This is a list of all the continuities in the series that have been broken.
In Episode 25 (Season 2, Episode 12, "The Way We Was") the Simpsons' television breaks down, Marge tells her children how she and Homer first met. Homer met with his guidance counselor who told him to apply for a job at the nuclear power plant that would be opening soon. However, in "The Blunder Year"", the fifth episode of the 13th season Homer is hypnotized into thinking he is twelve years old again. As Homer starts to reminisce, he starts screaming incessantly all through the night. The next day, Homer's co-workers Lenny and Carl bring him home early from work, still screaming. They finally manage to calm him down with some Yaquitea. He starts to recall the events leading up to the scream-inducing incident. In a flashback, Homer, Lenny, and Carl are hiking in the woods and are confronted by a young Fat Tony, but they are saved by a young Moe.
Upon noticing that his bar was empty, the present-day Moe arrives at the Simpsons' home. Moe remembers that while they sat by a fire, they saw a near-meltdown at the Springfield Nuclear Power Plant. The next day, they go to the old quarry for a swim, and Homer jumps in, only to find that there was no water but only mud. Though Homer admits that he remembers falling into the mud, he also recalls that there was no water in the quarry because something was blocking the inlet pipe. When Homer unblocks it, all the water came out and he finds a rotting corpse on top of his legs, causing him to scream incessantly.
Since Homer never told about his painful memory of the corpse to anyone, the Simpsons realise that it is still in the old quarry and decide to investigate. They go to the old quarry where they meet Chief Wiggum, who comes with them. Marge uses Burly paper towels to drain the water from the quarry. Then, they find the body, now a skeleton, and go into the inlet pipe to see where the body came from. They find that the pipe leads to a hatch which, in turn, leads to Mr. Burns's office in the nuclear power plant. They confront him about the body after he accidentally says 'corpse hatch' once they opened the hatch. Knowing that this would come, Burns confesses to them that the dead man is Smithers' father, Waylon Smithers Senior. However, Burns swore that he did not murder him, and to prove his point, he shows an old surveillance tape, filmed during the 1960s when Smithers' father goes into an unstable reactor core to prevent an imminent meltdown that would destroy the city.
This plot infers that the nuclear power plant had opened long before Homer's high school graduation in 1974.
Continuities Regarding Characters
This section is for character back-story events that conflict with other events mentioned in previous episodes.
- In "Much Apu About Nothing", as Lisa mentions that the Simpson family were original immigrants, Abe recalls how his family originally lived in the unnamed "Old Country" and eventually moved into the Statue of Liberty.
- In "The Blunder Years", Homer recalls his child years at the age of 12, which took place "30 years ago". This implies that he is 42.
- In "Angry Dad: The Movie", Bart mentions that he watch the early episodes of SpongeBob SquarePants as a toddler, a show that debuted 10 years after the debut of the Simpsons series. This story is set in 2011.
- In "Bart's Dog Gets an "F"", Bart claims that the Simpsons have never had a family meeting before, but they did in "There's No Disgrace Like Home".
- In "The War of the Simpsons", Homer mentions "that big bash we had with all the champagne and musicians and holy men and everything", while Marge points out that it was their wedding. However, in "I Married Marge", Homer was only able to afford a shotgun marriage (upon finding out the Marge was pregnant).
- In "Please Homer, Don't Hammer 'Em", Bart is supposed to be allergic to shrimp. However, in "The Frying Game", he says that he ate shrimp in the studio.
- In "Hello Gutter, Hello Fadder", Homer wears his old Pin-Pals shirt in one scene. However, in "Homer's Phobia" John is wearing Homer's Pin Pals shirt and states that someone (Marge) gave it to Goodwill.
- In "The Wandering Juvie", Bart and Gina Vendetti become friends. However, in "Moonshine River", Gina is about to hit Bart angrily without any reasons, in contrast with other Bart's girlfriends.
- In "Bart Carny", Spud says that Lisa's eyes are blue. However, Milhouse once mentions her eyes are gray. It's possible that either Spud or Milhouse are colorblind.
- In "Homer's Enemy", Homer says Lisa's IQ is 156. However, Lisa says that her IQ is 167 in "They Saved Lisa's Brain" and 159 in "Smart and Smarter".
- In "Homer's Enemy", Frank Grimes asks how Homer even got his job, and Carl (and Lenny) say that he turned up on the opening of the plant and got hired. However, in "The Blunder Years", when Homer is distressed about seeing a body in the old quarry, you can see the Nuclear plant in the background. This was when Homer was only 12. Also, in "The Way We Was", Homer was asked about the plant's opening, and the episode took place in the '70s. In "I Married Marge", the plant was open and Homer didn't have the job until the end of the episode. It's possible that the plant was closed briefly after the death of Waylon Smithers Sr and reopened after Homer graduated, turning up and being hired, then he was fired again but reapplied and got the job, Mr. Burns has a habit of forgetting Homer's name so it would make sense.
- In "Lisa's First Word", Ned first introduce himself to the Simpsons when they move to Evergreen Terrace.
- In "Lisa the Vegetarian" and "The Bob Next Door", it is shown that Ned's other relatives use the same nonsensical talk as he does.
- In "Hurricane Neddy", it is revealed that Ned's parents sent him to see Dr. Foster 30 years ago for anger treatment, when Ned was a child, he should have been 30. It is also revealed that treatment also resulted in his trademark nonsensical jabbering.
- In "Viva Ned Flanders", Ned Flanders reveals that he is 60 years old.
- In "Dangerous Curves", Homer and Marge in their dating years first meet Ned and Maude, who just got married. This takes place 20 years earlier.
- In "Burns' Heir", when Mr. Burns' life flashes before his eyes, we see a brief flash back of him as a baby, who fires his nanny.
- In "Rosebud", Mr. Burns grew up in a poor family as child, until a twisted, loveless billionaire came by and offered him to come live with him. He was also related to George Burns.
- In "Monty Can't Buy Me Love", Mr. Burns mentions that his first "gay" experience was when his father took him on a picnic at age 6.
- In "Them, Robot", Marge comments that Mr. Burns was originally a nice man when he first came to Springfield.
- In "The Simpsons 138th Episode Spectacular", Troy McClure mentions that Waylon Smithers is in his early 40's.
- In "The Blunder Years", Smithers' father, Waylon Smithers, Sr. saves Springfield from a nuclear meltdown 25 years earlier, but shorty died of radiation overexposure, leaving Mr. Burns to raise Smithers. This would have made Smithers only in his late 20s instead of early 40s.
- In "Bye Bye Nerdie", Homer recalls beating up Smithers in middle school.
- In "Mother Simpson" (aired in 1995), Clancy appears to be 16 in a flashback to 1969. It means he is 42 in the present.
- In "Weekend at Burnsie's" (aired in 2002), Clancy appears as a young adult in a flashback to 1978. He would be probably 25 years old that time going by the timeline established in "Mother Simpson". He also appears to be much slimmer than when he was younger.
- In "The Way We Weren't" (aired in 2004), Clancy appears in a flashback set when Homer was 10. Clancy seems to be almost Homer's age now, although there is at least 6-7 years of difference between them in the present.
- In "Poppa's Got a Brand New Badge" (aired in 2002), Clancy says he first got his job as a cop by someone handing the badge to "the first person he saw".
- In "Uncut Femmes" (aired in 2021) A flashback element shows Clancy at a younger age working as a front desk security guard at a pent house, but in any of his origin stories or backstories of him becoming a cop or prior to becoming a cop have no mention of him being a security guard, specifically at a pent house, or mention that is where he met his wife Sarah. In the same episode, it is shown he met his wife Sarah while on the job with the young Sarah being a criminal with her 3 partners and worked as the distraction of the group with her partners robbing the pent house safe and Sarah needing to get the key from Clancy to open the safe, but she ultimately fell in love with him after grabbing the key despite not intending to. But in "A Star is Born-Again" (aired in 2003), it is shown he met Sarah while already a cop by planting crystal meth on her (despite Sarah being innocent) because he was too shy to go up and talk to her, so that way he can have an excuse to arrest her as well as talk to her, and later on with him marrying her. If he "arrested" her, that implies Clancy was already a cop prior to meeting her.
- In "Uncut Femmes" (aired in 2021), Sarah's design, as well as personality is changed from being a laid back elated sugar and sweets housewife, to a rebellious cocky criminal both in the present and flashback sequence, as well as a celebrity Voice Actor change to complement the personality attitude change for the episode. The story on how her and Clancy met was also changed then what has been established in "A Star is Born-Again" (aired in 2003). Also in "Uncut Femmes", in the flash back sequence, her design at a younger age is different then her at a younger age shown in the episode "Walking Big & Tall" (aired in 2015) during the "Old Springfield Anthem".
- In "Moonshine River", Mary Spuckler is shown to have aged a few years past Bart, making her much older than she originally was in "Apocalypse Cow".
- In "Love is a Many Splintered Thing", Mary is 13.
- In "Changing of the Guardian", Brandine says that they have 70 children. However, their number varies in other episodes. It is also said the Spuckler family has 27, 10, 9, 7, 19 , 39 and other different numbers. After counting all the kids that appear or are mentioned by names in episodes, there are exactly 50 children plus one unborn.
- In "Alone Again, Natura-Diddily" and "There's Something About Marrying", we learn that Cletus and Brandine are actually siblings.
- In "The Italian Bob", Brandine remarks Cletus as her husband and son.
- In "Little Big Girl", we see the family tree drawn by one of Cletus' children. According to this diagram, Brandine is the child of Cletus and an alien.
- In "The Italian Bob", Sideshow Bob moves to Italy when he marries Francesca Terwilliger and they have one son called Gino. When the Simpsons meet Bob in Italy, Gino can walk and speak very well, making him be at least 3 years old. Plus wedding and pregnancy, it means Bob spent at least 4 years in Italy. However, when he meet the Simpsons again, the family is still the same age as when Bob left the USA.
- In "The Seemingly Never-Ending Story", Carl's dad is a black man.
- In "The Blue and the Gray", we meet Carl Carlson's sister who is also black.
- In "The Saga of Carl", however, we learn that Carl is actually adopted and his adoptive parents are white. It is unknown who actually were his dad and sister from two previous episodes. Maybe it took some years until he met his real family.
- In "The Saga of Carl", Carl also writes to his friend that he is "coming home" and they don't know where his home is. However, in "'Scuse Me While I Miss the Sky" Carl tells his friends that he spent part of his boyhood in Iceland. They should suppose that he probably means Iceland as his home.
- In "Walking Big & Tall", Moe Szyslak walks on stage and rips off his bib and in the next frame it is back on his neck and gone again when they cut back to him again.
Explainable Plot Holes
This section is for plot holes that are possibly explainable.
- In the Season 1 episode "Krusty Gets Busted," Krusty says he is (and always has been) illiterate. In "Lisa's First Word", however, when Krusty is handed the wire communique, he quickly reads it over and understands it is about the Soviets boycotting the Olympics. He could have learned how to read to some degree between this point in time and then, or he may have been lying about his illiteracy all along.
- In "Lisa's First Word", Maude Flanders is mysteriously absent during the flashback, even when Ned and Todd introduce themselves to Homer. It's possible that she's out of town during this time, or that her absence is due to the result of Marge's storytelling.
- In "Sweet Seymour Skinner's Baadasssss Song", the Kwik-E-Mart appear to be destroyed by a round of redirected mortar shells from Fort Springfield, presumably taking Apu and Sanjay with it. However Apu reappeared alive and well in the following episode, "The Boy Who Knew Too Much". It's possible that he and Sanjay manage to escape the explosion in time. Meanwhile the Kwik-E-Mart reappeared completely intact in "Secrets of a Successful Marriage". It's possible that the shop was quickly rebuilt.
- In "Fear of Flying", Marge is highly afraid of flying, but in Season 3's "Mr. Lisa Goes to Washington," she had no trouble flying. It's possible that this episode took place before that episode.
- Also in the same episode, Moe bans Homer from his tavern after he unscrewed the sugar canister that was meant to be a prank, however Homer is seen at Moe's again in later episodes. It's possible that Moe forgives Homer and lifts the ban.
- In "Miracle on Evergreen Terrace", all of the Springfieldians grew hostile to the Simpsons when they found out that Bart lied about a burglar stealing their tree and presents when in actuality, he destroyed them both by accident, and at the end of the episode, they took all of the Simpsons possessions as an act of revenge. However, the Simpsons got all their stuff back and the Springfieldians treated them nicely again in future episodes. It's possible that they eventually apologized to the Simpsons and gave back their belongings. Or that Bart actually has a false awakening after dreaming about water early in the episode.
- In "Kill the Alligator and Run", the Simpsons were banned from Florida, as well as every other state other than Arizona and North Carolina. However, in later episodes, the Simpsons have been to many other states such as Delaware, Missouri, Washington D.C., New Jersey, California, New York, Nevada, Oregon, Vermont, Illinois, Utah, as well as Florida, twice after Season 12. It's possible that their statewide bans were eventually lifted.
- The Twisted World of Marge Simpson
- Little Big Girl (seen on a family tree)
- The Food Wife
- Yokel Chords
- Whiskey Business (written on the board)
- Simpsons Tall Tales
- The Old Man and the Key
- Mr. Spritz Goes to Washington
- Catch 'Em if You Can
- Bart-Mangled Banner
- Bart-Mangled Banner
- We're on the Road to D'oh-where
- We're on the Road to D'oh-where
- Moe'N'a Lisa
- He Loves to Fly and He D'ohs
- Any Given Sundance
- Special Edna, Catch 'Em if You Can