The Larry Sanders Show. But now it embraced it wholeheartedly. Under the aegis of showrunner Mike Scully, no character, no series institution, was safe from being recontextualized, if only for the sake of a joke. Principal Skinner was revealed to be a drifter who had impersonated the real Skinner in Vietnam (despite years of continuity to the contrary). The town was destroyed and moved a number of times. Maude Flanders was killed off at random. And Homer, who had been a genuinely sympathetic character since the beginning, became a crude, stupid caricature of his former self, dubbed "Jerkass Homer" by fans. It was as if the show were inviting the viewers to take Frank Grimes' position, to see the Simpsons not as basically good people striving for self-worth and understanding, but as spoiled, dumb, entitled assholes obsessed with material goods and social status. "Behind The Laughter" (2000) reveals The Simpsons to have been a reality show the whole time, with Homer and Marge as real-life celebrities with massive egos and bitter rivalries. It felt like a metaphor for the series' decline, with genuine emotion and warmth revealed as artifice. You couldn't watch the show without being aware that the characters' ugly behavior likely reflected a lot of tension and conflict among the people who created the show. (By this point, Sam Simon was long gone, having departed at the end of Season Four over creative differences; Groening was off running Futurama, which seemed in many ways to be closer to his heart.)


5. Pop Culture Chatroulette (2001-2011)

In a lot of ways, The Simpsons never really fully recovered from the end of the '90s. Critics and fans alike were turned off by the show's spiteful turn; even cast members like Harry Shearer were leery of the stories' coarsening tone. It's significant that when Mike Scully quit in 2001, the producers hired Al Jean to take over the show. Jean was a producer and writer for the series in the early '90s, and wrote a number of beloved episodes from the "humanist" era, including "The Way We Was." The move indicated a desire to return to the character-focused, story-oriented shows of the '90s, which were already acknowledged as classics, and were by then selling well on DVD. Jean's still running the show now, nearly fourteen years later.


But while there were a number of solid character-based episodes, like the Lisa-centric "She of Little Faith," the show never quite returned to form. Part of that was simply because the world had changed so much in the ten years since the show's premiere. Not necessarily in the post-9/11 sense — though there would be an increasing level of quasi-libertarian paranoia over surveillance and control as the show wore on, especially in 2007's The Simpsons Movie — but because the cultural landscape the show had satirized so nimbly in its earlier years had transformed dramatically in the interim. In 1990, there were three major networks (Fox was still considered an experiment at the time) and virtually no commercial Internet outside of "gated community" services like CompuServe and AOL. (And of course, Usenet, though as Homer would point out, that existed mainly so nerds could argue about Star Trek.) Outside of premium channels, cable was largely reruns, second-tier sporting events, and educational programming. Most people got their news from Dan Rather or Tom Brokaw (CNN wouldn't become a big deal until Desert Storm), and learned about new music from Top Forty stations. Most bookstores were smallish places in malls with a limited amount of floor space and a heavy emphasis on bestsellers like Sidney Sheldon and Tom Clancy. Video games and comics were considered entertainment for small children and cretins. If you were a nonconformist, creative person — a Lisa Simpson, in other words — it could seem like a small, vulgar and oppressive world. And that Hooray For Everything! world was the target of The Simpsons' scorn for much of the early-to-mid '90s.


By the 2000s, however, the media landscape was vastly different, bigger and more fractured, and The Simpsons reflected that. An episode might parody George Lucas' career, or riff on iPhones and Steve Jobs' cult of personality, or the popularity of Harry Potter-style YA fantasy. Stan Lee and Michael Chabon would appear, and be given the same amount of attention that just a few years earlier might have been paid to Mel Gibson or Johnny Carson. Thomas Pynchon himself appeared twice. The show even adopted comic book conventions, like retcons: in "That '90s Show" (2008), Marge and Homer's youth is moved from the '70s to the '90s; Homer fronts a grunge band and Marge sports a "Rachel" haircut. Though a flashback in a subsequent episode has the characters back in the '70s, suggesting the possibility of "imaginary stories" and alternate histories. Gradually, the show began to feel less like a "grounded" reflection of real life, or a deconstruction of media. It had crossed entirely into the realm of genre fiction.


6. Triumph of the Nerds

In "Lisa's Substitute," the B-story involves Bart's unsuccessful run for class president. His rival is the bookworm Martin Prince, who runs his campaign on the promise of creating "An A-B-C of the overlords of the genre: Asimov! Bester! Clarke!" "What about Ray Bradbury?" asks one of his classmates. "I'm familiar with his work," Martin replies, disdainfully.


At the time, this was seen as a slight against Bradbury, who'd allegedly said some nasty things about the show. But on a deeper, nerdier level, it revealed something crucial about Martin: He knew who Alfred Bester was. For a network TV comedy in 1991, referencing the author of The Demolished Man and The Stars My Destination was a willful act of esotericism. It revealed that the writers had deep interests in weird stuff that went beyond the mundane world of sitcoms. And when Futurama premiered a little under a decade later, Groening's deep interests in science fiction and fantasy became apparent.


Today, Futurama is no more (for now...), but The Simpsons is saturated with genre references — and not in the "mainstream" sense of Batman or Star Wars. Marge's sisters speak Dothraki, the TARDIS shows up, and Neil Gaiman guest-starred in an episode. Harlan Ellison has appeared as himself. Entire sequences are given over to pay homage to Miyazaki, or horror and fantasy writers, including Lovecraft, Matheson, and Bradbury. (One wonders what he'd have made of that form of immortality.) The cast of Futurama drop in from the 31st Century; Kang and Kodos cross the line from being "imaginary" characters to the real world of Springfield. The LEGO episode, "Brick Like Me," ends up being revealed as a riff on the works of Philip K. Brick... er, Dick. Like a lot of people, Homer used to make fun of nerds, but now he kind of is one. In effect, it has become a genre show, or at least, the dominant strain of pop culture that it references is science fiction and fantasy. If it's still a reflection of our wacky, mixed-up lives, it shows that what was once on the obscure margins of our culture is now central to it, and what was shunned is now accepted. Lisa Simpson, once a secondary character compared to Homer and Bart, now enjoys a plurality of stories every season. Even the Comic Book Guy found himself a wife, thanks to Stan Lee... or was it The Watcher?

So, in that respect, The Simpsons is a lot like Doctor Who, which has evolved into something more accessible and mainstream, even as The Simpsons has willfully abandoned the consensus reality of its earlier self to embrace a multiverse of genres. That's a conundrum that the Doctor himself might have trouble wrapping his head around. Where it goes next, or how long it will last, is a question that cannot be answered. But it will probably end up being both down-to-earth and completely off the wall, and swarming with magic robots. CONSUME IT. CONSUME NOW. RUB IT ON YOUR FLIPPERS.