Graduation - S5-E24
Factual error: In the episode Class Pre-Union, they were the class of 2000. In the episode Graduation, they were the class of 1998.
Factual error: Throughout the series we are told over and over that Cory and Shawn have known each other forever. We see the boys and Topanga meet when they are about 6 years old, and Cory says at one point that Mr. Feeny has always been their teacher. But in this episode Mr. Feeny says Shawn was born in Ohio, lived in Oklahoma and was in and out of 5 schools by the age of 12. This implies that the boys did not meet until middle school, (age 12, when Shawn arrived in PA).
Factual error: When Shawn has first infiltrated the college philosophy class, the professor begins to resume the class' previous lesson on what he calls "Buridan's paradox," relating a dog caught equidistant between two bowls of food. This paradox in real life is known as "Buridan's ass," and as the name would suggest, concerns a donkey. While the name was probably changed to sound more family friendly, a college philosophy professor would certainly know the proper name and details of said paradox.
Factual error: When Topanga and Ricky are looking at the Starry Night painting, Topanga reads from her pamphlet and says it mentions Vincent Van Gogh became religious around the time he painted it. Van Gogh grew up in a religious household, with his father being a minister of the Dutch Reformed Church, and Vincent himself actually had a desire to become a pastor. On the contrary, however, when he painted Starry Night, although he still believed in an afterlife, he was actually disillusioned with religion.
The Eskimo - S5-E13
Factual error: When Shawn and all the other contestants - as well as the radio DJs and onlookers - are standing out in the cold for a chance to win Super Bowl tickets, no-one's breath is visible, nor are any parts of their faces red.
A Very Topanga Christmas - S5-E11
Factual error: This episode takes place near and on Christmas, but an establishing shot of the Matthews' house early in the episode shows the trees to still have very green leaves, and outdoor plants and the front lawn are still alive and healthy looking. None of this is possible in winter in Philadelphia.
Sixteen Candles and Four-Hundred-Pound Men - S4-E9
Factual error: The match between Vader and Jake the Snake is supposed to be taking place in Philadelphia, presumably the Spectrum, but the establishing shot of the building is actually the Great Western Forum in Inglewood, California.
Factual error: In this episode, Eric and Cory stop in Pottstown, Pennsylvania on their way back to Philadelphia. Cory protests, reasoning that stopping there is pointless because they are only three hours from home. Pottstown is roughly 40 miles from Philadelphia. It certainly wouldn't take three hours to get to one location from the other under normal driving conditions.
Shallow Boy - S4-E5
Factual error: After Eric offends Corinna, she is able to write, record, mix, package and distribute an album of music within, at most, a matter of days to spite him. Accomplishing all that within such a short amount of time would be logistically impossible.
Factual error: When Cory and Topanga first enter their new couples dorm, they discover it to be a dump. The entire dorm is filthy, cabinets are falling apart, there are large bugs crawling on the floor, and there is no clean running water. Student housing laws would require the university to restore the dorm to liveable conditions before any student could move in. If the health department saw the conditions of the room, the university would undoubtedly be fined for failing to take corrective action. (00:07:45 - 00:10:36)
Factual error: The Starry Night painting that characters look at in the Van Gogh exhibit is mentioned as being the original painting itself. However, if you compare the painting presented in this episode with the real-life painting that is displayed in the Museum of Modern Art, you can see that it is an imitation, as the colors are brighter and the little details in the painting are not as prominent.
Answer: Topanga's middle name is never specified. Considering her sister's name is Nebula Stop-the-war Lawrence, Topanga's is probably something equally unusual.