The walls of the Delta Tau Chi fraternity house at Faber College are covered with graffiti, cheesecake posters, stuffed moose heads, holes, stolen road signs, and—over the mantle—a crest that bears the brotherhood’s motto: “Ars gratia artis,” Latin for “art for art’s sake.” The phrase dates back to the early 19th century, and has been taken up for centuries by great thinkers like Samuel Taylor Coleridge, Edgar Allan Poe, and Oscar Wilde, who believed a work of art need serve no higher moral purpose beyond its own artistry. Later, it became the motto of MGM Pictures; it’s on the film strip above the famous roaring-lion logo.

“Ars gratia artis” is a strange creed for a bunch of fratboys. The ill-mannered man-children of Delta, the stars of National Lampoon’s Animal House, definitely aren’t artistic—and neither is National Lampoon’s Animal House. Like its subjects, the film is scruffy and silly, potty-mouthed and poorly behaved. The residents of Delta House aren’t great thinkers like Coleridge, Poe, and Wilde. Most of them probably haven’t even heard of those guys.

And yet these schlubby college students serve as ideal, though unknowing, exemplars of their credo. Their misadventures in Animal House are disgusting, obnoxious, puerile, sexist, and borderline racist—and often hilarious. If art needs to have some kind of redeeming aesthetic, political, or moral value, or if it requires good taste, common sense, and basic decency, then Animal House is a disgrace. If art demands no greater function than entertainment and amusement, it’s a triumph.

This triumph of disgrace began on shaky ground, as a screenplay by frustrated National Lampoon magazine co-founder Douglas Kenney and SCTV performer and head writer Harold Ramis. Their original concept was called Laser Orgy Girls, a comedy about serial killer Charles Manson in high school. Producer and Lampoon executive Matty Simmons suggested they move the story to college, and Chris Miller, who had been writing stories for the Lampoon about his own experiences at Dartmouth, was brought in to round out the team.

Kenney, Miller, and Ramis spent three months dredging up every funny anecdote they could recall from their undergraduate days. Many of Animal House’s characters were informed by guys Miller knew in his frat at Dartmouth, which had its own smooth-talking Otter (Tim Matheson), awkward Flounder (Stephen Furst), and geeky Pinto (Thomas Hulce). The rest of the Deltas were deliberate archetypes, designed to remind the audience of guys everyone met in college. Those included anxious Hoover (James Widdoes), sarcastic Boon (Peter Riegert), eccentric D-Day (Bruce McGill), and, of course, wild man John “Bluto” Blutarsky, played with total abandon and an astonishing array of cartoonish facial expressions by John Belushi.

Animal House’s plot was brilliantly simple, and it quickly became a template for an entire subgenre of slobs-vs.-snobs comedies. The troublemakers of Delta, the so-called “worst fraternity on campus” at Faber (a fictional school played in the film by the University Of Oregon), are placed on “double secret probation” by the perpetually uptight Dean Wormer (John Vernon). The Deltas continue to escalate their war with the Dean and his preppy allies from Omega Theta Pi until they’re kicked out of their house and expelled from school.

The names of the film’s fraternities are telling, and surely deliberate. The villains are “the Omegas”—sniveling, sexually repressed bullies who represent humanity at its absolute nadir. But note that Animal House’s protagonists aren’t named “the Alphas.” They aren’t set up as the Omegas’ polar opposites, or as a shining pinnacle of empathy and human benevolence. Frankly, the Deltas are kind of terrible. They cheat on tests, lie to coeds to con them into bed, and kill at least one barnyard animal, although it’s sort of by accident. The Deltas aren’t the good guys of Animal House; they’re the less-bad guys.

Viewed through the significantly more politically correct lens of 2013, the Deltas’ antics look a lot less charmingly chaotic and a lot more uncomfortably distasteful. A modern Animal House remake would surely look completely different from the one directed by John Landis in 1978. It would likely remove the sequence where Otter leads his brothers on a road trip to a nearby college, where they trick a bunch of women into going out with them, then freak out when the bar they wander into is full of African-Americans. And it definitely would get rid of the scene, played for laughs, where virginal Pinto struggles to decide whether to have sex with a girl who is passed-out drunk. Ars gratia artis is all well and good, but some of this stuff is really over the line.

Although Animal House is rarely considered in those terms, it might be instructive to consider it as a product of the 1960s and 1970s tradition of Hollywood antiheroes that created Bonnie And Clyde, “Dirty Harry” Callahan, and Travis Bickle. Many of the era’s biggest hits followed characters who would have qualified as villains in traditional Hollywood films—drug dealers, gangsters, and vigilantes. These antiheroes were hailed for their rebellious spirits and anti-establishment values, both of which the Deltas share.

Their slightly sinister demeanor is underscored by the only scene in Animal House that’s set in an actual college classroom. It’s an English lecture about Paradise Lost by Donald Sutherland’s lecherous Professor Jennings, who says Milton “was trying to describe the struggle between good and evil,” particularly in his portrayal of Satan, whom Jennings considers the most interesting character in the poem. “Now,” he continues, “is Milton trying to tell us that being bad is more fun than being good?”

Milton may not have been trying to tell us that, but Kenney, Miller, Ramis, and Landis definitely were. The Deltas look like they’re having a hell of a good time, particularly Belushi’s Bluto, whose manic, drunken pirate energy is infectious. While some of the Deltas are borderline assholes, there’s always something sweet and almost innocent about Bluto, even as he peeps through sorority-house windows.

Belushi performance is rare, in that it’s hysterical without any funny dialogue. It’s not what Bluto does, but how he does it: the way he tiptoes into Dean Wormer’s office, or devours a plate of Jell-O in one monstrous slurp, or demolishes the fourth wall with an eyebrow-arch. He’s having a blast, and his every wink and smirk beckons us to join him. When I went to college in the late 1990s and early 2000s, the image of Belushi in his “COLLEGE” sweatshirt, as if he was the walking embodiment of American university life, was still a dorm-room staple.

In true 1970s antihero fashion, Animal House ends with a slightly Pyrrhic victory. Instead of getting reinstated, the Deltas get revenge against their oppressors. Turning a borrowed car into an enormous tank, they attack the local homecoming parade, transforming it from orderly celebration into chaotic riot. They don’t really defeat Dean Wormer, they just embarrass him. The Deltas have no larger plan besides anarchy. Before they head into battle, Otter calls their homecoming raid a “really futile and stupid gesture.” It seeks no larger goal, and serves no larger point. It’s simply an excuse to do something big and dumb, to piss some people off, and make other people laugh. That’s what the Deltas are here for, and absolutely nothing else.

Tomorrow, our Movie Of The Week discussion of Animal House delves into the film’s legacy, the role of nostalgia in the film, its funniest moments, and more. Then on Thuesday, Nathan Rabin takes a look at the National Lampoon movies that fell through the cracks between pop-culture staples like Animal House and Vacation.