Origin Fallacy

The fallacy of judging something based solely on its origins, rather than its current state, context, or merit. An example of this would be, "Jane Foster is a nurse the Thor comics. Therefore, Jane is a nurse in Thor movie." (She isn't. She's an astrophysicist.)

Or, as a more complex example, Lucas refers to Protestantism as "a branch of Catholicism." Kirstie points out that he's technically incorrect, since Protestants lack several beliefs and practices that are considered fundamental to being Catholic. Lucas responds, "Of course Protestantism is part of Catholicism; Martin Luther was a Catholic priest!" While this is technically true, Martin Luther rejected many of the tenets and doctrines considered by Catholics to be fundamental to Catholicism - so Martin Luther could not truthfully be referred to as Catholic, nor his church as a "branch of Catholicism."

Or, Becky makes a flawed argument (for the sake of argument, "Toto is a furry animal, cats are furry animals, therefore Toto is a cat"). Todd points out that her reasoning is logically fallacious, as her conclusion isn't necessarily supported by it. Becky retorts, "logical fallacies aren't real, because they were invented by heathen Greeks!" Following that reasoning, then the sun must orbit the Earth, too. (See also: Attack the Source.)

Or, Patrick refuses to buy a book based on the grounds that its author once held bigoted views and donated to a hate group. His friend Kevin points out that the author has since disavowed the hate group and no longer donates to them, and has acknowledged that she made a mistake and that her views at the time were hateful and small. Patrick rolls his eyes and says, "Whatever. Once a bigot and supporter of [group], always a bigot and supporter of [group]." (In reality, people can and do genuinely change their views on things.)

Or, Kevin asks Patrick if he wants a bunch of grapes. Kevin responds, "I think you mean, do I want a racemus." Kevin is bewildered and asks Patrick what he means by that. Patrick responds, "The word grape comes from the word grap which was the hooked tool used to pick the fruit, so when you ask me if I want a bunch of grapes, you're asking me if I want a bunch of hooked tools." Of course, language changes and evolves over time, and if Kevin insisted on applying the same logic to every word he used, he'd be nigh incomprehensible to anyone he tried to talk to. Wherever the word "grape" came from, people now understand it to refer to a certain type of fruit, and that's what matters - the purpose of language is to effectively and efficiently communicate, after all.